UNITED STATES DEPARTMENT OF THE INTERIOR 

Harold L. Ickes, Secretary

GEOLOGICAL SURVEY 

W. C. Mendenhall, Director

Water-Supply Paper 772

STUDIES OF RELATIONS

OP

RAINFALL AND RUN-OFF IN THE 

UNITED STATES

\ BY

W. G. HOtT AND OTHERS

a

UNITED STATES

v_

GOVERNMENT PRINTING OFFICEWASHINGTON : 1936

For sale by the Superintendent of Documents, Washington, D. C. - - - Price 25 cents (Paper cover)

CONTENTS

Page

Foreword. ............................ 9

Authorization .......................... 12

Administration and personnel. .4................ 12

Advisory coordination ...................... 14

Acknowledgments ......................... 15

Previous studies. ........................ 16

Aims of present study ...................... 19

Precipitation .......................... 20

Changes in precipitation in continental United States. ... 20

Changes in annual precipitation, by geographic provinces . . 22

Years of high precipitation. ................ 22

Periods of high precipitation. ............... 27

Years of low precipitation ................. 29

Periods of low precipitation .........*...... 31

Changes in precipitation, by areas ............. 33

Changes in seasonal precipitation, by geographic provinces . 43

Changes In winter precipitation ............ 43

Changes in precipitation in growing season. ...... 45

Changes in fall precipitation ............. 45

Average monthly precipitation. ............... 48

Changes In temperature. ..................... 49

Changes in run-off. ....................... 58

Precipitation, temperature, and run-off, by basins. ....... 60

Red River Basin above Grand Forks, N. Dak. ......... 61

Mississippi River Basin above Keokuk, Iowa ......... 65

Neosho River Basin above lola, Sans. ............ 74

Merrlmack River Basin above Lawrence, Mass.. ........ 78

James River Basin above Cartersvllle, Va.. ......... 82

Tennessee River Basin above Chattanooga, Term. ....... 86

Chattahoochee River Basin above West Point, Ga.. ...... 91

General accuracy of precipitation, temperature, and run-off data. 92

Changes in rainfall, by basins. ................. 96

Changes In temperature, by basins ................ 97

Changes in run-off, by basins .................. 97

Relations between rainfall and run-off. ............. 100

Stream flow ........................... Ill

Stream-flow separation ................... Ill

Depletion curves. ................... 114

Recession curves.................... 113

Ground-water levels and accretion ........ ... 117

Unit hydrographs. ................... 118

Infiltration capacity and storage factors ....... 118

Meteorologio factors. ................. 119

Channel storage .................... 119

Surface run-off ......................... 120

Quantitative analysis, by basins ........ ...... 120

Unit-hydrograph analysis of surface run-off. ........ 123

The unit hydrograph and distribution graph and their preparation ...................... 124

Unit hydrographs and distribution graphs by basins ..... 133

Muskingum River Basin above Dresden, Ohio ....... 134

Wabash River Basin above Logansport, Ind. ....... 141

Embarrass River Basin above Ste. Marie, 111.. ..... 148

Skunk River Basin above Augusta, Iowa ......... 155

Susquehanna River Basin above Towanda, Pa........ 165

Delaware River Basin above Port Jervis, K. Y. ..... 176

French Broad River Basin above Dandrldge, Term. .... 186

Red River Basin above Denison, Tex. .......... 196

Summary ........................ 209

Application of the unit-graph principle. .......... 211
Page

The unit-hydrograph method and storm transposition iu flood problems relating to great storms in the Eastern and 

Central United States, by Merrill Bernard. .... 218

Flood coefficients. .................. 218

Storm rainfall. .................... 221

Storm index ...................... 230

Storm transposition .................. 230

Storm superposition .................. 235

Delaware River Basin above Port Jervls, N. Y.. . . 235

French Broad River Basin above Dandridge, Tenn.. . 237 

Wabash River Basin above Logansport, Ind.. .... 241

Skunk River Basin above Augusta, Iowa. ...... 241

Floods influenced by snow ............... 244

Conclusion* ...................... 244

Ground-water run-off. .......... ............ 245

Soil moisture .......................... 248

Run-off during drought periods. ............... .. 255

Comparison of deficiencies in ground-water run-off with deficiencies in rainfall ............... 257

Ground-water levels ....................... 269

Comparison of graphs of minimum flow. .............. 273

Report of the Advisory Committee of the Section of Hydrology of

the American Geophysical Union .......... 275

References. ........................... 283

Index .............................. 295

ILLUSTRATIONS

Page

Figure 1. Year of ma-srimiTm annual precipitation at selected

long-time Weather Bureau stations ........ 26

2. Year ending 10-year period of maximum precipitation

at selected Weather Bureau stations ....... 28

3. Year of minimum annual precipitation at selected

long-time Weather Bureau stations ........ 30

4. Year ending 10-year period of minimum precipitation

at selected Weather Bureau stations ....... 32

5. Map showing annual precipitation changes over United

States. ..................... 36

6. Annual and seasonal precipitation changes (Maine to

Florida). .................... 37

7. Annual and seasonal precipitation changes (Michigan

to Louisiana) .................. 38

8. Annual and seasonal precipitation changes (Minnesota

to Texas. .................... 39

9. Annual and seasonal precipitation changes (Montana

to Arizona) ................... 40

10. Annual and seasonal precipitation changes (Washington, Oregon, California)............. 41

11. Map showing annual temperature changes in United

States. ..................... 50

12. Annual temperature changes (Maine to Florida). ... 51

13. Annual temperature changes (Michigan to Louisiana) . 52

14. Annual temperature changes (Minnesota to Texas). .- . 53

15. Annual temperature changes (Idaho and Montana to

Arizona)..................... 54

16. Annual temperature changes (Washington to California) ..................... 55

17. Map showing annual run-off changes in United States. 59

18. Base data for Red River Basin above Grand Forks, K.

Dak.. ...................... 64

19. Base data for Mississippi River Basin above Keokuk,

Iowa. ...................... 73

20. Base data for Neosho River Basin above lola, Kans. . 77

21. Base data for Merrimack River Basin above Lawrence,

Mass. ...................... 82

22. Base data for James River Basin above Cartersville,

Va. ....................... 85
Figure 23. Base data for Tennessee River Basin above Chattanooga, Tenn.................... 90

24. Base data for Chattahoochee River Basin above V/est

Point, Ga.. ................... 94

25. Rainfall and run-off relations, Red River. ..... 101

26. Rainfall and run-off relations, Mississippi River. . 102

27. Rainfall and run-off relations, Neosho River .... 103

28. Rainfall and run-off relations, Merrimack River. . . 104

29. Rainfall and run-off relations, James River. .... 105

30. Rainfall and run-off relations, Tennessee River. . . 106

31. Rainfall and run-off relations, Chattahoochee River. 107

32. Rainfall and run-off relations, combined all basins. 108

33. Typical unit hydrograph - Muskingum River at Dresden

Ohio. ...................... 127

34. Map of Muskingum River Basin above Dresden, Ohio . . 127

35. Unit hydrographs - Muskingum River at Dresden. . . . 137

36. Unit hydrographs - Muskingum River at Dresden (continued) ..................... 138

37. Unit hydrographs - Muskingum River at Dresden (continued) ..................... 139

38. Superimposed distribution graphs - Muskingum River

at Dresden. ................... 142

39. Map of Wabash River Basin above Logansport, Indiana. 145

40. Unit hydrographs - Wabash River at Logansport. . . . 146

41. Unit hydrographs - Wabash River at Lo^ansport (continued) ..................... 147

42. Superimposed distribution graphs - Wabash River at

Logansport. ................... 149

43. Map of Embarrass River Basin above Ste. Marie, 111.. 152

44. Unit hydrographs - Embarrass River at Ste. Marie . . 153

45. Unit hydrographs - Embarrass River at Ste. Marie

(continued) ................... 154

46. Superimposed distribution graphs - Embarrass River

at Ste. Marie .................. 156

47. Map of Skunk River Basin above Augusta, Iowa .... 160

48. Unit hydrographs - Skunk River at Augusta. ..... 161

49 Unit hydrographs - Skunk River at Augusta (continued) ..................... 162

50. Superimposed distribution graphs - Skunk River at

Augusta ..................... 164

51. Map of Susquehanna River Basin above Towanda, Pa.. . 172

52. Unit hydrographs - Susquehanna River at Towanda. . . 173

53. Unit hydrographs - Susquehanna River at Towanda

(continued) ................... 174

54. Unit hydrographs - Susquehanna River at Towanda

(continued) ................... 175

55. Superimposed distribution graphs - Susquehanna River

at Towanda. ................... 177

56. Map of Delaware River Basin above Port Jervis, N. Y. 182

57. Unit hydrographs - Delaware River at Port Jervis . . 183

58. Unit hydrographs - Delaware River at Port Jervis

(continued) ................... 184

59. Unit hydrographs - Delaware River at Port Jervis

(continued) ................... 185

60. Superimposed distribution graphs - Delaware River at

Port Jervis ................... 185

61. Map of French Broad River Basin above Dandridge,

Tenn. ...................... 191

62. Unit hydrographs - French Broad River at Dandridge,

Tenn. ...................... 192

63. Unit hydrographs - French Broad River at Dandridge.

Tenn. (continued) ................ 193

64. Unit hydrographs - French Broaa River at Dandridge,

Tenn. (continued) ................ 194

65» Superimposed distribution graphs - French Broad

River at Dandridge. ............... 195

66. Map of Red River Basin above Denison, Texas. .... 197

67. Unit hydrographs - Red River at Denison, Texas . . . 205

68. Unit hydrographs --Red River at Denison (continued). 206

69. Superimposed distribution graphs - Red River at

Denison ..................... 208

70. Average distribution graphs for selected drainage

basins. .................... . 210

71. Flood hydrographs and flood coefficients (c) for

Muskingum River at Dresden, Ohio. ........ 222
Page

Figure 72. Flood hydrographs and flood coefficients (c) for

Wabash River at Logansport, Ind. ......... 223

73. Flood hydrographs and flood coefficients (c) for

Skunk River at Augusta, Iowa ........... 224

74. Flood hydrographs and flood coefficients (c) for

Susquehanna River at Towanda, Pa*. ........ 225

75. Flood hydrographs and flood coefficients (c) for

Delaware River at Port Jervis, N. Y. ....... 226

76. Flood hydrographs and flood coefficients (c) for

French Broad River at Dandridge, Tenn. ...... 227

77. Flood hydrographs and flood coefficients (c) for

Red River near Denison, Texas. .......... 228

78. Flood coefficients for selected drainage basins . . . 229

79. Map of eastern United States showing storm indexes 

and geographic position of the centers of great 

storms ...................... 232

80. Map of eastern United States showing location of

storm area relative to selected drainage basins. . 236

81. Storm of Oct. 8-11, 1903, with relative location of 

Weather Bureau stations and the Delaware River 

Basin above Port Jervis, N. Y., in its actual 

position (a) and shifted to give a maximum depth 

of rainfall on the basin (b) ........... 238

82. Pluviagraphs and hydrograph of computed flood flow 

resulting from storm of Oct. 8-11, 1903, in its 

actual position (a) and shifted so as to give a 

maximum average depth of rainfall on the basin 

position (b) .................... 239

83. Storm of July 15-16, 1916, in actual position on

French Broad River Basin over Dandridge, Tenn., 

and resulting pluviagraph and hydrograph of computed flood flow ................. 240

84. Storm of March 24-26, 1913, with relative location 

of Weather Bureau stations superposed on Wabash 

River Basin above Logansport, Ind., and resulting pluviagraph and hydrograph of computed flood 

flow ....................... 242

85. Storm of Aug. 25-28, 1903, with relative location of 

Weather Bureau stations superposed on Skunk River 

Basin above Augusta, Iowa and resulting pluviagraph and hydrograph of computed flood flow. ... 243

86. Observed and estimated metorologic and hydrologic

data for Skunk River Basin above Augusta, Iowa . . 254

87. Comparison of soil moisture changes - Skunk, Black,

and Rock Rivers .................. 256

88. Ground-water levels in Platte River Valley in

Nebraska ..................... 272

89. Graphs of minimum flow. ............... 274

TABLES

Page

Table 1. Average annual precipitation over the United States by

5-year periods................... 21

2. Precipitation at long-time Weather Bureau stations . . 23

3. Changes in winter precipitation. ........... 44

4. Changes in summer precipitation. ........... 46

5. Changes in fall precipitation. ............ 47

6. Changes in annual temperature by areas ........ 56

7. Precipitation stations in or near Red River Basin

above Grand Forks, N. Dak.. ............ 62

8. Base data for Red River Basin above Grand Forks,

N. Dak. ...................... 63

9. Precipitation stations in or near Mississippi River

Basin above Keokuk, Iowa. ............. 67

10. Base data for Mississippi River Basin above Keokuk,

Iowa. ....................... 72

11. Temperature stations in or near Mississippi River

Basin above Keokuk, Iowa. ............. 74
Table 12. Precipitation stations in or near Neosho River Basin

above lola, Kans.................. 75

13. Base data for ITeosho River Basin above lola, Kans. . . 76

14. Precipitation stations in or near Merrimack River

Basin above Lawrence, Mass. ............ 79

15. Base data for Merrimack River Basin above Lawrence,

Mass. ....................... 81

16. Precipitation stations in or near James River Basin

above Carteraville, Va. .............. 83

17. Base data for James River Basin above Cartersville,

Va. ........................ 84

18. Precipitation stations in or near Tennessee River

Basin above Chattanooga, Term............ 87

19. Base data for Tennessee River Basin above Chattanooga,

Term. ....................... 89

20. Precipitation stations in or near Chattahoochee River

Basin above West Point, Ga. ............ 92

21. Base data for Chattahoochee River Basin above West

Point, Ga.. .................... 93

22. Basin changes in precipitation ............ 98

23. Basin changes in temperature ............. 98

24. Basin changes in run-off ............... 99

25. Average anmial surface run-off for typical basins. . . 120

26. Average annual surface run-off in Mississippi River

Basin above Keokuk, Iowa... ............ 121

27. Typical unit-hydro graph storm - Muskingum River Basin

above Dresden, Ohio ................ 128

28. Derivation of typical distribution graph - Muskingum

River at Dresden, Ohio. .............. 129

29. Unit-hydrograph storms - Muskingum River Basin above

Dresden, Ohio ................... 134

30. Surface run-off from unit storms - Muskingum River at

Dresden ....................... 140

31. Distribution graphs - Muskingum River at Dresden . . . 141

32. Unlt-hydrograph storms - Wabash River Basin above

Logansport, Ind.. ................. 143

33. Surface run-off from unit storms - Wabash River at

Logansport. .................... 148

34. Distribution graphs - Wabash River at Logansport . . , 148

35. Unit-hydrograph storms - Embarrass River Basin above

Ste. Marie, 111.. ................. 150

36. Surface run-off from unit storms - Embarrass River at

Ste. Marie. .................... 155

37. Distribution graphs - Embarrass River at Ste. Marie. . 155

38. Unit-hydrograph storms - Skunk River Basin above

Augusta, Iowa ................... 157

39. Surface run-off from unit storms - Skunk River at

Augusta ...................... 159

40. Distribution graphs - Skunk River at Augusta ..... 163

41. Unit-hydrograph storms - Susquehanna River Basin above

Towanda, Fa..................... 165

42. Surface run-off from unit storms - Susquehanna River

at Towanda. .................... 176

43. Distribution graphs - Susquehanna River at Towanda . . 176

44. Unit-hydrograph storms - Delaware River Basin above

Port Jervis, N. Y.................. 178

45. Surface run-off from unit storms - Delaware River at

Port Jervis .................... 181

46« Distribution graphs - Delaware River at Port Jervis. . 186

47. Unit-hydrograph storms - French Broad River Basin

above Dandridge, Tenn.. .............. 187

48. Surface run-off from unit storms - French Broad River

at Dandridge. ................... 190

49. Distribution graphs - French Broad River at Dandridge. 196

50. Unit-hydrograph storms - Red River Basin above

Denison, Texas. .................. 198

51. Surface run-off from unit storms - Red River at

Denison ....................... 207

52. Distribution graphs - Red River at Denison ...... 207

53. Average distribution graphs for selected drainage

basins in percent ................. 209

54. Development of flood coefficients for Susquehanna

River above Towanda, Pa.. ............. 220

55. Flood coefficients for Delaware River at Port Jervis,

N. Y. ....................... 234
Page

Table 56. Flood coefficients for French Broad River at

Dandridge, Tenn.. ................. 234

57. Flood coefficients for Wabash River at Logansport,

Incl.. ....................... 234

58. Flood coefficients for Skunk River at Augusta, Iowa. . 235

59. Ground-water run-off for typical basins. ....... 246

60. Ground-water run-off, Upper Mississippi River Basin. . 247

61. Observed and estimated meteorologic and hydrologie

data for Skunk River Basin above Augusta, Iowa. . . 252

62. Drought data for Red River Basin above Grand Porks,

N. Dak. ...................... 259

63. Drought data for Black River Basin above Neillsville,

Wis.. ....................... 262

64. Drought data for Rock River Basin above Afton, Wis.. . 264

65. Drought data for Skunk River Basin above Augusta,

Iowa. ....................... 265

66. Drought data for Mississippi River Basin above Keokuk,

Iowa. ....................... 267
STUDIES OF RELATIONS OP RAINFALL AND 

RUN-OFF IN THE UNITED STATES

By W. G. Hoyt and others

Foreword

Human relations to the waters of the earth have developed from a 

simple but very significant' status in the haphazard life of primeval man 

to a complex and often economically limiting status in connection with the 

present-day activities of a highly organized civilization.

The present wide scope of the uses of water for domestic supply, 

power development, irrigation, navigation, and recreation and the extensive 

human activities for protection against floods, drainage of wet lands, 

control of erosion, and control of pollution are generally accepted as 

matters of course. It is notable, nevertheless, that the severe drought, 

wliich persisted for about 5 years from 1950 to 1934 including the disastrous summer of 1934 has impressed on many people as never before the 

essential character and the importance of our water resources.

As a consequence the attention not only of Federal and State 

Governments but of the people as a whole is being turned to an evaluation 

of water that embraces not only its use and control in the common ways 

above mentioned but its conservation to a degree and through broad policies 

never before considered. Heretofore, except of course for the great interest of farmers in rain, the popular and generally recognized interest 

in water has tended to begin at the time when it has appeared in the surface streams or has become stored in the ground. But the failing streams 

of drought-affected regions and the disastrous erosive action of waters 

before they reach well-defined watercourses have notably quickened the regard for the uses and control of water at an earlier stage in the complex 

cycle through which it passes after its occurrence as rain.
10 RAINFALL AND RUN-OFF IN THE UNITED STATES

After precipitation, and before it finally reaches well-defined 

stream channels, water is subjected to the action of numerous agencies, 

including ground and water-surface evaporation, transpiration in plant and 

tree growth, infiltration and absorption by the ground, passage through 

the shallow storage upon ill-drained lands, and surface run-off through 

systems of trickles and streamlets. The importance of the subtractions 

from precipitation before it becomes stream flow may be illustrated by 

statement of the fact that to produce 1 pound of dry vegetable substance 

of a growing plant several hundred pounds of water is taken up from the 

soil by the roots of the plant, passes through the growing plant tissues, 

and then evaporates into the air from the leaf surfaces. Thus to obtain 

satisfactory crop yields many inches of water over the crop-producing area 

must be used in this way. It is evident, therefore, that in arid and 

semiarid regions, and indeed in humid regions in times of drought, the 

flow of surface streams constitutes a surprisingly small part of the water 

initially falling as rain.

The conservation of even a small part of the precipitation that 

under present conditions does not reach the streams may be extremely desirable and important, provided it is practicable and economical. Much 

more trustworthy information than now available concerning rainfall, runoff, and related factors is desirable for wise planning of water conservation and utilization. There is also need for investigating those factors which are alleged to have caused some regions, within the period of 

apparent human occupancy, to change at least temporarily in their degree 

of aridity or humidity.

Early in its consideration of Public Works water projects, the 

Mississippi Valley Committee realized the great need for more information 

on the conditions affecting rainfall, run-off, and related factors. It was 

recognized that to a great extent the available climatic and hydrologic 

data have never been adequately analyzed with a view to deducing the particular knowledge that would be helpful. Moreover, it was believed that 

such broad fundamental questions were largely outside the field in which 

private individuals and institutions could generally be active and hence 

were especially suited to investigation by an agency or agencies of the 

Federal Government.
FOREWORD

It was with an appreciation of the need and opportunity thus 

afforded that the present studies were undertaken. The studies were 

authorized and directed by the Mississippi Valley Committee of the Emergency Administration of Public Works, now the Water Planning Committee of 

the National Resources Board, and the work was done by the United States 

Geological Survey. Most valuable and.helpful advice has been received 

from a special committee of the Section of Hydrology of the American Geophysical Union. The objective has been primarily the presentation of 

facts, generally elementary and basic, as disclosed by observed data or by 

their simple analysis. It is believed that the results contained in this 

report present much fundamental information, an understanding of which is 

essential to adequate long-time planning and execution of projects for the 

use and control of the water resources of the country.

The Mississippi Valley Committee also found desirable a study of 

floods and, as a project, that study was combined with the study of the 

relations of rainfall, run-off, and related factors. Both investigations 

have been carried forward concurrently with unified control and supervision, yet with the requisite independence of approach to call forth the 

best efforts of the separate groups at work. The results of the flood 

study are contained in another report to be published as Water-supply 

Paper 771.

Harlan H. Barrows

Herbert S. Crocker

Glen E. Edgerton

Henry S. Graves

Edward M. Markham

Charles H. Paul

Sherman M. Woodward

Barlow S. Person (acting chairman) 

Water Planning Committee of the National 

Resources Board, formerly Mississippi 

Valley Committee of the Federal Emergency 

Administration of Public Works.
12 ' RAINFALL AND RUN-OFF IH THE UNITED STATES

Authorization

Late in 1933 and during the first few weeks of 1934 members of 

the scientific staff of the Geological Survey appeared before the Mississippi Valley Committee of the Federal Emergency Administration of Public 

Works to discuss certain aspects of hydrology, such as floods, droughts, 

and ground-water conditions, which had been found to be involved in the 

consideration of the numerous applications for Public Works projects in the 

Mississippi Valley presented to the committee for study and recommendation. 

These discussions emphasized the need of studies of available hydrologic 

and climatologic information, with a view to determining the Implications 

of the data with respect to various questions of planning and design and to 

placing such information in a form in which it could be used and its value 

realized.

As a result of these conferences, the Mississippi Valley Committee recommended and obtained from the Public Works Administration late in 

February 1934 an allotment for studies of this character to be made in collaboration with the Geological Survey, under two headings - (1) the magnitude and frequency of floods and (2) rainfall, run-off, and related factors 

Formal authorization of the studies by the Geological Survey was contained 

in a letter of the Federal Emergency Administration of Public Works dated 

March 6, 1934.

Administration and personnel

Arrangements were made during March 1934 for the studies to be 

made in the water-resources branch of the Geological Survey under the 

general administrative supervision of N. C. Grover, chief hydraulic engineer, and under the direct administrative supervision of R. W. Davenport, 

chief of the division of water utilization. W. G. Hoyt was designated as 

the responsible head of the studies relating to rainfall, run-off, and related factors. In order to obtain the benefit of their special training 

and qualifications and to furnish an experienced nucleus for- a staff of 

investigators two engineers and one geologist of the Survey were detailed 

to the studies. The remainder of the personnel were made up of temporary 

employees appointed by the Secretary of the Interior from the list of
ADMINISTRATION AND PERSONNEL 13

applicants eligible for appointment in connection with projects- of the 

Public Works Administration. The personnel and periods worked up to the 

time the report was finished, June 30, 1935, are as follows: 

Regular employees:

W. Or. Hoyt, hydraulic engineer, one-half time, since March 1, 

1954.

L. L« Harrold, assistant engineer, since March 8, 1934. 

R. C. Cady, junior geologist, part time, since July 1, 1934. 

Temporary employees:

Merrill M. Bernard, senior engineer, Crowley, La., part time, 

April 1, 1954, to May 15, 1935.

A. L. Alin, junior engineer, Portland, Oreg., March 21 to 

May 2, 1954.

Franklin P. Snyder, junior engineer, Columbus, Ohio, since April 

16, 1954.

D. M. Paul, assistant clerk, Odebolt, Iowa, since March 12, 1934.

J. Paul Bowker, assistant clerk (computer), Washington, D. C., 

since October 24, 1934.

C. E. Kitchin, assistant clerk (computer), Hyattsville, Md., 

since October 25, 1934.

The division of work has been somewhat as follows:

Merrill M. Bernard has devoted his time almost exclusively to 

the application of the unit hydrograph and distribution graph to the analysis of flood flows and wrote the discussion "The unit-hydrograph method 

and storm transposition in flood problems." Mr. Bernard brought to the 

studies a wealth of original experience in analyzing storm precipitation of 

high intensity and his knowledge of the unit graph devised by L. K. Sherman 

and more especially the distribution graph and the pluviagraph devised by 

himself.

L. L. Harrold in the early part of the studies devoted a large 

part of his time to the study of ground-water flow, soil moisture, and related matters - subjects which he had been previously investigating. Later 

he carried on and supervised work of the general computation in connection 

with precipitation, temperature, and run-off trends and relations.

Franklin F. Snyder, In addition to routine computation, spent a 

very considerable portion of his time in analyzing the fundamentals of the 

unit hydrograph, distribution graph, and pluviagraph, methods of presentation, and possibilities of application, and he lias prepared much of the 

text relating to these subjects.
14 RAINFALL AND RUN-OFF IN THE UNITED STATES

R. C. Cady, as a member of the staff of the ground-water division, 

devoted much of his time to the determination of ground-water flow from the 

hydrograph of total stream flow and the study of relations between groundwater flow, water-table level, precipitation, and related factors.

Messrs. Paul, Alln, Bowker, and Kltchln have assisted in general 

compilations, preparation of charts, and clerical activities.

Advisory coordination

The Water Planning Committee of the National Resources Board and 

its predecessor the Mississippi Valley Committee maintained contact with 

the studies through Prof. Sherman W. Woodward, of the University of Iowa, 

member of the Mississippi Valley Committee, and Prof. Thorndike Saville, 

of New York University, executive engineer of the Water Resources section. 

In addition the Section of Hydrology of the American Geophysical Union, at 

the request of the chairman of the Mississippi Valley Committee, appointed 

during May 1934 the following engineers and hydrologists as a committee of 

advisers and consultants:

Wesley W. Horner, consulting engineer, St. Louis, Mo. 

(chairman).

A. F. Meyer, consulting engineer, Minneapolis. Mlnn* 

G. W. Pickels, professor, University of Illinois, Urbana, 111, 

L. K. Sherman, president, Randolph-Perkins Co., Chicago, 111. 

Hoy Towl, mayor, Omaha, Nebr.

J. W. Woerman, senior civil engineer, U. S. Engineer's Office, 

Chicago, 111.

R. E. Horton, consulting engineer, Voorheesville, N. Y., was 

added to this advisory committee in January 1935.

Since May 1934, some of the members of this committee nave been 

in continuous contact with the studies, either personally or through correspondence, and generous acknowledgment is due and here given for the valuable assistance thus rendered.

Observations and recommendations of the committee of the Section 

of Hydrology have been freely referred to throughout the text of this report, and a statement by the committee is presented as an appendix. All 

compilations of records and various memoranda prepared by the Geological 

Survey staff have been made available to the committee members. The material has been the subject of correspondence between the committee members
ACKNOTCEDGMENTS 15

and of conferences and correspondence between certain of the members of 

the committee and members of the Survey staff.

Nearly all compiled records and memoranda have also been sent to 

each member of the Flood Protection Data Committee of the American Society 

of Civil Engineers appointed to advise in the flood studies, the membershii 

of which is as follows:

Gerard H. Matthes, principal engineer, office of the president, 

Mississippi River Commission, Vicksburg, Miss, 

(chairman).

Frederick H. Fowler, consulting engineer, San Francisco, Calif. 

Robert E. Horton, consulting engineer, Voorheesville, N. Y.

Ivan E. Houk, senior engineer, U. S. Bureau of Reclamation, 

Denver, Colo.

Charles W. Sherman, consulting engineer, Boston, Mass.

C. W. Kutz, Brigadier-General, U. S. Army (retired). 

Washington, D. C.

Daniel C. Walser, vice president, Charles B. Hawley Engineering 

Corporation, Washington, D. C.

Although this committee as a whole has not made definite recommendations with respect to the studies of rainfall in relation to run-off, 

pertinent comments have been received from individual members.

Ac knowledgment s

The staff engaged on the rainfall and run-off studies have received encouragement, advice, and criticism from so many sources that full 

acknowledgment and credit are difficult. Throughout the studies Messrs. 

Grover and Davenport for the water-resources branch and Professors Woodward 

and Saville for the Mississippi Valley Committee and the Water Planning 

Committee have been in close touch with the progress of the work and have 

been a continuing source of advice and encouragement. In a very large 

measure the methods of attacking the problems have bee-n developed as a 

result of the frequent personal contacts, conferences, and exchange of correspondence with members of.the committee of the Section of Hydrology, more 

especially its chairman, Mr. Horner, and Messrs. Sherman, Meyer, and Horton. 

0. E. Meinzer, chief of the division of ground water, water-resources 

branch, and members of his staff have made helpful suggestions. Acknowledgment is due the U. S. Weather Bureau, the records of which have been 

used freely in this report, and special acknowledgment is due'J. B. Kincer, 

chief, Division of Climate and Crop Weather, for his cordial and helpful 

cooperation.
16 RAINFALL AND RUN-OFF IN THE UNITED STATES

Previous studies

Among the first attempts In this country to determine the relations between rainfall and run-off -were those made in the early 1890's by 

F. H. Newell, Henry Gannett, and C. C. Babb, of the United States Geological Survey. On the basis of very meager rainfall and run-off data, 

Newell, In the Fourteenth Annual Report (1892) of the Geological Survey, 

presented two curves showing the relation between mean annual precipitation and mean annual run-off - one for mountainous regions, the other for 

streams draining basins having broad valleys. The same report also contains rainfall and run-off maps of the United States. Henry Gannett later 

prepared more detailed maps of the United States, on one of which were 

shown lines of equal annual rainfall and on another lines of equal annual 

run-off. These maps had wide circulation and have been reproduced as late 

as 1928 (122, fig. 180).* Gannett was among the first of those in the 

United States to study run-off as a residual of rainfall after losses. 

Maps similar to those prepared by Gannett but based on much more information have recently been prepared by the Water Resources Section of the 

National Resources Board and are contained In the report of the Mississippi 

Valley Committee of the Public Works Administration dated October 1, 1934, 

and also in the report of the National Resources Board dated December 1, 

1934 (obtainable from the Superintendent of Documents, Washington).

C. C. Babb, in 1893 (3), presented curves showing monthly run-off 

in terms of percentage of annual run-off, the annual run-off being computed 

as a percentage of the annual precipitation. The year previous, Desmond 

Fitzgerald presented a paper (39) in which run-off, in terms of a percentage of rainfall, is discussed.

In 1903, George W. Rafter, after many years of study on the problem, presented a report (141) on the relation of run-off to rainfall. He 

discussed previous studies, including that of C. C. Vermeule in New Jersey. 

Vermeule (187) in an attempt to «xpress the relation between rainfall and 

run-off, used a constant plus a percentage for the several months of the 

year and varied the relation with the mean annual temperature. Rafter presented curves showing the general relation between rainfall and run-off for

# Numbered citations in parentheses refer to the list of references at the 

end of this pSper.
PREVIOUS STUDIES 17

three periods of the year, designated by him the storage period (December 

to May), growing period (June to August), and replenishing period (September to November). He drew numerous general conclusions, of which one was 

as follows (141, p. 81): "There is no general expression giving accurately 

the relationship of rainfall to run-off. The run-off of a stream is affected by so many complex elements that the data are lacking for final conclusions. Every stream is in effect a law unto itself. An empirical 

formula may, however, be made which will give for some streams approximately the run-off for a series of years."

D. W. Mead in 1904 brought together in a single treatise (109), 

for the first time in the United States, information available as of that 

date on the fundamental phenomena of hydrology. These notes were superseded in 1919 by his complete textbood entitled "Hydrology, the fundamental basis of hydraulic engineering" (111).

In 1914 J. D. Justin (86) expressed the annual run-off by a product consisting of a coefficient (which varied with slope and mean annual 

temperature) multiplied by the square of the annual rainfall.

A. F. Meyer in 1915 presented a comprehensive paper entitled 

"Computing run-off from rainfall and other physical data" (121), and in 

191V published his textbook "Elements of hydrology" an enlarged second 

edition of which was published in 1928 (122). Meyer, like Gannett, considered run-off a residual of rainfall after all losses had been deducted. 

He established curves by which the evaporation and transpiration from 

various drainage basins could be determined. Meyer"s paper made a great 

advance over any previous study, in that he undertook to ascertain in 

rational ways the losses from precipitation after it reaches the ground, in 

order to determine run-off.

The technical reports of the Miami Conservancy District, published in 1921, especially part 8, "Rainfall and run-off in the Miami Valley" (72), by Ivan E. Houk, presented a great advance in the knowledge of 

rainfall and run-off relations. Of special interest was Houlc's study of 

absorption rates and the distribution of stream flow into two parts - 

surface run-off and grourtd-water run-off - and quantitative analysis of the 

hydrologic cycle.

Results of studies made by John F. Hayford concerning the relations between rainfall and run-off, under the auspices of the Carnegie 

Institution of Washington, were published in 1929, 4 years after his

5955 O 35 2
18 RAINFALL AND RUN-OFF IN THE UNITED STATES

death (57). The studies continued over several years and were, so far as 

known, the most exhaustive yet made in an attempt to express mathematically the factors influencing daily stream flow. Hayford considered stream 

flow in two parts - "normal stream flow," or that portion derived from 

ground water, and "flood run-off," or the portion above the normal flow. 

The results indicated that so many constants must be determined in connection with any drainage basin that the studies are apparently not suited to 

practical application, although they are of considerable scientific 

interest.

In 1932 W. T. Collins and Franklin F. Snyder, students at Ohio 

State University, prepared a thesis (31) in which they derived formulas 

for expressing the mean monthly flow of certain Ohio streams, using a 

method of approach similar to that used by Professor Hayford. Reasonable 

agreement was reached between the computed flow and the observed flow for 

the particular streams and periods used in determining the several constants.

In 1932 L. K. Sherman (158) presented the idea that surface runoff from rainfall occurring within the same time Interval, such as a day 

or an hour, may be expressed in unit hydrographs- having equal bases on the 

time axis, the ordinates varying with the intensity of the rainfall.

In 1934 Merrill M. Bernard presented a paper (13) which develops 

certain features of the unit hydrograph and introduces the distribution 

graph and pluviagraph. The concepts developed by Sherman and Bernard provide a new approach to ttie analysis of the relation between precipitation 

and surface run-off.

In 1935 Robert E. Horton gave (70a) an analysis of the hydrograph describing and discussing "the natural processes involved in surface 

run-off quantitatively and in their natural sequence."

At the end of this report is a bibliography or papers, largely 

American, discussing relations between rainfall and run-off and related 

subjects, not including references relating to precipitation or run-off of 

high intensity. The bibliography is not complete with respect to the extensive and valuable literature on hydrology in foreign countries. Neither 

is it complete with respect to many articles and discussions which have 

been presented in the publications of the American Geophysical Union, 

American Society of Civil Engineers, American Water Works Association, New 

England Water Works Association, and other organizations, which can readily 

toe found by reference to the indexes of these publications. Many of the
AIMS OP PRESEHT STUD! 19

authors of these papers have spent the greater part of their professional 

careers In a study of the intricate problems involved in the hydrologlc 

cycle, and comments on the results of their studies would fill many volumes.

Aims of present study

The preceding brief discussion of previous studies, when read in 

connection with the partial bibliography, indicates that many minds have 

been engaged for a period of nearly 50 years in an attempt to determine and 

express the relations between rainfall and run-off. Although great progress has been made, there are many relations that still remain obscure. 

Early in the present study it was decided that in the light of prior investigations it was unwise to undertake a broad general study for the purpose 

of developing empirical formulas for expressing relations between rainfall 

and mean annual, monthly, or daily run-off. The study was directed, 

instead, along two rather definite lines of approach - (1) investigation of 

relations between annual and monthly precipitation, temperature, evaporation, transpiration, direct surface run-off, ground-water run-off, and 

infiltration as a basis for the quantitative analysis of the hydrologic 

cycle over broad areas and of trends and changes therein; (2) investigation 

of relations between storm precipitation and direct surface run-off.

It was felt that the investigations thus outlined would be of 

immediate value to the Mississippi Valley Committee and its successor the 

Water Planning Committee in connection with consideration of problems involving the utilization and conservation of water and would also form a 

logical extension of past hydrologic studies. Such a study would not 

encroach on the field of experimental research that was being carried on 

by many organizations and individuals. Rather it would be an attempt to 

bridge the gap between the small experimental area under controlled and 

simple conditions and the larger river-system areas of multiple and complex 

conditions.

It was hoped that the study of trends in the relations disclosed 

between rainfall and run-off might throw some light on perplexing questions 

In any broad consideration of hydrologic and climatic factors which had 

been presented to the Mississippi Valley Committee in the projects submitted to it for consideration and recommendation. It was also the purpose 

of tae study to disclose weaknesses and limitations in the application of
20 RAINFALL AND RUN-OFF IN THE UNITED STATES

the hydrologic and climatologic information and thus to be valuable in 

connection with the improvement or extension of fact-finding services engaged in collecting these basic data.

Precipitation*

Precipitation, or rainfall, is essentially the source of all 

water on the earth's surface and hence is commonly considered the starting 

point of the hydrologic cycle. A very considerable part of the present 

study has therefore been devoted to the investigation of precipitation with 

reference to annual and seasonal changes over broad areas, as well as to 

the study of the relation of precipitation to stream flow. Throughout the 

study of changes 10-year progressive averages have been generally used, and 

in the various diagrams the plotted points represent the average of the 

figures for the 10-year period ending with the year for which the point is 

plotted. The inherent limitation as to absolute accuracy of precipitation 

records is recognized and has been kept in mind in an attempt to avoid 

irrational and unsound use.

Precipitation records have been compiled for the purpose of determining within reasonable limits information concerning (1) possible 

changes in the precipitation over the continental United States as a whole 

since 1881; (2) possible changes over broad geographic provinces (a) on an 

annual basis and (b) on a seasonal basis; (3) possible changes over typical 

river basins; and (4) relations between annual precipitation and annual 

run-off.

Changes in precipitation in continental United States

Averages of precipitation by States are available from 1881 to 

1934 and are published in Water-Supply Paper 680. There has been a progressive increase in the accuracy of the State averages as a result of the 

increase in the number of Weather Bureau stations, refinements of methods 

of recording, and better geographic distribution of the stations used to

 » For the most recent map showing distribution of mean annual rainfall 

in the United States and variations from the mean together with a discussion of precipitation in general see section m of the Report of the 

Water Planning Committee to the Chairman of the National Resources Board 

dated November 15, 1934 (obtainable from the Superintendent of Documents, 

Washington, for $1.00).
PRECIPITATION 21

compute the State averages. To a greater or less extent, also, similar 

Increases In accuracy are shown by nearly all the basic data used In the 

present study. The relatively less reliability of the earlier data and 

greater reliability of the later data should be borne in mind in connection 

with any conclusions that may be drawn.

Because much of the country has had a period of deficient rainfall during the last few years the question naturally has been raised as to 

what changes In precipitation, if any, have taken place over the country as 

a whole during the last 55 years. The following table shows averages, 

weighted for area, of the mean annual precipitation by successive 5-year 

periods from 1881-85 to 1926-30 and for the 4-year period 1931-34. The 

figures were obtained by multiplying the mean annual precipitation computed 

for 5-year periods In each State by the area of the State In square miles, 

adding the products, and dividing the sum by the area of the United States 

In square miles.

Table 1.- Average annual precipitation over continental

United States, by 5-year periods

(Area 3,026,719 square miles)

5-year period

ending

1885

1890

1895

1900

1905

1910

1915

1920

1925

1930

1934 (4 years)

Precipitation

( inches )

31.13

28.92

28.02

29.07

29.52

29.82

30.24

29.21

28.53

29.43

27.63

Average 29.23

Variation from

average percent

+ 6.50

~ 1.06

 4.14

 .55

+ .99

 f 2.02

+ 3.46

 .07

 2.40

+ .68

 5.47

The computed average Is probably somewhat small, owing to the 

Inadequate distribution of stations in mountainous areas of the West.

This table seems to indicate that over the United States as a 

whole the variation shown on the basis of 5-year periods is relatively small 

when compared with variations for small areas or for individual stations. 

That the early eighties were, as here appears, years of extremely high 

precipitation is further indicated by data that follow. The early nineties and the early thirties were dry in many regions. The following study
RAINFALL AND ROT-OFF IN THE UNITED STATES

by broad areas indicates that country-wide changes tend to reflect in reduced degree wider departures that occur in different localities*

Changes in annual precipitation, by geographic provinoea

In the study of changes In precipitation by basins or States 

Information regarding direction of change and approximate magnitude was 

desired, rather than information as to amounts over wide areaa; therefore, 

precipitation stations having the longest records In each State were selected as a basis for the analysis. Table 2 lists comparative data for 

the stations used.

Years of high precipitation

The long-time stations Hated in table 2 are shown In figure 1 

together with lines drawn to a time scale showing the year of maximum 

annual precipitation. Only four of the 22 stations for which records are 

available prior to 1850 - Hanover, N. H.j St. Paul, Mlnn.; Farmersburg, 

Iowa; and Cincinnati, Ohio, - recorded years of maximum precipitation prior 

to 1850, and only two more - Muscatine, Iowa (1851), and Santa Fe, N. Mex. 

(1854), - recorded years of maximum precipitation during the period 1850 to 

1857. The first year In which five or more stations recorded maximum precipitation was 1858, when such records were made at Marietta, Ohio; 

Marengo and Peoria, 111.; St. Louis, Mo.; Leavenworth, Kans.; and The Dalles, 

Oreg. The grouping of five of these six stations In the Central Vest indicates the probability that 1858 was a year of maximum precipitation in oertain parts of that region. From 1859 to 1879 few stations recorded maximum 

annual precipitation. There was a wide-spread distribution of stations 

that recorded maximum annual precipitation during the eighties. The following list shows years in which five or more stations recorded maxima:

1882 Evansville, Ind. 1884 Battle Mountain, Nev.

Garrison, N. Dak. Havre, Mont.

Lexington, Ky. Los Angeles, Calif.

Little Rock, Ark. Sacramento, Calif.

Louisville, Ky. San Diego, Calif.

Portland, Oreg. San Francisco, Calif* 

Spokane, Wash.

1889 Baltimore, lid. 

Lynchburg, Va. 

New Brunswick, N. J, 

Norfolk, Va. 

Richmond, Va.
PRECIPITATION

Table 2.- Precipitation at long-time Weather Bureau stations

Station

Alabama

Mobile

Montgomery

Union Springs

Arizona

Phoenix

Univ. Arizona

Yuma

Port Smith

Helena

Little Rook

California

Indio

Los Angeles

Sacramento

San Diego

San Francisco

Colorado

Denver

Las Anlraas

Pueblo

Connecticut

Canton

Delaware

Bridgeville

Millsboro

Florida

Jacksonville

Key West

St. Augustine

Georgia

Atlanta

Augusta

Rome

Idaho

Boise

Moscow

Porthlll

Illinois

Chicago

Harengo

Poor i a

Indiana

Evans ville

Indianapolis

Lafayette

Iowa

Dubuque

Farmer sburg

Muscatine

Kansas

Hays

Lawrence

Leavenworth

Manhattan

Kentucky

Lexlngton

Louisville

Paducah

Period 

of 

record

1871-1934

1873-1934

1868-1934

1877-1934

1868-1934

1870-1934

1878-1934

1874-1934

3.878-1934

1878-1934

1878-1934

1850-1934

1850-1934

1850-1934

1872-1934

1867-1934

1884-1934

1859-1923

1891-1934

1893-1934

1867-1934

1870-1934

1877-1934

1868-1934

1869-1934

1866-1934

1868-1934

1892-1934

1890-1934

1871-1934

1856-1934

1856-1934

1877-1934

1867-1934

1880-1934

1851-1934

1837-1930

1846-1934

1868-1934

1868-1934

1836-1934

1858-1934

1858-1934

1871-1934

1882-1934

Average 

annual 

(inches)

61.61

51.19

50.72

7.78

11.52

3.47

33*85

53.47

48.38

3.01

15.23

17.95

10.30

22.02

14.05

12.41

11.67

51.12

42.78

43.90

49.74

38.11

47.97

48.27

44.90

49.36

13.10

23.08

20.02

32.86

33.11

34.89

43.16

39.90

38.71

32.90

31.67

36.72

22.91

36.38

34.74

31.49

43.35

43.26

46.56

Maximum

Year

1881

1929

1912

1905

1905

1905

1890

1877

1882

1927

1884

1884

1884

1884

1909

1923

1921

1866

1906

1934

1885

1870

1920

1929

1929

1932

1871

1913

1893

1883

1858

1858

1882

1876

1927

1881

1849

1851

1878

1915

1858

1915

1882

1882

1927

% of 

average

150

153

156

254

210

329

166

151

156

26S

264

194

268

176

164

172

174

157

147

144

165

183

149

140

164

157

197

131

193

140

15S

153

164

145

14S

168

169

203

154

14S

17S

161

146

131

155

Minimum

Year

1904

1931

1927

1924

1924

1928

1917

1918

1924

1894

1898

1932

1863

1917

1911

1894

1934

1860

1930

1930

1927

1893

1911

1904

1933

1867

1868

1911

1929

1934

1901

1910

1930

1934

1914

1894

1895

1901

1894

1897

1864

1860

1930

1930

1887

% of 

average

64

67

59

39

44

14

51

67

65

0

32

37

29

41

55

22

50

68

60

57

61

58

66

69

62

64

51

48

62

69

59

66

59

63

65

59

58

58

52

65

42

48

57

55

519

Maximum 10 -yr.

Period 

ending

1885

1924

1909

1914

1884

1914

1895

1886

1891

1921

1893

1889

1893

1887

1915

1915

1923

1872

1911

(1906

(1907

1887

1884

1886

1889

1881

1920

1879

1903

1901

1885

1885

1884

1886

1883

1929

1885

1885

1858

1905

1909

1885

1911

1888

1884

1934

% of 

average

108

109

120

161

119

140

118

112

114

133

134

121

120

116

116

121

116

117

108

107

118

113

109

117

113

114

121

102

134

121

109

111

115

121

107

125

118

130

116

110

117

116

116

115

110

Minimum 10-yr.

Period 

ending

1910

1904

1881

1929

1903

1904

1919

1904

1925

1887

1903

1932

1865

(1906

(1932

1904

1897

1934

1884

1918

1918

1918

1899

1918

1934

1934

1890

1933

1931

1931

1901

1904

1894

1933

1908

1919

1910

1901

1917

1896

1934

1847

1875

1908

1934

1894

% of 

average

94

92

85

82

84

57

82

86

90

68

73

69

74

86

90

72

91

87

93

92

84

91

89

89

91

88

86

88

101

90

91

91

91

91

89

87

87

85

88

88

83

85

85

89

82
RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 2.- Precipitation at long-time Weather Bureau stations.-Continued

Station

Louisiana

Monroe

New Orleans

Shreveport

Maine

Cornish

Gardiner

Orono

Maryland

Baltimore

Emmitsburg

Massachusetts

Boston

Lowell

Michigan

Detroit

Lansing

Marquette

Minnesota

Duluth

Mlnneapoll s

St. Paul

Mississippi

Canton

Columbus

Vicksburg

Missouri

Hermann

Oregon

St. Louis City

Montana

Ag. College

Havre

Miles City

Nebraska

Blair

North Platte

Nevada

Battle Mt.

Elko

Imlay

New Hampshire

Hanover

Lakeport

New Jersey

New Brunswick

New Mexico

Ag. College

San Marcial

Santa Fe

New York

Albany

New York

Rochester

North Carolina

Lenolr

Weldon

Wilmington

Period 

of 

record

1886-1934

1870-1934

1872-1934

1857-1924

183"-1934

1870-1930

1817-1934

1867-1934

1818-1934

Average 

annual 

( inches )

51.72

57.46

43.37

46.12

43.00

41.30

42.56

43.86

40.14

1326-1934 41.47

1

1371-19341 32.05

1364-1934

1873-1334

1871-1934

1360-3934

1837-1933

1383-1934

1856-1870

1875-1934

1840-1853

1872-1934

1875-1934

1856-1934

1837-1934

1874-1885

1893-1934

1380-1934

1378-1934

1868-1934

1875-1934

1870-1934

1870-1934

1870-1934

1835-1855

1867-1934

1857-1932

31.43

32.47

27.94

27.66

27.27

49.07

53.93

51.93

38.50

35.95

37.44

18.35

13.90

13.79

29.37

18.39

6.40

3.51

5.45

35.25

41.34

1854-1934 45.47

1851-1861

1865-1934

1850-1862

1865-1934

1850-1934

1826-1934

1826-1934

1829-1934

1872-1934

1872-1934

1871-1934

8.57

9.13

14.27

38.38

42.99

32.83

51.44

45.97

, Maximum Minimum

Year

1920

1375

3330

1902

1387

192G

1389

1912

1363

1388

1880

1883

1918

1379

18 08

1849

1923

1932

1380

1927

1902

1858

1385

1884

1879

1369

1915

1234

1904

1390

1343

1888

1889

1905

1859

1854

1871

1859

1873

1901

1891

46.93 1877

% of 

average

1 154

149

154

' 137

127

130

146

149

169

143

149

154

129

162

151

1 132

Year % of 

average

|

1899 63

1899 1 54

1899 53

1880 73

1838 70

1921 62

1930

1338

1322

1914

1889

1930

1925

1910

Maximum 10-yr.

Period 

ending

1928

1934

1885

1902

1859

1891

51 1892

59 1 1920

68 ! 1870

67 j 1933

j

66

59

61

65

1910 | 42

1910

139 1924

143 1904

162 1924

37

59

67

1882

1885

1884

% of 

average

116

116

128

114

112

116

120

108

143

113

118

115

105

1882 127

1876

1874

1923

1884

60

i ;

137

141

174

1901

1910

1930

58

59

C2

178 1934 57

135

165

162

1905

1934

1934

178 1P31

219

223

285

158

133

1.-918

1 C1 72

1929

1871

1394

(1930

135

199

269

174

148

139

152

'1932

1873

1901

1917

1930

1835

1834

159 1933

130 1931

178 1909

49

40

61

54

1884

1929

1905

1^59

1385

1389

1915

1378

1909

38

11

31

64

75

7?

41

12

35

66

67

52

63

62

59

1892

1905

1927

1851

1893

1874

1906

1884

1861

1878

1933

1878

1906

1896

1885

121

118

106

110

122

107

115

123

117

Minimum 10-yr.

Period

ending

1902

1899

1899

1915

1914

(1923

(1924

1872

1901

1914

1917

1891

1895

1932

1926

1934

1891

1933

1910

1933

1887

1918

1908

1903

103 ! 19] 3

122 1890

114 1895

316 j 1901

134

159

130

127

109

115

125

123

119

113

116

118

108

113

1923

1380

1903

1084

1930

1934

1880

1901

% of 

average

86

82

86

88

90

89

73

93

88

81

90

86

92

89

87

87

93

89

88

92

85

92

°4

88

80

83

82

74

51

68

83

82

85

83

73

1875 88

1914 78

1840 81

1841 86

1934

1934

127 1918

85

87

89
PRECIPITATIOH

Table 2.- Precipitation at long-time Weather Bureau stations-Continued

Station

Horth Dakota

Devil's Lake

Garrison

Ohio

Cincinnati

Cleveland

Marietta

Toledo

Oklahoma

Law ton

Oklahoma City

Tula a

Oregon

As tor la

Portland

The Dalles

Pennsylvania

Philadelphia

Pittsburgh

Rhode Island

Providence

South Carolina

Camden

Charleston

South Dakota

Huron

Rapid City

Yankton

Tennessee

Clarksvllle

Knoxvllle

Texas

Austin

Brownsville

Galveston

Utah

Moab

Salt Lake City

Vermont

Burlington

Chelsea

Virginia

Lynchburg

Norfolk

Richmond

Washington

Spokane

Walla Walla

West Virginia

Rowlesburg

Wisconsin

Milwaukee

Wyoming

Cheyenne

Lander

Period 

of 

record

1870-1890

1897-1934

1870-1883

1892-1934

1835-1934

1871-1934

1826-1934

1861-1934

1871-1934

1891-1934

1888-1934

1854-1934

1872-1934

'1853-1865

|1875-1934

1820-1934

'1839-1865

1872-1934

1832-1934

1850-1934

(1738-1765

;i832-1934

1882-1934

1888-1934

1874-1934

1854-1934

1871-1934

1856-1934

1871-1934

1872-1934

1890-1934

1874-1934

(1838-1866

P.872-1934

1886-1934

1872-1934

1871-1934

1872-1934

1882-1934

1873-1934

1885-1933

1844-1934

1871-1934

1892-1934

Average 

annual 

( Inches )

18.04

16.38

38.55

33.82

42.25

32.03

31.53

31.15

37.40

77.05

41.62

15.72

40.41

36.17

39.19

45.56

45.22

20.65

17.98

25.30

48.46

47.38

34.08

27.40

44.77

9.41

16.13

31.61

35.78

40.53

44.09

42.02

16.62

17.01

48.67

30.08

14.99

12.63

Maximum

Year

1921

1882

1847

1878

1858

1881

1905

1908

1915

1933

1882

1858

1867

1890

1898

1928

1876

1914

1915

1881

1919

1875

1919

1886

1900

1918

1927

1875

1897

1897

1889

1889

1889

1882

1893

1907

1876

1905

1923

% of

average

141

167

169

158

146

144

159

167

168

148

162

277

151

140

162

183

MinlBnon

Year

1889

1874

1901

1934

1930

1894

1901

1901

1896

1884

1929

1889

1922

1930

1914

1879

173 1850

146

151

162

152

156

190

219

175

170

147

138

134

150

160

171

156

136

148

167

151

171

1925

1931

1894

1918

1930

1917

1917

1917

1898

1890

1881

1899

1930

1930

1876

1929

1922

1886

1901

1876

1902

% of

average

58

48

47

65

59

67

51

51

64

64

63

48

72

63

75

67

52

49

52

57

70

71

46

44

48

46

64

66

76

49

61

66

45

66

39

62

34

57

Maximum 10-yr.

Period 

ending

1905

1884

1855

1885

1891

1870

1908

1927

1929

(1880

(1902

1883

1865

1874

1873

1895

1929

1879

1921

1929

1883

1928

1882

1927

1887

1882

1918

1915

1866

1895

1902

1895

1895

1902

1902

1914

1878

1930

1924

% of

average

108

107

131

117

110

123

116

111

115

110

134

165

125

113

130

119

139

108

115

114

116

116

119

145

119

121

108

112

112

115

122

117

111

112

115

118

117

118

lHn<nnnn 10-yT.

Period 

ending

1917

1877

1903

1923

1901

1902

1918

1918

1897

1931

1931

1931

1886

1846

1918

1888

1909

1934

1900

1934

1918

1900

1912

1902

1898

1904

1896

1933

1888

1917

1930

1934

1885

1926

1930

1895

1902

1882

1902

*°f 

average

92

86

84

87

91

87

90

85

87

89

85

77

91

93

90

85

82

75

79

78

93

93

82

64

81

80

91

89

89

82

83

82

77

84

81

92

65

99
See table 2 for list of 

Weather Bureau stations used.

Figure l.-Year of maximum annual precipitation at selected long-time 
PRECIPITATION 27

Prom 1890 to 1904 there are no large groups but 1905, 1915, and 

1927 were outstanding wet years, five or more long-time stations having recorded maxima as follows:

1905 Agricultural College, N. Hex. 1915 Lawrence, Kans. 

Cheyenne, Wyo. Manhattan, Kans. 

Phoenix, Ariz. North Platte, Nebr. 

University of Arizona, Ariz. Rapid City, S. Dak. 

Yuma, Ariz. Tulsa, Okla. 

Lawton, Okla.

1927 Hermann, Mo. 

Indio, Calif. 

Lafayette, Ind. 

Moab, Utah 

Paducah, Ky.

A study of the characteristics of the precipitation at each of 

the long-time stations for these long-time maxima would be of interest. 

For all the stations the average ratio of the maximum to the average annual 

precipitation is 1.66. Stations at which the ratio is over 1.80 are situated largely in the Southwest.

Periods of high precipitation

The long-time stations listed in table 2 are shown in figure 2 

together with a line drawn to the time scale showing the end of the 10-year 

period of maximum precipitation. The records for a few stations in the 

Middle Atlantic and New England areas and a few isolated stations elsewhere 

show that the 10-year maximum period occurred prior to 1880. The 10-year 

maxima ended at the greatest number of stations during the period 1884 to 

1895 and were especially confined to three 10-year periods, as follows:

10 years

ending Columbus, Miss. 1885 Agricultural College. Mont. 

1884 Garrison, N. Dak. Chicago, 111.

Key West, Pla. Cleveland, Ohio. 

Louisville, Ky. Dubuque, Iowa. 

Marquette, Midi. Parmersburg, Iowa. 

Peoria, 111. Lansing, Mich. 

San Marcial, N. Mex. Leavenworth, Kans. 

University of Arizona, Ariz. Marengo, 111. 

Vicksburg, Miss. Mobile, Ala.

Shreveport, La. 

Wilmington, N. C.

1895 Chelsea, Vt.

Port Smith, Ark. 

Norfolk, Va. 

Providence, R. I. 

Richmond, Va.

During the period 1923 to 1929 there was also a group of stations, located largely in the South and Southeast, that recorded 10-year
RAINFALL AND RUN-OFF IN THE UNITED STATES
PRECIPITATION 29

maxima. Since 1930 4 stations - Lowell (Mass.), New York, Paduch (Ky.), 

and New Orleans - have recorded 10-year maxima.

The average ratio of the maximum 10-year period to the mean 

for all stations is 1.19.

Years of low precipitation

The long-time stations listed in table 2 are shown plotted on 

figure 3 together with a line drawn to a time scale shovd.ng the year of 

minimum precipitation.

Prior to 1851 six of the 22 stations operating at that time recorded their minimum for the period of record - namely, Boston, Mass., 1822; 

Rochester, N. Y., 1834; New York City, N. Y., 1835; Gardiner, Maine, 1838; 

Lowell, Mass., 1846; Charleston, S. C., 1850. These records indicate that 

in all probability recent droughts in certain parts of the East as regards 

precipitation may not have been as severe as some that occurred about a century ago.

During the 40-year period 1851 to 1890 only 23 stations recorded 

minimum annual precipitation. Beginning with 1894 more and more stations 

recorded their minima, and except in only a few years minima were recorded 

at one or more stations, with the major grouping as follows:

1894 Dubuque, Iowa 1910 Duluth, Minn.

Hays, Kans. Minneapolis, Minn. 

Indio, Calif. Oregon, Mo. 

Lakeport, N. H. Peoria, 111. 

Las Animas, Colo. St. Paul, Minn. 

Toledo, Ohio. 

Yankton, S. Dak.

1917 Austin, Tex.

Brownsville, Tex.

1901 Cincinnati, Ohio. Port Smith, Ark. 

Hermann, Mo. Galveston, Tex. 

Lawton, Okla. San Francisco, Calif. 

Marengo, 111. Santa Pe, N. Mex. 

Milwaukee, Wis. 

Muscatine, Iowa.

Oklahoma City, Okla. 1924 Canton, Miss. 

San Marcial, N. Mex. Little Rock, Ark.

Phoenix, Ariz.

University of Arizona

Vicksburg, Miss,
See table 2 for list of 

Weather Bureau stations used.

Figure 3. Tear of minimum annual precipitation at selected long-time 
PRECIPITATION 31

1930 Albany, N. Y. 

Baltimore, Md. 

Bridgevllle, Del. 

Evansville, Ind. 

Knoxville, Tenn. 

Lansing, Mich. 

Lexington, Ky. 

Louisville, Ky. 

Lynohburg, Va. 

Marietta, Ohio. 

Millsboro, Del. 

New Brunswick, N. J. 

Norfolk, Va. 

Pittsburgh, Pa. 

St. Louis City, Mo.

1931 Montgomery, Ala.

North Platte, Nebr. 

Rapid City, S. Dak. 

Weldon, N. C.

1934 Blair, Nebr.

Cleveland, Ohio 

Chicago, 111. 

Indianapolis, Ind. 

Miles City, Mont. 

Agricultural College, Mont. 

Pueblo, Colo.

The average ratio of the annual minima for all stations to the

average is 0.56.

Periods of low precipitation

The long-time stations listed in table 2 are plotted on figure 

4 together with lines drawn to the time scale showing the end of the minimum 10-year period. Pour of the long-time stations recorded minimum 

10-year periods prior to 1850 - New York, 1840; Rochester, N. Y., 1841; 

Pittsburgh, Pa., 1846; Leavenworth, Kans., 1847 - indicating that not only 

were there Individual years of minimum precipitation prior to 1850 but 

10-year periods as well. During the 21-year period 1850-70 only one longtime station recorded its 10-year minimum, and from 1871 to 1890 only a few 

scattered stations. Beginning with 1890 more and more stations recorded 

their 10-year minima, with an exceptionally large number during the last 4 

years. Outstanding 10-year periods were as follows:

10 years

ending Chicago, 111. 

1901 Emmitsburg, Md.

Parmersburg, Iowa. 

Marietta, Ohio. 

North Platte, Nebr. 

San Marcial, N. Mex.

1902 Agricultural College, Mont, 

Brownsville, Tex. 

Milwaukee, Wis. 

Monroe, La. 

Lander, Wyo. 

Toledo, Ohio.

1904 Denver, Colo. 

Helena, Ark. 

Moab, Utah. 

Marengo, 111. 

Montgomery, Ala. 

Yuma, Ariz.

1918 Bridgeville, Del. 

Clarksville, Tenn. 

Jacksonville, Pla. 

Lawton, Okla. 

Millsboro, Del. 

Oklahoma City, Okla. 

Oregon, Mo. 

Providence, R. I. 

St. Augustine, Pla. 

Wilmington, N. C.

1931 Astoria, Oreg. 

Moscow, Idaho. 

Porthill, Idaho. 

Portland, Oreg. 

The Dalles, Oreg.

1932 Marquette, Mioh.

Sacramento, Calif. 

San Francisco, Calif.
See table Z for list of 

"leather Bureau stations used.

Figure 4. Year ending 10-year period of minimum precipitation at selected 
PRECIPITATION 33

10 years 

nding Boise, Idaho

1933 Canton, Miss.

Evansville, Ind. 

Salt Lake City, Utah. 

VIcksburg, Miss.

1934 Atlanta, Ga. 

Augusta, Ga. 

Huron, S. Dak. 

Lawrence, Kans. 

Lenoir, 11. C. 

Louisville, Ky. 

Minneapolis, Minn. 

New Brunswick, N. J. 

Norfolk, Va. 

Pueblo, Colo. 

Weldon, N. C. 

Yankton, S. Dak.

The average ratio of the 10-year minima for all stations to the 

average is 0.85.

Changes in precipitation, by areas

The preceding discussion Indicates that period? of either high 

or low precipitation occur simultaneously over large aress, and as storms 

over the United States are known to follow fairly well defined paths it has 

seemed worth while to Investigate whether over large areas precipitation, 

trends might be related to the same general pattern. This suggested a study 

in the areal grouping of stations that show similar trends of precipitation.

The progressive 10-year averages for a number of the long-time 

stations listed in table 2 and for 5 additional stations were plotted and 

closely compared, and the stations that showed the same general type of 

variation were then grouped. It was found that these groups embraced stations having much the same geographic location, as follows:

1. North Atlantic group (fig. 6):

Gardiner, Cornish, and Orono, Maine.

Lakeport and Hanover, N. H.

Boston and Lowell, Mass.

Providence, R. I.

Canton, Conn.

Albany and New York, N. Y.

New Brunswick, N. J.

2. Middle Atlantic group (fig. 6):

Philadelphia, Pa.

Baltimore and Emmitsburg, Md.

Lynchburg, Richmond, and Norfolk, Va.
34 RAINFALL AND RUN-OFF IN THE UNITED STATES

3. South Atlantic group (fig. 6):

Wllmlngton, Lenoir, and Weldon, N. C. 

Charleston and Camden, S. C. 

Atlanta, Augusta, and Rome, Ga. 

Jacksonville, Key West, and St. Augustine, Fla.

4. Great Lakes group (fig. 7):

Milwaukee, Wls.

Marengo, Peorla, and Chicago, 111.

Evansville, Lafayette, and Indianapolis, Ind»

Lanslng, Detroit, and IJarquette, Mich.

Marietta, Cincinnati, Cleveland, and Toledo, Ohio.

Rochester, N. Y.

Pittsburgh, Pa.

5. Tennessee River group (fig. 7):

Clarksvllle and Knoxvllle, Tenn. 

Louisville, Lexlngton, and Paducah, Ky.

6. Gulf group (fig. 7):

Union Springs, Mobile, and Montgomery, Ala.

Vicksburg and Columbus, Miss.

New Orleans and Shreveport, La.

Helena, Fort Smith, and Little Rock, Ark.

Galveston, Tex.

7. North Central West group (fig. 8):

St. Paul, Minn.

Muscatine and Farmersburg, Iowa. 

Blair and North Platte, Nebr. 

Yankton and Huron, S. Dak. 

Devils Lake and Garrison, N. Dak.

8. Central West group (fig. 8):

Leaven-worth, Manhattan, and Hays, Kans. 

St. Louis, dregon, and Hermann, Mo.

9. South Central West group (fig. 8):

Austin, Tex.

Tulsa, Lawton, and Oklahoma City, Okla.

10. Northwest Interior group (fig. 9):

Walla Walla and Spokane, Wash.

The Dalles, Oreg.

Boise, Idaho.

Elko and MeGill, Nev.

11. Northern and Western Plains group (fig. 9):

Miles City and Havre, Mont.

Cheyenne and Lander, Wyo.

Pueblo, Denver, and Las Animas, Colo.
PRECIPITATION 35

12. Great Basin and Southwest group (fig. 9):

Salt Lake City, Scipio, and Moab, Utah.

Phoenix, Yuma, and University Station, Ariz.

Santa Fe, San Marcial, Port Wingate-McGaffey Ranger Station,

and Agricultural College, N. Mex. 

Indio, Calif.

13. North Pacific coast group (fig. 10):

North Head, Wash. 

Astoria, Oreg.

14. Central Pacific coast group (fig. 10):

San Francisco and Sacramento, Calif. 

Imlay and Thorne, Nev.

15. South Pacific coast group (fig. 10): 

San Diego and Los Angeles, Calif.

The average of the progressive 10-year averages of the stations in 

the groups designated above is plotted on figure 5 for annual values and on 

figures 6 to 10 for annual and seasonal values (December to April, May to 

August, and September to November). Figures 6 to 10 also show the average 

precipitation by months for all the stations in each group. That portion of 

the graphs indicated by a dashed line represents a number of stations less 

than the total for the group. The figures for these points, however, were 

adjusted so as to be comparable with the remaining record.

That the average of the 10-year progressive averages for the group 

of stations shown does not represent the average precipitation over any area 

is of course recognized, but it is believed to show the direction of periodic 

trends and the approximate magnitude of changes in each area. The trends 

indicated are interesting, and consideration of them may indicate areas where 

climatic conditions seem to be critical and where further detailed study of 

precipitation is desirable.

The preliminary study of 10-year progressive average annual precipitation leads to the following deductions:

(1) The minimum 10-year period at the exceptionally long-time stations at New York City and Rochester, N. Y., Pittsburgh, Pa., and Leavenworth, 

Kans., ended in the 1840"s (fig* 4). The minimum for any 10-year period since 

1850 at these stations has been consistently above these early minima t 

except New Bedford, Mass, which recorded a low for the 10-hear period ending 

1930 that was 15 percent below the minimum 10-year period prior to 1850. The 

early history of lakes in sections of the West indicates that in the late 

1840's their beds were dry and were crossed by emigrant trails (55). Data 

from the records and diaries of early settlers and travelers as compiled by
RAINFALL AND RUN-OFF IN THE UNITED STATES
PRECIPITATION

Maryla Baa

Florida, Oaorgl North arollna, 

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Ayeraga nonthly preolpitatlon

 _n-i

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Averaga monthly preoipltatlon

4 I jj 4 11 f ! I i I

Figure 7.-Average of 10-year progressive annual and seasonal p

average monthly distribution for long-time Heather B
Oklahoma, Central Texas Missouri, Kansas

16

La 

g 10

Sep;anfi)<

Hay - August

8 S S

Average monthly preolpitation Average monthly preoipltation 

* 4 tIIII I!fIi

Figure 8. Average of 10-year progressive annual and seasona

average monthly distribution for long-time Weath
New tlexloo, Arizona, 

Southeastern California, Utah

Oolorado, Wyoming, Montana

/ ^

Hay - August

September - November

Average monthly precipitation Average monthly precipitation 

ii:- ii 14 a! i ii 

Figure 9. Average of 10-year progressive annual and seasonal p

average monthly distribution for long-time Weather 
PRECIPITATION
42 RAINFALL AND RUN-OFF IN THE UNITED STATES

H. B. Lynch (102) indicate a period of deficient precipitation in southern 

California about 1830 which has not since been surpassed. Composite treering studies in northern California indicate a 5-year period ending in 1850 

when tree rings were prevailingly thin (18a). All these evidences seem to 

point to a severe drought of wide extent about the period 1830 to 1850.

(2) The trend of precipitation for the 30-year period 1850-80 

seems to have been generally upward over most of the United States. During 

this period only a few stations registered minimum 10-year averages (fig. 4). 

On the other hand, beginning as early as 1855, maximum 10-year averages are 

noted (fig. 2) culminating in 10-year periods ending in 1886, when 23 out 

of 98 long-time stations in the United States showed maximum 10-year averages. In no other decade has there been such a grouping of maximum 10-year 

averages at so many stations. There seems to be little doubt that the 

average annual precipitation for the 5 years ending in 1885, over a very 

considerable part of the United States, has not been exceeded during the 

period 1830-1934. Other periods when in some sections maximum precipitation 

was recorded were 1902 for stations in the Northwest, 1914-15 for the 

Central West and Southwest, and 1927, 1928, and 1929 for stations in the 

Central West and South. These trends are clearly shown on figures 1 to 5.

(3) Beginning about 1894 more and more of the stations recorded 

minimum 10-year averages (fig. 4). Between 1894 and 1904 37 of the longtime stations recorded 10-year minima. The minima at most of the remaining stations were scattered through the 30-year period 1904-34, with the 

.largest number culminating 10-year lows in'1930, 1931, 1933, and 1934. 

The long-time stations recording their' minimum 10-year average in 1934 

were Chicago, Cleveland, Indianapolis, Miles City, Agricultural College 

(Mont.), and Pueblo.

Insofar as the annual averages of these stations are indicative 

of annual changes over the respective areas these data indicate that

(1) The persistent downward trend in annual precipitation for 

the last two or three decades has been generally confined to (a) the Northwest Interior, North Pacific coast, and Central Pacific coast areas, embracing Washington, Oregon, Idaho, Nevada, and central and northern California; 

(b) the upper Mississippi Valley, embracing parts of North and South Dakota, 

Nebraska, Iowa, Wisconsin, and Minnesota; and (c) the North Atlantic and 

Middle Atlantic areas embracing all the New England States, the eastern part 

of New York, and Pennsylvania, Delaware, Maryland, and Virginia.
PRECIPITATION 43

(2) The trend in the annual precipitation during the decade 

ending in 1930 was stationary or slightly upward in the Southwest, Great 

Basin, Northern and Western Plains, and Great Lakes area and rather decidedly upward in the South Atlantic-and Tennessee River areas.

(3) Since 1930 the Northern and Western Plains area has experienced a dropping off, while the North Pacific coast area has turned 

abruptly upward.

Changes in seasonal precipitation, by geographic provinces

An examination of the seasonal changes in precipitation in 

certain areas indicates that they did not always correspond to the changes 

shown in yearly precipitation. For the purpose of examining the seasonal 

trends over all the areas the monthly averages of all the long-time records at stations used for the yearly trends were combined into three 

seasons - December to April, May to August, and September to November. 

These three seasons correspond rather closely over the United States as a 

whole to the three periods found by experience to be of special significance in the study of hydrology - namely, the replenishing period, September, October, and November, when accretions to soil moisture and ground 

water commonly occur; the storage period, December through April, when 

losses are at a minimumj and the growing season, May through August, when 

evaporation and transpiration are most active, with resulting depletion of 

soil moisture and minimum recharge to the ground water. As the storm 

tracks apparently vary by seasons, it is possible that the study of their 

changes by seasons will tend to disclose some of the reasons for the variations in yearly trends. Changes in seasonal precipitation may also be 

reflected in significant changes in seasonal run-off which are not disclosed by changes in the annual amounts.

In tables 3, 4, and 5 are shown data by seasons for each areal 

group of stations.

Changes in winter precipitation

The 10-year progressive averages of the precipitation for the 

winter season (December to April) shown in figures 6 to 10 and comparisons 

shown in table 3 indicate that -
RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 3.- Precipitation, December to April, 1871-1934

Area*

1

2

5

4

5

6

7

6

9

10

11

12

15

14

15

Average ( inches )

1871- 

1934

17.11

16.54

17.48

13.09

SI. 01

23.32

5.98

9.64

11.04

7.25

3.97

3.94

41.14

8.86

10.24

1871- 

1902

17.92

16.90

18.30

13.11

21.25

23.80

6.29

10.12

10.48

8.12

3.90

3.63

43.60

9.70

10.11

1903- 

1934

Iti. 30

16.11

16.67

13.07

20.77

22.85

5.68

9.16

11.59

6.38

4.04

4.04

38.68

0.02

10.36

Ratio last 32 

years to first 

32 years 

(percent)

91

95

91

100

98

96

90

91

111

79

104

105

89

83

102

Average for 10 

years ending 

1934 

( inches )

15.B6

15.19

16.89

12.19

19.58

22.70

5.22

8.94

11. BO

6.20

3.65

3.54

40.43

7.11

9.76

Ratio last 10 years 

(percent)

To long time 

average

93

92

97

93

93

97

87

93

107

86

92

90

98

80

95

To last 32 

years

97

94

101

93

94

99

92

?8

102

97

90

88

105

89

94

Area*

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Maximum 10-year 

period

Inches

19.20

18.64

19.38

14.56

S3. 55

S5.45

6.92

10.74

12 .73

8.43

4.48

4.72

46.90

11.66

13.55

Date of 

ending

1891

1892

1883

1885

1883

1884

1897

1882

1923

1890

1922

IS 14

1880

1881

1893

Minimum 10-year 

period

Inches

15.69

15.19

15.28

12.19

19.58

21.45

5.22

8.88

9.14

5.98

3.18

3.08

33.89

7.00

7.46

Date of 

ending

1931

1934

1916

1934

1934

1896

1934

1926

1910

1931

1882

1904

1931

1933

1903

Ratio last 10 years 

to minimum 10 years

(percent)

101

100

111

100

100

106

100

101

129

104

115

115

119

102

131

* Numbers correspond to those of groups listed on pages 33-35.
PRECIPITATION 45

(1) Except In the Southwest, the average winter precipitation 

for the last 32 years of record has been less than that for the first 32 

years.

(2) Except in the South Central West area and the Northern and 

Western Plains area, the 10-year average winter precipitation in the 1880's 

and 1890's was generally at a maximum.

(3) The trend is still downward in several areas, as indicated 

by the fact that the average for the last 10 years is the same or nearly 

the same as that for the minimum 10 years.

(4) Insofar as the few stations in the Northwest Interior area 

may be indicative of the winter precipitation in the adjacent mountain 

areas, the downward trend is critical, because the economic life of these 

areas depends to a considerable degree upon the winter precipitation.

Changes in precipitation in growing season

The 10-year progressive averages shown on figures 6 to 10 and 

comparisons shown in table 4 indicate that -

(1) Except in the Northern and Western Plains area and the 

Southwest, the average summer precipitation during the last 32 years of 

record has been less than that for the first 32 years.

(2) Except in the southwest, the trend is generally downward, 

and in several areas the average for the 10 years ending in 1934 is the 

same or nearly the same as the minimum for the period of record.

(3) In general the percentage decrease from the first to the 

last 32 years of record is comparable with the decrease in winter precipitation.

(4) The persistent downward trend is becoming critical in areas 

such as the upper Mississippi Valley, where the summer precipitation is so 

large a proportion of the total precipitation.

Changes in fall precipitation

The 10-year progressive averages shown on figures 6 to 10 and 

comparisons shown in table 5 indicate that for the fall precipitation 

(September to November) -

(1) There has been a decided reversal from the winter and summer 

trends.
RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 4.- Precipitation, May to August, 1871-1954

Area*

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Average (Inches)

1871- 

1934

14.37

16.59

19.08

13.56

15.46

17.18

13.10

16.10

13.92

2.80

6.84

3.63

8.18

.95

.52

1871- 

1902

15.04

16.60

19.35

14.08

15.73

17.52

13.29

16.57

13.98

2 99

6.83

3.46

9.02

.96

.60

1903- 

1934

13.71

16.58

18.80

13.04

15.18

16.84

12.90

15.63

13.85

2.60

6.86

3.80

7.34

.94

.44

Ratio last 32 

years to first 

32 years 

( percent )

91

100

97

93

96

96

97

94

99

87

100

110

81

98

73

Average for 10- 

years ending 

1934 

( Inches )

13.42

15.43

17.78

12.33

15.37

16.05

11.15

15.11

13.14

2.22

6.51

3.84

7.55

1.00

.45

Ratio last 10 years 

(percent)

To long-time 

average

93

93

93

91

99

93

85

94

94

79

95

106

92

105

87

TO last 32 

years

98

93

95

95

101

95

86

97

95

85

95

101

103

106

102

Area*

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Maximum 10-year

period

Inches

15.78

18.36

20.66

15.49

16.95

18.82

15.16

18.00

16.58

3.37

7.51

4.23

10.18

1.33

.80

Date of

ending

1893

1894

1894

1884

1884

1895

1908-9

1904

1908

1913

1930

1915

1882

1892

1S92

Minimum 10-year

period

Inches

12.41

14.64

17.70

12.33

14.38

15.64

11.15

14.21

11.80

2. 82

6.35

3.03

6.55

.59

.27

Date of

ending

1914

1885

1933

1934

1908

1933

1934

1920, 26

1918

1934

1894

1892

1925

1881-82

1918

Ratio last 10 years

to minimum 10 years

(percent)

108

105

100

100

107

103

100

106

111

100

102

127

115

169

167

* Numbers correspond to those of groups listed on pages 33-35.
PRECIPITATION

Table 5.- Precipitation, September to November, 1871-1954

Area*

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Average ( inohe s )

1871- 1871- 

1934 1902

10.41 11.02

9.34 10.15

10.70 11.35

8.32 8.31

9.21 9.36

10.50 10.86

5.24 5.02

8.06 7.40

8.40 7.98

3.20 3.19

2.45 2.22

2.44 2.32

18.42 19.20

2.12 2.45

1.68 1.80

1903- 

1934

9.80

8.14

10.04

8.32

9.06

10.15

5.46

8.71

8.83

3.21

2.68

2.56

17.63

1.80

1.57

Ratio last 32 

years to first 

32 years 

(percent)

89

80

88

100

97

93

109

118

111

101

121

110

92

74

87

Average for 10 

years ending 

1934 

( inches )

11.06

9.06

10.49

9.40

10.37

11.39

5.90

9.75

9.6S

3.08

2.33

2.69

18.00

1.90

1.80

Ratio last 10 years 

(percent)

To long-time 

average

106

99

98

113

113

108

113

121

115

96

95

110

98

90

107

To last 32 

years

113

111

104

113

114

112

108

112

109

96

87

105

102

106

115

Area*

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Maximum 10-year 

period

Inches

11.80

10.59

12.62

9.52

10.71

13.02

5.90

9.75

11.98

4.04

3.08

2.83

22.48

2.75

2.17

Date of 

ending

1897

1882

1885

1884

1889

1886

1934

1934

1927

1902

1920

1914

1900

1883

1892

.Minimum 10-year 

period

Inches

8.20

6.98

9.49

7.02

7.80

B.64

4.04

5.82

6.65

2.31

1.99

2.11

15.31

1.18

1.28

Date of 

ending

1917

1923

1910

1908

1917

1904

1897

1897

1912

1892

1893

1885

1925

1914

1899

Ratio last 10 years 

to minimum 10 years

(percent)

135

130

110

134

133

132

146

168

145

133

117

127

118

161

141

* Numbers correspond to those of groups listed on pages 33-35.
48 RAINFALL AND RUN-OFF IN THE UNITED STATES

(2) Except in the extreme East and the extreme V/est the average for the last 32 years has been above that for the first 32 years.

(3) Except in one area the trend is still upward, the precipitation for the last 10 years being above the average for the last 32 years 

in all areas except the Northern and Western Plains and, in general, averaging from 20 to 30 percent above the minimum 10-year average.

It is believed that the information disclosed by the study of 

seasonal trends indicates the great desirability for further study of the 

subject and the breakdown into months, especially with respect to the upward trend In fall precipitation compared with the generally declining 

trend in winter and summer precipitation, in order to determine whether 

more exact knowledge can be developed regarding these interesting relations.

Average monthly precipitation

The graphs of average monthly precipitation shown on figures 6 

to 10 are of interest in showing the marked differences in seasonal distribution. Special attention is called to the monthly distribution of rainfall in the interior States, from Missouri, Iowa, and Minnesota westward 

across the plains to the Rocky Mountains. The source of atmospheric water 

vapor from which rainfall is derived is evaporation from oceans, lakes, 

creeks, rivers, swamps, and other wet or moist surfaces, and transpiration 

by vegetation. Mead states (111, p. 164):

"The precipitation on the continental interior lands is, however, 

the phenomenon in which the engineers are more generally interested, and 

the source of this precipitation is derived most largely from moisture 

that obtains from the continental evaporation, from land surface, and from 

the surface of rivers, lakes, and swamp areas, and indirectly by the transpiration from animal and vegetable life."

There is a marked similarity between the graphs of monthly precipitation in these areas and the known evaporation and transpiration 

characteristics. In this connection the uniform rainfall distribution 

throughout the year in the areas shown for the New England States on figure 

6 is of interest. The graph of precipitation in that region bears little 

if any relation to the probable graph of continental evaporation and transpiration. The thought is suggested that if over broad areas air movements 

and air temperatures could be taken into consideration, a study of the
CHANGES IN TEMPERATURE 49

differences between the precipitation and the moisture put into the air 

through evaporation and transpiration might throw some light on the probable source or sources of precipitated moisture.

Such a study, if possible, would be valuable in continental 

areas such as the upper Mississippi River basin and the Red River Basin, 

where the decline in summer precipitation has been long continued, and 

where in certain instances steps are being taken to store and retard surface run-off in reservoirs.

Changes in temperature

Joseph B. Klncer (87) presents graphs and tables showing annual 

and seasonal changes in temperature recorded at several Weather Bureau 

stations in the United States and in foreign countries. He concludes that 

"the practically unanimous testimony of these graphs not only establishes 

the realness of these upward temperature trends but shows that they are 

operative on an extensive geographic scale."

As a companion to the study of changes in precipitation and a. 

continuation of the studies by Klncer, the 10-year progressive average 

temperatures nave been compiled for groups of stations situated in the 15 

areas used in the precipitation study. Figure ll shows the average of the 

10-year progressive averages for the stations in each of 15 groups.

Figures 12 to 16 show by groups the plotting of the 10-year progressive

\ 

averages for each station. The records used are those published in United

States Weather Bureau Bulletin W. Since 1889 the same basis of determining the mean annual temperature has been used - namely, the average of the 

daily maximum readings plus the average of the daily minimum readings 

iivided by 2. Prior to that date they may be on a somewhat different 

basis. The 10-year progressive average temperature at each station prior 

to 1889 was recomputed by the methods now used by the Weather Bureau and 

is shown by a dotted line on figures 11 to 16.

The study of temperature changes as summarized in table 6 indicates that in the country as a whole (a) the average temperatures for the 

last 52 years of record were greater than those for the preceding 32 years; 

(b) the average temperature for the 10-year period ending 1954 was nearly 

1.4° higher than for the first 52 years of record; (c) the average temperature for the last 10 years was the maximum 10-year average for the period 

of record; and (d) the average temperature for the last 10 years was 1.9° 

above that for the 10-year period of minimum temperature, which ended, in

5955 O S6 *
I*

Km

^

J

/

\

AV

/ V

J

v

......Corrected to oonformN

to present methods of 

computing average 

annual temperature. 

see p. 49.

,V wJ

/ 

Figure ll.-itMrag* of 10-y«ar progreMive annual temperature for groups 
CHANGES IN TEMPERATUItE
RAINFALL AND RUN-OFF IN THE UNITED STATES
Texas, Oklahoma Kansas, Missouri 

Ablleni 64

Amarillo 57

Oklahoma Oity 60

Amarillo, Tax*

Oklahoma Oity, Okie.

}

Dodge Oity 54

Oonooriia 54

St. Louis 56

-*^

A

J

Dodj

r*

7

0(

/

/

^

\ \

 e City, Kans.

Av

nsordi

'V

St.

\

V^

a, Kai

,A

Louis,

/^

V

/y

3*

/

H

/

Baoh Tertioal interval for the graphs represents 1°. A single temperat

Average monthly temperature Average monthly temper

Figure 14. Ten-year progressive average annual temperature and average mo
TIVJUIVH aw ^o-tuiH HI HHI oaiim saivis 
Southern California Horthern California, Weste

San Diego £2

Los Angeles £4

- >

V

Sa

^

*\

Los

X

i Dieg

^

Angel

r

I, Oal

"A/

33, oa

>v

.f.

r

uf. ^

A/

XSan Franolsoo 57

Bed Bluff 6Z

Reno 49

^

^

San

^

Bei

"\

B

V

?ranoi

^^

1 Bluf

^^

9no, N

/

/

800, G

,

^

'., Oal

^Vy_,

9V 

f~r\

t*s

ali

^

If,

,

/

Each vertical Interval fop the graphs represents 1°. A single tempera tu

Ayerage monthly temperatu Average monthly tempera

1I III i 11III J2i!l4

Figure 16.-Ien-yaar progressive average annual temperature and average mont
RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 6.- Annual temperature (°F.) 1871-1934

Area*

1

2

3

4

5

6

7

8

9 *-*

10

11

12 #

13 JfJf 14 n

15 ##

Area*

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

1871-1934

48.5

55.7

65.4

50.0

58.5

65.7

44.4

54.7

60.2

50.1

46.6

56.4

52.8

56.2

62.0

Average

1871-1902

48.3

55.4

65.3

50.0

58.3

65.6

44.0

54.3

59.8

49.8

46.4

56.4

52.6

55.8

61.6

Increase in lost 

10 years over

Long-time

average

1.0

1.2

.8

.6

1.9

.7

1.4

1.3

1.4

1.1

1.1

.8

1.0

1.4

1.3

First half

of period

1.2

1.5

.9

.6

1.1

.a

1.8

1.7

1.8

1.4

1.3

.8

1.2

1.8

1.7

1903-34

48.7

56.1

65.5

50.1

58.7

65.8

44.8

55.1

60.8

50.4

46.8

56.5

53.0

56.6

62.3

Inoreaae in last half over

first half of period

0.4

.7

.2

.1

.4

.2

.8

.8

1.0

.6

.4

.1

.4

.8

.7

MflTHmlim

10-year

average

49.5

56.9

06. 2

50.6

59.4

66.4

45.8

56.0

61.6

51.2

47.7

57.2

53.8

57.6

63.3

Date of

ending

1934

1934

1934

1934

1934

1934

1934

1934

1934

1934

1934

1934

1934

1934

1934

Minimum

10-year

average

47.9

55.1

64.8

49.4

57.9

65.0

43.4

53.7

59.4

49.2

46.0

55.8

52.2

55.2

61.3

Date of

ending

(1893

<1894

(1910

(1881

<1893

(1894

1910

1892

1893

1895

1892

1892

1895

1899

1884

1920

1902

1899

1881

10-year progressive average

ending 1934

49.5

56.9

66.2

50.6

59.4

66.4

45.8

56.0

61.6

51.2

47.7

57.2

53.8

57.6

63.3

Increase in last 

10 years over

minimum 10 years

1.5

1.8

1.4

1.2

1.5

1.4

2.4

2.3

2.2

2.0

1.7

1.4

1.6

2.4

2.0

* Numbers correspond to those of groups listed on pages 33-35.

*« Record available 1886-1934; divided 1886-1910, 1910-34.

# Record available 1874-1934; divided 1874-1904, 1904-34.

## Record available 1872-1934; divided 1872-1903, 1903-34.
CHANGES IN TEMPERATURE 57

general, in the 1890*3. Nearly all the stations used in the compilation 

of records in this report are located in cities where temperatures may be 

affected by conditions that do not exist in rural areas. Klncer (87) in 

connection with his study made a long-time comparison between three urban 

and three rural stations - namely, Lynchburg and Dale Enterprise, Va., 

Baltimore and Easton, lid., and Philadelphia and West Chester, Pa., - and 

found the changes at the rural stations were as pronounced as the changes 

at the nearby city stations. This phase of the question, however, should 

be given further study, because naturally if the increased temperature 

trends were confined entirely to urban areas they would have little significance in the problem under consideration. Further evidence that the 

increased temperature trends are widespread is presented by T. C. Main 

(105), who found by comparing 20-year progressive averages, increases of 

1.0° to nearly 4.0° P. in annual temperature since about 1880 at a group 

of stations in Alberta and Saskatchewan. In addition to such further 

studies as may be necessary to determine the extent to which temperature 

may have increased over broad areas embracing river basins, it is especially desirable in hydrologic studies that a complete breakdown of 

temperature records be made by seasons and possibly by months. Kincer 

presents seasonal graphs on the basis of 20-year averages for the two 

long-time temperature records in the eastern United States. The records 

at New Haven, Conn., beginning with 1781, and Washington^ D. C., beginning 

with 1817, showed that the largest changes occurred in the fall, winter, 

and spring and the least in the summer. A similar tendency is shown for 

Iowa temperature on the basis of 20-year progressive averages beginning in 

1892.

Although the temperature study outlined above is far from complete with respect to several phases, it seems to indicate conclusively 

that there has been an increase in temperature over wide areas in the 

United States, at least since the 1890's. It also seems reasonably certain 

that the increased temperatures may have operated with the decreased precipitation to create, in certain sections of the country, a condition that 

is increasingly unfavorable to the maintenance of water supplies, both in 

surface streams and in the ground. This condition is especially acute in 

the upper Mississippi Valley and Red River Valley, where, as will be shown 

later, the average annual losses through evaporation and transpiration so 

nearly equal the average annual precipitation that any changs which would
58 RAINFALL AND HUM-OFF IN THE UNITED STATES

tend to increase the losses would materially affect the amount of water 

available for stream flow and for replenishment of soil moisture and ground 

water.

Changes in run-off

The basins in which a detailed study of rainfall and run-off has 

been made are those of the Mississippi, Red, Merrimack, James, Chattahoochee, Tennessee, and Neosho Rivers. In addition the 10-year progressive 

average annual run-off for the following streams has been compiled and the 

results plotted on figure 17 for a study in connection with the similar 

graphs of precipitation and temperature:

Spokane River at Spokane, Wash., 1892-1934.

Willamette River at Albany, Oreg., 1895-1934.

Kings River at Piedra, Calif., 1896-1934.

San Gabriel River near Azusa, Calif., 1896-1934.

Snake River near Moran, Wyo., 1904-1934.

Colorado River at Lees Ferry, Ariz., 1851-1934.

The gage heights on Lake Superior, 1869-1934, were also compiled 

and plotted.

The run-off records have been corrected for storage. The early 

records at Lees Ferry were estimated by E. C. La Rue (92a).

A general comparison of the change for the comparatively short 

run-off records with the long-time precipitation and temperature records 

indicates clearly, it is believed, that any averages based on the run-off 

records available in most sections of the country might vary considerably 

from averages for, say, 100 years. This is a factor which naturally must 

be given serious consideration in connection with studies or plans based 

on the available records.
CHANGES IN RUN-OFF

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H DART

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T

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SoC6I 

It

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OE6I 

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put

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^

s

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Blwr antes llorta. naar o cg o> r-to lr. 

3 S 

I g g

~-~>

V

s

If

k£ A

Tillamett* I

at Albany,

x^-

C

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OS6t 

0261 

OT6T 

068T,

0

 ^^

eenoc

^

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^>

'^

^

9 UJ <

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Colorado Bivarat IiMaFerry. Ar

lam.

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i at jjo«nns
60 RAINFALL AND RUN-OFF IN THE UNITED STATES

Precipitation, temperature, and run-off, by basins

The changes in the precipitation and temperature already shown by 

geographic provinces are qualitative rather than quantitative. In the following presentation of the changes in precipitation, temperature, and runoff, by basins, it has been the aim to determine as accurately as possible 

the magnitude of the several factors. As would be expected, changes within 

a basin correspond roughly with the changes previously indicated for the 

particular geographic province or provinces in which the basin may be 

located.

The correlation of annual rainfall, temperature, and run-off 

based on long-time averages 'is necessarily confined to basins where (a) 

concurrent long-»time records are available, (b) the mean annual precipitation and temperature over the entire basin and run-off from the basin have 

been determined with a fair degree of accuracy, (c) the run-off has not 

been appreciably changed by storage or diversion, and (d) the precipitation 

exceeds the combined losses resulting from evaporation and transpiration.

These requirements limit the areas in the United States where 

studios of this type may be carried on. Many areas in the West cannot be 

studied, either because the prscipitation ovar ths basin as a whole is not 

accurately known or because storage and diversions are of such magnitude as 

to affect natural relations materially. Likewise in much of the plains 

area the annual evaporation and transpiration so nearly squal the annual 

precipitation that the residual run-off approaches zero.

Records showing annual precipitation, annual temperature, and 

annual run-off have been made and compiled for the following basins for the 

periods of record as Indicated:

Red River Basin above Grand Forks, N. Dak., 1882-1934.

Mississippi River Basin above Keokuk, Iowa, 1878-1934.

Neosho River Basin above lola, Kans., 1896-1903, 1918-34.

Merrimack River Basin above Lawrence, Mass., 188O-1934.

James River Basin above Carteraville, Va., 1899-1934.

Tennessee River Basin above Chattanooga, Term., 1881-1934.

Chattahoochee River Basin above West Point, Ga., 1897-1934.

As a basis for the preliminary study information for each basin 

has been compiled and is presented in tables 7 to 21. All precipitation 

and run-off data are stated in inches over the basin, and all figures are
PRECIPITATION, TEMPERATURE, AND RUN-OFF, BT BASINS 61

on the basis of the calendar year except those for the Merrimack River 

Basin, which are on the basis of the year ending September 30.

The precipitation, run-off, and precipitation minus run-off for 

each basin are presented In the form of graphs on figures 18 to 24.

Red River Basin above Grand Forks,, N. Dak. 

(Drainage area, 25,500 square miles. Records available, 1882 - 1934)

The Ottertall River, the head of the Red River, rises in the 

southwest corner of Clearwater County, Minn., at an altitude of about 1,550 

feet, and flows south and west to Wahpeton, N. Dak., whence the Red River 

flows north in a continuous series of short loops, forming the boundary between North Dakota and Minnesota. The basin is very flat, the slope from 

the sides toward the stream for distances of 5, 10, or 20 miles Is usually 

only a few feet to the mile, In places less than 2 feet to the mile, and 

the downward slope of the baein to the north is less than 1 foot to the 

mile, averaging 9 inches to the mile from Wahpeton, N. Dak., about 30 miles 

north of the southern boundars of the State, to Pargo, and 6|- Inches to the 

mile from Fargo to Grand Forks.

Run-off»- The gage-height record and a few discharge measurements 

from 1882 to 1901 were collected by the United States Corps of Engineers; 

since 1901 the United States Geological Survey has maintained the staff 

gage. The control which consists of clay and silt, shifts slightly, and 

the stage-discharge relations are affected by ice in winter and aquatic 

growths in summer.

The winter run-off prior to 1906, with the exception of 1898, 

1899, and 1900, was estimated by P. T. Simons, senior drainage engineer, 

United States Department of Agriculture, who aleo gave a table of monthly 

run-off from 1882 to 1919 (163). The figures for run-off since 1919 have 

been taken from the water-supply papers of the United States Geological 

Survey. All run-off figures are on the basis of the calendar year.
62 RAINFALL AND RUN-OFF IN THE UNITED STATES

Precipitation.- The precipitation records for 1882 to 1919 were 

taken from the paper by Simons (163), and those for 1920 to 1923 from a 

compilation by E. F. Chandler (25); those for 1924 to 1934 were computed 

by using the arithmetic average of the station records. For the early part 

of the period of record, when few stations were maintained, Simons calculated separately the average precipitation in each of five subdivisions of 

the basin and weighted these figures according to their respective areas to 

get the basin average. The precipitation stations used to compute the 

basin average were as follows:

Table 7.- Precipitation stations in Red River Basin 

above Grand Forks, N. Dak.

Station

Minnesota:

Angus #

Bemidji *

Campbell *

Crooks town »

Detroit Lakes *

Fergus Falls *

Fosston *

Gonvick

Moorhead *

Redby *

Thief River Falls *

Wheaton SiNorth Dakota:

Amenia *

Cooperstown

Devils Lake

Forman

Grand Forks *

Hillsboro *

Larimore *

Lisbon *

McLeod *

Maddock *

Manfred

Mayville *

Power

Sharon

Valley City *

Wahpeton *

Altitude 

(feet)

870

1,400

975

888

1,364

1,210

1,289

1,454

935

1,158

1,137

1,018

954

1,428

1,478

1,249

830

901

1,134

1,091

1,075

1,604

1,605

975

1,020

1,516

1,245

962

Period 

of 

record

1920-

1899-1905,1912-

1873-80,1912-

1890-

1896-

1888-

1910-

1922

1881-

1910-

1915-

1915-

1896-

1890-1907,1915-

1870-90,1897-

1892-

1892-

1906-

1893-

1904-

1912-

1915-

1903-

1896-

1892-1932

1924-

1905-

1892-

Mean annual 

precipitation 

(inches)

18.68

23.88

23.74

20.92

24.84

23.96

20.12

19.83

23.34

21.84

21.32

20.75

20.10

17.79

18.04

20.72

19.49

20.55

21.13

20.82

21.49

16.33

17.55

19.88

20.94

19.06

18.36

21.52

 » Station used to compute average basin temperature.

The figures for average annual precipitation over the basin 

subsequent to 1900, when from 22 to 28 stations fairly well distributed 

were used, should be fairly accurate. In 1882 there was on the average one 

station to about 8,500 square miles; in 1930, one to about 910 square miles.
PRECIPITATION, TEMPERATURE, AMD RUN-OFF, BY BASINS

Table 8.- Precipitation, temperature, and run-off data for 

Red River Basin above Grand Forks, N. Dak.

Year

1882

83

84

85

86

87

88

89

1B90

91

92

93

94

95

96

97

98

99

1900

01

02

03

04

05

06

07

08

09

1910

11

12

13

14

15

16

17

18

19

1920

21

22

23

24

25

26

27

28

29

1930

31

32

33

34

Total

Av.

Precipitation

(inches)

Annual

27.36

18.74

25.26

18.73

18.80

21.77

17.09

15.33

20.26

25.62

20.97

20.45

19.32

19.55

27.20

22.34

19.80

20.63

23.78

26.02

22.46

21.77

22.10

26.92

24.96

18.48

21.84

22.25

12.21

22.17

22.63

19.49

24.22

23.06

27.76

13.41

19.64

23.02

18.81

22.41

22.47

18.84

20.68

22.76

18.74

22.49

21.26

15.32

17.95

19.67

17.94

16.50

14.67

1108.42

20.91

Accumulated

27.36

46.10

71.36

90.09

108.89

130.66

147.75

163.08

183.34

208.96

229.93

250.38

269.70

289.25

316.45

338.79

358. 59

379.22

403.00

429.02

451.48

473.25

495.35

522.27

547.23

565.71

587.55

609.80

622.01

644.18

666.81

686.30

710.52

733.58

761.34

774.75

794.39

817.41

836.22

858.63

581.10

899.94

920.62

943.38

962.12

984.61

1005.87

1021.69

1039.64

1059.31

1077.25

1093.75

1108.42

_

-

Progressive 10-

year

average

_

_

-

-

-

-

-

-

20.90

20.26

20.43

19.83

19.92

20.76

20.81

21.08

21.61

21.97

22.01

22.16

22.29

22.56

23.30

23.08

22.69

22.90

23.06

21.90

21.52

21.53

21.30

21.52

21.13

21.41

20.90

20.68

20.76

21.42

21.44

21.43

21.36

21.01

20.98

20.08

20.99

21.15

20.43

20.34

20.07

19.62

19.38

18.78

_

-

Temperature at

Moorhead, Minn.

(°F.)

Annual

38.4

34.1

36.4

38.0

37.7

36.4

36.6

40.2

38.8

38.9

38.5

35.0

40.8

38.5

37.7

39.2

40.2

39.2

42.0

41.5

40.7

38.9

38.4

40.1

40.1

37.8

41.6

39.6

41.9

39.5

39.6

40.7

41.1

41.0

37.7

37.4

41.3

40.0

40.8

43.0

41.5

41.5

39.0

41.2

40.4

39.3

42.2

39.0

42.8

45.8

41.0

41.7

42.8

2107.5

39.8

Progressive 10-

year

average

_

-

-

-

-

_

_

_

_

37.6

37.6

37.7

38.1

38.2

38.2

38.4

38.8

38.7

39.0

39.3

39.5

39.9

39.6

39.8

40.0

39.9

40.0

40.1

40.1

39.9

39.7

39.9

40.2

40.3

40.1

40.0

40.0

40.0

39.9

40.3

40.5

40.5

40.3

40.3

40.6

40.8

40.9

40.8

41.0

41.3

41.2

41.2

41.6

_

-

Run-off at Grand Forks

(inches)

Annual

3.06

2.22

1.56

1.70

1.04

.56

1.50

.42

.44

.66

2.04

1.93

1.15

.45

1.85

3.05

.89

1.14

1.02

1.74

1.72

1.59

2.60

2.09

2.46

1.89

1.64

1.41

1.27

.39

.47

.74

.93

1.57

3.12

1.19

.52

1.18

1.69

.80

1.27

.70

.38

.71

.64

1.41

1.00

.80

.63

.18

.32

.21

.13

66.07

1.25

Accumulated

3.06

5.28

6.84

8.54

9.58

10.14

11.64

12.06

12.50

13.16

15.20

17.13

18.28

18.73

20.58

23.63

24.52

25.66

26.68

28.42

30.14

31.73

34.33

36.42

38.88

40.77

42.41

43.82

45.09

45.48

45.95

46.69

47.62

49.19

52.31

53.50

54.02

55.20

56.89

57.69

58.96

59.66

60.04

60.75

61.39

62.80

63.80

64.60

65.23

65.41

65.73

65.94

66.07

_

-

Progressive 10-

year

average

_

_

_

-

-

-

-

-

-

1.32

1.21

1.18

1.14

1.02

1.10

1.35

1.29

1.36

1.42

1.53

1.49

1.46

1.60

1.77

1.83

1.71

1.79

1.82

1.84

1.71

1.58

1.50

1.33

1.28

1.34

1.27

1.16

1.14

1.18

1.22

1.30

1.30

1.24

1.16

.91

.93

.98

.94

.83

.77

.68

.63

.60

_

-

Precipitation

minus run-off

(inches)

Annual

24.30

16.52

23.70

17.03

17.76

21.21

15.59

14.91

19.82

24.96

18.93

18.52

18.17

19.10

25.35

19.29

18.91

 19.49

22.76

24.28

20.74

20.18

19.50

24.83

22.50

16.59

20.20

20.84

10.94

21.78

22.16

18.75

23.29

21.49

24.64

12.22

19.12

21.84

17.12

21.61

21.20

18.14

20.30

22.05

18.10

21.08

20.26

15.02

17.32

19.49

17.62

16.29

14.54

1042.35

19.67

Progressive 10-

year

average

_

_

-

-

-

_

_

_

_

19.58

19.05

19.25

18.69

18.90

19.66

19.46

19.79

20.25

20.55

20.48

20.67

20.83

20.96

21.53

21.25

20.98

21.11

21.24

20.06

19.81

19.95

19.80

20.19

19.85

20.07

19.63

19.52

19.62

20.24

20.22

20.13

20.06

19.77

19.82

19.17

20.06

20.17

19.49

19.51

19.30

18.94

18.75

18.18

..

-

Ratio

run- Off

to

precipitation

10- year

progressive

average

(percent]

_

-

-

-

-

_

_

..

_

6.32

5.97

5.78

5.75

5.13

5.30

6.48

6.12

6.29

6.46

6.96

6.72

6.55

7.09

7.60

7.93

7.54

7.82

7.89

8.40

7.95

7.34

7.05

6.19

6.06

6.26

6.07

5.60

5.49

5.52

5.70

6.07

6.08

5.90

5.53

4.53

4.43

4.63

4.60

4.07

3.84

3.47

3.24

3.19

_

-
64 RAINFALL AND RUN-OFF IH THE TOUTED STATES

Ol Ol

(o) Annual and 10-year progressive average 

precipitation In Red River Basin

(d) Annual ami 10-year progressive average run-off

(e) Annual precipitation minus run-off 

10-year progressive average

21

19 19

Note 10-year average plotted at end of period shown thus 

Figure 18,-fielations between rainfall and run-off in Bed River Basin 

above Grand Forks, N. Dai.
PRECIPITATION, TEMPERATURE, AND RUN-OFF, BY BASINS 65

Differences In precipitation between one part of the basin and another 

probably result more from differences In geographic location than from differences In altitude. Such differences show a range from about 24.8 to 

16.3 Inches on the basis of long-time averages and from about 33.8 to 17.5 

inches on the basis of yearly figures. Precipitation generally Increases 

from west to east. The precipitation records are on the basis of the calendar year.

Temrara-cure.- The mean annual temperatures for the period of 

record at the stations In and adjacent to the basin were averaged and compared with the mean annual temperature recorded at Moorhead and found to be 

essentially the same. The Moorhead record of annual temperature was therefore used as an approximation of the average annual temperature for the 

basin. The stations in the basin averaged to compute the normal annual 

temperature for the basin are Indicated In the table of precipitation stations. The temperature records are on the basis of the calendar year.

Mississippi River Baaln above Keokuk, Iowa 

(Drainage area, 119,000 square miles. 

Records available, 1878-1934.)

The Mississippi River rises In an area of small lakes In northeastern Backer County, Mlnn., at about 1,570 feet above sea level, and 

flows In a general south and southeast course to Keokuk, Iowa. The major 

tributaries above Keokuk are the Minnesota, Iowa, and Skunk Rivers from the 

west and the St. Crolx, Chlppewa, Wisconsin, and Rock Rivers from the east.

That portion of the basin above St. Paul, an area of 35,700 

square mllea, is for the most part relatively flat and covered with glacial 

drift, Into which rainfall percolates rapidly. In this part of the basin 

there are numerous swamps and lakes. The precipitation in this area of 

35,700 square miles ranges from an average of about 28 Inches a year In the 

southeastern part to about 23 inches along the northwestern border and 

averages about 26.5 Inches.

The middle portion of the basin, between St. Paul and Le Claire, 

comprising 52,900 square miles, Is also covered with glacial drift. The 

topography is rougher, however, with increasing slopes toward the river 

courses. The precipitation on this area averages about 31.2 Inches a year. 

69S5 O 35 5
66 RAINFALL AND RUN-OFF IN THE TWITED STATES

The precipitation on the remainder of the Mississippi River Basin 

above Keokuk, comprising a V - shaped area of 30,400 square miles, covered 

mostly with alluvial soil, averages 33.0 inches a year.

The fall of the river for about the first 600 miles averages 

about 1.3 feet to the mile, and the fall in the lower part of the river, 

from St. Paul to Keokuk, averages between 0.4 and 0.5 foot to the mile.

Run-off.- All the records of flow available for Keokuk prior to 

1913 have been based on readings of a gage at the upper lock of the canal, 

at a place then called "Nashville," now Galland, Iowa, about 8 miles above 

Keokuk. The gage was founded on a rock and was read twice daily from 1878 

to the time when it was drowned out by backwater from the Keokuk Dam, in 

1913. The rock bed of rapids below the Nashville gage furnished an excellent control, which is permanent for all stages. Records subsequent to 

1913 have been computed as the sum of the flow through the turbines and 

over the spillways of the power development of Keokuk. All records of flow 

have been computed and compiled by the Mississippi River Power Co.

There are numerous hydroelectric power developments and several 

storage reservoirs on the main streams and tributaries, but it is believed 

that their combined effect on the annual discharge is very small.

Precipitation.- The average annual precipitation ranges from 

about 25 to 35 inches across the basin. The estimates of annual precipitation over the basin probably increase rather rapidly in accuracy from 1878 

to 1900 and should be reasonably accurate and consistent from 1900 to date. 

Prior to 1900, but more especially prior to 1890, not only were the precipitation stations few but their distribution was poor, especially in Wisconsin. The number of precipitation stations available in determining the 

annual precipitation over the basin was as follows:

1871 - 18 stations 1910 - 178 stations 

1878 - 40 stations 1920 - 178 stations 

1890 - 63 stations 1930 - 181 stations 

1900 - 144 stations

The precipitation stations used to compute the basin average were as 

follows:
PRECIPITATION, TEMPERATURE, AND RUN-OFF, BY BASINS 67

Table 9.- Precipitation stations in or near 

Mississippi River Basin above Keokuk, Iowa

Station

Illinois :

Aledo

Dixon

Elgin

Freeport

Galena

Galesburg

Galva

Geneseo

La Harpe

Marengo

Monmouth

Morris on

Mount Carroll

Oregon

Paw Paw

Rochelle

Rockford

Sycamore

Walnut

Iowa:

Allison

Anmng

Ames

Baxter

Belle Plaine

Belmond

Bonaparte

Boone

Britt

Burlington

Cedar Rapids

Charles City

Clinton

Columbus June t i on

Davenport

Decorah

Delaware

Dubuque

Elkader

Falrfleld

Fairport

Farmersburg

Fayette

Forest City

Fort Madison

Grinnell

Grundy Center

Hampton

Independence

Iowa City

Iowa Falls

Keokuk

Lansing

Maquoketa

Altitude 

(feet)

739

696

717

762

603

758

849

639

691

819

763

670

817

702

928

798

720

840

714

1,000

721

926

993

866

1,181

563

894

1,236

544

737

1,015

595

595

580

872

1,083

700

751

780

600

1,079

1,003

1,226

522

1,031

976

1,142

956

733

1,127

614

632

692

Period 

of 

record

1901-

1887,1892-

1898-1900,1911-

1886-89,1909-

1896-1901,1928-

1862-71,1885-89

1895-1909,1927-

1865-69, 1873-88, 1893-

1873-82,1886-87

1895-1908,1925-

1895-

1856-

1894-

1896-

1887-91,1895-

1893-94,1896,1910-

1913-

1924-

1874-

1882-

1892-

1914-

1876-1915

1876-

1899-1932

1876-

1909-

1886-89,1891-

1871-81,1894-

1876,1879-89,1897-

1876-82,1897-

1882-

1875-

1865-71,1878 

1879-87,1900-

1871-

1844-46 , 1878-83, 1892-

1854-58,1875-1921,1930-

1851-

1872-1920

1856-59,1876-88

1891-1902,1908-

1921-30

1836-1930

1888-

1887-89,1894-

1848-1918

1876,^878,1880-83

1888-90,1893-

1891-

1877-81 , 1888-1915 , 1924-32

1860-

1857-

1863-72,1892-

1871-

1896-1904,1912-32

1876 , 1878-84 , 1887-90

1892-93,1896-1906

1914-20,1925-

Mean annual 

precipitation 

(inches)

33.87

33.19

32.67

32.69

32.07

35.45

33.12

34.55

36.38

33.11

34.51

34.07

33.97

32.17

32.51

36.15

34.64

34.63

33.60

30.72

33.32

30.58

31.73

34.25

32.18

33.52

32.88

28.14

36.63

31.22

31.49

35.76

34.15

32.14

32.96

33.53

32.90

32.80

36.21

35.83

31.67

34.04

29.33

36.58

34.43

32.86

33.76

32.87

36.22

33.85

32.64

32.47

33.62
68 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 9.- Precipitation stations In or near 

Mississippi River Basin above Keokuk, Iowa Continued

Station

Iowa Continued.

Marshalltown

Mason City

Monroe

Mount Pleasant

Muscatine

New Hampton

Northwood

Oelwein

Olin

Osage

Oskaloosa

Ottumwa

Pella

Postville

Sigourney

Stockport

Tipton

Toledo

Washington

Waterloo

Waverly

Webster City

Whitten

Williams-burg

Minnesota:

Albert Lea

Ah-gwa-ohing *

Alexandria

Artichoke Lake

Bagley

Beards ley

Bemidji

Bird Island

Brainerd

Caledonia

Canby

Cass Lake

Chatfield

Collegeville

Detroit Lakes

Pairbault

Fairmont

Farminston

Fergus Falls

Fort Ripley

Glencoe

Gonvick

Grand Meadow

Hinckley

Hutchison

Itasca State Park

Lake Crystal

Leach Lake Dam

Little Falls

Long Prairie

Lynd

Mankato

Altitude 

(feet)

947

1,148

922

730

546

1,169

1,222

1,036

750

1,163

835

649

850

1,192

785

747

806

847

757

854

936

1,042

1,036

805

1,229

1,336

1,391

1,075

1,438

1,090

1,400

1,039

1,215

1,179

1,243

1,323

975

1,242

1,364

1,003

1,240

902

1,210

1,136

1,006

1,454

1,338

1,050

1,040

1,500

990

1,301

1,115

1,229

1,175

773

Period 

of 

record

1876-88,1891-

1887-89 , 1893-19OO, 1903-

1911-

1876-

1846-

1897-

1896-

1923-

1898-

1876-1916,1925-

1876-

1876 , 1878-80 , 1884-86 , 1894-

1898-1903, 1905-25, 1927-28

1891-

1896-

1901-

1876-80 , 1891-94 , 1901-

1894-

1875-

1876-88,1895-

1878-81,1887-89,1896-

1870 , 1876-81 , 1885-94

1896-1900,1905-

1897-1920

1916-

1886 , 1892-1900 , 1902-

1908-13,1916,1919-

1888-

1918-

1907-16

1894-1907 , 1915-24 , 1928-

1912-19,1922-

1885-86,1892-

1889 , 1899-1902 ,1912-

1890-1908 , 1911-14 , 1918

1917 , 1919-24 , 1926 , 1929-31

1908-

1914-27

1893-

1896-

1897-98 , 1900-10 , 1914-

1887-

1888-1918,1920-22,1924-

1888-

1889-94,1907-

1894-1910,1912,1915-17

1922-

1886-

1910, 1914-15 , 1917-21

1893-99,1917-20

1912-14, 1916-18, 1921-

1912,1914-15,1917-18

1888-

1908-9, 1914, 1917 , 1921-

1893-1908 , 1910 , 1917

1893-1927

1867-91,1905-

Mean annual 

precipitation 

(inches)

31.99

29.56

34.04

34.15

36.72

31.74

33.46

32.70

34.21

30.75

31.12

33.16

30.86

33.6.1

33.18

34.34

34.80

32.87

33.14

31.21

31.69

30.13

31.49

33.24

29.20

22.52

22.98

18.96

22.78

22.56

23.88

24.18

23.37

32.08

25.34

21.95

29.81

22.88

24.84

25.84

28.10

27.23

23.96

21.30

25.51

19.83

31.66

25.85

25.54

22.61

29.61

25.20

24.24

24.26

25.15

27.79

* Formerly known as State Sanitarium.
PRECIPITATION, TEMPERATURE, AND ROT-OFF, BY BASINS 69

Table 9.- Precipitation atationa in or near 

Mississippi Rive.i" Basin above Keokuk, Iowa Continued

Station

Minnesota Continued.

Maple Plain

Milaca

Milan

Minneapolis

Montevideo

Moose Lake

Mora

Morris

New London ""*

New Richland

New Ulm

Northfield

Ortonville

Park Rapids

Pine River Dam

Pipe stone

Pokegama Falls

Redby

Red Lake Falls

Red Wing

Redwood Falls

Reeds

Rochester

St. Charles

St. Cloud

St. Paul

St. Peter

Sandy Lake Dam

Stillwater

Taylor Falls

Tracy

Wadena

Waseca

Willmar

Windom 

Winnebago

Winnibigoshish Dam

Wlnona

Zumbrota

South Dakota:

Brookings

Milbank

Roslyn

Watertown

Webster

Wisconsin:

Amery

Antigo

Baraboo

Altitude 

(feet)

1,025

1,072

955

918

900

1,085

1,001

1,170

1,215

1,180

791

916

990

1,426

1,251

1,710

1,280

1,158

1,001

680

1,050

681

991

850

1,020

837

825

1,254

694

759

1,403

1,350

1,153

1,135

1,556 

1,000

1,515

700

917

1,628

1,142

1,813

1,754

1,841

1,070

1,489

854

Period 

of 

record

1892-1907,1915-

1898-1900,1903-5

1908-9,1917-

1894

1856-59,1866-

1890-99,1901-

1899-1902,1904-5,1915-17

1905-

1886-1917,1920-

189S1902-6 , 1908-12, 1914-18

1865-77,1894-

1882-92

1888-1908

1885-87,1893-

1887-

1899-1903,1906-13

1916,1921-

1888-

1910-12 , 1914-15 ,1917-

1915-21,1923,1925

1927-30,1932-

1886-1919,1931-

1888-94,1907-11

1916-19,1921-

1893-1919,1931-

1909-19,1929-

1890-1901,1904-22

1893-1914,1916-18,1921-

1836-1932

1888-91 , 1894-1909 ,1912

1914-16,1919-

1895-1909,1911-

1908,1810-18

1908-9,1912-15,1917-

1888-90,1914-

1905-6,1921, 1924-28

1951,1934

1916-

1893-1900,1917-

1893,1908-10,1914-15,1917 

1895-1917,1920-

1888-

1886 , 1893-99 , 1902-26

1928-29,1931-

1894-96,1904-10

1912-19,1921-

1889-

1890-

1899-1902,1906-19

1895,1895-

1896,1899-1905

1906-19,1921-

1922-

1894-

1892-94,1914-21

Mean annual 

precipitation 

( inches )

29.91

25.44

23.23

27.66

23.41

27.73

26.47

23.57

22.75

29.61

29.40

29.94

23.60

24.65

25.75

23.34

24.90

21.84

21.37

29.24

24.73

28.84

28.16

30.62

26.62

27.27

26.74

24.99

29.92

26.27

22.36

24.16

28.04

24.03

27.50 

28.50

24.67

50.29

27.47

20.18

23.31

21.84

21.11

22.22

26.81

29.55

35.72
70 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 9.- Precipitation stations in or near 

Mississippi River Basin above Keokuk, Iowa Continued

Station

Wisconsin Continued.

Barren

Beloit

Big St. German Dam

Brodhead

Burnett

Coddington

Crandon

Danbury

Darlington

Deerskin Dam

Dele van

Dodgeville

Downing

Eau Claire

Grantsburg

Hancock

Hafcfield

Hayward

Hillsboro

Koepenick

La Crosse

Lake Mills

Lancaster

Long Lake

Madison

Marshfield

Ma the r

Mauston

Meadow Valley

Medford

Menomonee Palls

Merrill

Milwaukee

Minocqua

Mondovl

Mount Horeb

Muscoda

Nelllsville

New Richmond

Osceola

Park Palls

Portage

Port Edwards

Prairie du Chien

Prairie du Sac

Prentice

Racine

Reedsburg

Rest Lake

Rhine lander

Rlchland Center

River Palls

Shullsburg

Solon Springs

Spooner

Stanley

Stevens Point

Sugar Camp Dam

Tomahawk

Twin Lakes Dam

Vlroqua

Vudesare

Altitude 

(feet)

1,115

750

1,590

812

880

1,074

1,650

908

867

1,685

920

1,220

983

800

1,095

1,086

973

1,197

980

1,681

714

847

1,060

1,592

974

1,250

962

882

974

1,420

842

1,267

681

1,604

758

1,226

666

1,060

990

806

1,492

809

969

628

750

1,551

633

876

1,600

1,560

73&

902

1,019

1,083

1,104

1,082

1,113

1,580

1,450

1,625

1,281

1,600

Period 

of 

record

1891-1921

1850-

1910-

1898-

1904-

1921-

1891-1905,1907-19

1920-

1901-5,1910-

1910-

1887-1905,1907-21

1897-1905,1914-16

1891-95,1898-

1891-

1889-90,1892-

1892-

1894-

1890-1923

1891-

1891-1918,1920-24

1873-

1891-

1891-1918,1921-

1908-

1869-

1915-

1905-

1896-1919,1924-

1891-

1890-

1909-15

1906-

1841 , 1844-52 , 1854-

1904-

1908-

1904-20

1909-19

1876-86,1890-

1905-17

1891-20

1910-

1889-

1910-19

1837-45,1891-

1908^

1898-

1897-

1914-19

1910-

1908-

1892,1908,1920-

1918-

1906-18

1906-

1894-

1903-

1893-

1910-20

1913-24

1910-20

1890-

1908-17

Mean annual 

precipitation 

(Inches)

31.36

33.18

30.19

33.71

29.34

29.90

28.01

26.45

32.72

29.82

30.65

31.53

31.49

32.63

30.11

30.76

30i27

28.69

32.17

31.54

30.81

32.84

31.58

29.31

31.98

31.47

32.10

31.88

29.42

32. 9a

34.19

30.88

30.08

29.71

31.96

34.12

30.38

33.26

29.38

30.72

32.98

31.15

32.73

30.96

28.50

31.99

30.81

32.26

30.48

29.67

31.48

29.73

35.77

28.19

27.54

33.55

31.94

30.03

31.03

27.46

33.16

31.72
PRECIPITATION, TEMPERATURE, AND RTJH-OPP, BY. BASIHS 71

Table 9.- Precipitation stations in or near 

Mississippi River Basin above Keokuk, Iowa Continued

Station

Wisconsin Continued.

Watertown

Waukesha

Wausau

West Bend

Weyerhauser

Whitehall

Williams Bay

Wisconsin Dells

Wisconsin Rapids

Altitude 

(feet)

824

864

1,247

941

1,337

675

1,025

900

1,036

Period 

of 

record

1891-

1892-

1896-1900,1902-

1895-1902,1922-

1895-96,1907-

1891-92,1895,1897-1906

1910-17,1919-20

1903-

1922-

1893-97,1903

Mean annual 

precipitation 

( inche s )

32.45

31.19

32.11

30.00

31.91

30.21

31.96

30.19

30.89

During the period 1871-77, 18 precipitation stations were usedj 

the records for 11 stations in the southern section, controlling 26.2 percent of the area, were averaged, and those for the remaining 7 stations 

were weighted according to area. The figures for Twin Cities and Duluth 

were modified according to their relation, during the period 1921-30, to 

the average for the stations lying within the areas controlled by Minneapolis, St. Paul, and Duluth. The same method was used for the period 

1878-85, the records for 29 stations in the southern section, controlling 

29.3 percent of the area, being averaged, and those for the remaining 11 

stations weighted according to area, Twin Cities, Duluth, and Neillsville 

being modified as stated above.

]'rom 1886 to 1934 the records for the stations lying within the

boundaries

that part of the area of the State lying in the Mississippi River drainage 

basin, in percentage of the area of the basin above Keokuk; from these 

weighted averages the average annual precipitation for the basin was determine d..

^emperature.- Seven stations with long records and well distribor each State were averaged, and this average was weighted as to

uted over 1;he basin were selected, and their records were averaged to 

determine the average annual temperature of the basin. These seven stations are Listed in table 11.
RAIHFALL AHD ROT-OFF IN THE OTITED STATES

Table 10.- Freclpltatlon, temperature, and run-off data for 

Mississippi River Basin above Keokuk. Iowa

Tear

1878

19

1880

81

82

83

84

85

86

87

88

89

1890

91

92

93

94

95

96

97

98

99

1900

01

02

03

04

05

06

07

08

09

1910

11

12

13

14

15

16

17

18

19

1920

21

22

23

24

25

26

27

28

29

1930

31

32

33

34

Total

AT.

Precipitation

(Inches)

Annual

30.60

31.74

33.15

41.28

31.49

30.47

34.33

27.82

26.96

97.92

28.00

23.27

29.82

26.79

34.76

27.56

23.77

23.56

32.93

27.30

28.46

29.94

32.87

24.17

35.22

34.65

29.09

34.21

32.83

29.09

31.36

32.79

18.24

34.53

27.67

29.86

31.04

33.67

31.46

25.89

29.87

32.43

28.87

29.53

26.92

24.93

30.27

27.69

31.28

29.73

31.63

26.61

25.40

28.64

26.42

24.63

26.57

1682 .IB

29.51

Accumulated

30.60

62.34

95.49

136.77

168.26

198.73

233 .06

260.88

287.84

315.76

343.76

367.03

396.85

423.64

458.40

485.96

509.73

533.29

566.22

593.52

621.98

651.92

684.79

708.96

744.18

779.03

808.12

842.33

875.16

904.25

935.61

968.40

986.64

1021.17

1048.84

1078.70

1109.74

1143.41

1174.87

1200.76

1230.63

1263.06

1291.93

1321.46

1348.38

1373.31

1403.58

1431.27

1462.55

1492.28

1523.91

1550.52

1575.92

1604.56

1630.98

1655.61

1682.18

_

-

Progressive 10-

year

average

_

_

_

_

_

_

_

31.58

31.32

30.47

30.14

28.69

29.01

28.72

27.67

27.24

27.84

27.78

27.82

28.49

28.79

28.53

28.68

29.31

29.84

30.90

30.89

31.07

31.36

31.65

30.19

31.22

30.47

29.97

30.16

30.11

29.97

29.65

29.30

29.47

30.53

30.03

29.95

29.46

29.38

28.79

28.77

29.15

29.33

28.75

28.40

28.31

28.26

28.23

27.86

-

Temperature *

(°F.)

Annual.

48.6

45.4

45.4

46.0

46.2

42.3

43.6

42.6

44.3

43.5

42.5

45.7

45.0

45.0

43.8

42.5

47.0

44.5

45.3

45.0

45.8

44.9

46.7

45.9

45.6

44.4

43.1

44.6

45.6

43.7

46.4

44.6

46.2

45.9

43.5

46.1

45.7

45.3

43.9

41.4

45.6

45.3

45.1

48.4

46.5

45.7

43.1

45.3

44.1

44.8

46.0

43.3

46.9

50.5

45.6

46.8

47.4

8573.9

45.2

Progressive 10-

year

average

_

_

_

_

_

.

_

_

44.8

44.2

44.2

44.2

44.1

43.8

43.9

44.2

44.4

44.5

44.6

45.0

44.9

45.1

45.1

45.3

45.5

46.1

45.1

45.2

45.0

45.1

45.1

45.0

45.0

44.8

45.0

45,2

45.3

45.1

44.9

44.8

44.9

44.8

45.0

45.3

45.3

45.0

45.0

45.1

45.4

45.4

45.2

45.4

45.6

45.5

45.6

46.1

-

Run-off at Keokuk

{ Inches )

Armnnl

6.96

5.49

8.59

13.19

10.92

9.11

9.34

8.99

7.57

5.88

9.61

4.65

6.16

5.29

9.07

7.20

5.53

3.49

5.41

7.77

4.87

6.65

6.55

5.55

7.12

10.73

7.49

9.44

9.94

9.01

8.19

8.36

4.74

5.75

7.10

6.07

5.77

8.62

9.41

6.76

5.96

8.11

7.55

5.48

6.44

4.48

6.03

4.21

6.38

7.92

8.17

7.77

4.47

3.62

5.04

4.70

3.12

397.79

6.98

Accumulated

6.96

12.45

21.04

34.23

45.15

54.26

63.60

72.59

80.16

86.04

95.65

100.30

106.46

111.75

L20.82

128.02

133.55

137.04

142.45

150.22

155.09

161.74

L68.29

173.84

180.96

191.69

199.18

208.62

218.56

327.57

235.76

244.12

248.86

254.61

261.71

267.78

373.55

282.17

291.58

298.34

304.30

312.41

319.96

325.44

331.88

336.36

342.39

346.60

352.98

360.90

369.07

376.84

381.31

384.93

389.97

394.67

397.79

_

-

Progressive 10-

year

average

_

_

_

_

_

8.60

8.87

8.78

8.54

7.75

7.57

7.38

7.00

6.44

6.23

6.42

5.94

6.14

6.18

6.21

6.01

6.37

6.56

7.16

7.61

7.74

8.07

8.24

8.06

8.08

8.08

7.61

7.44

7.36

7.30

7.08

6.85

6.83

7.11

7.08

7.02

6.86

6.88

6.44

6.14

6.26

6.48

6.44

6.14

5.95

5.81

5.83

5.54

_

-

Precipitation

minus run-off

( Inches )

ApTynni

23.64

26.25

24.56

28.09

20.57

21.36

24.99

18.83

19.39

22.04

18.39

18.62

23.66

21.50

25.69

20.36

18.24

20.07

27.52

19.53

23.59

23.29

26.32

18.62

28.10

24.12

21.60

24.77

22.89

20.08

23.17

24.43

13.50

28.78

20.57

23.79

25.27

25.05

22.05

19.13

23.91

24.32

21.32

24.05

20.48

20.45

24.24

23.48

24.90

21.81

23.46

18.84

20.93

25.02

21.38

19.93

23.45

1284.39

22.53

Progressive 10-

year

average

_

_

_

w

_

_

_

22.98

22.45

21.69

21.60

20.94

21.44

21.34

20.67

20.80

21.61

21.36

21.88

22.35

22.61

22.32

22.57

22.94

23.28

23.74

S3. SB

23.33

23.29

23.41

22.13

23.14

22.39

22.36

22.72

22.75

22.67

22.57

22.65

22.64

23.42

22.95

22.93

22.60

22.50

22.35

22.63

22.89

22.85

22.31

22.26

22.36

22.45

22.40

22.32

^

-

Ratio

run-off

to 

precipitation

10-year

progressive

average

( percent )

.

_

-

-

.

-

-

-

.

27.2

28.3

28.8

28.3

27.0

26.1

25.7

25.3

23.7

22.4

23.1

21.4

21.6

21.5

21.8

21.0

21.7

22.0

23.2

24.6

24.9

25.7

26.1

26.7

25.9

26.5

25.4

24.7

24.4

24.3

23.9

23.2

23.2

23.3

23.6

23.4

23.3

23.4

22.4

21.4

21.4

22.1

22.4

21.6

21.0

20.6

20.6

19.9

_

-

* Stations used to compute average temperature over the baain are given In table 11.
PRECIPITATION, TEMPERATURE, AND RUN-OFF, BY BASINS

$ 8 § £ 2

(a) Annual and 10-year progressiv 

average precipitation at St. Louis, Ho

(b] Annual and 10-year prograaslre 

average preotpltetlon at St. Paul, Hlnn

(o) Annual and 10-year progressive average preolplta

in Mississippi River Baa

sslve average run-off

(e) Annual precipitation minus rent-off, 

10-year progressive average

Rote 10-year average plotted at end of period shown tons 

Figure 19. Relations between rainfall and run-off in Mississippi Biver Basin above 

Keolculc, Iowa.
74 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 11.- Temperature stations in or near 

Mississippi River Basin above Keokuk, Iowa

Station

Iowa:

Dubuque 

Keokuk

Minnesota:

Duluth 

Moor he ad 

St. Paul

Wisconsin:

La Crosse

Madison

Altitude 

(feet)

700

614

1,135 

935 

837

714 

974

Period 

of 

record

1851- 

1872-

1871- 

1881- 

1820-1932

1873- 

1869-

Mean annual 

temperature 

(°F.)

48.1 

52.2

58.0 

39.2 

44.2

46.2 

45.8

Neosho River Basin above lola, Kans.

(Drainage area, 3,800 square miles. Records

available, 1895-1903, 1918-54.)

The Neosho River rises in the north-central part of Morris 

County, Kans., at an altitude of about 1,500 feet, and flows in a general 

southeasterly direction to lola, Kans., a distance of about 120 miles. In 

this distance the average fall is about 4 feet to the mile. The average 

width of the basin is about 30 miles. The Neosho River drains a rich agricultural territory which is in a good state of cultivation.

Run-off.- For the period October 12, 1917, to December 31, 1934, 

a water-stage recorder was located Z\ miles south and l£ miles west from 

lola, Alien County, half a mile below Elm Creek and 8 miles above Owl 

Creek. From August 1, 1895, to November 30, 1903, there was a staff gage 

4 miles downstream from the present location. The drainage area for this 

early period as printed was 3,670 square milesj the figure 3,800 square 

miles was considered a correction to the original measurement.

From 1895 to 1903 the United States Geological Survey published 

daily gage heights, rating table, and a summary of monthly discharges. The 

records of daily discharge for this period are published in "Surface water 

of Kansas, 1895-1919," by the State of Kansas Water Commission, 1920. Since 

October 1917 the United States Geological Survey has published records of 

daily and monthly discharge. The low-water flow is regulated to a slight
PRECIPITATION, TEMPERATURE, AND RUN-OFF, BY BASINS 75

extent by dams upstream. The stage-discharge relation for the later period 

is practically permanent, and the records are considered good. The control 

for the earlier record was composed of gravel and shifted somewhat, but 

three to five discharge measurements were made each year to define the 

rating, and the records were considered fair to good. The records here 

used are for the calendar year.

Precipitation.- The average annual precipitation over the basin 

was computed by averaging the annual records at all the precipitation stations in and adjacent to the basin. These stations are listed below.

Table 12.- Precipitation stations In or near 

Neosho River Basin above lola, Kans.

Station

Kansas :

Bazaar

Burlington *

Council Grove

Elmdale

Emporia *

Eskridge

Garnett

Herrington

He ss ton

lola

Lebo «

Le Roy

Lindsborg

Marion

McPherson *

Neosho Rapids

Newton *

Osage City *

Yates Center

Altitude 

(feet)

1,260

1,010

1,234

1,195

1,138

1,412

1,046

1,328

1,483

984

1,138

990

1,333

1,310

1,495

1,092

1,454

1,081

1,068

Period 

of 

record

1902-3,1905-

1894-

1909-

1925-

1881-

1907-

1906-14,1918-

1918-

1923-

1906-

1887-

1909-

1911-23,1930-

1908-

1877,1889-

1906-

1897-

1897-1912,1914-

1880-1921,1923-28

Mean annual 

precipitation 

(inches)

31.36

36.52

30.89

30.46

33.17

35.29

37.95

31.15

32.08

37.65

35.59

36.34

26.98

31.31

30.66

33.27

31.73

33.99

35.96

* Station used in 1897 along with Yates Center.

The accuracy of the computed average precipitation probably increases rather rapidly from 1904 to 1908 and is probably .good thereafter. 

Differences in precipitation between one part of the basin and another 

probably result more from differences in geographic location than from differences in altitude. Such differences showed a range from about 27.0 to 

38.0 inches on the basis of the long-time average, and the maximum range 

in 1912 was from about 21.1 to 47.9 inches. The records are on the basis 

of the calendar year.
RAINFALL AMD RUN-OFF IN THE UNITED STATES

Table IS.- Precipitation, temperature, and run-off data for 

Neoaho River Basin above lola, Kang.

Tear

1896

97

98

99

1900

01

02

OS

04

05

06

07

08

09

1910

11

12

13

14

15

16

17

18

19

1920

21

22

23

24

25

26

27

28

29

1930

31

32

55

34

Total

Av.

Preolpltatlon

( Inches)

Annual

34.09

24.76

42.49

32.49

38.82

23.66

47.09

40.78

41.02

34.85

32.40

33.45

41.20

39.18

27.90

27.71

31.67

28.67

29.02

48.74

35.73

24.38

31.33

26.84

31.63

28.59

39.14

34.75

30.23

29.73

36.09

42.94

41.12

34.86

27.71

32.26

29.41

25.89

26.76

1309.37

33.57

Accumulated

34.09

68.85

101.34

133.83

172.65

196.31

243.40

284.18

325.20

360.05

392.45

425.90

467.10

506.28

534.18

561.89

593.56

622.23

651.25

699.99

735.78

760.10

791.42

818.26

849.89

878.48

917.62

952.37

982.60

1012.33

1048.42

1091.36

1132.48

1167.34

1195.05

1227.31

1256.72

1282.61

1309.37

_

-

Progressive 10-

year

average

_

-

_

-

-

.

35.52*

_

36.01

35.84

36.71

36.58

37.25

36.15

36.56

35.02

33.81

32.61

33.99

34.33

33.42

32.43

31.20

31.57

31.66

32.41

33.01

33.14

31.23

31.27

33.13

34.11

34.91

34.52

34.88

33.91

33.02

32.66

-

Temperature at

Wlohlta, Kans.

 Inus 1° (OP.)

Annual

57.0

56.2

54.6

54.7

56.4

56.3

54.7

54.3

55.2

54.2

54.5

55.6

56.2

55.0

56.4

56.4

53.3

55.6

56.3

54.4

54.8

53.6

55.4

54.5

54.8

58.2

56.2

55.9

53.9

56.3

5S.1

55.4

56.1

54.0

56.2

58.3

55.8

58.9

58.7

2169.4

55.6

Progressive 10-

year

average

_

-

_

_

_

_

_

_

_

55.4

55.1

55.1

55.2

55.2

55.2

55.3

55.1

55.2

55.4

55.4

55.4

55.2

55.1

55.1

54.9

55.1

55.4

55.4

55.2

55.4

55.4

55.6

55.6

55.6

55.7

55.7

55.7

56.0

56.5

-

Run-off at lola

(Inches)

Annual

4.74

1.51

8.01

4.01

5.71

3.65

12.27

12.40

-

-

-

_

_

-

_

_

-

_

_

.

_

1.52

4.37

1.41

1.79

6.67

5.51

2.67

1.95

6.08

11.50

8.78

7.08

2.13

2.69

3.24

1.37

1.04

70.00*

4.12"1

Accumulated

4.74

6.25

14.26

18.27

23.98

27.63

39.90

52.30

.

_

-

_

»

_

-

.

_

-

_

_

_

_

1.52

5.89

7.30

9.09

15.76

21.27

23.94

25.89

31.97

43.47

52.25

59.33

61.46

64.35

67.59

68.96

70.00

_

-

Progressive 10-

year

average

.

-

-

-

-

-

6.54*

-

-

-

.

_

_

-

_

_

-

_

-

_

_

-

-

-

-

-

..

_

4.35

5.07

5.34

5.42

5.53

5.18

4.77

4.61

_

-

Precipitation

minus run-off

(Inches)

Annual

29.35

23.25

34.48

28.48

33.11

20.01

34.82

28.98

-

-

-

_

..

_

-

_

-

.

-

-

-

29.80

22.47

30.28

26.80

32.47

29.24

27.56

27.78

30.01

31.44

32.34

27.78

25.58

29.37

26.17

24.52

25.72

479 .27i!

28.19#

Progressive 10-

year

average

_

-

-

-

-

-

28.98*

-

_

-

_

_

_

-

_

_

_

_

_

_

.

.

-

-

-

-

-

-

_

28.78

29.03

29.56

29.10

29.36

28.73

28.26

28.07

Ratio

run-off

to

precipitation

10-year

progressive

average

(percent

-

-

-

-

-

-

18.4*

-

-

-

_

H

_

-

-

-

-

-

-

..

-

13.1

14.9

15.3

15.7

15.8

15.3

14.5

14.1

_

-

* Average of 8 years

f For the period 1918-34
PRECIPITATIOH, TEMPERATURE, AND RUN-OFF, B? BASINS

8

(a) Animal and 10-year progressive 

average precipitation at teaTemtartn, Eana

(bl Annual and 10-year progressive 

average precipitation at Biporia, Kans

o) Annual and 10-year progressive average preoipltation 

In Seosho Blver Basin

(d) Annual and 10-year progressive 

average run-off

(el Annual preoipitatlon minus run-off, 

10-year progressive average

Hots,- 10-year average plotted at end 

at period shown thus 

8-year average plotted at end 

of period shown tons 

figure 20«-Kelation between rainfall and run-off In Hsosho Blver Basin atove 

lola, Kans.
78 RAINFALL AND RUN-OFF IN TEE UNITED STATES

Temperature.- The normal annual temperature for the period of 

record of the stations in and adjacent to the basin was averaged and compared with the normal annual temperature at Wichita and was found to be 

about 0.8° lower. The annual temperature at Wichita minus 1° was taken as 

representative of the average annual temperature for the basin.

Merrimack River Basin above Lawrence, Mass.

(Net drainage area, 4,461 square miles.

Records available, 1880-1934.)

The Merrimack River, the fourth largest stream in New England, 

begins at Franklin, N. H., and is formed by the junctions of the Pemigewasset and Winnepesaukee Rivers, which have drainage areas of 1,085 and 

435 square miles, respectively. The Pemigewasset rises in the White 

Mountains of New Hampshire at an altitude of 5,000 feet and flows 70 miles 

south to Franklin, with an average slope of 15 feet or more to the mile. 

The Merrimack flows from Franklin south 40 miles to Manchester, N. H. 

(altitude 110 feet), then south 30 miles to Lowell, Mass, (altitude 50 

feet), and then east 15 miles to Lawrence, Mass, (altitude 40 feet).

The length of the Merrimack and Pemigewasset Rivers above Lawrence is about 155 miles and the average width of the basin about 50 miles. 

The total drainage area is 4,672 square miles, which includes parts of the 

basins of the Nashua and Sudbury Rivers and Lake Cochituate from which 

water is diverted.

The upper part of the basin, in the White Mountains, is largely 

covered with second and third growth forest and is sparsely settled, but 

farther downstream the improved areas are more extensive. The topography 

of the White Mountain district is very rugged, with steep slopes and narrow 

valleys. From Franklin southward the country becomes more hilly, then 

rolling.

The lake and pond area amounts to 183 square miles. The largest 

lake is Lake Winnepesaukee, which has a water area of 72 square miles.

Run-off.- An accurate record has been kept of the flow over the 

dam and through the wheels and gates of the Essex Co. at Lawrence, Mass., 

since January 1, 1880. The flow is regulated to some extent by storage in 

Lake Winnepesaukee. Low-water flow is affected by operation of various 

power plants above Lawrence. The record is furnished by the Essex Co. and
PRECIPITATION, TEMPERATURE, AND RUN-OFF, BY BASINS 79

Is considered good throughout. The records up to September 30, 1915, are 

revised and published in United States Geological Survey Water-Supply Paper 

415. The records as here used are on the basis of the year ending September 30.

Precipitation.- The figures for monthly and annual precipitation 

for the basin used here were taken from the water-supply papers. The precipitation as recorded for 1932 was the mean of 33 stations. The precipitation records as herein used are on the basis of the climatic year ending 

September 30. The following precipitation stations are in or adjacent to 

the basin.

Table 14.- Precipitation stations in or near the 

Merrimack River Basin above Lawrence, Mass.

Station

Maine :

Hiram

Massachusetts:

Ashby

Ashland

Beryls ton

Clinton

Concord *

Cordaville

Fitehburg *

Framingham

Groton

Haverhill

Jefferson

Lake Cochituate

Lawrence

Leominster

Lowell *

Princeton

Sterling

Sudbury

Wachusett Lake

Worcester *

Altitude 

(feet)

400

1,000

227

540

398

139

250

402

172

325

50

820

148

57

540

85

1,050

555

260 ,

880

625

Period 

of 

record

1926-29,1931-

1915-

1890-

1896-

1902-

1885-87,1891-

1894-

1865-

1876-

1886-1908,1913-

1900-30

1898-1900,1902-5,1907-14

1916-22,1924-

1852-1930

1856-60,1864,1866-67

1869,1871-80,1885-

1885-1932

1826-

1885-91,1897-

1897-

1899-

1915-

1841-55, 1857-62, 1865-71

1876-77 , 1882-86 , 1888-90

1893-97,1901-

Mean annual 

precipitation 

(inches)

40.22

44.93

43.45

45.34

44.91

40.61

46.00

41.29

43.85

43.34

38.02

47.49

45.27

41.93

44.08

41.47

45.41

43.54

42.34

46.13

42.40

w Station used in computing temperature average for basin.
80 RAINFALL AND ROT-OFF IN THE UNITED STATES

Table 14.- Precipitation atatlons In or near the 

Merrimack River Basin above Lawrence, Mass. Continued

Station

New Hampshire:

Bethlehem

Concord «

Durham

Franklin *

Glencliff «

Hanover *

Keene

Lakeport

Lincoln

Manchester

Nashua *

Plymouth *

Altitude 

(feet)

1,440

350

83

390

1,650

603

550

500

1,200

171

125

500

Period 

of 

record

1893-

1853,1857,1859-

1893,1895-

1902-

1910-

1835-55,1867-

1892-

1857-1933

1921-30,1933-

1875-

1884-

1888-1933

Mean annual 

precipitation 

(inches)

35.52

37.51

38.73

39.50

40.36

35.25

37.70

42.42

45.73

38.65

39.31

39.16

* Station used in computing temperature average for basin.

Temperature.- The average annual temperature for the period of 

record of each of the stations marked * in the preceding table was averaged 

and compared with the normal annual temperature at Concord, N. H., and was 

found to agree so closely that the Concord record has been used to represent the average temperature for the basin. The temperature records as 

used herein are on the basis of the calendar year.

James River Basin above Cartersville, Va. 

(Drainage area, 6,240 square miles. 

Records available, 1899-1934.)

The Jackson River rises on the West Virginia - Virginia State 

line, flows south 57 milea^ and Joins the Cowpasture River to form the James 

River, which flows generally south of east for 187 miles to Cartersville, 

Va. The average width of the drainage basin is about 50 miles. The 

western part of the basin lies in the Appalachian and Blue Ridge sections 

and is rugged to mountainous. The Piedmont section extends from the Blue 

Ridge tc the Pall Line near Richmond, 50 miles below Cartersville, and is 

characterized by low hills and broad valleys. Nearly half of the area 

consists of timber land and wood lots. The basin is primarily an agricultural area.

The Jackson River rises at an altitude of about 2,400 feet and 

descends to about 1,000 feet where it forms the James River. The James 

River has an average slope of 5.5 feet to the mile in the mountain section
PRECIPITATION, TEMPEBATTJRE, AMD RUN-OFF, BT BASINS

Table 15.- Precipitation, temperature, and run-off data for 

Merrimack River Baaln above Laurence, Hasa.

Year 

ending

September

1880

81

82

85

84

85

86

87

88

89

1890

91

92

93

94

95

96

97

98

99

1900

01

02

03

04

05

06

07

08

09

1910

11

12

13

14

15

16

17

18

19

1920

21

22

25

24

25

26

27

28

29

1930

31

52

33

34

Total

Av.

Precipitation

(inches)

Annual

54.57

39.54

44.53

31.38

41.61

41.53

45.03

49.28

48.59

47.57

51. OO

46.84

40.94

38.85

55.72

35.48

47.54

44.01

46.81

44.70

41.20

47.29

47.59

45.58

42.10

37.14

39.46

58.20

40.90

38.04

34.21

32.96

40.06

38.08

38.85

58.95

44.91

35.60

40.12

40.53

48.34

41.77

49.66

34.73

46.47

36.23

37.09

42.42

51.48

35.91

33.07

42.35

40.49

50.31

44.49

2289.46

41.63

Accumulated

54.57

74.11

118.64

150.02

191.63

255.16

278.19

327.47

576.06

423.65

474.63

521.47

562.41

601.24

654.96

670.44

717.78

761.79

808.60

855.30

894.50

941.79

989.58

1034.76

1076.86

1114. OO

1153.46

1191.66

1232.56

1270.60

1304.81

1337.77

1577.83

1415.91

1454.74

1493.69

1538.60

1574.20

1614.32

1654.65

1702.99

1744.76

1794.42

1829.15

1875.62

1911.85

1948.94

1991.36

2042.84

2078.75

2111.82

2154.17

2194.66

2244.97

2289.46

_

_

Progressive 10-

year

average

_

-

-

-

-

-

-

-

-

42.36

44.01

44.74

44.58

45.12

44.33

43.75

43.96

45.45

43.25

42.97

41.99

42.03

42.70

43.55

44.19

44.56

43.57

42.99

42.40

41.73

41.03

39.60

38.84

38.11

57.79

37.97

38.51

38.25

38.18

58.40

39.82

40.70

41.66

41.32

42.09

41.82

41.03

41.72

42.85

42.41

40.88

40.94

40.02

41.58

41.38

_

-

Temperature at

Concord, N. H.

(°P.)

Annual

48.8

48.5

47.0

45.2

46.3

44.6

46.3

45.9

44.4

47.7

45.3

47.0

45.5

Progressive 10-

year

average

_

-

-

-

-

-

-

-

-

46.45

46.10

45.97

45.82

41.9 ! 45.49

45.7

45.7

45.4

45.6

46.4

45.0

45.7

45.0

45.2

45.5

42.6

44.6

45.8

43.8

46.3

45.7

46.0

46.1

45.2

47.6

44.0

46.9

45.1

43.2

41.1

46.4

45.8

47.7

46.1

45.2

44.9

45.8

43.8

46.3

45.9

45.7

46.9

48.0

46.9

46.3

45.5

2510.4

45.6

45.43

45.54

45.45

45.42

45.62

45.55

45.39

45.19

45.16

45.50

45.19

45.08

45.12

44.94

44.93

45.00

45.03

45.14

45.14

45.37

45.51

45.74

45.67

45.61

45.09

45.16

45.14

45.30

45.39

45.15

45.24

45.13

45.00

45.31

45.79

45.72

45.83

45.66

45.94

46.05

46.11

-

Run-off at Lawrence

(inches)

Annual

17.60

18.90

21.63

12.76

20.90

15.72

24.58

26.27

25.08

25.76

27.42

28.96

16.42

19.19

15.75

13.60

22.73

23.15

23.14

23.20

19.77

22.08

26.05

26.25

19.82

16.01

19.98

15.42

23.07

14.09

14.98

10.65

19.11

17. 1O

20.09

15.06

24.15

19.71

14.49

19.37

25.19

21. 6O

26.54

17.39

22.00

16.15

17.06

16.15

31.54

22.06

12.58

15.15

16.30

24.79

22.60

1106.91

20.13

Accumulated

17.60

36.50

58.13

70.89

91.79

107. 51

132.09

158.36

183.44

209.20

236.62

265.58

282. OO

301.19

516.94

330.54

553.27

376.42

399.56

422.76

442.53

464.61

490.66

516.91

536.75

552.74

572.72

588.14

611.21

625.30

64O.28

650.93

670.04

687.14

707.23

722.29

746.44

766.15

780.64

800.01

825.20

846.80

873.14

890.53

912.53

928.68

946.74

961.89

993.43

1O15.49

1028.07

1043.22

1O59.52

1084.31

1106.91

_

-

Progressive 10-

year

average

_

-

-

-

-

-

-

_

20.92

21.90

22.91

22.39

23.03

22.52

22.30

22.12

21.81

21.61

21.36

20.59

19.90

20.87

21.57

21.98

22.22

21.94

21.17

21.16

20.25

19.78

18.63

17.94

17.02

17.05

16.95

17.37

17.80

16.94

17.47

18.49

19.59

20.31

20.34

20.53

20.64

19.93

19.57

21.28

21.55

20.29

19.64

18.64

19.38

19.44

.

-

Precipitation

minus run-off

( inches ]

Annual

16.97

20.64

22.90

18.62

20.71

25.81

20.45

23.01

25.51

21.81

23.58

17.88

24.52

19.64

17.97

21.88

24.61

20.66

23.67

21.50

21.43

25.21

21.54

19.13

22.28

21.13

19.48

22.78

17.85

23.95

19.23

22.31

20.95

20.98

18.74

23.89

20.76

15.89

25.63

20.96

23.15

20.17

23.32

17.34

24.47

20.08

20.03

26.27

19.94

13.85

20.49

27.20

24.19

25.52

21.89

1182.55

21.50

Progressive 10-

year

average

_

-

-

-

-

-

-

_

-

21.44

22.10

21.83

21.99

22.09

21.82

21.43

21.84

21.63

21.64

21.61

21.40

22.15

21.83

21.78

22.21

22.14

21.62

21.82

21.23

21.48

21.26

20.97

20.91

21.09

20.74

21.01

21.14

20.45

21.23

20.93

21.33

21.11

21.35

20.98

21.56

21.18

21.10

22.14

21.57

20.66

20.60

21.30

21.39

22.2O

21.95

-

-

Ratio

run- off

to

precipitation

10-year

progressive

average

(percent)

_

-

-

-

-

-

-

-

49.4

40.8

51.2

50.5

51.0

50.8

51.0

50.3

50.2

49.9

49.7

49.1

47.4

48.9

49.8

49.8

50.1

50.4

49.3

49.9

48.5

48.2

47.0

46.2

44.7

45.1

44.6

45.1

46.5

44.4

45.5

46.4

48.1

48.7

49.3

48.7

49.4

48.6

46.9

49.7

5O.9

49.7

48.0

46.6

46.5

47.0

-

-

5955 O 85 8-
RAIHFALL AND RUN-OFF IN THE UNITED STATES

a I Animal and 10-year progressive 

average praoi litation at loston. lias

(b) Annual and 10-year progressive 

average preoipltation at Oonoord, S.H

\ (o) Annual and 10-year progressive average 

in Harrlmaok Elver Basin

(d) Annual and 10-year progressive 

average run-off

(e) Annual preoipltation minaa run-off, 

10-year progressive average

Note*- 10-year average plotted at end of period shown thus 

Figure 21. Belations between rainfall and run-off in lierrlmaok Elver Basin above 

Lawrence, Mass.
PRECIPITATION, TEMPERATURE, AND RUN-OFF, BY BASINS 83

of 88 mile and of 2.9 feet to the mile in the Piedmont section to the 

Fall Line.

Run-off.- The gage is located on the James River between Pemberton and Cartersville, Cumberland County, 1 mile below the mouth of the 

Willis River. A wire gage was used from January 1899 to July 23, 1903, and 

a chain gage from July 24, 1903, to June 3, 1927. Since June 3, 1927, a 

water-stage recorder has been in operation* The daily records are fair to 

good prior to the installation of the water-stage recorder and good to 

excellent thereafter.

The flow at Cartersville is regulated to a small extent by nine 

hydroelectric power plants on the main stream and tributaries, the nearest 

of which is about 95 miles upstream. The only storage used is the small 

amount of pondage at the power developments. The records are for the 

calendar year.

Precipitation.- The annual precipitation over the basin was computed by averaging the annual records at all the fairly well distributed 

precipitation stations in and adjacent to the basin, which are listed 

below:

Table 16.- Precipitation stations in or near 

James River Basin above Cartersville, Va.

Station

Virginia :

Blacksburg * 

Buchanan 

Catawba Sanitarium

Charlottesville 

Columbia

Farmville »

Hot Springs 

Lexington 

Lynchburg 

New Canton

Staunton

Altitude 

(feet)

2,100 

820 

2,100

854 

246

316

2,195 

1,060 

681 

300

1,480

Period 

of 

record

189S1893-95,1904- 

1911-

1849,1874-78,1882- 

1899-

1897-1906

1892- 

1869-83 , 1885-86 , 1889- 

1872- 

1894-

1869-72,1890-1923,1925-

Mean annual 

precipitation 

(inches)

41.65 

41.19 

42.12

43.58 

41.44

41.02

40.35 

39.30 

40.53 

41.17

37.68

* Station replaced by another or record discontinued prior to 1911.

Because of the rough topography over the basin, differences in 

precipitation between one part of the basin and another probably result 

largely from differences in altitude. The precipitation ranges from about 

37.7 to 43.6 inches on the basis of the long-time average, and in one year 

the range was from 29.4 to 54.1 inches. Records are on the basis of the 

calendar year.
RAINFALL AND RUH-OFP IN THE UNITED STATES

Table 17.- Precipitation, temperature, and run-off data for 

James River Basin above Cartersvllle, Va.

Year

1899

1900

01

02

03

04

05

06

07

08

09

1910

11

12

Precipitation

(inches)

Annual

44.03

40.68

54.03

41.96

44.74

32.30

44.01

47.05

44.44

45.09

Accumulated

44.03

Progressive 10-

year

average

_

84.71

138.74]

180.70

225.441

257.74

301.75

348.80

393.24

438.32

34.20 ; 472.52

39.43 511.95

41.39

42.42

13 45.01

14

15

16

17

18

19

1920

21

£2

23

24

25

26

27

28

29

1930

31

32

33

34

Total

Av.

36.59

41.19

37.92

36.56

45.30

42.49

45.15

32.89

41.67

37.71

47.30

2P.84

39.67

41.84

42.94

44.56

21.16

37.31

44.21

3R.01

44.43

14S8.51

40.79

553.34

595.76

640.77

677.36

71B.55

756.47

793.03

_

-

-

-

43. ns

42.85

42.72

41.46

41.51

Temperature at

lynchburg, Va.

ml?°F.)' 5

Annual

54.2

56.1

53.4

54.5

54.1

52.5

53.8

55.2

53.7

54.5

54.6

54.2

55.7

54.2

Progressive 10-

year

average

_

.

_

Run-off at Cartersville

(inches)

Annual

18.40

15.56

25.06

I 18.87

! 21.52

_

_

_

_

54.2

54.2

54.1

54.3

54.3

41.53 56.6 54.5

41.96 54.6 ] 54.7

41.63

40.77

39.98

838.331 40.00

880.32

925.97

958.36

1000.53

1038.24

40.83

41.40

40.55

40.48

39. 75

1085.54 40. n,2

1114.33

1154.05

1195. P9

1238.83

1283.39

1304.55

1341.06

1386.07

1424.08

1468.51

-

-

39.58

39. 76

40.29

40.05

40.26

37.86

36.30

38.55

38.58

38.30

_

-

54.9 1 54.8

54.7

52.5

54.4

55.6

53.6

57.1

55.8

55.4

53.3

55.7

54.7

55.9

55.0

55.2

55.7

56.9

56.6

56.8

55.3

3977.0

54.9

54.8

54.7

54.6

54.7

54.7

54.8

55.0

54.9

54.7

54.8

54.8

55.2

55.2

55.2

55.4

55.4

55.4

55.6

55.8

_

-

10.21

14.75

20.20

19.65

19.36

16.37

12.86

12.79

17.73

17.31

14.14

17.10

12.64

13.06

16.95

17.26

17.26

11.85

15.77

12.08

19.78

9.86

13.19

15.73

16.90

18.80

7.00

8.00

14.84

15.15

13.33

561.33

15.59

Ac cumulated

18.40

33.96

59.02

77.89

99.41

109.62

124.37

144.57

164.22

183.58

199.95

212.81

225.60

243.33

Progressive 10-

year

average

.

-

»

_

-

-

-

_

18.36

18.16

17.89

16.66

16.54

260. 64 i 16.12

274.78

291.88

304.52

317.58

334.53

351.79

369.05

380.90

396.67

408.75

428.53

43Q.39

451.58

467.31

484.21

503.01

510.01

518.01

532.85

548.00

561.33

_

-

16.52

Precipitation

minus run-off

Ratio

run-off

(incnes) to

precipAnnual

25.o3

25.12

28.97

23.09

23.22

22.09

29.26

26.85

24.79

25.72

17.83

26.57

28.60

24.69

Irogres- itation

sive 10-

year

average

-

-

-

-

-

-

-

-

-

25.47

24. b9

24.84

10-year

progressive

average

(percent)

-

-

-

-

-

-

-

-

-

41.8

4S.3

41.8

24.30' 40.2

24.96 39.8

27.''0j 25.41

22.45 25.45

16.75 24.09 24.93

38.8

39.3

40.2

16.00 25.231 24.77| 39.2

15.34 1 23.50

15.10

15.18

15.62

15.53

15.33

14.81

15.38

14.65

14.71

14.97

14.97

15.12

14.10

13.71

13.62

13.93

13.28

.

-

28.35

25.23

24.64i 08.4

24.91 37.3

25.65 37.2

27.89 25.78 37.7

21.04 25.02 30. 3

25. 90 ! 25.14 37.8

25.63J 24. 94' 37.2

27.521 25.44; 37.7

18.98 24.93 37.0

26.48, 25.05 5".0

26.11

26.04

25.76

14.16

29.31

29.37

22.86

31.10

907.18

25.20

25.31! 37. £

25. OB 37.4

25.14 37.6

23.76 37.2

24.59 35.8

24.94 35.3

24.66 36.1

25.02 34.7

" 1 ~

- 1
PRECIPITATION, TEMPERATURE, AND RUH-OFF, BY BASINS

3 8

(b) Annual and 10-year progressive 

average precipitation at Ljraohlrur(, Va

\ (a) Annual and 10-year progressive average preoipi 

in Jamas River Basin

(d) Annual and 10-year progressiv

e) Annual precipitation minus run-o 

10-year progressive average

la) Annual and 13-year progressive 

average precipitation at Baltimore, Hd.

Note 10-year average plotted at end 

of period shown tnua *

Figure 22. Relations between rainfall and run-off in Janes River Basin above 

Oartersville, T«.
86 RAINFALL AND RUN-OFF IN THE UNITED STATES

Temperature.- The mean annual temperature for the period of record at the stations in and adjacent to the basin was averaged and compared 

with the mean annual temperature at Lynchburg and was found to be about 

2.3° lower. This amount was then subtracted from the figures of annual 

temperature at Lynchburg to arrive at the average annual temperature for 

the basin.

Tennessee River Basin above Chattanooga, Term.

The Tennessee River is formed at Knoxville, Term., by the junction of the French Broad and Holston Rivers, which rise in western North 

Carolina and southwestern Virginia and have drainage areas of 5,140 and 

3,810 square miles respectively. From Knoxville the Tennessee flows 188 

miles in a southwesterly direction to Chattanooga. The headwater area is 

mountainous country, with altitudes ranging from 3,000 to 6,700 feet. At 

Chattanooga the altitude ia about 620 feet, and the drainage area 21,400 

square miles.

The river distance from Chattanooga to the head of the French 

Broad is about 360 miles, and to the head of the Holston about 385 miles. 

The average width of the drainage basin is about 85 miles.

The average slope of the Tennessee River from Knoxville to 

Chattanooga is about 1.0 foot to the mile; that of the French Broad River 

from its mouth to a point 197 miles above is about 6.6 feet to the mile; 

and that of the Holston River from its mouth to a point 143 miles above is 

about 2.5 feet to the mile.

Run-off.- For the period 1874 to 1913, prior to the building of 

the Hales Bar Dam, the Chattanooga gage record alone was used; from October 

22, 1913, to February 28, 1915, and October 1, 1918, to January 5, 1921, the 

gage record at Bridgeport, Ala., was used; from March 1, 1915, to September 

30, 1918, and from January 6, 1921, to June 1930 the Chattanooga gage was 

used, adjusted by means of the upper and lower gages at Hales Bar Lock and 

Dam, 33 miles below Chattanooga.

Since July 1930 gage-height records have been obtained from a 

water-stage recorder just below Hales Bar Lock and Dam, where the drainage 

area is 22,000 square miles.
PRECIPITATION, TEMPERATURE, AND RUN-OFF BY BASINS 87

Because the stage-discharge relation is not permanent, several 

rating curves were used, and the low-water records since the completion of 

Hales Bar Dam, in 1913, may be subject to some error owing to the indirect 

method of determining the discharge. The run-off records are for the 

calendar year.

Precipitation.- The accuracy of the annual precipitation records. 

in representing the mean annual precipitation over the basin above Chattanooga is problematic. The accuracy probably increases from 1889 to 1898 

and should be fairly satisfactory since 1898. Prior to 1889 the number of 

precipitation stations was small, but their distribution was fairly uniform 

over the area. The annual precipitation data prior to 1889 were weighted 

in relation to area represented, and those subsequent to 1889 were averaged to get the annual precipitation for the basin. The approximate number of precipitation stations used to compute the basin average is as 

follows:

1885 - 6 stations 

1890 - 15 stations 

1900 - 31 stations

1910 - 36 stations 

1920 - 39 stations 

1930 - 38 stations

The following is a list of stations in the basin above Chattanooga used to compute the annual precipitation:

Table 18.- Precipitation stations in or near 

Tennessee River Basin above Chattanooga, Term.

Station

North Carolina:

Altapass

Andrews

Asheville

Brevard

Bryson City

Cullowhee

Hendersonville

Highlands

Hot Springs

Jefferson

Linville

Linville Falls

Marshall

Montreat

Murphy

Parker

Waynesville

Altitude 

(feet)

2,740

1,800

2,253

2,230

2,000

2,100

2,153

3,350

1,326

2,900

3,800

3,300

1,646

2,600

1,614

4,075

2,756

Period 

of 

record

1913-

1909-33

1869-78 , 1889-91 , 1893-

1902-34

1889-

1910-

1898-

1879-81 , 1883-84 , 1892-

1906-

1903-6,1910-

1895-1906

1916-

1899-

1917-

1873-75,1877-82,1889-

1918-

1894-

Mean annual 

precipitation 

(inches)

50.89

62.08

40.28

62.13

54.06

43.80

60.13

81.44

43.68

48.86

62.72

58.13

39.40

53.97

58.47

50.15

45.57
88 RAINFALL AND RUB-OFF IN THE UNITED STATES

Table 18.- Precipitation stations in or near 

Tennessee River Basin above Chattanooga, Tenn. Continued

Virginia:

Big Stone Gap

Dante

Elk Knob

Marion

Mendota

Saltvllle

Speers Perry

Tennessee:

Bluff City

Bristol

Chattanooga

Clinton .

Copperhill

Crossvllle

Dandrldge

Decatur

Elizabethton

Greenville

Harriman

Jefferson City

Johnson City

Kingston

Knoxville

Loudon

Maryville

Me Ghee

Mountain City

Newport

Parksville

Rockwood

Rogersville

Rugby

Sevierville

Springdale

Tazewell

Tellico Plains

Altitude 

(feet)

1,966

2,000

3,243

2,145

1,350

1,770

1,221

1,400

1,757

808

800

1,624

1,820

1,050

850

1,575

1,581

841

1,117

1,717

751

977

816

1,050

850

2,471

1,100

840

725

1,160

1,410

900

1,058

1,350

1,000

Period 

of 

record

1891-1911

1917^

1904-19

1884-1911

1905-

1896-97,1924-

1896-1932

1868-

1894-1908,1927-32

1879-

1889-91,1893-

1914-

1912-

1905-

1896-

1869-70,1872

1895-1906,1908-

1884-1906,1916-19

1921-25,1933-34

1891 , 1893, 1895-1911

1910-28

1886,1896-1930

1889-93,1898-

1854,1871-

1889-96,1905-

1883-85 , 1888 , 1898-1912

1905-

1898-1920

1892-

1883-1914,1925-

1889-97,1923-33

1886-

1884,1889-

1906-30

1889-1909,1911

1898-1926

1897-1908,1927-

Mean annual 

precipitation 

(inches)

50.66

48.63

48.46

43.29

47.81

43.22

49.45

44.46

41.29

51.61

52.49

54.86

55.92

45.84

54.92

44.55

43.37

51.41

45.75

44.39

51.42

47.38

50.96

51.57

50.15

47.07

44.45

50.25

5.2.35

44.82

55.69

47.94

48.63

50.45

53.19

The precipitation records are on the basis of the calendar year.

Temperature.- The mean annual temperaturee for the period of 

record at the stations in the basin were averaged and compared with the 

mean annual temperature at Knoxville and were found to be about 2.5° lower; 

therefore 3° was subtracted from the figures of annual temperature at 

Knoxville to arrive at the average annual temperature of the basin.
PRECIPITATION, TEMFHUTDKE, AM) RTJH-OKF, BY BASINS

Table 19.- Precipitation, teaperature, and nut-off data for 

Tennessee River Basin above Qiattanooga, Tenn.

Tear

1861

82

83

84

85

86

87

88

89

1890

91

92

93

94

95

96

97

98

99

1900

01

02

03

04

05

06

07

08

09

1910

11

12

13

14

15

16

17

18

19

1920

21

22

23

24

25

26

27

28

29

1930

31

32

33

34

Total

Av.

Precipitation

(Indies)

Annual

53.20

64.10

50.60

54.90

47.50

57.00

41.10

47.10

42.80

51.10

53.93

53.66

48.32

40.68

46.10

48.15

52.34

51.56

51.88

49.0O

61.68

46.02

51.11

39.85

50.49

56.12

49.49

48.82

54.39

45.76

50.51

52.50

48.10

46.55

52.84

51.98

52.67

53. SO

47.59

58.61

48.26

54.10

51.35

51.12

36.17

51.89

49.56

55.38

62.41

37.63

44.37

58.69

44.02

51.69

2719.64

50.36

Accumulated

53.20

117.30

167.00

222.80

270.30

327.30

368.40

415.50

457.70

508.80

562.73

616.39

664.71

705.39

751.49

799.64

851.98

903.64

956.42

1004.42

1066.10

1112.12

1163.23

1203.08

1253.57

1309.69

1359.18

1408.00

1462.39

1508.15

1558 .66

1611.16

1659.26

1705.81

1758.65

1810.63

1863.30

1916 .80

1964.39

2O23.OO

2071.26

2125.36

2176.71

2227.83

2264.00

2315.89

2365.45

2420.83

2483.24

2520.87

2565.24

2623.93

2667.95

2719.64

_

-

Progressive 10-

year

average

_

-

_

-

-

_

-

_

50.88

50.95

49.91

49.68

48.26

48.12

47.23

48.36

48.80

49.77

49.56

50.34

49 .57

49.85

49.77

50.21

51.01

50.72

50.45

50.70

50.37

49.26

49.90

49.60

50.27

50.51

50. 09

50.41

50.88

50.20

51.49

51.26

51.42

51.75

52.20

50.54

50.53

50.22

50.40

51.89

49.79

49.40

49.86

49.12

49.18

-

Temperature at

Knoxvllle,

Tenn.

aimis 3° (°F.)

Annual

56.5

56.4

55.8

55.4

53.4

53.5

55.8

55.4

55.2

57.1

55.2

54.5

55.0

56.1

54.0

56.6

56.1

55.8

55.3

56.S

53.3

55.2

54.5

54.3

54.8

55.8

55.4

56.1

55.6

54.6

57.5

54.4

56.8

55.4

55.7

55.6

53.3

56.2

57.1

54.7

58.2

57.4

56.1

54.4

57.7

55.5

57.6

55.0

55.5

56.4

58.1

57.6

58.5

57.1

3011.0

55.8

Progressive 10-

year

average

_

_

_

-

_

_

_

_

_

55.4

55.3

55.1

55.0

55.1

55.2

55.5

56.5

55.6

55.6

56.5

55.3

55.4

55.3

55.2

55.2

55.2

55.1

55.1

55.2

55.0

55.4

55.3

55.5

55.6

55.7

55.7

55.5

55.5

55.7

55.7

55.7

56.0

56.0

55.9

56.1

56.1

56.5

56.4

56.2

56.4

56.4

56.4

56.6

56.9

-

Run-off at Chattanooga

(Inches)

Annual

23.68

34.12

25.16

31.46

23.61

32.79

23.09

27.20

24.34

28.16

31.12

26.28

23.69

16.63

20.48

19.86

26.69

22.22

27.80

20.69

32.25

24.73

25.98

13.95

21.58

28.62

23.99

25.01

29.91

18.49

21.90

25.55

22.11

17.36

23.44

24.64

27.44

22.77

23.64

31.88

22.04

27.27

26.97

23.63

14.60

19.96

23.99

27.94

33.46

15.15

14.98

26.11

21.64

18.32

1309.17

24.24

Accumulated

23.68

57.80

82.96

114.42

138.03

170.82

193.91

221.11

245.45

273.61

304.73

331.01

354.70

371.33

391.81

411.67

438.36

460.58

488.38

509.07

541.32

566.05

592 .03

605.98

627.36

655.98

679.97

704.98

734.89

753.38

775.28

BOO. 83

822.94

840.30

863.74

888.38

915.82

938.59

962.23

994.11

1016.15

1043.42

1069.39

1093.02

1107.62

1127.58

1161.57

1179.51

1212.97

1228.12

1243.10

1269.21

1290.85

1309.17

_

-

Progressive 10-

year

average

_

-

-

-

 

«

..

..

_

27.36

28.11

27.32

27.17

25.69

26.38

24.09

24.45

23.95

24.29

23.55

23.66

23.50

23.73

23.47

23.56

24.43

24.16

24.44

24.65

24.43

23.40

23.48

23.09

23.43

23.64

23.24

23.59

23.36

22.73

24.O7

24.09

24.26

24.65

26.27

24.39

23.92

23.58

24.09

25.07

23.40

22.70

22.58

22.15

21.62

^

-

Precipitation

minus run-off

( Inches )

Annual

29.52

29.98

25.44

23.44

23.89

24.21

18.01

19.90

17.86

22.94

22.81

27.38

24.63

24.05

25.62

28.29

25.65

29.34

24*08

28.31

29.43

21.29

25.13

25.90

29.11

27.50

25.5O

23.81

24.48

27.27

28.61

26.95

25.99

29.19

29.40

27.34

25.23

30.73

23.95

26.73

26.22

26.83

25.38

27.49

21.57

31.93

25.57

27.44

28.95

22.48

29.39

32.58

22.38

33.37

1410.47

26.12

Progressive 10-

year

average

_

-

-

-

-

-

_

23.52

22.85

22.59

22.51

22.57

22.74

23.15

23.91

24'.86

25.48

26.02

26.68

26.07

26.12

26.30

26.65

26.57

26.56

26.01

26.06

25.94

25.86

26.43

26.51

26 .84

26.87

26.85

26.83

27.52

27.47

27.41

27.17

27.16

27.10

26.93

26.15

26.61

26.64

26.31

26.81

26.39

26.70

27.28

26.98

27.57

_

-

Ratio

run-off

to

precipitation

10-year

progressive

average

(percent

-

-

-

 

-*

53.8

55.1

54.7

54.7

53.3

52.8

51.0

50.6

49.1

48.8

47.5

47.0

47.4

47.6

47.2

46.9

47.9

47.6

48.4

48.6

48.5

47.5

47.0

46.6

46.6

46.8

46,4

46.8

45.8

45.2

46.8

47.0

47.2

47.6

48.4

48.3

47.4

46.9

47.8

48.4

47.0

45.9

45.3

45.1

43.9

_

-
RAINFALL AND RUN-OFF IN THE UNITED STATES

a) Annual and progressive 10-year average 

ipitatlon at Nashville, Tenn.

(b) Annual and 10-year progressive 

average precipitation at Knoxville, Term

o) Annual and 10-year progressive average preoipltation 

in Tennessee River Basin

(d) Annual and 10-year progressive average run-off

(e) Annual precipitation minus run-off, 

10-year progressive average

§

Note. 10-year average plotted at end-of period shown thus 

Figure 23*-Kelations between rainfall and run-off in Tennessee River Basin above 

Chattanooga, Tenn.
PRECIPITATION, TEMPERATURE, AND RUN-OFF, BY BASINS 91

Chattahoochee River Basin above West Point, Ga.

(Drainage area, 3,550 square miles.

Records available, 1896-1934.)

The Chattahoochee River rises in the Blue Ridge in White County, 

Ga., at an altitude of about 4,000 feet, and flows in a southwesterly 

direction to West Point, Ga., on the Georgia - Alabama State line, at an 

altitude of about 550 feet. The length of the river above West Point is 

about 200 miles, and the average width of the drainage basin is 30 miles. 

From the lower edge of Lumpkin County down to West Point, a distance of 

about 145 miles, the Chattahoochee River has a fall of 484 feet, an average of about 3.3 feet to the mile.

Run-off.- The original gage, established in July 1896, was a 

standard chain gage on the downstream handrail of the Montgomery Street 

Bridge in West Point, Ga. On October 20, 1912, the gage was moved 1 mile 

upstream, to a point opposite the city pumping plant. A staff gage (0 to 

18 feet) was placed on the left bank and was read from the right bank by 

means of a telescope until January 14, 1920, when the section 0 to 6.7 feet 

was moved to the right bank. Since January 26, 1925, the gage has been a 

continuous water-stage recorder in a concrete stilling well on the right 

bank 500 feet below the West Point waterworks pumping plant. The gage was 

read to tenths three times daily prior to the installation of the waterstage recorder. The records throughout are considered fair to good. The 

operation of hydroelectric power plants upstream causes slight diurnal 

fluctuations at West Point. The run-off figures are on the basis of the 

calendar year.

Precipitation.- The annual precipitation over the basin was computed by averaging the annual records at all the precipitation stations 

listed below, located in and adjacent to the basin.
92 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 20.- Precipitation stations in or near 

Chattahoochee River Basin above West Point, Ga.

Georgia:

Atlanta

Canton

Clayton

Dahl onega

Gainesvllle

Gillsville

Lost Mountain

Marietta

Newnan

Norcross

Tallapoosa

Tocoa

West Point

Altitude 

(feet)

1,173

894

2,100

1,519

1,254

1,052

1,175

1,135

959

1,025

1,150

1,050

620

Period 

of 

record

1859,1866,1868-

1879,1892-

1894-1920,1922-

1885,1894-

1875-86,1895-

1890-

1901-19

1889-98,1920-27

1895-

1911-32

1897-

1892-

1894-

Mean annual 

precipitation 

(inches)

48.27

52.33

70.07

61.25

54.92

51.25

50.86

50.20

51.12

51.33

51.65

57.98

51.78

Differences in annual precipitation between one part of the basin 

and another probably result largely from differences in altitude. The 

range shown by long-time averages is from about 48.3 to 70.1 inches; in one 

year the range was from 53.4 to 91.6 inches. Precipitation figures are on 

the basis of the calendar year.

Temperature.- The mean annual temperature for the period of record at the stations in and adjacent to the basin was averaged and compared 

with the mean annual temperature at Atlanta and was found to be about 0.5° 

lower. The Atlanta record was therefore taken to represent the average 

temperature of the basin. Temperature figures are on the basis of the 

calendar year.

general accuracy of precipitation, run-off, and temperature data

During the periods of record there has unquestionably been a 

gradual increase in the accuracy of the base data used. In the determination of the mean annual precipitation it has been necessary to base the 

average during the earlier part of the period on a fewer number of stations 

than were available during later years. The records in the earlier part of 

the period have generally been weighted according to area represented. For 

several basins comparisons were made of the relations both on an annual and 

on a monthly basis between the straight average of all the stations and the 

weighted average. In most of these comparisons the differences shown were 

so small that the straight average has been used in general. Basin trends
PRECIPITATION, TEMPERATURE, ADD RUN-OFF, EC BASINS

Table 21.- Precipitation, temperature, and run-off data for 

Chattahoochee River Basin above West Point, Ga.

Year

1897

98

99

1900

01

02

03

04

05

06

07

08

09

1910

11

12

13

14

15

16

17

18

19

1920

21

22

23

24

25

26

27

28

29

1930

31

32

33

34

Total

Av.

Precipitation

( inches )

Annual

50.36

59.42

49.97

63.81

67.02

49.05

55.0«

36.03

53.71

63.75

49.01

52.63

59.55

45.05

49.94

66.64

50.21

48.64

60.04

50.75

54.10

58.02

58.99

70.27

47.11

61.17

56.59

51.00

41.26

52.27

44.98

57.33

78.46

43.76

45.75

72.96

42.16

57.47

2074.27

54.59

Accumulated

50.36

109.78

159.75

223.56

290.58

339.63

394.67

430.70

484.41

548.16

597.17

649.80

709.35

754.40

804.34

870.98

921.19

969 .83

1029.87

1080.62

1134.72

1192.74

1251.73

1322.00

1369.11

1430.28

1486.87

1537.87

1579.13

1631.40

1676.38

1733.71

1812.17

1855.93

1901.68

1974.64

2016.80

2074.27

_

-

Progressive 10-

year

average

_

-

-

-

-

-

_

-

54.82

54.68

54.00

54.96

53.08

51.38

53.14

52.65

53.91

54.55

53.25

53.76

54.29

54.24

56.76

56.48

55.93

56.57

56.80

54.93

55.08

54.17

54.10

56.04

53.39

53.26

54.44

53.00

53.64

-

Temperature at

Atlanta. Ga.

<°F.i

Annual

61.8

61.5

61.6

61.9

59.4

61.1

60.1

60.2

60.5

61.1

61.7

61.7

61.4

60.6

62.9

60.1

61.9

61.1

61.4

61.4

59.6

61.7

62.2

60.0

63.5

62.6

61.4

60.2

63.4

61.0

63.2

60.7

61.4

61.5

63.0

62.3

63.2

61.2

3335.5

61.5

Progressive 10-

year

average

_

-

-

-

-

-

-

-

60.9

60.9

60.9

60.9

60.8

61.1

61.0

61.2

61.3

61.4

61.4

61.2

61.2

61.3

61.2

61.3

61.5

61.5

61.4

61.6

61.6

61.9

61.8

61.7

61.9

61.8

61.8

62.0

62.1

_

-

Run-off at West Point

(inches)

Annual

19.07

20.37

22.80

28.85

33.20

26.20

29.84

11.57

16.63

28.45

19.52

23.06

28.73

17.10

16.19*1

30.14

19.77

13.62

23.25

22.21

25.92

20.41

27.13

33.46

18.79

28.03

23.01

19.07

17.77

18.40

14.30

22.08

37,61

17.49

12.71

25.65

18.65

17.05

848.10

22.32

Accumulated

19.07

39.44

62.24

91.09

124.29

150.49

180.33

191.90

208.53

236.98

256.50

279.56

308.29

325.39

341.58

371.72

391.49

405.11

428.36

450.57

476.49

496.90

524.03

557.49

576.28

604.31

627.32

646.39

664.16

682.56

696.86

718.94

756.55

774.04

786.75

812.40

831.05

848.10

_

-

Progressive 10-

year

average

_

~

-

-

~

~

-

-

M

23.70

23.74

24.01

24.61

23.43

21.73

22.12

21.12

21.32

21.98

21.36

22.00

21.73

21.57

23.21

23.47

23.26

23.58

24.13

23.58

23.20

22.04

22.20

23.25

21.66

21.05

20.81

20.37

20.17

_

-

Precipitation

minus run-off

(inches)

Annual

31.29

39.05

27.17

34.96

33.82

26.85

25.20

24.46

37.08

35.30

29.49

29.57

30.82

27.95

33.75*

36.50

30.44

35.02

36.79

28.54

28.18

37.61

31.86

36.81

28.32

33.14

33.58

31.93

23.49

33.87

30.68

35.25

40.85

26.27

33.04

47.31

23.51

40.42

1226.17

32.27

Progressive 10-

year

average

_

-

-

-

-

-

-

-

31.12

30.94

29.99

30.35

29.65

29.65

31.01

31.54

38.59

32.56

31.89

31.76

32.56

32.66

33.55

33.01

32.67

32.99

32.68

31.35

31.88

32.13

31.89

32.79

31.74

32.21

33.63

32.62

33.47

_

-

 Ratio

run-off

to

precipitation

10-year

progressive

average

(percent

_

-

-

-

-

-

-

-

43.2

43.4

44.4

44.7

44.2

42.3

41.6

40.1

39.5

40.3

40.1

40.9

40.0

39.7

40.9

41.6

41.6

41.7

42.5

42.9

42.1

40.7

41.0

41.5

40.6

39.5

38.2

38.5

37.6

_

-

Run-off estimated for 1911.
RAINFALL AND RUN-OFF IN THE UNITED STATES

(a) Annual and 10-year progressive 

average preolpltatlon at Montgomery, Ala

Cb| Annual and 10-year progressive 

average precipitation at Atlanta, Ga.

I I I

(o) Annual and 10-year progressive 

average preolpltatlon In 

Ohattaoooohee River Basin

(d) Annual and 10-year progressive 

average run-off

3} Annual preolpltatlon minus rtm-off, 

10-year progressive average

Note. 10-year average plotted 

at end of period shown thus 

Figure 24.-Eelatlon between rainfall and run-off In Ohattahooohee River Basin above 

West Point, Ga.
GENERAL ACCURACY OF PRECIPITATION, ROT-OFF, AND TEMPERATURE DATA 95

In the precipitation based on all the stations can be checked against the 

trends shown by geographic provinces, and where the data are available 

figures 18 to 24 also show the mean annual and 10-year prpgressive annual 

precipitation for one or two long-time stations within or directly adjacent 

to the basin.

Whether or not the figures given for the mean annual precipitation represent closely the amounts that fell on the basin is subject to 

question. For basins In which the precipitation Is more a function of 

geographic location than of altitude the estimates of average precipitation 

over the basin are believed to be fairly reliable, at least for the later 

periods. For basins where differences in altitude as well as geographic 

location affect the magnitude of the precipitation the probability of 

errors Is greater.

In general the estimates of the mean annual temperature have been 

based on records at a few stations corrected to the mean by comparisons of 

the average for all the stations in each basin during the later part of the 

period with the temperature at the base station used.

With respect to the increased temperature In the later years 

there appears to be little doubt. There is doubt, however, as to the accuracy of the estimates of temperature Increases here given. Part of the 

doubt rests on the belief that the indicated Increase at the stations used 

may not be Indicative of the temperatures over the basin. This phase Is 

discussed In the section on temperature. There Is also some question as to 

the accuracy and homogeneity of the record for the periods used. The records of the United States Weather Bureau have been used as given In 

Bulletin W and other Weather Bureau publications for the period 1889 to 

1934, during which the average temperatures have been based on the average 

of the average dally maxima and average daily minima. For the relatively 

few records prior to 1889 the figures given in Bulletin W have been corrected, where possible, to conform with the system used since 1889. Such 

corrections have, In general, changed the 10-year average as compiled from 

Bulletin W by only 0.2 or 0.3°. Although the temperatures as given may not 

represent the average temperatures over the basins, especially In the 

basins having considerable differences In altitude, the indicated changes 

should at leaat be fairly representative of changes over the basins.
96 RAINFALL AND ROT-OFF IN THE UNITED STATES

So far as water stages are concerned the accuracy of the run-off 

records has probably increased from the beginning of the record at least up 

to the time when recording gages have been installed. In the matter of 

stage-discharge relations the accuracy probably increased from the beginning of the record up to about 1910 to 1915, when refined methods of 

current-meter suspension made possible more accurate determinations of 

depth and of velocity. In general, however, in spite of probable errors in 

the base data, the analyses which have been made disclosed few apparent inconsistencies resulting from the data used. In view of the fact that no 

attempt has been made to recompute or recompile published figures, this 

consistency is a favorable commentary on the work of ttie agencies that have 

collected and compiled the meteorologic and hydrographlc data. This does 

not mean, however, that some of the changes in relations between rainfall 

and run-off that have been credited to changes in either precipitation or 

temperature may not be more properly credited to errors in base data or to 

changes not related to either rainfall or temperature.

The relations between rainfall and run-off, shown in the tables 

as "ratio of run-off to precipitation", have been determined on the basis 

of 10-year averages. In some basins the hydrologic cycle may be completed 

in a much shorter period of time, but Hayford (57) has pointed out, for the 

small steep Wagon Wheel Sap area in Colorado, that the stream flow on any 

particular day was influenced by the train of events occurring in the preceding 257 days. If such time elements are involved in a steep basin 

embracing a few hundred acres, the time required to complete the cycle in 

all its phases in basins such as the upper Mississippi is probably measurable in years rather than months or days.

In tables 22, 23, and 24 are summarized by basins the basic precipitation, temperature, and run-off data.

Changes in rainfall, by basins

Although the periods of record for the several basins are somewhat different, the presentation allows rough comparisons as between the 

different basins and also comparisons with the changes as given by areas. 

Except possibly in the Mississippi, Red, and Tennessee River basins the 

periods covered by concurrent precipitation, temperature, and run-off records do not embrace early years when, on the basis of long-time records,
CHANGES IN RAINFALL, TEMPERATURE, AND RUN-OFF, BY BASINS 97

the precipitation was considerably higher than any Included in the basin 

averages shown in table 22. For example, as shown in figure 21, the precipitation at Boston during the 10-year period ending 1870 was materially 

above any shown by subsequent periods, and a similar situation is shown 

with respect to other long-time stations in or near the basins studie-d. 

The averages for the Mississippi, Red, and Tennessee River basins include 

the high precipitation periods of the 1880 ! s, and the average given may be 

fairly representative of a series of both high and low years. The studies 

indicate clearly that averages based on records for the last 30 to 40 years 

in the eastern part of the United States may not embrace periods of maximum 

precipitation. On the other hand, there seems to be the possibility that 

in the plains country west of the 100th meridian and also in the Great 

Basin area (55) records for similar periods do not cover years of prevalent 

droughts, as shown by the graph of the Colorado River at Lees Ferry, Ariz. 

(fig. 17). The tables and graphs for the basins studied furnish a convenient record from which those interested may draw their own conclusions 

with respect to the magnitude of changes for different periods.

Changes in temperature, by basins

The temperature changes correspond with the changes previously 

indicated for areas. All the basins except the Merrimack show higher average temperatures for the last half of the record, and the average for the 

last 10 years was the highest for the period of record. The average temperature as given, in so far as it reflects the temperature over the basin, 

is probably too low in basins where there are marked differences ift altitude. The changes indicated, however, should represent approximately the 

changes over the basins.

Changes in run-off^ by basins

The apparent changes in run-off are consistent with the indicated 

changes in the precipitation and temperature. As was to be expected, the 

average run-off during the last half of the period of record was less than 

during the first half. Except in the Merrimack River Basin, where the 

minimum 10-year period occurred in 1918, the average run-off for the 10- 

year period ending 1934 is the lowest for the period of record. For the 

3966 O-«5 7
RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 22.- Average Annual Precipitation

Basin

Red

Mississippi

Neosho

Merrimack

James

Tennessee

Chattahoochee

Basin

Red

Mississippi

Neosho

Merrimack

James

Tennessee

Chattahoochee

Period of

record

1882-1934

1878-1934

1896-1934

1880-1934

1899-1934

1881-1934

1897-1934

Ave r age ( inche s )

Whole

period

20.91

29.61

33.58

41.63

40.79

50.36

54.59

First

half

21.76

30.18

35.00

42.56

42.03

50.34

54. SO

Last

half

20.06

28.84

32.16

40.70

39.55

50.38

54.98

Ratio

last

half

to

first

half

(percent)

92

96

92

96

94

100

101

Average

for

10

years

ending

1934

(inches)

18.78

27.86

32.68

41.38

38.30

49.18

53.64

Ratio last 10

years (percent)

To

long

time

av.

90

94

97

99

94

98

98

To

first

half

86

92

93

97

91

98

99

Maximum year

Inches

27.76

41 .28

48.74

61.48

54.03

64.10

78.46

Tear

1916

1881

1915

1928

1901

1882

1929

Maximum 10 -year

period

Inches

23.30

31.65

37.25

45.12

43.83

52.20

56.80

Year of

ending

1905

1909

1909

1893

1908

1924

1924

Minimum year

Inches

12.21

18.24

23.66

31.38

21.16

36.17

36.03

Year

1910

1910

1901

1883

1930

1925

1904

Minimum 10-year

period

Inches

18.78

27.24

31.20

37.79

37.86

47.23

51.38

Year of

ending

1934

1895

1919

1914

1930

1896

1911

Ratio

of 

last

10

years

to

minimum

10

years

( percent )

100

102

105

109

101

104

104

Table 23.- Average temperature (°F.)

Basin

Red

Mississippi

Neosho

Merrimack

James

. Tennessee

Chattahoochee

Basin

Red 

Mississippi

Neosho 

Merrimack

James 

Tennessee 

Chattahoochee

Period of

record

1882-1934

1878-1934

1896-1934

1880-1934

1899-1934

1881-1934

1897-1934

Average ( Inches )

Whole

period

39.8

45.2

55.6

45.6

54.9

55.8

61.5

First

half

38.7

44.9

55.4

45.6

54.5

55.3

61.2

Last

half

40.8

46.5

56.8

45.6

55.3

56.3

61.8

Difference

last

half

from

first

half

4- 2.1

4- .6

4- .4

0

4- .8

4- 1.0

4- .6

Average

10

years

ending

1934

41.6

46.1

56.5

46.1

55.8

56.9

62.1

Difference last

10 years from

Whole

period

4- 1.8

-(- .9

 + .9

-t- .5

4- .9

4- 1.1

4 .6

First

half

4-2.9

41.2

4-1.1

4 .5

4-1.3

41-6

4 .9

Maximum year "F.

45.8 

50.5

58.9 

48.8

57.1 

58.5 

63.5

Year

1931 

1931

1933 

1880

1921 

1933 

1921

Maximum 10-year

period

°F.

41.6 

46.1

56.4 

46,5

55.8 

56.9 

62.1

Year of

ending

1934 

1934

1934 

1889

1934 

1934 

1934

Minimum year

"P.

34.1 

41.4

53.3 

41.1

52.5 

63.3 

59.4

Year

1883 

1917

1912 

1918

1904 

1901 

1901

.Minimum 10-year

period °F.

37.6 

43.8

54.9 

44.9

54.1 

65.0 

60.8

Year of.

ending

1891 

1892

1920

1908

1910 

1893 

1910

Difference

last

10

years

from

minimum

10

years

4 4.0

+ O "Z 6fO

 + 1.6

J- T T J. c,P

4- 1.7 

4- 1.9 

+ 1.3
CHANGES IN ROT-OFF BY BASINS

Table 24.- Average annual run-off

Basin

Red

Mississippi

Heosho

Merrlmack

James

Tennessee

Chattahoochee

Period of

record

1882-1934

1878-1934

1896-1903 

1918-1934

1880-1934

1899-1934

1881-1934

1897-1934

Average ( inches )

Wiole

period

1.25

6.98

4.12

20.13

15.59

24.24

22.32

First

half

1.57

7.54

«

21.00

16.92

25.18

22.55

Last

half

0.94

6.52

«

19.08

14.27

23.30

22.09

Ratio

last

half

to

first

half

(percent)

60

86

«

91

84

93

98

Average

for

10

years

ending

1934

(inches)

0.60

5.54

4.61

19.44

13.28

21.62

20.17

Ratio last 10

years (percent)

To

Whole

period

48

79

«

97

85

89

90

To

First

half

38

74

«

93

79

86

89

Basin

Red

Mississippi

Neosho

Merrlmack

James

Tennessee

Chattahoochee

Maximum year

Inches

3.12

13.19

*

31.54

25.06

34.12

37.61

Year

1916

1881

«

1928

1901

1882

1989

Maximum 10-year

period

Inches

1.84

8.87

«

23.03

18.36

28.11

24.67

Year of

ending

1910

1888

«

1893

1908

1891

1909

Minimum year

Inches

0.13

3.12

«

10.65

7.00

13.95

11.57

Year

1934

1934

«

1911

1930

1904

1904

Minimum 10-year

period

Inches

0.60

5.54

«

16.94

13.28

21.62

20.17

Year of

ending

1934

1934

«

1918

1934

1934

1934

Ratio

of

last

10

years.

to

minimum

10

years

(percent)

100

100

*

115

100

100

100

* The broken record makes it Impossible to present comparable data.
100 RAINFALL AND RUN-OFF IN THE UNITED STATES

basins shown the period of record probably covers the minimum 10-year 

period of record except for the Neosho River Basin, where as indicated by 

the Leavenworth record (fig. 20) a lower minimum may have occurred in 1847 

or 1869; and for the James River Basin (fig. 22), where a lower minimum 

during the early seventies is indicated by the Baltimore record.

Relations between rainfall and run-off

The most commonly expressed relation between rainfall and runoff is the ratio obtained by dividing the run-off for a given period by the 

precipitation for the same period. The concept of run-off thus conveyed is 

faulty and may be misleading. A sounder concept of the relation is that 

run-off is a residual of rainfall after the deduction of losses by evaporation and transpiration. However the ratio as commonly derived, properly 

considered, is of some interest and is presented for the basins studied in 

tables 8, 10, 13, 15, 17, 19, and 21 by 10-year progressive periods. In 

figures 25 to 31 are plotted the average annual precipitation against the 

average annual run-off for each year covered by the period of record, and 

the total precipitation by 10-year periods against the total run-off for 

the same 10-year periods.

For the purpose of ready comparison of the relations between 

rainfall and run-off for the several basins, figure 32 shows to a common 

scale the average annual precipitation by 10-year periods plotted against 

the average annual run-off for the same periods. This figure is identical 

with similar data plotted on figures 25 to 31 with the exception of the 

scales. The data thus presented disclose several interesting and significant features.

On the basis of the long-time averages it appears that in the 

Red River Basin a change of 1 inch in annual rainfall is reflected by a 

change of about 0.3 inch in run-off. On the other hand, in the basins of 

the James, Merrimack, Tennessee, and Chattahoochee Rivers a change of 1 

inch in rainfall is reflected by changes of 0.7 inch to 0.9 inch in runoff. In the Mississippi River Basin a change of 1 inch in rainfall is 

reflected by a change of about 0.5 inch in run-off.

The transpiration and evaporation as measured by "precipitation 

minus run-off" as given in tables 8, 10, 13, 15, 17, 19, and 21 and shown 

graphically in figures 18 to 24 averages about 20 inches for the Red River
.RELATIONS BETWEEN RAINFALL AND RUB-OFF

<e:

 :

 1!

fit 91

 :

.12 "» 

 li *921

 19!

95«

933

 1(

34

 1887

14 

890

> 18

26 *''

89

 1£ 

 1913

3

 1929

914

 1900

22

1928

 1(

 « 2

 oe

c

99

98 

 1894

 1886

 ] 917

(.1910

 1884

 96

 1902

)3 ..0«

SB*'

 1!

893

 ]

JOT

883

4

 191

 1882

 189'

6

1.5 2.0 

Ban-Off in Inches

Figure 85a. Annual precipitation and annual run-off 

in the Bed Biver Basin above Srand Porks, K.Dak.

10 11 12 13 14 15 16 

Ban-off In inches

Figure asb. Total precipitation and total run-off by 10-year periods 

in the Bed Elver Basin above Grand Forks, H.Dak.
RAIHFALL AND ROT-OFF IN THE UNITED STATES

 li

 1934

 189

31 .

 192E

H^

 :

 96

 79

 : 24] 2li18' * li

98

L.

*"- .,

5 «

 :

 94

910

911

 1<

4. 26

&

87-12 

 22

 1902

00

G

 8C 

- 09 *19

28 *08 

78

° 

°*»K

*93- 

86...

»

_

9

 92 

4«.Q5

 19] 

 1883

1907 

85- 1'

 1

1906

6 

903

1882

 1881

3 45 6 7 8 9 10 11 12 13 14 15 

Run-off in inches

Figure 26a. Annual precipitation and annual run-off 

in the Mississippi Elver Basin above Keokuk, Iowa.

70 75 

Run-off in inches

Figure 26b. Total precipitation and total run-off by 10-year period * 

in the Mississippi River Basin above Keokuk, Iowa.
.RELATIONS BETWEEN RAINFALL AND RUN-OFF 1.05

 1918

J -1

4 1925 

 1921

< 1934 

~»193

 18

 1930

>7

1931

324

 193

 1

1899

i

 19

301

 1

 19

.9

)00 * 1

!3

)22

 1929

1898

.928

 19

 190

27

 190

I

3

1 2 3 4 5 6 7 8 9 10 11 12 13

Ban-off in inches

Figure 27a. Annual precipitation and annual run-off 

in the ffeosho River Basin above lola, Kans.

355

350

1 

 S 345 

a

 H

8 340 

+>5

ft 335

I 

* 330

325 

320

10-yea 

ending

r peri 

1927

r'

)d ;

x-

 {934

^

/

/

/

A

/

iKl QW\

40 42 44 46 48 50 52 54 56 58 60 62 64 6 

Ban-off in inches

Figure 27b. Total precipitation and total run-off by 10-year periods 

In the Neosno River Basin above lola, Kans.
Precipitation in Inches 

at o oi o w

*r

*J5 M

M «

Es

8Slu

2S*:§ ;J E

V,

1 NT N^

_^L2

Figure 28a. in theMerr

pitation Basin ab
.RELATIONS BETWEEN RAINFALL AND RUN-OPE 105

52 

48

8 **

 H 

 H 40 

|

H 36

3

S 32 £

28 

24 

20

 19

1931

50

23

 04 *

1925

1934*

 11

rav^ti

46 

IT1921

D5*3-2- 

27.

 L

 19 

.1914

18-f 

2^9 si9:i5 900

33

 1909

24. 

08 

29» '.

U .190

 1906 

37 !

3

903

 19 01

8 10 12 14 16 18 20 22 24 26 28 30 

Run-off in inches

Figure 29a. Annual precipitation and annual run-off

in the James River Basin above Cartersville, Va.

150 160 

Run-off in inches

Figure 29b.^Total precipitation and total run-off by 10-year periods 

in the James River Basin above Cartersville, 7a.
MINFALL AND RUI-OPP II THE TJNITED STATES.

66 

64 

62 

60 

58 

56 

J3 54

3 52 

§

15 50 

S

Sf

§ 48 

£

46 

44

42 

40 

38 

36

 19!

 IS 

,192i

 1!

1

 189'

SO

 1934

:

14

 191C

905 

 190C 

96

- -189E

 1932

.!<:

L8» .81 * 92 

 15 .12^3

TsT-t-16 ^ 

11 'f . 8I°3

 127 '

f hu fi

. 

 1£

I

-«i9o:

 1889.

87

18

 16

1928

£2 _ '. 

917

 1890

88

09 '' 

 « !£

 :

 1901

1980

 18<

884

1.1883.

929

6

14 16 18 20 22 24 26 28 30 32 34 36 38 

Run-off in inches

Figure 30a. Annual precipitation and annual run-off 

in the Tennessee River Basin above Chattanooga, Tenn.

840 250 260 

Ban-off In inches

Figure 30b.-Total precipitation and total run-off by 10-year periods 

in the Tennessee River Basin above Chattanooga, Tenn.
-RELATIONS BETWEEN RAINFALL AND RUN-OFF. 107

rtfi

64

60

52

:

11

 14

 31

 2"

904

 34

 05

tsr*

 18 

28'. f

 1932

_ iar\i

Il922

. 

3

 19C

.1917

.26 »1908

 -24 . 16.

. 97»|13 * < 

 07

 1921

.10

 1933

 192J5

 

)9 .!<102

. 192

 190!

)3

.192

:0

,

:9

12 16 20 24 28 32 

Run-off in inches

36 40 44

Figure 31a. Annual precipitation and annual run-off 

in the Chattahoochee River Basin above West Feint, Ga.

510

220 230 

Run-off in inches

Figure 31b. Total precipitation and total run-off by 10-year periods 

in the Chattahoochee Elver Basin above West Point, Ga.
RAINFALL AMD RUN-OFF IN THE UNITED STATES

58 

56 

54 

52 

50 

48 

46 

44 

42 

1 40

5

§ 38

<H 

4»

5

ft 36

 H

l»

32 

30 

28 

26 

24 

22 

20 

18

>

;f

Cbattahooohee BlTer Basin 

above West Point, Ga.

James River Basin 

above Oartersvllle, Ta.

Heoaho RlTer Basic 

above lola, Eans.

..«'

'f *

: '"

_..

r.'

.-

. » 

Mississippi River Basin 

above Eeokok, lova.

Red BlTer Basin 

above Grand Forks, U. Dak.

;'

.

 ,

' l

 * ] ". *' V

Tennessee Hivei 

above Ohattanoof

Herrlaack RlTer Baa) 

above Icmrence, Mas:

 Basin 

a, Tenn.

10 12 14 16 16 20 

Run-off In Inohes

Figure 32. 10-year progresslTe average precipitation and 10-year progressive average run-off 

for selected drainage basins.
RELATIONS BETWEEN RAINFALL AND RUN-OFF 109

Basin, 21 inches for the Merrimack River Basin, 23 inches for the Mississippi River Basin, 25 inches for the James River Basin, 26 inches for the 

Tennessee River Basin, and. 52 inches for the Cnattahoochee River Basin,

In the Red River Basin the normal loss by evaporation and transpiration is so great that the average annual run-off amounts to less than 

10 percent of the average annual precipitation. The average annual precipitation during the last 10 years has apparently been less than the 

normal demands of transpiration and evaporation. The stream flow that has 

occurred under such conditions must have resulted mostly from the small 

amounts of surface run-off resulting from intense rainfall of short duration or melting snow which the ground could not absorb or from seepage 

from ground water which has escaped the demands of evaporation and transpiration. Figure 25 showing rainfall, run-off, and "precipitation minus 

run-off" for the Rod River Basin, illustrates in a striking manner the fact 

that during recent years the amount of moisture available in this basin has 

not been sufficient to satisfy normal evaporation and transpiration demands 

and that the amount of precipitation that eventually finds its way to the 

stream has been declining for the last 20 or 25 years.

On the other hand, in the basins of the Merrimack, James, Tennessee, and Chattahoochee Rivers the average precipitation exceeds the normal 

transpiration and evaporation demands by 20 to 25 inches. There is normally in these basins a large supply of water available for replenishment 

of ground-water reserves and stream flow. Changes such as have occurred 

in the precipitation are of less vital concern than they are in areas where 

there is little or no surplus moisture.

The plotted relations between rainfall and run-off as shown in 

figures 25 to 31 indicate that except in the Neosho Basin and possibly in 

the Merrimack River Basin there is a tendency for the points, both annual and 

10-year total, indicating the relation during the earlier parts of the record periods, to plot toward the right-hand side of the group of points, 

and for the points indicating the relation during the later parts of the 

record periods to plot toward the left-hand side. In other words, the 

relations thus presented disclose a rather decided tendency for a somewhat smaller amount of run-off for a given amount of precipitation during 

the later half of the period than during the first half.

This apparent change in rainfall and run-off relations could have 

resulted from a combination of any or all of the following circumstances:
110 RAINFALL AND RUN-OFF IN THE UNITED STATES

1. The average precipitation as compiled for the basin during 

the first part of the period may be less than the amount that fell on the 

basin, or the observed run-off may be too high. In general it is believed 

that in so far as the run-off records are concerned, the earlier measurements of flood flows may have had a tendency to overregister rather than 

underregister, and in so far as the annual averages are based on discharge 

measurements during high stages, they are probably an overestimate rather 

than an underestimate. In basins where precipitation is related to altitude the earlier precipitation records probably underestimate the precipitation over the basin. There seems to be the possibility, therefore, that 

at least a part of the apparent change in the indicated relations may 

result from errors inherent in the basic data.

2. There may have been a change either in the seasonal distribution of the rainfall or in some other of its characteristics. The preceding analysis of the seasonal precipitation for the long-time Weather 

Bureau stations indicates that there has been an apparent seasonal change, 

the fall precipitation trending upward and the winter and summer precipitation trending downward. The same tendency is noted in the seasonal 

analysis of precipitation by basins, the records indicating a general tendency for a larger proportion of the annual precipitation to occur in the 

fall during the second half of the period than during the first half. An 

analysis has not been made to determine whether or not there have been 

other changes in rainfall characteristics. Just what effect the indicated 

change would have on run-off is problematic.

3. Changes are supposed to have resulted from man's occupancy. 

The change in the relations by which less annual run-off has come from the 

same amount of annual precipitation appears, however, to be somewhat at 

variance with the opinion frequently expressed. The question arises 

whether cultivation has not accomplished conservation of moisture for crop 

production in amount sufficient to overweigh any increased surface run-off 

that might have been occasioned as a result of agricultural and other 

activities of man.

4. Increased transpiration and evaporation may have accompanied 

increased temperatures. With moisture available an increase in temperature 

would increase transpiration and evaporation. The present studies, however, have not been carried to a point where the losses can be correlated 

with the indicated increases in temperature.
RAINFALL AND RUN-OFF IN THE UNITED STATES 111

Stream flow

It is generally understood that run-off, the portion of the precipitation that appears as flow in surface streams, occurs in two ways - 

namely, (a) as surface run-off, or that part of the precipitation which 

reaches surface streams by flowing over the surface of the ground and into 

tributary streams, and (b) as ground-water run-off, or that part of the 

precipitation which before reaching surface streams has passed through the 

ground. Ground-water run-off is sometimes termed "seepage flow from ground 

water" and occasionally "base flow" or "sustained flow."

It is axiomatic that if the greater part of the precipitation 

runs off the surface of a drainage basin the resulting stream flow will be 

erratic and irregular and will continue for only relatively short periods 

of time during and after rains. Little opportunity will be afforded for 

replenishment of ground-water reserves, and where the run-off is concentrated and erodible material is present erosion will result. On the other 

hand, if the greater part of the precipitation reaches the stream as seepage from ground water, stream flow will be regular and well sustained 

through drought periods, and ground-water reserves will be well maintained.

Stream-flow separation

In hydrologic investigations and especially in quantitative 

studies of factors of the hydrologic cycle, it becomes desirable to separate run-off into its surface and ground-water components. The efforts 

to make such separation are met with many practical difficulties and complexities. However, some progress has been made by various investigators 

in the development of methods of separation, and despite the recognized 

limitations qf present knowledge, a brief account of their experience seems 

appropriate.

First a general contrast may be drawn between the characteristics of surface and ground-water run-off.

Ordinarily, soon after rain falls with sufficient intensity to 

produce a flow of water across the ground surface, surface run-off begins 

to appear in the channels of the stream system. Usually, where storage is 

negligible, not long after the rainfall ceases all such surface run-off is 

in the channels of the stream system, and within a period ranging from a 

day or less to a month or more, depending on the size and characteristics
112 RAINFALL AND RUN-OFF IN THE UNITED STATES

of the basin, it has passed out of the stream system. The characteristics 

of the flow of surface run-off are related to the essential characteristics 

of the drainage basin and the stream system, including shape of the basin, 

channel velocities, etc. Many of the features of such basin characteristics are believed to be reflected by the unit hydrograph and the distribution graph, discussed elsewhere in this paper.

On the other hand, the ground-water run-off ordinarily is delayed 

more or less in passage through the ground, so that the part of the precipitation which takes this course is reflected in stream flow more tardily 

than the surface run-off, the intervening time involving weeks, months, or 

even longer.

A customary procedure in estimating ground-water run-off is to 

present the run-off to be analyzed in the form of a hydrograph of total 

flow and then undertake to draw a graph to represent the ground-water component of the flow. Any flow above that indicated by the graph of groundwater run-off will then necessarily represent the surface run-off component 

of the flow. In making such separation full advantage is taken of the 

knowledge that in general the average annual rate of ground-water run-off 

is at least equal to the minimum daily rate of discharge of the stream. 

Above this discharge the determination of the ground-water run-off becomes 

increasingly uncertain. There is opportunity for the development of a 

well-defined technique for this determination, but in the absence of such 

technique the only recourse is to apply the best methods based on experience and science that may be available.

Ivan E. Houk (72) made a separation between ground-water run-off 

and surface run-off by drawing on the hydrograph of total stream flow 

"lines representing the rate of ground-water flow ... so as to pass 

through the low points only" of the hydrograph. "The endeavor was to draw 

the line so that the increased flow of tiles immediately after a flood - 

that is, the drainage of the surface soil - would be included in the surface or flood run-off rather than in the ground-water run-off, since such 

flow acts more nearly like surface flow than like low-water flow. It was 

also assumed that no percolation occurs during the growing season."

Meinzer and Stearns (115), in an effort to determine the quantity 

of ground water that percolated into the Pomperaug River and was carried 

out of the basin, followed the general method used by Houk. In addition 

they took into account the probable time element in connection with the
STREAM PLOW 113

passage of the surface run-off out of the basin, and during periods of 

flood run-off "the curves showing the ground-water run-off were brought up 

somewhat to meet the descending curve that shows total run-off."

Approximately this same method was used by L. K. Sherman (158) 

in determining his unit graph of surface run-off. He made the separation 

under conditions pf low ground-water flow uncomplicated by antecedent, 

effects.

One of the major complexities associated with the problem is the 

consideration of stored surface water in the drainage basin. Although on 

most streams a large part of the surface run-off appears at the gaging 

station fairly promptly after the rainfall from which it originates and is 

shown by a definite rise in the hydrograph of stream flow, there may be in 

some basins an appreciable amount of surface run-off which is held in 

storage, either artificially or naturally, in lakes, ponds, reservoirs, and 

marshes, and which eventually appears at the gaging stations so closely 

associated with ground-water flow that exact differentiation would require 

details of information that are rarely if ever available. Also the hydrograph of the peak or rise in stream flow may represent to some extent increased ground-water run-off resulting from recharge to the zones of 

saturation and increased contributions from those zones.

In the absence of information permitting greater refinement, 

surface run-off is tentatively regarded in this report as that part of the 

total run-off that appears systematically and regularly in the stream 

channel as the rise directly responsive to rainfall or the melting of snow. 

(For classification of stream rises see 70, p. 455.) The rise probably 

does not include all surface water, because some of it may be materially 

delayed by storage in reaching the gaging station. The rise may include 

some ground water that has been held in ground reservoirs that feed the 

streams, especially after prolonged intense rainfall, with a responsiveness that is only somewhat less pronounced than that which characterizes 

surface run-off. This condition may occur especially in basins where 

perched water tables exist or in tiled areas.

Ground-water run-off as considered in this paper is the estimated 

seepage flow directly into the stream from the main zone of saturation and 

from perched water tables. (For definitions of ground-water terms see 

Meinzer, 113). In view of the approximations involved in the separation 

of ground-water and surface run-off, a ground-water graph may include 

some water that has been stored on the surface and may exclude

5955 O 35 8
114 RAINFALL AND RUN-OFF IN THE UNITED STATES

some ground water which in the promptness of its reaching the stream channels behaves so much like surface run-off that it is difficult to mske a 

distinction.

There is no question that the occurrence and movement of ground 

water depends on and is affected by a wide variety of topographic, geologic, and soil conditions. There is also no question that with these 

conditions constant for any basin, the occurrence and movement of the 

ground water will vary with meteorologic conditions. In a study of the 

problems of.separating ground-water run-off from surface run-off in a basin 

of material size it may therefore be desirable and necessary to take into 

account as many relations and as many flow characteristics as can be developed. Such relations and flow characteristics may include depletioncurves, recession curves-, recharge curves, unit hydrographs, infiltration 

and storage factors, together with the effect of meteorologic conditions. 

The following is a brief summary of some of the observations and methods of 

investigators who have attempted to ascertain the facts and truths relating 

to this particular phase of ground water.

Depletion curves

Samuel Hall (53) observed in connection with the recession of 

stream flow that in "the gently falling and lowest parts of the curve due 

to percolation discharge, one characteristic is the steady fall, showing 

not only that the rate of flow decreases but that its rate of decrease also 

diminishes; in other words, the curve gets flatter from day to day throughout a rainless period," and further, that after additional precipitation 

"not only has there been a large immediate yield, as shown by a peak, but 

the stream has gained in staying power. . The conclusion drawn is that new 

supplies of percolation water have increased the amount in storage, with 

result of increased discharge."

Studies of the fluctuations of the water surfaces in observed 

wells unaffected by pumping and below the effect of transpiration and 

evaporation support Hall's observations and indicate that during periods 

Hnrhen there is no recharge the decline of the water surface in the well, or 

the draining out or depletion of the water in the zone of saturation in the 

vicinity, of the well, proceeds at a fairly uniform rate for any given stage 

of the water table or amount of water in ground storage. It seems
STREAM PLOW 115

reasonable to assume, therefore, that the seepage into the stream from the 

ground-water supply or the ground-water run-off should also be marked by 

uniformity except as affected by evaporation and transpiration.

Robert E. Horton (70, pp. 448-449) refers to early observations 

and presentations of depletion curves of ground-water levels by Maillet in 

1905 and D. Halton Thompson in 1921 (180). The methods of these early investigators have been extended to the separation of ground water from surface run-off by Horton and others, and the theory of this separation is 

presented by Horton (70, pp. 446-460).

Studies of the hydrographs of some streams seem to indicate conclusively that during drought periods, when the stream flow is supplied 

wholly or in large part by seepage from the reservoir of ground water, the 

rate of decline for corresponding flow stages and climatic conditions tends 

to be very nearly the same. In other basins, where water-bearing formations or other conditions may be more complex, the rate in the decline of 

stream flow during drought periods seems to vary somewhat.

The seepage flow into the streams is supplied from an irregular 

and interrelated body of water in the ground. It is water that has escaped 

transpiration and evaporation, the effects of which in many basins are 

believed to be greatest in the vicinity of stream channels, where the water 

table is nearest the ground surface. In such localities the effects of 

evaporation and transpiration may vary greatly from year to year and from 

season to season, depending upon a variety of conditions. Some investigators have found by extensive observation that marked regularity characterizes the behavior of ground water in relation to season, temperature, 

and other factors. Horton (70) makes the following statement in regard to 

what is termed a normal depletion curve in the study of ground-water runoff:

"For streams where the ground-water level underneath the drainage basin is at a depth beyond the reach 

of the direct abstraction of plants or vegetation, the 

normal depletion curves in different years are often 

nearly identical throughout their common range, within 

the limit of error of observation and excluding the 

effects of barometric changes, etc., on ground-water 

flow. The normal depletion curves may differ to a considerable extent in different years or seasons in cases
116 RAINFALL AMD RUN-OFF IN THE 'UNITED STATES

where there is a direct abstraction of ground water 

from the water table by vegetation or evaporation. 

Even in such cases the differences between stnmnerseason depletion curves in different years is often 

so small that for practical purposes in separating 

ground-water and surface run-off, an average normal 

depletion curve can be used."

Tomihisi Iwasaki (82), by a detailed study of the run-off from a 

fairly mountainous drainage area of 156 square miles, developed a standard 

depletion curve and also determined the approximate relation between precipitation and the increment of ground-water and surface run-off and was 

thus able to build up a hydrograph of total run-off.

It is seemingly permissible in the absence of any better method 

of approach to utilize in this problem the tendency to regularity that may 

be detected in & comparison of depletion curves, but the possibility that 

there may be material deviations from normal depletion curves should not be 

overlooked. In basins where closely comparable depletion curves can be 

obtained for different seasons or where the characteristics of depletion 

curves can be correlated to some degree with climatic or soil conditions, 

they seem to afford useful and valuable tools in efforts to separate 

ground-water run-off.

Recession curves

A recession curve, as the term is here used, is the descending 

limb of a hydrograph of stream flow, including both surface run-off and 

ground-water run-off, as it recedes from a peak downward to the point of 

zero surface run-off. Most streams rise more or less frequently to a flood 

peak and, before subsidence from it has been completed, rise to another 

peak. For many streams the hydrographs for the winter and early spring are 

characterized by peaks in such rapid succession that only rarely does the 

surface run-off have a chance to drain out. Such peaks make the task of 

drawing a ground-water hydrograph difficult and the results uncertain.

It has been observed that during periods of frequent floods the 

descending limbs of storm peaks become graded to a higher level than isolated peaks occurring during periods of low flow. Through a study of the 

descending limbs of hydrographs of storms occurring during the summer, when
STREAM PLOW 117

ground water is low, it may become possible to develop a composite recession curve. Such a composite curve used on the descending limb of a storm 

hydrograph when ground water is high seems to be valuable in locating the 

probable intersection of the hydrograph of surface run-off with the hydrograph of ground-water run-off. This method, like the other methods described, has its limitations. In practice It is found that the curvatures 

of the descending limbs during the summer are sonewhat different from 

those during the winter. It is also found that the descending limb of a 

storm peak is often affected by rainfall - that is, the ra*e of descent is 

not as rapid as the recession would be if there was no rain after the flood 

peak, and fitting a recession curve to this descending limb results in 

erroneous estimates of ground-water flow.

Byron E. White (187a), in an original study of relations between 

rainfall and run-off when there was no snow on the ground and no freezing 

and thawing, definitely correlated the form and rate of recession of the 

recession side of the hydrograph with calendar dates and mean atmospheric 

temperatures. In a letter dai;ed April 29, 1935, he says: "An attempt to 

determine stream flow on this theory, together with some simple relations 

between initial flow, an Imaginary instantaneous flow, and the mean rainfall on the area, which is described therein, failed to give close results, 

in part because of insufficient and inadequate rainfall data and in part 

because of insufficient data regarding other phenomena."

Ground-water levels and accretion

The portion of the precipitation that seeps through the soil into 

the zone of saturation forms an increment to the ground water in the zone 

of saturation.

On January 1, 1935, the water surface of more than 3,000 wells 

was being periodically measured by the United States Geological Survey and 

cooperating organizations. The publication year by year of the levels thus 

observed, in a manner similar to the publication of the stream-flow records, 

is a procedure that is greatly needed. Preliminary studies of precipitation, accretion to the water table, and seepage from the ground-water 

reservoir into the stream channels have indicated that the relations are 

involved. In general, information is not available for making an exact 

correlation, even where many well records are at hand. If however,
118 RAINFALL AND RUN-OFF IN THE UNITED STATES

through a study of well records or of the hydrographs of stream flow some 

idea can be gained of the rapidity with which accretion to the water table 

takes place, or the rapidity with which seepage from ground water may increase, such information will be valuable in the determination of the 

hydrograph of ground-water run-off.

Unit hydrographs

As described more fully in the discussion of the unit-hydrograph 

method of analy2ing surface run-off (pp.123-133) the lengths of the bases 

of hydrographs of surface run-off of storms of a certain duration, such as 

an hour or a day, are approximately the same for any given basin. In 

other words, the interval between the time when the surface run-off from 

a 1-day storm first reaches a gaging station and the time when all such 

surface run-off has passed the gaging station appears to be approximately 

the same, regardless of the storm intensity. Through a study, therefore, 

of the hydrographs of run-off from appropriately selected storms it is 

possible to determine the approximate time required for surface run-off to 

pass out of the basin, and hence, by a study of the hydrograph of stream 

flow used in conjunction with precipitation records, to determine periods 

when there is no appreciable surface run-off in the stream or when the 

hydrograph of total stream flow approximates the hydrograph of seepage flow 

from ground water.

Much of the information of the unit hydrograph, embodying essential features of the characteristics of the flow from surface-water run-off, 

is based upon studies of flow at times when uncertainties as to groundwater run-off are relatively small. A carefully derived unit hydrograph 

unquestionably shows valuable information concerning the characteristics of 

surface run-off that seemingly may be used in an appropriate way in times 

of uncertainty, to learn more about the ground-water flow.

Infiltration capacity and storage factors

Robert E. Horton, a member of the Advisory Committee, has

suggested that it may be possible eventually, through a knowledge of infiltration capacity, field-moisture deficiencies, and storage factors, defined 

by him in a recent publication (70a), to determine surface run-off and 

conversely ground-water run-off.
STREAM PLOW 119

Meteorologic factors

It is a well-known fact that during rainless periods in the 

autumn the flow of many springs and streams increases. This increase is 

usually associated with the end of the growing season and the decline in 

transpiration losses. A depletion curve of ground-water run-off loses its 

downward projection under such conditions, and the ground-water run-off 

presumably increases by an amount approximating the reduction in losses 

from transpiration. Prom studies of the relations between the decline in 

ground-water levels and changes in the rate of ground-water discharge, it 

has been observed that in certain instances a decline in water levels during a period when evaporation and transpiration are active causes a 

decrease in the rate of ground-water discharge noticeably smaller than 

that effected by the same amount of water-table lowering during a period 

of dormant vegetation. Although effects of other factors could be pointed 

out, it seems obvious that the problem of separating ground-water run-off 

from surface run-off requires a consideration of meteorologic conditions. 

Adolph P. Meyer (122) describes methods whereby meteorologic factors may 

be used in the determination of the amount of water available for replenishment of soil moisture and recharge to ground water. A discussion of 

methods devised by Meyer to evaluate evaporation and transpiration losses 

is given on pages 250 and 251.

Channel storage

0. E. Meinzer, of the United States Geological Survey, has suggested a method whereby ground-water run-off may be directly determined 

through a study of changes in channel storage. The method requires the 

determination of the amount of run-off that is held as channel storage at 

any time. It is based on the hypothesis that as soon as essentially all 

the direct surface run-off reaches the channel the total amount of direct 

surface run-off that will pass the gaging station can be calculated from 

the changes in channel storage. When, during a certain day in which no 

surface water is added to the stream system, more water is measured at the 

gaging station than is represented by the changes in channel storage, the 

excess is attributed to ground-water run-off. Field experiments are now 

being carried on under the direction of Meinzer to determine changes in 

channel storage on a small basin near Washington, D. C.
120 RAINFALL AND RUN-OFF IN THE UNITED STATES

Surface run-off 

Quantitative analysis, by basins

The following tables show for typical basins in the United States 

and for major subdivisions of the Mississippi River above Keokuk, Iowa, an 

estimate of the mean annual surface run-off expressed in inches and as a 

percentage of precipitation. All figures are in general based on a 5-year 

annual average for the period noted and were obtained by subtracting from 

the total stream flow the ground-water run-off as estimated from a study of 

the plotted hydrograph of stream flow, using, in part, methods previously 

discussed. It should be clearly recognized that the estimates given are 

subject to error. Further refinement in the methods of determination and 

more exhaustive application of known factors might change the results 

materially. They are, however, believed to be of sufficient accuracy to 

make comparisons between typical basins of a very important phase of the 

hydrologic cycle, and this is a primary purpose of their presentation.

The figures given for the Miami River Basin, Ohio, and for the 

Pomperaug River Basin, Conn., are based on general straight lines as previously outlined, and the results may not be entirely comparable with the 

figures given for the other basins.

Table 25.- Average annual surface run-off for typical basins

Basin

Red River above

Grand Forks, N. Dak.

(1928-52)

Mississippi River above

Keokuk, Iowa

(1928-32)

Neosho River above

lola , Kans .

(1928-52)

Merrimack River above

Lawrence, Mass.

(1928-32##)

James River above

Cartersville, Va.

(1928-S2)

Precipitation 

(inches)

18.55

28.64

33.07

40.66

S8.04

Surface run- off

Inches

O.S5

3.56

4.06

-* 9.94

7.02

Percent of 

total runoff

59.3

56.2

82.5

50.9

53.5

Percent of 

precipitation

1.9

11.7

12.3

24.5

18.5

* Probably too small. 

«-* Years ending September 30.
SURFACE RUN-OFF 121

Table 25.- Average annual surface run-off for 

typical basins continued

Basin

Tennessee River above

Chattanooga, Tenn.

(1901-5)

Chattahoochee River above

West Point, Ga.

(1928-32)

Miami River above

Dayton, Ohio#

(1894-1919**)

Pomperaug River above

Bennetta Bridge, Conn.##

(1914-16**)

Precipitation

(inches)

49.83

59.65

37.07

44.48

Surface run-off

Inche s

15.30

11.59

7.77

11.90

Percent of

total runoff

64.4

50.1

65.6

57.6

Percent of

precipitation

30.7

19.4

21.0

26.8

# See ref. 72.

*# Years ending September 30. 

## See ref. 115.

Table 26.- Average annual surface run-off for major 

subdivisions of Mississippi River Basin above Keokuk

Subdivision

Minnesota River above

Mankato, Minn.

(1930-32*)

Zumbro River above

Zumbro Falls, Minn.

(1931-32*)

Maquoketa River above

Maquoketa, Iowa

(1931-32*)

La Cross e River above

West Salem, Wis.

(1928-32*)

Root River above

Houston, Minn.

U931-32*)

Kickapoo River above

Gays Mills, Wis.

(1928-32*)

Rock River above

Afton, Wis.

(1928-32*)

Iowa River above

Wapello, Iowa

(1928-32*)

St. Croix River above

Rush City, Minn. 

(1928-32*)

Precipitatipn 

(inches)

22.22

26.35

30.64

30.35

27.98

29.67

29.62

32.83

25.32

Surface run-off

Inches

0.42

1.70

2.89

2.64

2.42

3.64

3.63

4.28

3.76

Percent of 

total runoff

61.0

48.8

51.5

26.6

44.6

40.0

49.0

61.1

51.7

Percent of 

precipitation

1.9

6.5

9.4

8.7

8.6

12.3

12.3

13.0

14.8

* Years ending September 30.
122 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 26.- Average annual surface run-off for major 

subdivisions of Mississippi River Basin above Keokuk Continued

Subdivision

Pecatonica River above

Freeport, 111.

(1928-32*)

Skunk River above

Augusta, Iowa

(1928-32*)

Yellow River above

Sprague, Wis.

(1928-32*)

Black River above

Neillsville, Wis.

(1928-32*)

Precipitation

(inches)

31.95

35.85

29.09

30.99

Surface run-off

Inches

4.77

5.47

4.87

7.84

Percent of

total runoff

47.7

69.8

71.7

84.1

Percent of

precipitation

14.9

15.3

16.7

25.3

Years ending September 30.

Although basin and precipitation characteristics have not been 

correlated with these surface run-off estimates, in all probability they 

would show about the same relations as between these characteristics and 

flood magnitudes. In other words, the greater the intensity of the precipitation, the more impervious the soil, and the greater the basin slopes the 

greater will be the direct surface run-off, and vice versa. The estimates, 

to the extent of their accuracy, represent roughly the amount of water that 

would be subject to regulation and control operations relating to surface 

run-off. There is probably a direct relation between the magnitude of 

these estimates and the magnitude of erosion by water in the respective 

areas.
RAINFALL AMD RUN-OFF IN THE UNITED STATES 123

Unit-hydrograph analysis of surface run-off

Surface run-off has been defined as that part of the precipitation v/hich reaches surface streams by flowing over the ground and into 

tributary streams. Once in the stream channel, surface run-off follows 

the laws governing the flow of water in open channels. The discharge of 

surface run-off into stream channels simultaneously over basin areas results in pronounced rises in stream levels, followed by periods of decline.

The plotted graph of stream flow, which presents graphically the 

rises and declines of run-off, has been used by many investigators as a 

basis for much of the available information regarding the phenomena of 

surface run-off and the relation of basin characteristics to them,

The Committee on Floods of the Boston Society of Civil Engineers, 

after a study of New England flood hydrographs, concluded (18) "that a 

flood hydrograph once determined for a given river, even for an ordinary 

flood, will serve as a basis for the estimation of greater flood run-off, 

due to the fact that the base of the flood hydrograph (or time-of-flood 

period) appears to be approximately constant for different floods." L. K. 

Sherman (158), in 1932, presented the idea that not only was there a definite total flood period corresponding to a given rainfall for the same 

drainage area but that surface run-off from rainfalls occurring within the 

same time interval, such as a day or an hour, will produce hydrographs 

whose ordinates will vary with the amount of the surface run-off. From the 

principles set forth by Sherman the hydrograph of surface run-off resulting 

from rainfall within a unit of time as a day or an hour may be called a 

"unit hydrograph."

Merrill M. Bernard (13), in 1934, developed certain features of 

the unit hydrograph, introduced added features of the distribution graph 

and pluviagraph, and suggested certain relations between rainfall and runoff within the storm period.

The development of unit hydrographs and distribution graphs has 

been based on a detailed study of the relations between rainfall and runoff as disclosed by hydrographs of stream flow, on the basis of both cumulative experience and scientific analysis. As in many other instances in 

the development of hydraulic science, reliance is placed to the fullest 

possible extent on available scientific theory, as well as on the cumulative evidence of general relations disclosed by analysis of experience or
124 RAINFALL AND RUN-OFF IN THE UNITED STATES

experiment. The use of these graphs is still largely in the experimental 

stage, and theoretically and practically there appear to be limitations of 

application that have not yet been well defined. Despite a variety of difficulties, the device seems to present a tool of very considerable value 

for resolving to some extent the complex relations of rainfall and run-off 

and for advancing the science of hydrology. Consequently in the present 

investigations considerable time has been given to the investigation of 

relations between rainfall and surface run-off as disclosed by the unit 

hydrograph and the distribution graph. These studies have been carried on 

along three lines - namely, (1) preparation of unit hydrographs for typical 

drainage basins, (2) general application of the unit-hydrograph method to 

hydraulic problems, and (3) application of the unit-hydrograph principle to 

flood studies.

Many rather baffling problems relating to the unit hydrograph 

have been encountered in these studies, and the following discussion and 

presentation of the underlying methods of application must be considered 

more or less provisional.

The unit hydrograph and distribution graph and their preparation

The terms used may be defined as follows:

A unit hydrograph is a hydrograph of surface run-off resulting 

from rainfall within a unit of time, as a day or an hour.

A distribution graph is a unit hydrograph of surface run-off 

modified to show the proportional relations of its ordinates in percentage 

of the total surface run-off.

In theory, at least, it would seem that the principles of the 

unit hydrograph deal only with surface run-off, and this discussion of the 

method of its preparation has been predicated on that assumption.

L. K. Sherman (159) describes the basic hypothesis of the unit 

hydrograph and distribution graph and their preparation as follows:

1. The unit-hydrograph method is a procedure for determining 

the peak and other rates of surface run-off from a particular basin, by 

analogy, from an observed rainfall and the corresponding observed hydrograph of surface run-off from the same given basin.

2. The hypothesis upon which the unit-hydrograph method is based 

is that in a given drainage basin surface run-off from rainfall occurring
OTIT-HYDROGRAPH ANALYSIS OP SURFACE RUN-OFF 125

in a wait of time will produce hydrographs of approximately equal bases, 

and the ordlnates will vary with the intensity of the net rainfall (net 

rainfall being rainfall minus infiltration and other losses).

3. The first step in the application of the method to a basin 

is to find a hydrograph of surface run-off due to an isolated one-day (or 

unit-time) rainfall from an inspection of daily rainfall and run-off 

records.

The average daily rates of observed flow for the run-off period 

are given in the United States Geological Survey water-supply papers. 

These daily rates of stream flow include both surface run-off and base or 

ground-water flow. Estimate this base flow. Subtract the base flow from 

each of the observed flows. Also deduct flow due to antecedent rainfall, 

if any. This will give the segregated flow or surface run-off due wholly 

to the rainfall in question. Find the percentage that each day of segregated flow bears to the total segregated flow. These figures will total 

100 percent and they form the distribution graph.

Unit hydrographs and distribution graphs have been prepared for 

a considerable number of rivers in the United States, and typical graphs 

are shown in figures 33 to 69. The problems and questions outlined below 

have been considered in connection with their preparation. It should be 

stated at the beginning that the particular hydraulic problem to be solved 

by means of the unit-hydrograph theory determines to a great extent the 

technique used in developing distribution graphs.

For the basins studied the calendar day has been used as the 

time unit. Basically the problem here discussed is the determination and 

comparison of the surface run-off resulting from the occurrence of rainfalls of 24-hour duration.

Weather Bureau records coincident with available run-off records 

are scanned, and all isolated storms that appear from the record to have 

occurred within a 24-hour period are noted. These storms are then compared with the corresponding run-off records as published in water-supply 

papers of the United States Geological Survey, and those storms which produced appreciable peaks in the hydrograph of total stream flow are selected 

as a basis for the preparation of unit hydrographs. The ideal storm would 

be one of 24-hours 1 duration coincident with the calendar day and with 

rainfall of uniform intensity over the basin. Storms that exactly fulfill
126 RAINFALL AND RUN-OFF IN THE UNITED STATES

these requirements seldom, if ever, occur in nature, and only approximations to the ideal can be expected.

It is not necessary to determine the average precipitation over 

the basin for the unit storm, to derive the resulting distribution graph. 

However, as an aid in studying variations in the distribution graphs, it 

is convenient to have at hand the recorded daily precipitation at the 

available stations. If the unit-hydrograph theory is applied in an intensive study of any particular basin it must be determined whether an average 

of the station records is satisfactory, or whether some method of weighting 

is required to obtain average daily depths of precipitation over the basin.

Few of the published records of the United States Weather Bureau 

indicate whether the recorded precipitation occurred during 1 hour or was 

well distributed over the 24 hours. A 24-hour storm that does not synchronize with the calendar day will be recorded on two consecutive days. This 

lack of definite information relative to the length and time relation of 

storm periods is a decided handicap in analyzing surface run-off, but it is 

a condition that will be improved as more recording rain gages are 

installed.

For each unit storm, so called, a hydrograph of stream flow is 

plotted covering a period that will embrace as a minimum all the time involved in the surface run-off of the storm and at least a month preceding 

and subsequent to it. The problem now involves the determination of the 

surface run-off resulting from the storm. The procedure includes the 

determination of (a) surface run-off resulting from precipitation antecedent to the storm, (b) surface run-off resulting from subsequent precipitation, and (c) ground-water run-off resulting from antecedent precipitation 

and from the storm itself.

Figure 33 (graph ABCDEF) is a typical hydrograph of stream flow 

following three storms, the recorded precipitation of which is listed in 

the following table. The unit hydrograph, table 28, column 5, is the surface flow resulting from the unit storm of June 26.
I 

8 

8 
128 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 27.- Typical unlt-hydrograph storms in 

Muskingum River Basin above Dresden, Ohio

(Precipitation In inches, measured in the afternoon except 

at stations marked #, where it was measured in the morning.)

Station

Ashland

Bangorvllle

Mansfield *

Wooster(no.l)

Cambridge

Coshocton *

Dennison

Dover #

Mlllersburg

Mount Vernon

Walhonding *

Zanesvllle *

Average

June 1927

14

0.20

.15

*x*x

.20

.18 

.62

.80

.55

.60

.40

.29

.51

.55

.94

6.32

.45

18

0.70

1.03

.56

.24

QQ

.38

.20

.45

.12

.57

.85

-

.36

6.28

.45

19

0.10

.05 

on

.44

.10

.32

.67

.13

.42

_

_

.85

.80

4.78

.34

21

0.05

.08

_

-

_

_

-

_

-

_

-

-

.13

.01

22

0.22

.35

.36

.20 

.26

.12

.05

.75

.01

.16

_

-

-

2.59

.19

23

0.20

.05

.02

.31

_

.07

-

_

-

_

-

.02

.67

.05

24

_

-

_

-

-

-

-

-

-

0.33

-

.32

.02

25

_

0.29

_

.97

_

_

-

_

.60

.23

-

-

2.09

.15

26

0.78

.08

1.11

.51

.30

.92

.75

1.59

1.20

.39

.61

.95

1.17

11.68

.83

July 1927

2

1.20

1.55

_

.01

.32

_

-

.02

1.10

.92

-

-

5.12

.37

Z

-

0.12

2.21

.03 

.40

1.28

1.18

.06

.02

_

.42

.50

6.22

.44

The hydrograph of ground-water run-off (graph GHJK fig. 33) has 

been determined by the method described and discussed on pages 111 to 119. 

The surface run-off from the storm preceding and the storm following the 

unit storm Is determined by the downward extension (graphs BH and DJ) of 

the hydrograph of total stream flow until it meets the hydrograph of ground 

water. To the extent that the various assumptions are correct, the crosshatched area (BCDJH) represents the surface run-off from the unit storm 

under consideration. The figures for mean daily surface run-off are thus 

determined and the ratio of each daily figure to the total volume Is computed. These ratios in percent constitute the dletrlbution graph for the 

particular unit storm under consideration. The following table represents 

the steps taken:
UNIT-HYDROGRAPH ANALYSIS OP SURFACE RUN-OFF 129

Table 88.- Derivation of distribution graph 

Musklngum River Basin above Dresden, Ohio

(The calendar day on which most of the 

rainfall occurred is denoted by *.)

Date

1

June 24,1927

25

26 -::-

27

28

29

30

July 1

2

3

4

5

Total run-off (second-feet)

Unit

storm

2

3,090

3,240

5,110

7,990

6,570

4,630

3,540

2,940

2,520

-

-

-

Recession

following

unit

storm

3

_

-

-

-

-

-

-

-

-

2,200

2,050

1,960

Recession

preceding

unit

storm

4

3,090

2,600

2,350

2,250

2,200

2,150

2,100

2,050

2,020

2,000

1,980

1,960

Surface run-off

from unit storm

(col. 2 or 3

- col. 4. )

(second-feet)

5

«

640

2,760

5,740

4,370

2,480

1,440

890

500

200

70

0

19,090

Distribution

graph

(col. 5 x

100 ;- total

of col. 5)

6

_

3.4

14.5

30.0

22.9

13.0

7.5

4.7

2.6

1.0

.4

0

100.0

Note.- Column 2 corresponds to graph BCD, figure 33; column 3 to graph 

DJ; column 4 to graph BH; and column 5 to the cross-hatched area. '

When the distribution graphs of the different unit storms considered are plotted with respect to the recorded time of the occurrence of 

the unit storms and with no consideration of a time unit less than 1 day, 

there is generally a variation in time between the day of recording of the 

precipitation and the peak run-off.

The average distribution graph for any basin wag determined by 

superimposing the separate graphs to the best fit. From a study of the 

individual unit storms, the average time between the .day of occurrence of 

the rain and the day of occurrence of the peak of the distribution graph 

was obtained; this time was then used in synchronizing the day of rain with 

the composite plot of all the distribution graphs.

In this connection it should be stated that the daily figures for 

the separate distribution graphs depend in part on the time of recording at 

the available precipitation stations, whereas the shape of the average distribution graph is independent. In other words, if the precipitation data 

to be used consist of records made at morning, afternoon, and midnight stations, the synchronization between recorded daily precipitation and resulting mean daily flows is variable.

5955 O 33 9
130 RAINFALL AND RUN-OFF IN TUB UNITED STATES

One continuous rainfall record on or near the basin aids materially in shifting recorded daily depths so as to obtain a good estimate of 

the precipitation occurring in any 24-hour period that has been synchronized with resulting stream flow.

The average of the peak figures on the separate graphs was used 

as a basis for determining the one or two peaks for the average graph, and 

the remaining figures for the average distribution graph were determined 

from the composite plot of all the graphs. This procedure was necessary, 

as the scattering horizontally of the peaks on the composite plat made the 

graphic determination of an average peak value impossible. This difficulty is eliminated where continuous-flow records rather than records of 

daily mean flow are available.

One of the principal causes for the variation in the time element 

for the basins studies is believed to lie in the limitations of the basic 

information, especially with respect to time. Another suggested cause is 

the position of the center of the storm in the basin with relation to the 

gaging station. A longer elapsed time is to be expected if the storm 

centers at a point remote from the gaging station than if it centers at a 

nearer point. The stage of the river at the time of the storm may also 

produce a variation. If river stage is high when the unit storm occurs, 

it is reasonable to expect that the time of occurrence of the peak would 

be shorter than at a low stage.

In addition to the time variation there is appreciable difference 

in the percentage for the peak day. Some of this difference is due to the 

fixed time of beginning and ending the calendar day and is eliminated if 

continuous records are available. For streams that reach and maintain a 

high flow for lees than 24 hours, the resulting distribution-graph peak 

will vary as to whether the period of high flow falls within one calendar 

day or is divided between two days.

On the other hand, it is entirely conceivable that with continuous discharge records it would be found that owing to variations in storm 

centers and differences in storm intensities, as close agreement could not 

be obtained as is indicated from the observed mean daily records, which 

tend to obscure many important factors.

Differences in intensity and duration of the several unit storms 

will also modify the peak to some extent, and so will the location and 

movement of the center of the storm. The more remote storms have a
UNIT-HTOROGRAPH ANALYSIS OP SURFACE RUN-OFF 131

greater opportunity for ironing out, thus producing flatter distribution 

graphs. Of course, a storm that traveled down the basin would produce the 

opposite effect.

Before describing problems of application of unit hydrographs 

and distribution graphs a general discussion based on experiences gained 

in the group study as well as by others seems desirable. Unquestionably 

the graphs have their limitations, and likewise it may be shown that some 

of the necessary assumptions are subject to error. The more clearly the 

limitations or effect of erroneous assumptions are recognized the greater 

the value of the graphs will be.

1. In the preparation of unit hydrographs it is necessary to 

separate ground-water flow from total stream flow, and because, as discussed elsewhere in this report, there seems to be no exact way that the 

separation can be made, it may be argued that the lack of definiteness 

imposes a serious limitation on the use of unit hydrographs. To overcome 

the limitation as far as possible, it is preferable to determine unit 

graphs from isolated storms that produce large surface run-off and occur 

when the ground-water flow is small. By so doing the probable errors in 

the determination of the ground-water flow are small, and the resulting 

distribution graphs are believed to represent closely the characteristics 

of surface run-off from that particular basin. As knowledge of the laws 

governing the flow of surface water and ground water is increased, difficulties incident to their separation will become less and the accuracy of 

the unit hydrograph in depicting surface run-off should increase.

2. It has been pointed out that "it does not seem entirely safe 

to assume that the analogy between small and large floods is a rigid one." 

The special committee of the Section of Hydrology of the American Geophysical Union has concluded that the validity of the unit-hydrograph 

theory seems strongly supported within practical limits by (a) the general 

agreement of distribution graphs derived under widely varying rates of 

rainfall and infiltration by the rainfall and run-off group - Sherman 

(158), Bernard (IS), Smart (167), and others; (b) test by application to 

the recorded stream flow; (c) studies by the Committee on Floods, Boston 

Society of Civil Engineers (18); (d) comparative analysis by Sherman (160).

3. Theoretically it would seem that, as a result of differences 

in channel velocities, the unit hydrograph of a 1-day storm occurring when 

the river is at a high stage would differ from one derived when the river
152 RAINFALL AND RUN-OFF IN THE UNITED STATES

Is at a low stage. Robert W. Gay, of the United States Engineer Office, 

Zanesville, Ohio, who has studied the unit graph Intensively in connection 

with hhiskingum River projects, In a letter dated February 28, 1935, states: 

"It is probably true that as the amount of Surface run-off per day Increases, there are increases In hydraulic radii of the conducting channels 

of all sizes and corresponding Increases In velocities of flow, which 

would tend to produce shorter run-off periods and apparently controvert to 

a greater or less extent the basic assumption of 'equal bases' for the 

graphs from various storms on the watershed. But before discarding the 

method on this ground, it must be shown that errors arising from the 

assumptions are sufficiently great to put this method at a disadvantage as 

compared with others."

The comparative analysis by Sherman (160) Indicates that "the 

hypothesis of direct proportion of ordinates In the unit hydrograph Is not 

accurate for small areas involving only a few acres. The relation rapidly 

improves In accuracy as the area increases to 2 square miles or more. 

This Is due to the "Ironing out process' with the element of time."

However, W, W. Horner and F. L. Flynt (61) found that the unithydrograph theory could be advantageously applied to areas as small as a 

city block. The data for such application were necessarily refined.

4. The variations In the geographic distribution of rainfall 

and in the Intensities of 1-day storms compared with longer storms impose 

limitations on the duration and application of graphs. L. K. Sherman has 

found that "Inequality of rainfall distribution over the basin does not 

materially affect the accuracy of results except under extreme conditions." 

R. W. Gay (letter dated February 28, 1935) states that "as the path of the 

storm center Is low down, high up, or across the center of the watershed, 

different graphs will result, the variations In the graphs depending upon 

the ratio of maximum precipitation to average precipitation and upon the 

shape and topography of the watershed." Insofar as the study of large 

floods Is concerned, the variations In unit hydrographs are probably not 

serious, because storms that produce large floods have a tendency to 

approach uniform distribution.

5. The lack of base data, especially with regard to the time 

element In connection with the precipitation, Is a handicap that undoubtedly will be remedied with time. Precipitation records showing the
UNIT-HYDROGRAPH ANALYSIS OP SURFACE RUN-OFF 133

beginning and end of all storms and intensities are of great value in connection with unlt-hydrograph studies.

6. Unit hydrographs of 1-day storms apparently cannot be obtained in basins where the infiltration capacity exceeds the rainfall or 

where, as a result of conditions of extreme artificial or natural storage, 

surface run-off may be materially delayed. Where these conditions are of 

such magnitude that isolated 1-day storms do not produce appreciable hydrographs of surface flow, it would seem that a time interval longer than 

a day would have to be used to determine distribution graphs.

These and other problems should be made the basis of much further 

study.

Unit hydrographs and distribution graphs, by basins

In accordance with a suggestion of the Advisory Committee of the 

American Geophysical Union, groups of unit hydrographs and distribution 

graphs have been prepared for typical basins in the central and eastern 

United States as follows:

Muaklngum River at Dresden, Ohio. 

Wabash River at Logansport, Ind. 

Embarrass River at Ste. Marie, 111. 

Skunk River at Augusta, Iowa. 

Susquehanna River at Towanda, Pa. 

Delaware River at Port Jervis, N. Y. 

French Broad River at Dandridge, Term. 

Red River near Denison, Tex.

For each of these basins are given below a brief descriptive 

text accompanied by a map of the basin showing principal streams and the 

location of the Weather Bureau stations, a table showing the recorded 

daily rainfall at these stations during the unit storms that have been 

used, diagrams showing the average precipitation over .the basin, hydrographs of stream flow, the estimated ground-water run-off and the distribution graph of surface run-off for the different unit storms and the 

superimposed distribution graphs, a table showing the distribution graph 

for each storm and the average distribution graph, and a table showing the 

approximate precipitation over the basin and the resulting surface run-off.
134 RAINFALL AND RUN-OFF IN THE UNITED STATES

Muskingum River Basin above Dresden, Ohio

The Muskingum Basin above Dresden, Ohio (fig. 34) is a fan-shaped 

area of 5,980 square miles. Three principal streams - the Walhonding 

River, Killbuck Creek, and the Tuscarawas River - flow in a southerly 

direction to form the Muskingum River about 18 miles above Dresden. Wills 

Creek enters from the east about 8 miles above Dresden. The northern and 

western portions of the basin are glaciated, and the remainder has a hilly 

topography. The river distance from Dresden to the headwaters of the Tuscarawas River (some at altitudes above 1,200 feet) is about 120 miles, and 

the average gradient is about 2 feet to the mile. The headwater region of 

the Walhonding River (Mohican Creek) contains areas 1,400 feet or more 

above mean sea level, and the average gradient of the stream is about 4 

feet to the mile. The zero of the gage at Dresden is 693.2 feet above 

mean sea level.

Daily discharges at this station have been published by the 

United States Geological Survey since September 1921. The original gage 

was a chain gage on a heavy steel eyebar suspension bridge half a mile 

east of Dresden. One reading was taken daily to hundredths. In August 

1925 an Au recorder was installed at the same datum 70 feet below the 

bridge on the right bank. The records are considered good.

Normally about 13 United States Weather Bureau stations are 

available to determine daily rainfall for the basin. The stations are 

well distributed within the basin, as shown on figure 34. Table 29 gives 

the daily precipitation recorded at the various stations for the storms 

analyzed. These storms produced the unit hydrographs at Dresden shown 

in figures 35, 36, and 37.

Table 29.- Typical unit-hydrograph storms in 

Muskingum River Basin above Dresden, Ohio

(Precipitation in inches, measured in the afternoon except 

at stations marked *, where it was measured in the morning.)

Station

Ashland 

Bangorville 

Cadiz 

Cambridge 

Canton

May 1925

10

0.40 

.55 

.44 

.80

11

0.70 

.85 

.98

16

0.15 

.16 

.12

17

0.45 

.10 

.66 

.70 

.26

June 1927

3

0.14 

.14

4

0.90 

2.10 

1.75 

.90 

1.15

5

0.64

11

0.18 

.15

13

0.02

14

0.20 

.15 

.62 

.80 

.33
UNIT-HYDROGRAPH ANALYSIS OP SURFACE RUN-OFF 135

Table 29.- Typical unit-hydrograph storms in 

Muskingum River Basin above Dresden, Ohio Continued

(Precipitation in inches, measured in the afternoon except 

at stations marked », where it was measured in the morning.)

May 1925

Station 10 11

Coshocton * - 0.81

Dennison 0.41

Dover « - .46

Mansfield .52

Miller sburg .55

Mount Vernon

Walhonding * .10 .30

Wooster(no.l) .73

Zanesville * .20 .97

4.70 5.07

Average .36 .39

Station

Ashland

Bangorville

Cadiz

Cambridge

Canton *

Coshocton *

Dennison

Dover *

Mansfield *

Millersburg

Mount Vernon

Walhonding *

Wooster (no.l)

Zanesville

Average

16

0.

.

,

_

71

-

04

39

.19

1. 76

14

17

0.62

.37

.80

.02

.16

.45

.05

.51

5.15

.40

June 1927

25 26

0.78

0.29 .08

1.32

- .92

1.11

_ .75

1.59

1.20

_

.60

.23

-

.97

.51

.39

.61

.95

.30

1.17

2.09 11.68

.15

Station

Ashland

Bangorville

Cadiz

Cambridge

Canton *

Coshocton *

Dennison

Dover »

Mansfield *

Millersburg

Mount Vernon

Walhonding *

Wooster (no.l)

Zanesville *

Average

.83

27

_

-

_

-

_

_

-

0.02

_

-

_

-

-

-

.02

-

June 1927

345

0.05 0.75 0.88

1.45

.82 .60

.68 .09

1.69

_ 1 Vt

.09 1.58

1.05 .01

.40 .50 .56

.82 16.69 2.78

.06 1.19 .20

11 13

_

_

0.07 0.40

.02

-

 TOJL.CI 

_

.21

.75 .42

.05 .03

14

0.55

.60

.40

.20

.29

.51

.55

.18

.92

6.30

.45

July 1927

2

1.20

1.55

_

.32

_

_

_

.02

_

1.10

.92

-

.01

-

5.12

.37

367

0.68

0.12 0.02 .22

.40

_

.14

1.28 - .10

1.18

.06 - .10

2.21 - .41

.02 .03 .11

_

.42 .10

.03 .02 .47

.50 - .02

6.22 .17 2.25

.44 .01 .16

8

_

-

_

-

0.22

_

_

.13

.01

_

.04

_

_

.16

.56

.04

July 1928

4

0.10

-

_

.23

_

-

-

-

.01

-

.56

_

-

.03

.93

.07

5

0.35

.66

.86

.59

.75

.65

.47

.33

.95

.52

.50

1.13

1.33

.38

9.47

.63

6

-

_

-

0.24

.35

-

.10

.05

-

_

_

-

-

.74

.05

9

0.52

.02

1.12

.80

_

.05

.43

.06

-

.19

.03

_

.08

-

3.30

.24

10 11

0.40

.85

.09

.70

0.12

.30

.19

.38 .03

.63 .06

.08

.13

.45 .46

.02

1.09

2.97 3.01

.21 .21
136 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 29.- Typical unit-hydrograph storms in 

Muskingum River Basin above Dresden, Ohio Continued

(Precipitation in inches, measured in the afternoon except 

at stations marked *, where it was measured in the morning.)

Station

Ashland

Bangorville

Cadiz

Cambridge

Canton *

Coshocton #

Dennison

Dover *

Mansfield »

Millersburg

Mount Vernon

Walhonding *

Wooster (no.l)

Zanesville »

Average

Station

Ashland

Bangorville

Cadiz

Cambridge

Canton- #

Coshocton -siDennis on

Dover -siMansfield #-

Millersburg

Mount Vernon

Newcomers town »

Walhonding *

Wooster (no.l)

Zanesville *

Average

Station

Ashland

Bangorville

Cadiz

Cambridge

Canton * 

Coshocton *

Dennison

Dover *

Mansfield *

Millersburg

Mount Vernon

Newcomers town *

August 1928

4

_

-

-

-

-

0.15

-

_

_

-

-

-

.10

.24

.49

.03

1.

1.

.

.

.

.

.

.

.

1.

1.

6.

5

26

62

30

30

02

05

03

-

11

70

10

-

50

-

99

50

6

0.10

-

.71

_

.89

_

.17

.80

.80

.30

.30

.10

.32

4.49

.32

8

_

10

_

0.01

.04

-

-

-

_

.05

0.33

-

.77

_

.26

.35

-

-

-

-

.04

-

.33

.02

June 1929

7

_

0.28

.51

-

_

.80

_

-

_

.03

.41

-

-

-

2.03

.14

8

0.18

.27

.11

.72

.40

-

.58

.40

.22

.27

.43

.66

.80

.19

1.30

6.53

.44

August

17 18

2.50

1

1

1

1 

1

.20 2

_

2

-

2

2

_

.55

.01

.29

.13 

.56

.20

.87

.08

.92

.06

.48

12

0 .16

.18

.05

-

_

_

_

-

.13

.10

_

_

-

.03

-

.65

.04

13

0.10

-

_

.68

_

_

_

_

_

-

_

.01

-

-

.29

1.08

.07

1932

19

_

-

_

-

0.07

_

_

_

-

-

.28

26

0.92

-

.04

.02

-

.11

_

-

.07

.47

-

27

_

-

0.10

.17

.62 

.69

.32

.78

.69

.01

_

.30

14

0.53

.26

.29

.35

.26

.50

.41

.27

.31

.22

.75

.70

.49

.23

.23

5.80

.39

-

1.52

.11

11

_

0.12

-

_

.31

_

.03

.26

.09

.12

.18

.50

-

.73

2.34

.17

August 1929

22

0.05

.57

.50

.52

_

-

.37

-

_

.33

.17

.01

-

.11

.04

2.67

.18

July

1 2

1.60

2.09

0.72 1.80

1.26

-

.57

-

.12

1.49

.57

-

23

0,

1.

ll

,

1.

9

1.

ll

1.

«

11,

04

45

28

75

75

15

23

64

55

43

16

11

37

09

92

92

80

24

_

-

0.03

-

.10

.15

_

.10

.04

-

_

.14

-

-

.48

1.04

.07

1933

3

0.

1.

1.

1.

_

-

05

-

83

_

30

77

-

-

37

9

0

_

-

-

.17

.07

.20

-

.02

-

.01

.05

10

_

-

0.38

-

_

.10

-

-

-
UNIT-HYDROGRAPH ANALYSIS OP SURFACE RTJH-OPP

12,000 

8,000- 

4,000

Surface run-off

Ground-water run-off

10 11 12 13 14 15 16 17 

June 1927

g 8,000

2,000

6,000

5,000

4,000

2,000

\

Ground-water run-off

7M

July 1927

Average dally rainfall

Indies. Each vertical 

Interval represents 

1 Inch.

Figure S5j Colt hydrogrophs for Ituskingnm BlTer at Dresden, Ohio.
Daily stream flow in second-feet
UNIT-HYDROGRAPH ANALYSIS OP SURFACE RUN-OFF

2,000 

1,500 

1,000 

500 

0

5,000 

4,000 

3,000 

2,000 

1,000

X

/////. vM

/

17 18

 ^W

w,

4

/

19

'///A

T

/

Surf

^

'

109 rm

\

N

l-Off

__...,-_

Ground-water run

X

off

20 21 22 23 

August

^

\

\s

Surface run-off -t-1-hGround-water run-off

^^

^

24

1932

^ 

^-

25

"»==

-p-^1

^ -

26 27 28 29 30

V////A Average dally rainY////A fall in inches* Each 

vertical interval 

represents 1 inch.

=; '

July 1933 

Figure 37. Unit hydrography for llusklngum Hiver at Dresden, Ohio.
140 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 29.- Typical unit-hydrograph storms in 

Muskingum River Basin above Dresden, Ohio Continued

(Precipitation In inches, measured In the afternoon except 

at stations marked #, where it was measured in the morning.)

Station

Walhonding « 

Wooster (no.l) 

Zanesville «

Average

August 1932

17

_

2.70 

.18

18

0.67 

1.25 

.90

19.97 

1.33

19

0.05

.40 

.03

26

0.17

1.80 

.12

27

0.55 

.03 

.04

4.30 

.29

July 1933

1

_

.72 

.05

2

0.82

10.32 

.69

3

2.10 

.87 

1.34

12.43 

.83

9

0.03

.55 

.04

10

0.03

.51 

.03

The storm of May 10-11, 1925, produced the flattest unit hydrograph (and distribution graph) of the group. This is believed to be due 

mainly to a long light rain. The sharpest unit hydrograph, resulting from 

the storm of July 2-3, 1927, was the result of poor distribution of rainfall. The greater amounts were concentrated on the Walhonding subbasin, 

and the resulting distribution graph at Dresden is typical of several distribution graphs that are available for the Walhonding River at Pomerene.

Table 30 gives the surface run-off from the unit storms with an 

approximation of the precipitation that caused the run-off.

Table 30.- Surface run-off from unit storms. 

Muskingum River at Dresden, Ohio

Storm

May 11, 1925

June 4, 1927

June 26, 1927

July 2, 1927

July 5, 1928

Aug. 5, 1928

June 7, 1929

Aug. 22, 1929

Aug. 18, 1932

July 2, 1933

Average of precipitation at stations

(Inches)

0.75

1.45

.98

.81

.75

.85

.58

1.05

1.54

1.57

Surface run-off

(inches)

0.18

.44

.12

.06

.09

.10

.05

.05

.05

.08

Ratio of

surface runoff to average precipitation

0.24

.33

.12

.07

.12

.14

.09

.05

.03

.05

Table 31 gives the daily percentages of the surface run-off for 

the ten distribution graphs. The first figure Is the percentage for the 

calendar day on which most of the rainfall occurred; other figures for 

succeeding days.
UNIT-EXDROGRAPH ANALYSIS OP SURFACE RUN-OFF 141

Table 31.- Distribution graphs for storms in 

Muskingum River Basin above Dresden, Ohio

May 11, 1925

June 4, 1927

June 26, 1927

July 2, 1927

July 5, 1928

Aug. 5, 1928

June 7, 1929

Aug. 22, 1929

Aug. 18, 1932

July 2, 1933

1.0

.8

3.8

.0

3.3

6.0

1.3

1.0

4.6

1.0

12.5

19.1

14.2

24.0

16.1

10.9

13.1

5.7

10.2

26.0

17.8

25.4

29.5

39.7

32.7

30.1

23.2

21.8

19.3

24.0

19.6

19.8

22.4

16.3

21.2

22.7

21.9

24.1

24.4

18.3

17.5

13.2

12.7

7.9

10.8

12.3

12.4

18.1

15.9

11.0

11.8

9.4

7.4

4.2

7.1

7.0

7.2

11.5

9.5

6.5

8.1

6.0

5.0

3.3

4.2

4.2

5.6

5.8

6.0

4.4

5.1

4.2

3.1

2.4

2.0

2.8

5.1

3.8

3.4

3.3

3.1

1.1

1.5

1.4

1.4

2.0

3.8

2.6

2.7

2.5

1.7

.5

.4

.8

.7

1.3

3.2

1.9

2.0

1.7

0.9

.3

-

-

.5

.7

1.9

1.9

1.3

0.9

0.6

.2

-

-

-

-

1.3

1.2

.7

.4

0.3

_

-

-

-

-

-

.6

-

-

The superimposed distribution graphs are shown in figure 38. If 

the two distribution graphs from the storm of May 10-11, 1925, and July 2- 

3, 1927, are disregarded the range of the remaining graphs is decreased. 

The average distribution graph determined for the Muskingum River at Dresden is 4, 15, 27, 21, 13, 8, 5, 3, 2, 1, 1 percent.

Wabash River Basin above Logansport, Ind.

The Wabash River rises in the Grand Reservoir, an artificial lake 

at Celina, Mercer County, Ohio, and flows in a northerly and westerly 

direction to Logansport, Ind., below which its direction is southwest. The 

Eel and the Mississinewa Rivers are the principal tributaries above Logansport. The drainage area above Logansport covers 3,830 square miles, is 

fan-shaped, and is about 90 miles in length and about 40 miles in average 

width. The length of the Wabash channel above Logansport is about 120 

miles. Much of the baain is glaciated. The maximum altitude is 1,285 

feet, in Randolph County, Ind.

A chain gage was established in April 1903 on the Cicott Street 

Bridge at Logansport. The record was discontinued in July 1906. A standard chain gage was established by the State of Indiana in May 1923 at the 

same location, with its zero 573.8 feet above mean sea level. Records are 

published by the United States Geological Survey. On March 31, 1927, the 

Wabash Hydroelectric Co. installed an enamel staff gage on the same bridge, 

with its zero 2.85 feet above the zero of the State chain gage. The chain 

gage was read once daily to tenths, and part of the time the staff gage 

readings to hundredths twice daily were furnished. The records are considered good except for periods of ice effect.
RAINFALL AND RUB-OFF IN THE UNITED STATES
UNIT-HYDROGRAPH ANALYSIS OP SURFACE RUN-OFF 145

Normally about 14 stations are available for the determination 

of daily precipitation. Figure 59 outlines the drainage basin and shows 

the location of the Weather Bureau, stations.

Table 52 gives the daily precipitation recorded at the precipitation stations for the storms that produced the unit hydrographs shown in 

figures 40 and 41.

Table 32.- Storms studied in connection with unit 

hydrographs for the Wabash River Basin above Logansport, Ind.

(Precipitation, in inches, measured in the afternoon except at stations 

marked *, where it was measured in the morning, and stations marked 

*», where it was measured at midnight.)

Station

Berne

Bluffton #

Columbia City

Fort Wayne *«

Huntington

Kokomo

Logansport «

Marion *

Rochester **

Wabash *

Winona Lake

Farmland

Muncie

Salamonia

Average

Station

Berne

Bluffton *

Columbia City

Fort Wayne # »

Huntington

Kokomo

Logansport *

Marion *

Rochester *

Wabash *

Winona Lake

Farmland

Muncie

Salamonia

Average

July 1925

3

0.05

_

.05

.02

.05

.28

-

_

_

_

-

.30

1.79

.43

2.97

.21

4

0.44

.20

.95

.56

1.17

.55

.78

.64

.72

.78

1.43

.62

.95

.37

10.16

.73

5

0.90

1.25

-

-

.07

.38

.18

2.70

.55

.41

-

_

_

-

6.24

.45

7

_

_

-

0.02

-

_

-

_

_

_

.07

_

_

.04

.13

.01

8

_

_

-

-

-

_

-

0.05

.30

_

-

_

_

-

.55

.02

9

1.50

_

.22

.24

-

.15

-

_

_

_

.05

_

.25

-

2.11

.15

10

_

0.55

_

-

.13

.54

.64

.42

.18

.10

1.43

1.10

1.24

.25

6.58

.47

September - October 1925

26

_

_

0.97

.99

-

-

-

_

-

_

-

1.22

_

-

5.18

.23

27

1.35

1.00

1.94

.59

1.5-7

1.55

1.50

1.52

.93

1.52

1.14

-

2.06

1.06

17.55

1.25

28

_

0.25

-

-

-

_

-

_

.35

.31

_

_

_

-

.91

.06

2

0.68

.20

.12

.77

.51

.50

.72

.15

-

.31

.02

.52

.45

.43

5.14

.57

3

_

0.28

_

.04

.02

.10

.05

.12

.13

.02

.

_

_

-

.76

.05

4

0.17

_

.25

.45

.21

_

.05

.12

.06

_

.25

.08

_

.14

1.78

.13
144 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 32.- Storm studied in connection with unit hydrographs 

for the Wabash River Basin above Logansport, Ind. Continued

(Precipitation, in inches, measured in the afternoon except at stations 

marked -::-, where it was measured in the morning, and stations marked 

*-::-, where it was measured at midnight.)

Station

Berne

Bluffton a

Columbia City

Fort Wayne **

Hunt ing ton

Kokomo

Logansport *

Marion *

Rochester *

Wabash *

Winona Lake

Farmland -»

Muncie

Salamonia

Average

Station

Berne

Bluffton *

Columbia City

Fort Wayne **

Huntington

Kokomo

Logansport «

Marion *

Rochester *

Wabash %

Winona Lake

Farmland *

Muncie

Salamonia

Average

August 1929

2

0.11

-

1.25

1.06

.11

.20

-

_

-

.38

-

.30

.04

3.45

.25

3

2.04

3.10

2.74

1.00

3.82

.04

.58

1.09

1.22

1.50

6.25

.65

.54

1.23

25.80

1.84

10

_

_

0.02

.17

1.47

.20

.08

.10

_

1.03

.01

.09

-

.16

3.33

.24

August 1929

13

1.03

-

.47

.38

1.49

_

-

_

_

-

.51

-

-

.25

4.13

.30

14

0.41

4.40

.06

-

-

_

.55

1.18

1.50

2.00

.55

2.22

2.07

1.51

16.45

1.18

June - July 1931

28

0.15

.07

.02

-

.06

_

-

-

_

_

.10

-

_

-

.40

.03

29

1.42

1.63

.73

1.07

.53

1.40

-

.05

.23

.67

.04

1.00

1.88

10.65

.76

30

_

0.14

-

-

-

_

1.15

1.26

-

1.09

-

.74

-

-

4.38

.31

1

_

_

-

0.78

-

_

-

_

_

_

-

_

1.09

.74

2.61

.19

2

0.07

-

.14

.33

-

_

-

.03

_

_

.07

.87

.04

-

1.55

.11

5

0.12

.22

.35

.79

.11

.28

-

-

_

.42

-

-

.26

2.55

.18

22

_

0.06

.10

-

.03

.04

-

.02

-

.09

-

-

-

.34

.02

23

0.20

.20

.02

.01

.18

.03

.02

.18

.03

.11

.01

-

.56

.41

1.96

.14

October 1932

4

0.88

-

1.32

1.54

1.57

1.38

-

1.87

.76

_

1.35

.90

.93

.75

13.25

.95

5

-

1.06

-

-

-

.09

1.04

_

_

.04

-

_

-

2.23

.16

10

0.80

-

.54

.57

.62

.62

-

.60

1.22

-

1.02

1.12

.95

1.02

9.08

.65

11

0.03.

.69

-

-

-

_

.86

.05

-

.71

.07

-

-

.08

2.49

.18

Table 33 gives the surface run-off from the unit storms with the 

approximate value of the precipitation causing the run-off.
UNIT-HYDROGRAPH ANALYSIS OF SURFACE RUN-OFF

 Boncie ^-". Farmland

10 20 3D 40 Miles

Figure 39. Wabash River Basin above Logansport, Ind. 

Drainage area 3,830 square miles

5855 O 36 10
Daily stream flow in second-feet

X
Daily stream flow In seoond-feet 

*a>

8
148 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 33.- Surface run-off from unit storms, 

Wabash River at Logansport, Ind.

Starm

July 4, 1925

Sept. 27, 1925

Aug. 2, 1929

Aug. 13, 1929

June 29, 1931

Oct. 4, 1932

Average of precipitation at stations

(Inches)

1.39

1.54

2.09

1.48

1.10

1.11

Surface run- off

(inches)

0.07

.10

.15

.25

.05

.05

Ratio of

surface runoff to average precipitation

0.05

.06

.07

.17

.05

.05

Table 34 gives the dally percentages for the six distribution 

graphs, and figure 42 shows the graphs superimposed. The average distribution graph determined for the station is 3, 12, 27, 24, 14, 9, 5, 3, '2, 

1 percent. The first figure Is the percentage of surface run-off for the 

day on which most of the rainfall occurs; other figures for succeeding 

days.

Table 34.- Distribution graphs for storms In 

Wabash River Basin above Logansport, Ind.

July 4, 1925

Sept. 27, 1925

Aug. 2, 1929

Aug. 13, 1929

June 29, 1931

Oct. 4, 1932

4.1

5.9

.7

.4

3.4

0

12.0

11.4

1.5

4.8

29.8

4.8

20.7

26.7

21.7

19.5

26.2

23.4

28.1

26.8

35.9

27.6

15.9

23.6

18.7

11.6

17.6

21.6

9.9

14.9

10.4

7.9

9.9

10.6

5.9

12.3

3.8

4.4

6.4

6.6

3.0

7.8

1.5

2.8

3.7

4.3

2.1

b.2

0.7

1.3

1.4

2.8

1.5

3.5

..

0.8

.7

1.0

1.2

2.4

_

0.4

.3

.5

.7

1.5

_

-

0.2

.2

.4

.6

_

-

-

0.1

-

-

Embarrass River Basin above Ste. Marie. 111.

The Embarrass River has its source in Champaign County, 111., 

just south of Urbana, and flows in a general southerly direction Into the 

Wabash River above St. Francisville. The altitude of the divide near 

Urbana Is 750 feet.

The basin above Ste. Marie (fig. 43) covers 1,540 square miles, 

Is about 80 miles long, and averages 19 miles In width. The average gradient for 40 miles above Ste. Marie is 2 feet to the mile.

The gaging station was established In October 1909 on the Main 

Street Bridge at Ste. Marie. A standard chain gage was fastened to the 

handrail on the downstream side of the bridge and was read to hundredths 

once dally. No records are available from December 1912 to August 1914.
UHIT-HYDROGRAPH ANALYSIS op SURFACE RUN-OFF
150 RAINFALL AND RUN-OFF IN THE UNITED STATES

The gage was transferred to the new highway bridge in April 1925. The zero 

of the gage is 447.1 feet above mean sea level. The records are considered

Seven precipitation stations of the United States Weather Bureau 

(see fig. 43) are generally available. If the daily rainfall is to be used 

extensively the station records should be weighted by some method.

Table 35 gives the daily precipitation recorded at the precipitation stations for the storms that produced the unit hydrographs shown in 

figures 44 and 45.

Table 35.- Storms studied in connection with unit 

hydrographs. Embarrass River above Ste. Marie, 111.

(Precipitation, in inches, measured in the afternoon except at stations 

marked ::-, where it was measured in the morning.)

Station

Casey 

Charleston 

Eff ingham * 

Olney * 

Paris * 

Tuscola 

Urbana *

Average

Station

Casey 

Charleston 

Eff ingham * 

Olney * 

Paris * 

Tuscola 

Urbana «

Average

June - July 1918

24

0.04 

.03

3.79

3.86 

.55

25

2.48 

2.94 

1.10 

.62 

2.45

3.05

12.64

1.81

28

1.35 

1.88 

.44 

.50 

.48 

1.27 

.64

6.56 

.94

29

1.30 

1.58 

.63

.87

4.18 

.60

30

0.04 

.02

.04

.10 

.01

1

0.26

.26 

.04

May 1920

11

0.10 

.08

.02 

.04

.24 

.03

12

2.21 

3.12 

.77 

.33 

2.40 

3.32 

1.38

13.53 

1.93

13

0.44 

.51 

.71

1.04

2.70 

.39

16

0.06 

.10

.10

.26 

.04

17

1.41 

1.72 

2.10 

1.95 

.80 

1.29 

1.15

10.42 

1.49

18

0.03 

.03 

.33 

.40 

.38 

.04 

.08

1.29 

.18
UWIT-HYDROGRAPH ANALYSIS OP SURFACE RUN-OFF 151

Table 35.- Storms studied in connection with unit 

hydrographs, Embarrass River above Ste. Marie, 111. Continued

(Precipitation, in inches, measured in the afternoon except at stations marked *, where it was measured in the morning.)

Station

Casey 

Charleston 

Ef f ingham * 

Olney * 

Paris * 

Tuscola 

Urbana -»

Average

Station

Casey 

Charleston 

Eff ingham * 

Newton * 

Paris * 

Tuscola 

Urbana *

Average

September 1920

14

-

0.02 

.10

-

.12 

.01

15

1.02 

1.94

1.30

4.26 

.61

16

0.01

1.28 

1.58

0*7

.67

4.51 

.64

June 1929

7

1.13 

.78 

1.00 

1.38 

1.80 

.72 

.25

7.06 

1.01

8

0.52

.52 

.07

23

0.01

.11

.04 

.02

.18 

.03

26

0.26

-

.13

.39 

.06

27

0.65

.08 

1.08

.54 

.55

2.90 

.41

September - October 1921

24

0.02 

.27 

.82

-

1.11 

.18

25

0.84 

2.34 

1.63

1.98 

.66

7.95 

1.32

30

1.19 

.83 

.93 

.76

.71 

.60

5.02 

.84

2

0.03 

.07

.01

.11 

.02

3

0.04 

.13

-

.17 

.03

June 1929

12

1.54 

1.35 

1.16 

1.63 

.92

.92

7.52 

1.09

13

0.72 

.17 

.85 

.64 

.60 

1.25 

.05

4.28 

.61

14

0.22 

.20 

.12

.54 

.08

15

0.32

.32 

.05

18

0.02

.02 

0

20

0.09 

.01

.52 

.16

.78 

.11

The superimposed distribution graphs for the Embarrass River 

above Ste. Marie (fig. 46) show an appreciable variation as a result of 

having one, two, or three peaks.

The storm of June 25, 1918, though of greater intensity in the 

upper part of the basin, which would flatten its peak, appears to have 

lasted about 12 hours, which would counteract the flattening effect. The 

result is a fairly average distribution graph.

The storm of May 12, 1920, was poorly distributed, with high intensities in the uplands and apparently about 24 hours duration. The 

result is a flat distribution graph.

The storms of September 15, 1920, and June 7, 1929, appear to 

have been short and slightly heavier on the lower part of the basin, thus 

giving high-peaked distribution graphs.

Table 36 gives the surface run-off from the unit storms.
RAINFALL AND RUN-OFF IN THE UNITED STATES

> Effingham

Olney

10 20 30 40 Mile

Figure 43.-Embarrass Biver Basin above Ste. Marie, 111. 

Drainage area 1,540 square miles
UHIT-HTDROGRAPH ANALYSIS OP SURFACE RUE-OFF

4,000 

3,500 

3,000 

2,500 

2,000 

1,500 

1,000 

500 

0

6,000 

5,000 

4,000 

S 3,000

I 2,000

a

 3 1,000

o

$

§ °

4»

B

I

^ 800 

600 

400 

200 

0

W///

/

W//, m !\i \

1

23 24 ^25

 S.

WA W/f

4

Sorts.

\

-X

oe ran

_ -

m

^

\

l-Off

'ML

\

^

QroTin

^^

.d-wate f 3TUH--off

-~ - ._-_- -u 

26 27 28 29 30 1 2 3 4 5 6 

Jane 1918

S

/

/y////

/

^^

Surfa k

^

\

V

\

.oe run-off

Ground-vat

/////

m

\

er roi

V

^ v

KOff

^

 -

" .

 L__-

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 

May 1920

'/////.

/

W/,

/

/

A

Surface

\

\

V^

nm-off

1 1 1 i i

^^ ^ ^

14 15 16 17 18 19 20 21 22 

September 1920

23 24 26

2,500 

2,000 

1,500 

1,000 

500 

0

_:

f////.

W//, 1 --.

^

Surfi

 \

l\

.oe rm

\

V

\

KOff

V

V

^

WA

/

-^.

^////A Ayeiage dally rainY////A fall in inches. Each 

vertical interral 

represents 1 inch.

'-*-^ 

aroond-^water ron-off

r±--^- =-

23 24 25 26 27 28 29 30 1 2 3 4 5

September 1921 

Figure 44. Unit hydrographs for Embarrass BiTer at Ste. Marie, 111.
Dally stream flow in second-feet
UNIT-HYDROGRAPH ANALYSIS OP SURFACE RUN-OFF 155

Table 36.- Surface run-off from unit storms, 

Embarrass River at Ste. Marie, 111.

Storm

June 25, 1918 

I'lay 12, 1920 

Sept. 15, 1920 

Sept. 25, 1921 

June 7, 1929 

June 12, 1929

Precipitation 

(Inches)

Average

2.36 

2.35 

1.26 

1.50 

1.08 

1.83

Geometrically 

weighted

2.86 

2.79 

1.35 

1.89 

.99 

1.66

Surface run- off 

(Inches)

0.26 

.58 

.04 

.23 

.25 

.49

Ratio of 

surface runoff to weighted 

precipitation

0.09 

.21 

.03 

.12 

.25 

.30

Table 37 gives the daily percentages for the six distribution 

graphs, and figure 46 shows the superimposed distribution graphs. An 

average distribution graph for the stations Is 5, 25, 29, 18, 10, 6, 3, 2, 

1, 1 percent. The first figure for each graph is the percentage of surface run-off for the calendar day on which most of the rainfall occurred; 

other figures for succeeding days.

Table 37.- Distribution graphs for storms In 

Embarrass River Basin above Ste. Marie, 111.

June 25, 1918

May 12, 1920

Sept. 15, 1920

Sept. 25, 1921

June 7, 1929

June 12, 1929

7.1

2.8

0

5.5

8.8

4.0

33.7

19.8

16.6

30.1

41.0

22.5

24.5

22.1

39.9

31.6

25.8

28.5

IK. 2

20.3

18.2

16.5

9.4

20.8

7.9

14.0

9.7

6.3

6.2

11.4

5.1

8.8

6.9

4.1

3.9

6.4

3.2

5.4

3.9

2.8

2.6

3.1

2.2

3.0

2.4

1.8

1.5

1.8

1.5

1.9

1.3

1.0

.8

1.0

1.0

1.0

.8

.3

-

.5

0.6

.6

.3

_

-

-

_

0.3

-

_

-

-

Skunk River Basin above Augusta, Iowa

The Skunk River rises at about 1,200 feet above sea level near 

the northeast corner of Hamilton County, Iowa, In the region of Wisconsin 

drift. The basin above Augusta (fig. 47) is long and narrow and covers 

4,290 square miles. The length of the stream above Augusta Is about 270 

miles. The basin Is about 170 miles long, and the average width Is 25 

miles. The North Skunk River and Cedar Creek are the principal tributaries 

and flow In the same general direction as the main stream.

In the upper 130 miles the river drops at an average rate of 3.4 

feet to the mile; the 140 miles next above the station has an average gradient of 1.4 feet to the mile. The station at Augusta is about 12 miles
OMV .aso-wia HI am daiian saivis 
UNIT-HYDROGRAPH ANALYSIS OP SURFACE RUN-OFF 157

above the mouth, where the river discharges into the Mississippi River pool 

above the Keokuk Dam.

About 9 percent of the basin is forest, 62 percent is cultivated, 

and 29 percent is grass land.

The United States Geological Survey chain gage was installed on 

the highway bridge near Augusta in June 1915. The chain was of iron and 

the links gave a good deal of trouble. It was replaced by a standard 

copper chain in July 191S. The gage is read to half tenths once a day. 

The zero of the gage is 528.6 feet above sea level, Memphis datum. The 

records are fair with slight regulation at low stages.

Normally 14 or 15 stations are available for the determination of 

daily precipitation. Figure 47 locates the United States Weather Bureau 

stations on, an outline of the drainage basin.

Table 58 gives the daily precipitation recorded at the Weather 

Bureau stations for the storms that produced the unit hydrographs shown in 

figures 48 and 49.

Table 38.- Storms studied in connection with unit 

hydrographs for the Skunk River Basin above Augusta, Iowa

(Precipitation, in inches, measured in the afternoon except at stations 

marked *, where it was measured in the morning.)

Station

Ames

Baxter

Bo one *

Grinnell

Monroe

Webster City

Burlington #

Fairfield

Mount Pleasant

Oskaloosa

Ottumwa

Sigourney

Stockport

Washington

Average

July 1924

22

_

_

0.05

-

_

-

.92

.01

.67

_

.72

-

.22

1.60

4.19

.30

24

0.15

.30

.13

4.40

.63

.92

2.27

2.53

3.49

.75

1.10

2.70

1.59

5.80

26.76

1.91

25

_

_

_

-

-

-

0.42

-

_

-

-

-

-

-

.42

.03

27

0.25

_

_

-

-

.04

-

.03

-

-

-

-

.05

-

.37

.03

28

_

0.30

.55

.14

.20

-

.03

_

1.06

.03

.12

.07

-

2.50

.18

29

0.16

.80

.54

.70

.73

.90

-

.59

.47

.59

.72

1.13

.66

1.00

8.99

.64

30

_

_

0.04

-

_

-

.54

.02

.05

_

-

-

.39

.23

1.27

.09
158 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 58.- Storms studied in connection with unit hydrographs 

for the Skunk River Basin above Augusta, Iowa Continued

(Precipitation, in inches, measured in the afternoon except at stations 

marked *, where it was measured in the morning.)

Station

Ames

Baxter

Boone -:.-

C-rinnell

Monroe

Webster City

Burlington «

Fairfield

Mount Pleasant

Oskaloosa

Ottutawa

Sigourney

Stockport

Washington

Average

Station

Ames

Baxter

Boone #

Grinnell

Monroe

Webster City

Burlington #

Fairfield

Mount Pleasant

Oskaloosa

Ottumwa

Sigourney

Stockport

Washington

Average

May 1927

17

1.25

.19

_

.15

-

1.00

.01

.01

.05

-

-

.58

-

.15

5.13

.22

18

0.66

.82

.04

.56

.63

.92

.03

2.40

1.93

.36

2.23

.40

2.56

.67

14.21

1.02

19

_

-

0.55

_

_

-

2.17

_

-

-

_

-

-

-

2.72

.19

20

0.76

.01

_

_

_

.67

-

_

-

-

-

-

-

-

1.44

.10

21

_

-

0.56

_

-

-

-

_

-

-

_

-

-

-

.56

.04

22

0.06

.15

_

.52

.27

.05

.06

.50

.47

.59

.56

.40

.28

.50

5.61

.26

23

0.92

1.09

.50

1.18

1.59

1.21

.64

.75

.29

.64

.08

.66

.19

.88

10.42

.74

June 1927

2

_

-

_

0.01

.54

-

.15

.10

.76

.14

.55

.17

1.20

5.42

.24

Station

Ames

Baxter

Boone -"-

Grinnell

Monroe

Webster City

Burlington *

Fairfield

Mount Pleasant

Oskaloosa

3

0.08

.13

.02

.22

.41

.03

.15

1.50

.43

.19

.70

.72

2.00

.63

7.21

.52

4

_

-

0.08

_

_

-

1.38

.22

1.95

.03

.10

.08

.18

1.13

5.20

.37

7

_

0.04

-

.16

_

-

-

-

-

_

_

-

-

-

.20

.01

8

_

0.61

_

.25

.55

-

-

_

_

.15

_

.06

_

.05

1.65

.12

9

0.15

.24

1.14

_

_

-

-

_

_

_

_

-

_

-

1.55

.11

10

_

0.14

_

.20

_

-

.06

.05

.12

.03

_

-

-

-

.60

.04

July 1928

4 8 9 10

1.10 0.15

1.17 .24 - 0.05

1.16 .23 - .05

1.02 .24 - .02

1.22 .22 - .64

.50 .09

.47 - 0.57

2.12 .71

1.46 .52 - .15

1.35 .70 - .33

11

0.42

_

.03

.04

.07

.20

_

_

-
UNIT-HYDROGRAPH ANALYSIS OP SURFACE RUN-OFF

Table 38.- Storms studied in connection with unit hydrographs 

for the Skunk River Basin above Augusta, Iowa Continued

(Precipitation, in inches, measured in the afternoon except at stations marked -:f, where it was measured in the morning. )

July 1928

Station 4

Ottumwa 1.01

Sigourney .91

Stockport 1.37

Washington 3.40

18.06

Average 1.29

Station

Ames

Baxter

Bo one *

Grinnell

Monroe

Newton

Webster City

Burlington *

Fail-field

Mount Pleasant

Oskaloosa

Ottutnwa

Sigourney

Stockport

Washington

Average

8 9 10

0.26 - 0.02

.91 .17 .05

.39 - .03

.28 .09 1.08

4.74 .63 2.33

.34 .04 .17

August - September 1931

30

0.02

.15

_

_

_

.12

-

-

.04

.04

-

_

-

-

-

.37

.03

31

_

0.03

-

-

1.28

.03

.03

-

.11

-

-

.38

-

.04

-

1.90

.14

1

0.49

1.02

.59

1.86

_

1.07

1.72

2.65

3.29

1.65

2.99

3.70

2.55

2.80

2.10

28.48

1.90

2

_

_

_

0.07

_

_

-

.09

_

-

-

_

-

-

-

.16

.01

3

0.11

.08

.04

.07

.16

.07

-

-

.04

.02

.15

.15

-

.05

-

.94

.06

11

0.07

-

-

-

.83

.06

June - July 1932

25

_

_

0.62

.03

_

.05

-

-

_

-

.76

-

.65

-

-

2.11

.14

26

0.59

1.14

.68

.32

.54

.98

.36

.02

3.25

2.00

5.45

2.28

2.55

.32

2.08

22.56

1.50

27

0.02

_

.12

.09

.65

_

-

.14

_

.03

.07

_

-

-

-

1.12

.07

1

_

_

_

_

_

-

-

-

0.16

.12

-

.12

-

-

-

.40

.03

3

0.89

.89

.75

.72

.79

.77

.75

.11

2.29

1.83

1.02

1.67

.96

1.03

.92

15.39

1.03

Table 39 gives the surface run-off from the unit storms and the 

approximate value of the precipitation that caused the run-off.

Table 39.- Surface run-off from unit storms, 

Skunk River at Augusta, Iowa

Storm

July 24, 1924

May 18, 1927

June 3, 1927

July 4, 1928

Aug. 31, 1931

June 26, 1932

Average of precipitation at stations

( inche s )

1.94

1.43

1.13

1.29

2.07

1.71

Surface run-off

(inches)

0.75

.34

.33

.42

.17

.49

Ratio of

surface runoff to average precipitation

0.39

.24

.29

.33

.08

.29
RAINFALL AND RUN-OFF IN THE UNITED STATES

\

Figure 47. Skuiflc Hirer Basin above Augusta, lows. 

Drainage area 4,290 square miles
Dally stream flow In (Mood-feet

K S
162 RAINFALL AM) RU1J_OFF IN THE UBITED STATES

6,000

£ 12,000

 3 10,000

p

30 31 1 

August

4567 

September 1931

Surface run-off

\

Ground-water run-off

272829301 2 3 4 5 6 

Jane July 1932

W////\ Average daily rainfall in inches. 

WW/0( Each vertical interval represents 1 inch.

Figure 49. Unit hydrographs for Skunk Elver at Augusta, lofea.
UNIT-HYDROGRAPH ANALYSIS OP SURFACE RUN-OFF 163

Table 40 gives the daily percentages for the six distribution 

graphs, and figure 50 shows the graphs superimposed. The average distribution graph determined for the basin is 1, 32, 27, 18, 11, 5, 3, 2, 1 

percent. The average graph reflects the long, narrow basin and the tributary drainage. The graph rises rapidly to its peak and then tapers out 

gradually. The first figure for each distribution graph is the percentage 

of surface run-off for the calendar day on which most of the rainfall 

occurred; other figures for succeeding days.

Table 40.- Distribution graphs for storms in 

Skunk River Basin above Augusta, lovre

July 24, 1924

May 18, 1927

June 3, 1927

July 4, 1928

Aug. 31, 1931

June 26, 1932

21.3

.7

.9

2.6

.4

1.8

28.7

37.2

37.4

31.6

27.6

27.3

21.1

26.1

31.0

27.4

28.4

26.3

13.2

13.8

15.5

19.4

20.5

21.6

7.0

9.2

7.8

10.1

12.6

13.6

3.5

5.3

3.b

4.2

5.9

5.0

2.1

3.5

1.9

2.3

2.7

2.3

1.5

2.0

1.1

1.4

1.1

1.1

0.9

1.2

.6

.7

.6

.7

0.5

.7

.3

.3

.2

.3

0.2

.3

-

-

-

-

Susquehanna River Basin above Towanda, Pa.

The Susquehanna River rises in Otsego Lake, in the Catskill 

Mountains, in Otsego County, II. Y., at about 1,193 feet above sea level. 

It flows in a southerly direction through Otsego, Chenango, and Broome 

Counties, N. Y., into Susquehanna County, Pa. It then flows in a west 

northwesterly direction, reenters New York, and flows westward through 

Broome and Tioga Counties, whence it turns south and again flows into 

Pennsylvania. The river distance from the State boundary to the Towanda 

station is about 20 miles. The Chemung River, flowing from the west and 

draining about 2,500 square miles, empties into the Susquehanna about 13 

miles above the station. (See fig. 51.)

The drainage area above Towanda is 7,770 square miles; the length 

is about 170 miles, and the average width about 46 miles. The stream, drops 

about 500 feet in the 170 miles above Towanda. The zero of the gage is 

693.4 feet above mean sea level. The part of the basin in Hew York is 

rolling and in places broken country.

Gage heights at the stations have been observed by the United 

States Weather Bureau since October 1892. The Water Supply Commission of 

Pennsylvania, in its annual reports, has published discharge measurements 

and gage heights beginning January 29, 1914, and daily discharge since
164 RAINFALL USD HOH-OFF IN THE UNITED STATES
UNIT-HXDROGRAPH ANALYSIS OP SURFACE RTO-OFF 165

October 1918. The stage-discharge relation is probably permanent except as 

affected by Ice.

The gage is a standard chain gage attached to the downstream 

side of the Bridge Street Bridge at Towanda and read to hundredths twice 

daily.

The United States Geological Survey has published the records 

for October 1918 to October 1920 and October 1951 to date. They are considered fair.

About 22 stations are normally available for the determination 

of daily rainfall. Figure 51 shows the principal drainage and the location 

of the precipitation stations.

Table 41 gives the daily precipitation recorded at the stations 

for the storms that produced the unit hydrographs shown in figures 52, 55, 

and 54.

Table 41.- Storms studied in connection with unit 

hydrographa for the Susquehanna River above Towanda, Pa.

(Precipitation, in inches, measured in the afternoon except at stations 

marked *, where it was measured in the morning, and stations marked 

*#, where it was measured at midnight.)

Station

New York:

Add! son

Alfred

Angelica

Elmira,

Haskinville

Bainbridge #

Binghamton *»

Cazenovia -*

Cooperstown

Cor t land

De Ruyter

Fishs Eddy

Newark Valley

New Berlin

New Lisbon

Norwich *

Oneonta

Roxbury

Sherburne *

Ithaca ##

Pennsylvania :

Lawrenceville

Montrose

Towanda

Wellsboro

West Bingham

Average

October 1918

3

0.30

.26

.11

.02

-

.49

.14

.73

-

.20

.42

.59

.63

.40

.64

.58

.38

.38

.25

.03

.58

.70

.70

.86

-

9.39

.38

5

_

_

-

-

-

0.94

_

.34

_

-

-

.01

_

_

_

_

-

-

.09

_

-

_

_

-

1.38

.06

6

0.88

.19

.15

.83

-

1.05

.25

.45

.04

.15

.46

-

.95

.80

.72

.32

.19

1.31

.20

.11

.80

1.16

1.01

1.28

1.28

13.35

.53

7

0.10

.14

.07

.38

.19

.01

.14

-

.36

-

.14

-

.01

.58

-

-

-

-

_

.10

.08

.16

1.03

3.49

.14

12

0.15

.30

.27

.02

.23

-

.05

_

.16

.08

-

-

.05

_

.12

-

-

.22

-

.04

_

.18

.09

.15

.32

2.43

.10

13

_

_

0.01

-

-

.09

.01

.02

.04

.07

.37

-

-

_

-

.11

.09

.10

.05

-

_

.22

_

.02

-

1.20

.05

14

0.05

.17

.15

.09

.12

.02

.03

.07

-

.06

.38

-

.14

.10

.07

.02

_

.15

.05

.23

_

.10

_

_

-

2.00

.08
166 RAINFALL AND ROT-OFF IN THE UNITED STATES

Table 41.- Storms studied In connection with unit hydrographs 

for the Susquehanna River above Towanda, Pa. Continued

(Precipitation, in inches, measured in the afternoon except at stations 

"marked. *, where it was measured in the morning, and stations marked 

*#, where it was measured at midnight.)

Station

New York:

Add! son

Alfred

Angelica

Elmira

Haskinville

Bainbridge *

Binghamton **

Cazenovia *

Cortland

De Ruyter

Morrisville

New Lisbon

Norwich *

Oneonta

Sherburne #

Ithaca ##

Pennsylvania :

Lawrenceville

Montrose

Towanda

Wellsboro

West Bingham

Average

Station

New York:

Addison

Alfred

Angelica

Elmira **

Haskinville

Bainbridge *

Binghamton #-*

Cooperstown

Cortland

De Ruyter

July 1921

12

0.06

.09

.14

_

.10

.22

-

-

-

.31

_

.04

.15

_

_

-

_

_

.0?

_

-

1.14

.05

13

.

0.03

.12

-

_

-

.03

-

_

-

_

_

-

_

-

-

_

.34

-

_

-

.52

.02

14

_

-

-

0.56

_

-

1.14

-

2.40

.55

_

.40

_

_

.

.24

_

.20

-

_

.40

5.89

.28

15

1.26

1.17

1.20

.10

.72

.63

.73

1.00

.36

.66

1.65

2.96

1.40

2.20

.89

1.21

.70

.22

.36

.09

.41

19.92

.95

16

0.05

-

-

-

_

.45

-

-

_

-

_

_

.30

_

.64

-

_

_

-

_

-

1.44

.07

19

1.04

1.53

1.25

.62

.73

-

.51

-

1.04

.59

.15

.80

-

1.24

-

.53

1.40

1.00

.84

1.14

1.43

15.84

.75

20

0.01

.11

.05

.65

.18

.99

.22

.70

.12

1.10

.70

.30

1.20

_

1.20

.22

.25

.25

.14

_

.05

8.44

.40

21

_

-

-

_

0.62

-

.58

_

.02

_

.26

.24

_

-

-

«.

-

-

_

-

1.72

.08

April 1923

3

_

0.10

.20

_

.07

-

-

-

_

_

4

0.23

.21

.20

.89

.19

-

.22

.15

.03

.10

5 6

1.05

1.20

1.00 0.02

.15

.98

.27 .72

.55

.80

1.79

1.72 .05

8

0.01

.03

-

_

-

-

.05

9 10

_

0.02

.14

.08

0.02 .10

.21

.03

.03 .20

 -

11

0.02

_

-

.02

.12

-

.06

.15

.06

12

0.12

.17

.15

-

.26

-

-

.17
UNIT-HYDROGRAPH ANALYSIS OP SURFACE RUN-OFF 167

Table 41.- Storms studied in connection with unit hydrographs 

for the Susquehanna River above Towanda, Pa. Continued

(Precipitation, in inches, measured in the afternoon except at stations 

marked *, where it was measured in the morning, and stations marked 

##, where it was measured at midnight.)

Station

New York 

Continued*

New Berlin

New Lisbon

Norwich *

Oneonta

Roxbury

Sherburne *

Ithaca » »

Pennsylvania :

Lawrenceville

Montrose 

Towanda

Wellsboro

West Bingham

Average

Station

New York: 

Add! son

Alfred

Angelica

Elmira **

Haskinville

Bainbridge *

Binghamton *#

Cooperstown

C or t land

Delhi

De Ruyter

Morrisville

New Berlin

Norwich *

Oneonta

Roxbury

Sherburne *

Ithaca #«

Pennsylvania :

Lawrenceville

Montrose

Towanda

Wellsboro

West Bingham

Average

April 1923

3

_

-

-

_

-

_

0.06

_

-

_

.12

.55

.02

4

_

0.09

.05

_

-

.12

1.10

_

.04

.23

.20

4.05

.18

5

1.25

.77

.43

1.18

.75

.24

.49

1.20

.84 

.47

1.02

1.3CT

19.45

.88

6

_

-

0.62

_

.10

.54

-

_

-

_

-

2.05

.09

8

0.05

_

-

_

.10

_

.02

_

-

_

-

.26

.01

9

0.08

-

-

_

-

.05

-

_

-

_

-

.39

.02

10

0.05

-

-

-

-

-

_

-

_

.05

.67

.03

11

0.13

.25

.13

.15

.30

.26

.06

.02

-

1.73

.08

12

_

0.04

-

-

.25

.14

-

_

-

_

.15

1.45

.07

September - October 1924

29

2.00

2.53

2.10

_

2.15

.14

2.04

1.96

3.12

.30

1.60

.90

.90

.18

.75

.23

1.90

3.14

1.25

1.30

1.92

1.95

1.80

34.16

1.49

30

1.57

1.45

1.12

4.00

1.56

2.68

2.95

1.55

.80

4.28

2.82

2.30

2.00

3.34

3.52

3.30

1.80

1.33

2.90

2.70

2.61

1.75

1.30

53.63

2.33

1

0.05

.05

_

.06

1.44

-

_

_

.28

-

_

1.20

1.22

-

.25

1.80

-

_

-

_

_

-

6.35

.29

2

_

-

_

_

-

-

_

_

-

_

0.50

-

_

-

_

-

_

_

_

_

-

.50

.02

7

0.15

.10

.10

.11

.07

-

.40

.20

.24

.07

.10

_

_

_

.06

.03

_

.12

.14

_

.05

.03

.10

2.07

.09

8

_

_

_

_

0.26

_

-

_

.07

.08

_

_

.29

_

.11

_

-

.04

_

.03

_

-

.88

.04
168 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 41.- Storms studied in connection with unit hydrographs 

for the Susquehanna River above Towanda, Pa. Continued

(Precipitation, In Inches, measured In the afternoon except at stations 

marked -::-, where it was measured in the morning, and stations marked 

 * :.', where it was measured at midnight.)

Station

New York:

Add is on

Alfred

Angelica

Elmira #&

Haskinville

Bainbridge -::-

Binghamton **

Cooperstown

Cortland

Delhi

De Ruyter

New Berlin

Norwich *

Oneonta

Roxbury

Sherburne *

Ithaca -:s-::-

Pennsylvania :

Lawrenceville

Montrose

Towanda

Wellsboro

West Bingham

Average

Station

New York:

Add! son

Alfred 

Angelica

Elmira ->:: 

Haskinville

Bainbridge *

Binghamton «-»

Cooperstown

Cortland

Delhi

De Ruyter

Morrisville 

New Berlin

Norwich *

Oneonta

Roxbury

Sherburne -::-

Ithaca «#

November 1924

21

_

-

-

_

_

0.3.0

-

.05

_

-

-

.50

-

-

_

_

.70

_

-

-

_

-

1.35

.06

22

0.18

.05

-

.52

.20

1.67

1.27

1.55

.98

1.73

1.37

.40

.73

1.56

1.45

.50

-

.50

.60

1.01

.35

.04

16.66

.76

23

0.02

.03

-

_

_

-

-

_

.03

.45

.08

_

1.39

.15

.08

_

-

_

.14

_

_

.10

2.47

.11

24

0.06

.08

.15

_

.21

-

.04

.03

_

.06

.12

_

.03

-

.06

_

.02

.10

-

_

_

.20

1.16

.05

28

^

0.02

.03

_

.06

.10

-

-

_

_

-

-

-

-

_

.15

-

_

_

_

_

.10

.46

.02

29

0.20

.08

.05

.02

.09

.03

.08

.20

.05

.10

.14

_

.15

.22

.25

.05

.11

.10

.10

.07

.08

-

2.17

.10

30

0.02

.05

_

_

_

-

-

.03

.10

.10

.90

.10

_

.01

.06

-

.05

-

.05

.06

.05

1.58

.07

November 1926

15

-

0.09

.30

.01

.15

_

-

.03

.02 

 zn . OW

_

-

-

-

16

1.46

1.27 

1.10

2.06

.62

.20

2.74

1.05

3.15

2.30

2.91

2.17 

1.45

.33

1.95

2.50

1.50

2.31

17

0.03

.06

1.70

-

-

_

-

.13

1.44

_

.27

_

-

18

0. 12

.40

.62

.10

.56

.47

.76

_

-

-

_

_

-

_

.40

19

0 53

1 07 

.12

.15

-

.02

-

.37

.62

.10

.75

.52

.37

.57

.10

20

0.04

_

-

-

.04

_

-

.03

-

_

_

-

-

.03

21

0.04 

.03

_

-

.07

.01

-

.06

.10

.05

_

-

-

.05

22

-

0.05

-

-

.03

-

-

.05

_

_

-

.09

-

23

0.02 

.10

_

-

-

-

_

.01

.02

.06

_

-

_

.01

24

0.07

.04

-

-

-

-

.15

.05

.05

_

-

-

.02

26

0.05

.14

.05

.10

-

-

_

.70

.10

.09

.01

.10

.50

.14

.08
UNIT-HTDROGRAPH ANALYSIS OP SURFACE RUN-OFF 169

Table 41.- Storms studied in connection with unit hydrographs 

for the Susquehanna River above Towanda, Fa. Continued

(Precipitation, in inches, measured in the afternoon except at stations 

marked #, where it was measured in the morning, and stations marked 

 *#, where it was measured at midnight. )

Station

Pennsylvania:

Lawrenceville 

Montrose

Morris Run

Towanda

Wellsboro

West Bingham

Average

Station

New York:

Add! son

Alfred

Angelica

Elmira ##

Haskinville

Binghamton *«

Cortland

Delhi

Morrisville

Norwich *

Oneonta

Roxbury

Sherburne *

Ithaca *»

Pennsylvania :

Lawrenceville

Montrose

Morris Run

Towanda

Wellsboro

Average

November 1926

15 16 17

1.65 

2 on n "i ^

0.05 5.24

2.77

1.75

1.37

.95 44.75 5.78

.04 1.86 .16

18

-

0.59

.15

.35

.50

4.60

.19

19

0.54

.4f

.63

.4C

-

7.2£

.3C

20 21 22

_

0.05

! « __

.05 0.05

.22 .46 0.22

.01 .02 .01

23

-

_

-

_

0.05

.27

.01

24 26

- 0.07

.14

.15

.15

.35

0.38 2.92

.02 .12

October 1929

1

_

-

-

_

-

-

0.26

-

.06

.14

_

-

.19

-

_

-

_

-

.65

.05

2

2.05

2.00

1.65

5.00

1.05

2.99

1.76

2.15

2.08

.10

2.12

1.40

.20

2.47

1.85

8.15

2.52

5.01

2.22

36.71

1.93

3

0.65

1.86

1.37

.05

1.45

.33

1.26

.35

.60

2.30

.27

2.29

.47

.60

.47

.92

.55

.83

16.62

.88

4

_

-

-

-

_

-

-

0.07

.15

.11

.04

.40

.14

-

_

_

_

_

-

.91

.05

7

0.08

.16

.22

.04

.20

.07

.58

.06

.48

.12

.04

-

.08

.22

.10

_

-

_

-

2.45

.13

8

_

-

-

-

_

-

-

0.05

.05

.12

_

.05

.14

-

_

_

-

_

-

.41

.02

13

0.16

.12

.11

.04

_

.09

.18

.04

.26

.07

.09

-

_

.16

.20

_

.10

.02

-

1.64

.09
170 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 41.- Storms studied in connection with unit hydrographs 

1 for the Susquehanna River above Towanda, Pa. Continued

(Precipitation, in inches, measured in the afternoon except at stations 

marked #, where it was measured in the morning, and stations marked 

*#, where it was measured at midnight.)

Station

New York:

, Addis on

Alfred

Angelica

Elmira **

Haskinville

Bainbridge *

Binghamton **

Cortland

Delhi

Morrisville

Norwich #

Oneonta

Roxbury

Sherburne «

Ithaca **

Pennsylvania:

Lawrenceville

Montrose

Morris Run

Towanda

Wellsboro

Average

Station

New York: 

Addison

Alfred

Angelica

Elmira ##

Haskinville

Bainbridge *

Binghamton ##

Cooperstown

Cortland

Delhi

Morrisville

Norwich *

Oneonta

Roxbury

Sherburne «

Ithaca -*«

April 1930

6

0.05

.07

-

.93

_

-

1.01

-

-

_

.04 '

-

.73

_

.21

.22

.23

.60

4.09

.20

7

1.05

.56

.50

.30

.62

.81

.60

1.40

.97

1.18

1.15

1.18

.85

.96

.88

.52

1.30

1.08

1.49

.40

17.80

.89

8

0.10

.05

.10

_

.09

.31

.16

.44

.11

.10

.19

.04

.07

.34

.18

_

_

.08

.02

.02

2.40

.12

11

_

_

-

0.06

-

-

-

.04

-

.02

.20

-

-

_

_

-

-

-

.32

.02

12

_

_

0.05

_

_

.11

-

_

.25

-

.19

.12

.04

.07

-

_

_

-

.02

-

.85

.04

13

0.26

.03

.05

.20

_

-

.10

_

-

-

_

_

-

-

-

.10

.41

.30

.28

.25

1.98

.10

14

..

_

-

0.05

.08

-

-

-

-

-

-

-

-

-

_

.40

-

-

-

.53

.03

June 1930

9

0.25

.09

.12

.45

.10

.11

.50

.58

.42

.51

.09

.08

.29

.24

.04

.52

10

1.26

1.00

1.50

.24

1.23

.81

.80

.10

.46

1.02

.94

.75

.75

.60

.55

1.07

11

_

0.04

_

.05

.44

-

.08

.08

.25

.49

.02

-

.64

-

16

0.26

.25

.15

.50

1.08

-

-

_

.78

_

.21

_

-

-

1.09

17

1.70

.55

.45

1.80

.46

-

.78

-

1.74

_

1.50

_

-

.27

.03

2.49

18

0.38

.50

.60

.01

.92

.08

1.87

.75

.72

.25

1.16

.35

.03

.25

.32

1.20

19

0.04

.10

.03

-

.80

.05

-

.24

.21

.52

.97

.22

.12

.47

.05
UNIT-HYDROGRAPH ANALYSIS OP SURFACE RUN-OFF 171

Table 41.- Storms studied in connection with unit hydrographa 

for the Susquehanna River above Towanda, Fa. Continued

(Precipitation, in Inches,measured in the afternoon except at stations 

marked *, where it was measured in the morning, and stations marked 

**, where it was measured at midnight.)

Station

Pennsylvania:

Lawrenceville

Montrose

Morris Run

Towanda

Wellsboro

Average

Station

New York:

Addis on

Alfred

Angelica

Elmira **

Haskinville

Bainbridge *

Binghamton ##

Coopers town

Cortland

Delhi

Morrisville

Norwich #

Oneonta

Roxbury

Sherburne #

Ithaca *»

Pennsylvania:

Lawrenc e vi lie

Montrose

Morris Run

Towanda

Wellsboro

Average

June 1930

9

_

0.22

.40

.20

-

5.21

.25

10

.40

1.60

1.51

.82

1.55

18.96

.90

11

1.00

-

-

-

-

3.09

.15

16

0.10

-

.18

-

-

4.60

.22

17

2.69

1.00

.18

.33

.32

16.29

.78

18

0.70

.75

.90

2.02

.52

14.28

.68

19

_

.38

-

.01

-

4.21

.20

October 1932

4

0.05

.02

.03

.12

.33

-

-

-

_

-

_

-

-

_

-

_

_

.06

_

.01

.62

.03

5

0.70

.59

.40

2.10

-

.60

3.59

.54

.30

.73

1.48

.41

.60

.23

.30

1.14

.43

2.20

.86

2.34

1.05

20.59

.98

6 7 11 12 13

1.96

1.33

1.27

.49

1.68

2.70

1.77

4.85

3.16

5.71

3.49

4.04

5.09

6.75

2.87

1.28

2.80

2.25

2.46

2.65

1.61

60.21

2.87

_

0.03

.05

_

-

.96

-

.04

_

.05

.02

.90

.06

.04

.94

-

_

_

_

_

-

3.09

.15

_

0.01

.04

_

_

-

.05

.08

.03

_

.15

.11

.02

.05

.11

.03

_

_

.01

_

-

.69

.03

_

0.20

.20

_

.20

.04

.02

.12

.46

.01

.08

.05

.08

.11

.02

.11

.10

_

.03

.04

-

1.87

.09

0.05

.10

.10

_

-

-

-

-

_

.08

.25

-

-

.11

-

_

_

-

_

-

.69

.03

Table 42 gives the surface run-off from the unit storms and the 

approximate depth of the precipitation that caused the run-off. Figures 

preceded by * include run-off from melting snow.
RAINFALL AND RUN-OFF IN THE UNITED STATES

Figure 51. Susquehanna Hirer Basin abore looanda. Fa. 

Drainage area 7,770 aqnare «il»a
UNIT HYBROGRAPH AHAlSSIS OF SURFACE RUN-OFF 173

*//$$

/ ^~^

vm

Surf]

^. 

Gram

A

oe rm

""~~

vUntt

s

\

-off

_ _ =

r nut

V

-off

^»^

^^

~ ^^ SR 

« 60,000

40,000

20,000

10 11 12 13 14 

October 1918

4.000 

2,000 

0

'//////jm

> ,«_ ?:=-

f A

Surft

s.

X

toe rm

Wk

x^

k-Off

 [- i _4 r H 

Ground-water nmw#<

^

-off

'f IJIIIII

^~s

s'

»»J nm_m»_i

14 15 16 17 18 19 20 21 22 23 24 26 

JUly 1921

282930 

September

676 

October 1924

Figare 52. Unit hydrographs for Susquehatma River at Towanda, Pa.
.RAINFALL AND RUN-OFF IN THE UNITED STATES

20 21 22 23 24 26 26 27 28 29

10 11 12

October 1929

30,000 

26,000 

20,000 

15,000

5.000

" 

w,

/

I

(\

1

Surfs

\

\

ice nu

\

\

J-Off

^t-F-1

Sround-water mn

\

^.

-off

V////A Average daily rain- 

\ffiffl, 'a11 ln Irishes- Eaoh 

Y////A TOrtical interval 

represents 1 inch*

-~ 

""" ^\

^- -^.

5 6 7 8 9 10 11 12 13 14 15 16 17 

April 1930

Figaro 53. Unit hyirographs for Susquebanna Hiver at Towanda, Fa.
Dally s

o 

« E"! ?

 [ S*l .S

'< il^1 8 9 {ft O M

! in e
176 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 42.- Surface run-off from unit storms, 

Susquehanna River at Towanda, Pa.

Storm

Oct. 6, 1918

July 15, 1921

Apr. 5, 1923

Sent. 30, 1924

Nov. 22, 1924

Nov. 16, 1926

Oct. 2, 1929

Apr. 7, 1930

June 10, 1930

Oct. 6, 1932

Average of precipitation at stations

(inches)

0.73

1.30

1.15

4.11

.93

2.06

2.86

1.21

1.30

4.00

Surface run-off

(inches )

0.22

.07

-::- 1.02

1.50

.15

* 1.42

.29

.50

.09

.71

Ratio of

surface runoff to average precipitation

0.30

.05

.89

.36

.16

.69

.10

.41

.07

.18

Table 43 gives the daily percentages for the 10 distribution 

graphs, and figure 55 shows the graphs superimposed. The average distribution graph determined for the basin is 12, 33, 24, 15, 8, 4, 2, 1, 1 

percent. The first figure of each distribution graph is the percentage of 

surface run-off for the calendar day on which most of the rainfall occurred; 

other figures for succeeding days.

Table 43.- Distribution graphs for storms in 

Susquehanna River Basin above Towanda, Pa.

Oct. 6, 1918

July 15, 1921

Apr. 5, 1923

Sept. 30, 1924

Nov. 22, 1924

Nov. 16, 1926

Oct. 2, 1929

Apr. 7, 1930

June 10, 1930

Oct. 6, 1932

20.1

0

6.8

13.8

1.6

7.8

.6

15.5

4.5

7.8

39.1

8.8

26.8

34.2

4.6

32.1

17.1

28.5

33.8

30.5

19.8

38.9

24.7

24.6

30.8

22.5

38.3

21.3

29.3

26.1

9.6

25.5

16.6

14.8

23.3

14.5

19.3

14.1

16.2

13.4

5.2

15.6

11.1

6.5

16.4

9.7

12.4

8.7

8.7

9.3

3.6

6.5

7.3

3.2

10.0

6.4

6.5

5.8

4.7

4.6

1.9

2.9

4.1

1.9

6.8

4.0

3.6

3.5

1.6

2.1

0.7

1.4

1.9

.8

3.9

2.1

1.7

1.9

.7

.9

-

0.6

.7

.2

1.9

.9

.5

.7

-

.3

_

0.4

-

-

.7

-

_

-

-

-

Delaware River Basin above Port Jervis, N. Y.

The headwaters of the Delaware River lie in Delaware, Greene, and 

Schoharle Counties, N. Y. The east branch rises at Grand Gorge, in northeastern Delaware County. The west branch has its source in a small lake 

near the Schoharie and Delaware County line at an altitude of about 1,886 

feet. The two branches flow in a southwesterly direction, and the main 

stream below their junction flows southeast. The drainage area above Port 

Jervis is 3,070 square miles, the length about 75 miles (river distance
UHIT-HTDROGRAPH ANALYSIS OF SURFACE RTO-OPP

595JO 85 12
178 RAINFALL AND RUN-OFF IN THE UNITED STATES

140 miles), and the average width about 41 miles. The Mongaup and Lackawaxen Rivers drain the principal subbasins. The gradient of the east and 

west branches above the junction is about 8 feet to the mile. From Hancock (the junction point) to Port Jervis (75 miles) the average gradient 

is about 6 feet to the mile.

The original gage, on the toll bridge at Port Jervis, was a 

chain established by the United States Weather Bureau in October 1904 for 

the purpose of flood predictions. The gage heights were supplied to the 

United States Geological Survey for determination of daily discharge.

A vertical and inclined staff gage was installed in June 1914. 

An automatic recorder was established in August 1928, about 350 feet below 

the bridge. The zero of the gage is 415.6 feet above mean sea level.

Records are available since October 1904 and are considered good. 

There are large diurnal fluctuations at medium and low stages, owing to the 

operation of power plants on tributary streams (12,200,000,000 cubic feet 

of storage in 1930).

Eight or nine Weather Bureau stations are normally available for 

the determination of daily precipitation. These stations and the principal 

drainage are shown in figure 56.

Table 44 gives the daily precipitation recorded at the Weather 

Bureau stations for the storms that produced the unit hydrographs shown in 

figures 57, 58, and 59.

Table 44.- Storms considered in connection with unit 

hydrographs for the Delaware River Basin above Port Jervis, N. Y.

(Precipitation, in inches, measured in the afternoon except at stations 

marked », where it was measured in the morning, and stations marked 

 SH*, where it was measured at midnight.)

Station

New York:

Bainbridge » 

Beerston

Jeffersonville

Oneonta

Port Jervis

Roxbury

October 1917

28

0.42 

.68

-

_

.33

.50

29

0.24 

.30

.11

_

.02

.23

30

1.30 

3.11

1.70

_

1.59

2.40

31

0.57

_

_

_

-

October 1918

5

-

-

_

_

-

6

1.05 

1.42

1.29

.19

.54

1.31

7

0.19

-

_

.14

-

12

-

0.42

_

.09

.22

15

0.09

.04

.09

-

.10

Station at Beerston was moved to Walton after October 10, 1918.
UNIT-HYDROGRAPH ANALYSIS OF SURFACE RUN-OFF 179

Table 44.- Storms considered in connection with, unit hydrographs 

for the Delaware River Basin above Port Jervis, H, Y. Continued

(Precipitation, in inches, measured in the afternoon except at stations 

marked «, where it was measured in the morning, and stations marked 

 »*, where it was measured at midnight;)

Station

Pennsylvania :

Gouldsboro *

Honesdale

Scranton #-*

Average

Station

New York:

Bainbridge *

Jeffersonville

Oneonta

Port Jervis

Roxbury

Walton

Pennsylvania:

Gouldsboro * 

Hawle T *'~

Scranton »#

Average

Station

New York: 

Bainbridge *

Delhi

Jeffersonville

Oneonta

Port Jervis

Roxbury

Pennsylvania :

Gouldeboro *

Hawley »

Scranton *#

Average

October 1917

28 29

0.47

.45

0.05

2.85 .95

.36 .12

30

1.80

2.10

2.12

16.12

2.02

31

0.6C

.

-

1.17

.IE

October 1918

5 6

. _

_

0.23 0.79

.23 6.59

.03 .82

June 1922

2

0.06

.60

.48

.48

.13

.43

.26

.41

2.85

.36

3

1.00

1.2C

1.81

1.34

1.70

2.41

1.04

1.80

12.30

1.54

4

1.24

_

-

_

-

-

1.42

-

2.66

.33

5

_

0.40

.18

1.03

.42

.55

-

.42

3.00

.37

6

0«18

_

-

.12

.02

.14

.24

.03

.73

.09

7

0.06

_

_

.03

-

-

-

-

.09

.01

7

_

-

0.11

.44

.06

12

_

0.25

-

.98

.12

13

_

_

-

0.32

.04

April - May 1923

28

0.30

.55

1.52

.49

2.20

1.28

-

1.75

8.09

.90

September - October

29

0.14

.30

.60

.75

1.02

.23

.22

-

2.00

5.26

.58

30

2.68

4.28

3.80

3.52

4.33

3.30

4.15

2.54

3. 33

31.93

3.55

1

1.44

.28

-

-

-

.25

1.72

2.2?

-

5.91

.66

29

0.86

.88

.32

.52

.50

1.04

.69

QI7

.07

5.75

.64

30

_

0.06

.11

_

-

.16

-

.14

.47

.05

1

_

_

_

_

0.08

-

.18

.45

.05

1924

7

0.07

.10

.06

.10

.03

«.

-

.08

.44

.05

8

0.26

.07

-

-

.17

.11

.20

.08

-

.89

.05
180 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 44.- Storms considered in connection with unit hydrographa 

for the Delaware River Basin above Port Jer-vis, N. Y. Continued

(Precipitation, In Inches, measured In the afternoon except at stations 

marked *, where It was measured In the morning, and stations marked 

«*, where it was measured at midnight.)

Station

New York:

Bainbridge *

Delhi

Jeffersonville

Oneonta

Port Jervis

Roxbury

Pennsylvania :

Gouldsboro «'

Hawley -»

Scranton -»

Average

Station

New York:

Bainbridge *

Delhi

Jeffersonville

Oneonta

Port Jervis

Roxbury

Pennsylvania :

Gouldsboro #

Hawley *

Scranton «--«-

Average

Station

New York: 

Bainbridge *

Delhi

Jeffersonville

Oneonta

Port Jervis

Roxbury

October 1926

5 6

0.40 2.00

2.23

1.53

.58 1.28

2.00

.03 1.70

1.35

.93

.33 .67

1.34 13.69

.15 1.52

7 10

0.10

.05

.03 0.10

.44

.05

.11 .35

.19

.03

.07 .30

.39 1.43

.04 .16

October 192V

3

_

-

_

0.13

1.00

-

_

-

2.60

3.73

.41

4

1.70

2.37

2.77

1.74

_

2.85

2.60

2.82

.29

17.14

1.90

8

_

0.41

.22

_

.15

.37

.42

.41

.34

2.32

.26

11

_

_

_

_

_

-

.38

.28

-

.66

.07

13

_

0.45

.18

.40

.03

.30

_

_

.IS

1.49

.17

14

_

_

_

_

_

-

.15

.16

-

.31

.03

October 1927

12

_

-

_

-

1.98

-

_

-

1.58

3.56

.40

13

1

1.

1

1,

2.

1.

11.

1.

50

55

80

69

_

66

18

78

14

30

26

17

0.40

.75

.72

.56

1.43

.36

.20

.39

.91

5.72

.64

18

1.50

.58

1.25

1.06

1.70

.78

1.60

.96

1.85

11.28

1.25

19

1.20

1.10

1.69

1.41

.10

1.22

1.68

2.32

1.11

LI. 83

1.31

September 1933

3 4

0.93

0.17 1.44

.80 1.50

.13 .44

.25 1.78

.35 1.22

6

0.38

_

.58

.

.74

7

0.04

.12

_

.14

.11

.25

10

_

_

_

0.17

.03

14

1.12

1.12

.40

.85

.82

.88
UNIT-HYDROGRAPH ANALYSIS OP SURFACE RUN-OFF 181

Table 44.- Storms considered in connection with unit hydrographs 

for the Delaware River Basin above Port Jervis, N. Y. Continued

(Precipitation, in inches, measured in the afternoon except at stations 

marked *, where it was measured in the morning, and stations marked 

«-», where it was measured at midnight.)

Station

Pennsylvania :

Gouldsboro -» 

Hawley * 

Scranton *«

Average

September 1933

3

0.02 

.12 

.90

2.74 

.30

4

2.51 

2.84 

.59

13.25 

1.47

6

:

1.70 

.19

7

:

0.66 

.07

10

0.45 

.36

1.01 

.11

14

0.14 

1.51

6.84 

.76

Table 45 gives the surface run-off from the unit storms and the 

approximate precipitation that caused the run-off.

Table 45.- Surface run-off from unit storms in 

Delaware River Basin above Port Jervis, M. Y.

Storm

Oct. 30, 1917

Oct. 6, 1918

June 3, 1922

Apr. 29, 1923

Sept. 30, 1924

Oct. 6, 19S6

Oct. 4, 1927

Oct. 13, 1927

Sept. 4, 1933

Average of precipitation at stations

( inches )

2.29

.91

2.23

1.54

4.79

1.71

2.31

1.66

1.77

Surface run- off

(inches)

1.34

.28

.80

.56

2.01

.29

.31

.50

.52

Ratio Of

surface runoff to average precipitation

0.58

.31

.36

.?6

.42

.17

.13

.30

.29

Table 46 gives the daily percentages for the nine distribution 

graphs, and figure 60 shows the graphs superimposed. The average distribution graph determined for the basin is 6, 43, 24, 13, 7, 4, 2, 1 percent. 

The first figure of each distribution graph is the percentage of surface 

run-off for the calendar day on which most of the rainfall occurred; other 

figures for succeeding days.
182 RAINFALL AND RUN-OFF IN THE UNITED STATES

 Bainbridge

Fort Jervis

GouldBbcro

10 10 20 30 40 Miles

Figure 56. Delaware River Basin above Pert Jervis, K.T. 

Drainage area 3,070 square miles
Daily stream flow in second-feet 

8

8
184 RAINFALL AND RUN-OFF IN THE UNITED STATES

80,000

17,500

15,000

12,500

10,000

7,500

5,000

2,500

80,000 

70,000 

60,000 

50,000 

40,000 

30,000 

20,000 

10,000 

0 

12,000 

10,000

6,000

 4,000 

fi

i

5 2,000 

|

3 o

1i-i

28 

S

.. 

W/f

/

29 

eptemb

VM!

i

WMp

/

r

30 

ear

W/t WA ^

i

VS

Surface run-off

 -i 4 

^

_--

~"^^ 

Grop

 

nd-wat

123456 

October 1924

A

^

\

s.^x

Surface run-off

___ l..-| 

Srotmd-water run1 1

 oft

^--

er run 

7

 __,

 . 

-off

8

4 5 6 7 8 9 10 11 12 13 14 

October 1926

10,000 

7,500 

5,000 

2,500 

n

/////<

 ^

WA w//, 3\p

Surf!

 -

\

\

ce rni

!

_,

\

^<> 

l-Off

 f-H Srcrand-wa

/ / / / /

^-

er TO

~~~-

>-ott

 WMK

6789 

October 1927

10 11 12

Surface run-off

Ground-water run-off

Average dally rainfall In lushes. Each 

rertlcal interral 

represents 1 Inoh.

11 12 13 14 15 16 17 18 19 20 21 

October 1927

Figure 58.-tJnit bydrographs for Delaware Elver at Port Jervis, H.T.
UNIT-HYDBOGRAFH ANALYSIS OF SURFACE RUN-OFF

2,500

\

Srotmd-mter run-off

2 3 4 5 6 7 8 9 10 11 12 

September 1933

iw/wj Arerage dally rainfall in inches. 

1%;%^) Each yertloal interval 

represents 1 inoh.

Figure 59. Unit hydrographs for Bslaware Biver at Fort Jerris, N.T.

Figure 60.-Superimposed distribution graphs for Delanmre Slyer Basin abore Fort Jervia, N.T.
186 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 46.- Distribution graphs for storms in 

Delaware River Basin above Fort Jervls, N. Y.

Oct. 30, 1917

Oct. 6, 1918

June Z, 1922

Apr. 29, 1923

Sept. 30, 1924

Oct. 6, 1926

Oct. 4, 1927

Oct. 13, 1927

Sept. 4, 1933

1.0

1.8

1.7

4.4

6.6

1.4

6.1

10.0

15.5

49.4

45.0

43.8

41.0

43.7

39.6

46.1

42.0

39.5

24.7

25.5

21.9

23.0

27.2

25.9

22.8

20.0

20.9

12.2

13*5

13.4

14.6

10.9

14.9

11.5

12.7

11.3

6.7

7.2

9.0

8.1

6.3

9.3

6.6

7.8

6.5

3.8

4.2

5.6

5.6

3.1

5.4

4.1

4.4

4.0

1.6

2.1

3.0

2.4

1.8

2.5

2.0

2.2

1.7

0.6

.7

1.3

.9

.6

1.0

.8

.9

.6

_

-

 0.3

-

-

-

-

-

-

The individual distribution graphs for the Delaware Basin when 

superimposed form a more uniform and compact plot than those for any of the 

other basins studied, although the Delaware Is the most rapidly concentrating stream and its distribution graph has the highest peaks of the group 

studied.

French Broad River Basin above Dandridge. Tenn.

The French Broad River rises in the Blue Ridge in Transylvania 

County, N. C., near the South Carolina boundary. It first flows in a 

northerly direction, then northwesterly to the Tennessee Valley, where it 

turns southwest.

The drainage area above Dandridge is 4,450 square miles, and the 

length of the river is about 150 miles. The Nolichuoky and Pigeon Rivers 

drain the principal subbasins. The upper 50 miles of the French Broad has 

an average slope of 3 feet to the mile, the next 50 miles 16 feet to the 

mile, and the 50 miles above Dandridge 5 feet to the mile. The zero of 

the gage is 902.8 feet above mean sea level. About 2,800 square miles of 

the area drained is in North Carolina and consists of high mountainous 

country with several peaks above an altitude of 5,000 feet. About 50 percent of the area Is forest, and the remainder is equally divided between 

crop and pasture.

The United States Geological Survey has published daily discharges at this station since October 1918. The United States Weather 

Bureau has obtained gage heights since December 1904. The gage that was 

used when the Geological Survey records began was painted (1.9 to 35.0 

feet) in feet and tenths on the shoreward side of the second concrete pier 

of the highway bridge. As the gage was difficult to read from the bank, a 

.rowboat was generally used in making a reading once dally. The records
UNIT-HYDROGRAPH ANALYSIS OP SURFACE RUN-OFF 187

are considered fair up to 25,000 second-feet and poor above. A new 

was installed In October 1925 on the right bank; the lower part Is a fsloping section, and the upper part Is a vertical staff gage bolted to the 

right-bank pier. This gage was set to a datum 0.04 foot lower than the 

Weather Bureau gage. The records are considered good below 50,000 secondfeet and fair above.

A water-stage recorder was Installed and has been in use since 

October 1951. Diurnal fluctuation during low stages is caused by regulation upstream.

The records of dally stream flow are considered poor for the 

development of any theory connected with the unit hydrograph.

The dally precipitation was obtained by taking the average of 12 

to 15 well distributed stations In or adjacent to the basin. The stations 

and principal drainage are shown on figure 61.

Table 47 gives the dally precipitation recorded at the Weather 

Bureau stations for the storms producing the unit hydrographs shown In 

figures 62, 63, and 64.

Table 47.- Storms considered In connection with unit 

hydrographs for French Broad River Basin above Dandridge, Tenn.

(Precipitation, In Inches, measured In the afternoon except at stations 

marked *, where it was measured in the morning, and stations marked 

*», where It was measured at midnight.)

Station

North Carolina: 

Altapass

Ashevllle *»

Banners Elk

Brevard

Cullowhee

Hendersonvllle

Hot Springs

Marshall

Montreat

Waynesvllle

Tennessee:

Dandridge *

Greeneville *

Newport *

Rogersvllle *

Average

August 1921

3

1.65

.51

2.60

_

1.50

_

1.56

1.85

.70

-

.56

.60

.05

.12

11.50

.88

4

0.40

.41

.05

.04

.05

.50

-

.45

.06

-

.34

1.00

.22

.29

5.77

.29

5

0.01

_

.75

2.10

.45

-

_

.02

-

.11

_

-

.04

3.46

.27

6

_

_

_

_

_

0.03

_

_

-

.19

-

-

.16

.38

.03

7

0.10

.49

.60

.20

.40

1.50

.88

.35

.23

-

_

.72

-

-

5.47

.42

8

_

-

_

0.05

.10

.13

-

-

.24

.26

.45

.34

1.57

.12
188 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 47.- Storms considered in connection with unit hydrographs 

for French Broad River Basin above Dandridge, Term. Continued

(Precipitation, in inches, measured in the afternoon except at stations 

marked «, where it was measured in the morning, and stations marked 

«#, where it was measured at midnight.)

Station

North Carolina:

Altapass

Asheville #-:;-

Banners Elk

Brevard

Oullowhee

Hendersonville

Hot Springs

Marshall

Montreat

Waynesville

Tennessee:

Dandridge »

Greeneville *

Newport *

Rogersville *

Average

Station

North Carolina:

Altapass

Asheville -:.< ::-

Banners Elk

Brevard

Hendersonville

Hot Springs

Marshall

Montreat

Mount Mitchell

Waynesville

Tennessee:

Dandridge *

Elizabethton *

Newport »

Rogersville -»

Average

April 1922

5

_

0.57

.10

.24

.05

.50

.11

.12

.19

.25

_

_

-

-

2.13

.15

6

1.30

.67

.36

1.56

.80

1.51

.34

.70

1.33

.88

.36

.30

.26

.83

11.20

.80

10

_

-

-

_

_

_

-

_

_

O.S3

_

_

-

.04

.27

.02

11

_

0.26

.20

.32

.25

_

.30

.22

.33

-

.14

_

.10

.24

2.36

.17

12

_

-

-

_

-

0.20

-

_

-

.07

.28

.16

.04

.75

.05

September 1923

20

_

_

_

_

0.04

.02

_

_

-

-

_

_

-

-

.06

-

21

0.85

.55

.45

_

4.30

.70

.07

1.98

1.10

.12

.62

1.30

.78

.33

13.15

1.01

22

_

-

-

-

0.04

-

_

_

.60

-

_

_

_

-

.64

.05

23

1.25

-

-

_

.24

-

.23

_

.

-

.05

_

.42

-

2.19

.17

24

1.10 (

-

_

-

_

-

_

.18

1.13 -

.01

_

_

-

-

2.42 '

.19

25

3.20

-

-

_

-

.20

L.20

.19

_

-

-

-

L.79

.14

13

_

-

0.10

_

-

_

.09

-

_

-

_

_

-

-

.19

.01

14

_

-

-

_

-

-

-

-

0.17

_

_

-

-

.17

.01

15

_

0.19

.41

_

.10

.16

.74

.17

.14

-

.30

.17

.65

.10

3.13

.22

April 1924

17

0.20

.41

-

-

.40

.12

.30

.13

1.57

.10

_

-

-

-

3.23

.23

18

1.00

.45

.20

2.25

1.80

.52

.57

.90

-

1.00

1.64

.40

1.15

1.47

13.35

.95

19

-

-

0.30

-

_

-

-

-

-

-

.12

.59

.15

.09

1.25

.09

22

-

-

-

-

-

-

-

-

-

0.05

.13

.09

.02

.29

.02

26

0.45

.35

.70

.05

.10

.33

.35

.26

.55

.10

.49

.27

.48

.25

4.73

.34
UHIT-HYDROGRAPH ANALYSIS OF SURFACE RUN-OFF 189

Table 47.- Storms considered in connection with unit hydrographs 

for French Broad River Basin above Dandrldge, Tenn. Continued

(Precipitation, in inches, measured in the afternoon except at stations 

marked *, where it was measured in the morning, and stations marked 

* »-, where it was measured at midnight.)

Station

North Carolina:

Asheville *« 

Banners Elk

Brevard

Henderaonville

Hot Springs * 

Linville Palls

Marshall * 

Mont re at #

Mount Mitchell

Waynesville

Tennessee:

Dandridge *

Embreeville *

Newport *

Roger svi lie *

Average

Station

North Carolina: 

Altapass

Asheville «sBanners Elk

Bender sonville

Hot Springs

Marshall *

Montreat *

Mount Mitchell

Waynesville

Tennessee:

Dandridge «

Embreeville »

Newport -.'< 

Rogersville *

Average

October 1927

11

0.20

_

-

-

1

AO 

. vj£i

.45

_

_

-

-

1.67

.12

12

1.98 

1.76

2.50

2.08

.21

S Q"Z yo

1.05 

1.08

2.10

1.15

.23

.10

.23

.26

18.66

1.33

13

-

_

0.02

.55

-

_

.67

.63

-

.35

2.22

.15

18

-

_

-

-

-

0.10

_

-

-

-

.10

.01

19

-

_

-

-

-

0.30

_

.19

.32

-

.81

.06

April - May 1928

27

0.97 

1.00

1.25

1.34

1.05

Ql

.70

QA

1.40

OR

.27

.22

.04

.22

10.52

.75

28

0.20 

.05

_

.52 

.88

.15

1.10

.85

.68

1.03

1.24

.64

7.34

.52

30

0.39

_

_

-

.25

_

_

-

-

-

.64

.05

1

0.02

_

.49

.30 

.08

.35

. *JCi RO

.52

.11

.03

.14

.07

2.63

.19

April - May 1931

21

0.17

1.80

.32

-

-

.07

.77 '

.04

_

-

-

-

3.17

.24

22

1.96

1.74

.94

1.74

1.37

1.35

2.05

2.25

2.32

1.28

.98

1.10

1.10

20.18

1.55

23

-

-

-

0.10

_

_

-

_

-

.06

.05

.21

.02

25

-

0.04

-

_

.06

_

.05

.16

.08

.10

.12

.61

.05

26

0.05

.14

.30

.02

,48

_

.16

.30

.46

.72

.28

.67

.45

4.03

.31

27

_

_

_

0.15

_

_

-

.08

_

.06

.01

.30

.02

1

0.10

.13

.

.15

.10

_

_

.37

.30

.03

_

.03

-

1.21

.09

2

0.03

_

.22

-

.10

.14

_

.02

.04

.12

.06

.11

.84

.06
190 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 47.- Storme considered in connection with unit hydrographs 

for French Broad River Basin above Dandridge, Tenn. Continued

(Precipitation, in inches, measured in the afternoon except at stations 

marked *, where it was measured in the morning, and stations marked 

**, where it was measured at midnight.)

Station

North Carolina:

Altapass

Asheville ##

Banners Elk

Hendersonville

Hot Springs

Marshall *

Montreat *

Mount Mitchell

Waynesville

Tennessee:

Dandridge *

Embreeville *

Newport *

Rogersville *

Average

September 1931

2

0.62

.13

_

.19

.05

_

_

.45

.20

_

-

-

-

1.62

.12

3

0.90

.90

2.21

.30

2.15

.71

1.10

1.20

.60

1.19

1.42

.84

1.42

14.94

1.15

4

_

_

_

-

-

0.69

.02

_

-

_

.58

.28

.01

1.38

.11

April - May 1932

30

0.10

1.32

2.42

.59

.32

-

1.92

1.05

.02

.09

-

-

.08

7.91

.61

1

2.55

.04

.

1.31

.90

1.55

-

2.50

1.14

1.49

1.65

1.45

1.23

15.81

1.22

8

fl.05

_

.25

.07

.08

_

_

.11

-

_

-

-

-

.56

.04

9

0.15

.20

.64

.02

.03

.05

.03

.15

.03

.67

.30

.22

.44

2.93

.23

10

0.95

_

.70

.71

.19

.25

.40

.56

.10

.35

1.04

.16

.50

5.91

.45

Table 48 gives the eurface run-off from the unit storms and the 

approximate precipitation that caused the run-off.

Table 48.- Surface run-off from unit storms in 

French Broad River Basin above Dandridge, Tenn.

Storm

Aug. 3, 1921

Apr. 6, 1922

Sept. 21, 1923

Apr. 18, 1924

Oct. 12, 1927

Apr. 27, 1928

Apr. 22, 1931

Sept. 3, 1931

Apr. 30, 1932

Average of precipitation at etations

( inche s )

1.44

.95

1.06

1.27

1.60

1.27

1.81

1.38

1.83

Surface run-off

(inches)

0.57

.26

.14

.50

.13

.45

.49

.27

.56

Ratio of

surface runoff to average precipitation

0.40

.27

.13

.39

.12

.35

.27

.20

.31

Table 49 gives the daily percentages for the nine distribution 

graphs, and figure 65 shows the graphs superimposed. The average distribution graph determined for the basin is 3, 29, 25, 15, 9, 7, 5, 3, 2, 1, 

1 percent. The first figure of each dietribution graph is the percentage
UKir-HYDROORAPH ANALYSIS OF SURFACE ROT-OFF

"~) «Ellzabethton 

 Johnson City

Banners Elk 

10 20 30 40 Biles

Figure 61. French Broad Hirer Ban In above Dandrldge, Tone. 

Drainage area 4 t450 square miles
RAINFALL AND RUN-OFF IN THE UNITED STATES

7777;

25,000

Surface run-off

Ground-water run-off

2 3 45 6 ^ 8 9 10 11 1? 13 14 15 16 

August 1921

15,000 

10,000 

5,000

n

V

\^

m

""- J

1^

i

Surfi

" -...

\

\

ice roi

--__

Gram

S

l-Off

id-»at

 1

\^

~~~-

fc ron--off

 ~^

T- 

^- .

- ^--

- --

 \

__

April 1922

30 21 22 23 24 25 26 27 28 29 30 1 2 3

20,000 

15,000 

10,000 

5,000

f 1 / / /

x .

m

-it

3

"**

A^

irfaoe

- >

Grooi

\

\

rnn-o

- .

id-Tiat

V^

'f

sr ran

^X

-Off

^

r////J Average dally rainr////| fan in indies. Bach 

vertical Interval 

represents 1 inoh.

 _

 

"--- 

I in

- £ - »

16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 

April 1924

Figure 62. Unit hydrographs for French Broad Elver at Dandridge, Tenn.
UHH-HTOBOGRAPH ANALYSIS OP SURFACE RUN-OFF

6,000 

5,000 

4,000 

3,000 

2,000 

1,000 

0 

20,000

15,000 

10,000

4>

1

§ 5,000 

I

3 

I

« 0 

n

*

g 25,000 

20,000

10,000 

5,000 

0

15,000 

10,000 

5,000

0

 ->v

//// w,

^<3

r\

\

N

Surface run-off

^-H=---4- -

(Sron ld-T»t 3r ranv^

-off

Iff 11 12 13 14 15 16 17 

October

\

'////

/ v:.

^

^

/ 

Surf;

"~~

\

ce m

 

GrTOIZ

s

\

r^)ff

 . __

id-«at

26 27 28 29 30 1 

April

-^

^~~*--

'////, '<////,

1

J

/\L

Surf)

Nv

\

ice run-off Hf 

1 Groi

"N

v

or Tun*

\

"

-off

^

18 

1927

S,

^

^

19

\

^

20

"^^l

"*"^ 

~~~- 

 __, 'T^rM»i

21 22 23 24

^

 -_ r=--s 

23456789 10 

Bay 1928

If / / 1

^S ^^

md-na1

 - 

" -

ter ma

 ^^_

1-Off

202122232425262728 

April 1931

^^. £ 

Wi.

1

A

/

\

V

Surface run-off

 -U~~L "1 r 

Sround-J«Bter ranV_

 Off

 «_ 

-^^ -^-^

 

na=cs

 -

S3 30 1 2 

Ma;

|////j| Average di 

f////J fall in li 

vertical 

represent

 

 

- ^.

- »

3 4

r

illy raialobes* fianli 

Interval 

> 1 inaa

1 2 54 5 4 7 89 10 11 12 13 14 IS

September 1931

figure 63^-Cnit hydrograpos for Breach Broad Elver at Dandrldge, team. 

S956O-35 13
194 RAINFALL AND RUN-OFF IN THE UNITED STATES

30,000 

o

 i 25,000 £

0

o

<D

" 30,000

g £ 15,000

I

8 10,000

^ 5,000 

n

 ...

I////

1

/ / / / J

W//

/

/ 

'

A

\

\

Surface ru.

Ground-wat 

1

k

a-off

er runs^_

-off

' 

I/////] Average daily rainI/////I fall in inches. Kach 

vertical interval 

represents 1 inch.

 - .

 - 

-

39 30 1 2 3 4 5 6 7 8 9 10 11 18 

April May 1933

Figure 64. Unit hydrographs for French Broad River at Dandridge. Tenn.
UNIT-HYDROGRAPH ANALYSIS OF SURFACE RUN-OFF
196 RAINFALL AMD RUB-OFF IH THE TOUTED STATES

of surface run-off for the calendar day on which most of the rainfall 

occurred; other figures for succeeding days.

Table 49.- Distribution graphs for storma In 

French Broad Elver Basin above Dandridge, Term.

Aug. 3, 1921

Apr. 6, 1922

Sept. 21, 1923

Apr. 18, 1924

Oct. 12, 1927

Apr. 27, 1928

Apr. 22, 1931

Sept. 3, 1931

Apr. 30, 1932

0

1.0

1.9

3.0

0

0

2.8

9.5

0

40.0

26.8

3.8

21.9

3.3

11.8

27.3

39.1

19.1

22.2

21.6

26.0

26.2

29.3

24.1

23.8

20.7

31.0

9.8

15.1

22.4

18.5

26.4

19.2

15.5

10.0

18.5

7.1

10.3

17.1

10.3

14.0

12.6

8.9

4.9

1O.1

5.7

7.8

9.1

6.7

9.6

9.6

6.5

4.2

6.2

4.7

6.5

6.9

4.6

6.9

7.4

5.0

3.5

5.1

3.5

4.5

5.1

3.2

4.6

5.3

3.5

2.9

3.9

2.7

2.7

3.7

2.4

2.9

3.9

2.6

2.3

2.5

2.0

1.9

2.3

1.7

1.8

2.7

1.9

2.1

1.8

1.3

1.3

1.1

1.0

O.9

1.8

1.2

O.8

1.2

0.7

0.5

0.6

0.5

0.3

1.2

0.7

_

0.6

0.3

_

_

-

_

0.4

0.3

-

5"

Red River Basin above Denison,, Tex.

The Red River heads in eastern New Mexico at an altitude of 

nearly 5,OOO feet and flows a little south of east across the panhandle of 

Texas, below which it forms the boundary between Oklahoma and Texas, 

draining areas in both States, but mainly from the north. The drainage 

area above Denison is 39,4OO square miles. The length of the river is 

roughly 550 miles; the length of the basin is about 4OO miles, and the 

average width about 1OO miles. The country is mainly rolling and hilly 

with some mountainous areas.

The gaging station at Denlson was established in October 1923. A 

standard chain gage was attached to the downstream handrail of the highway 

bridge 4^ miles northeast of Denlson and is read twice daily to hundredths. 

The control is shifting, and the stage-discharge relation is subject to 

change. On October 1, 1931, the gage datum was raised O.22 foot owing to 

shortening of chain. The records are considered fair, and there are no 

diversions.

Normally about 35 Weather Bureau stations are available for determining daily precipitation records. These stations are shown in figure 66.

Table 50 gives the daily precipitation recorded at the Weather 

Bureau stations for the storms producing the unit hydrographs shown in 

figures 67 and 68.
UMIT-HYIHOGRAPH AHAIYSIS V SDEPACE ROT-OFF
198 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 50.- Storms considered in connection with unit 

hydrographs for Red River Basin above Denlson, Tex.

(Precipitation, in inches, measured in the afternoon except at stations 

marked », where it was measured in the morning.)

Station

Texas: 

Canyon

Chillicothe *

Clarendon

Claude

Dlmmitt

Dundee

Memphis

Paducah *

Plainview

Quanah #

Tulia

Vega -:t

Denison *

Henrietta *

Sherman *

Oklahoma :

Ardmore

Chic kasha

Marlow

Pauls Valley

Ravia

Altus

Apache

Arapaho

Carnegie

Cloud Chief

Erick

Frederick

Haitxmon

Kobart

Hollis

Lawton

Mangum

Walters

Average

December 1925

10

0.58

.10

.10

_

_

.57

.06

.37

.50

-

.48

.49

.40

_

.70

.14

.10

.62

.05

.09

-

.29

.20

-

_

_

.85

_

-

_

.20

-

-

6.69

.20

11

0.17

.28

.25

.40

.6?

.45

.15

.40

.10

.23

_

.76

1.40

.25

1.70

1.47

.73

.68

1.33

1.25

.41

.84

.50

.90

.42

.43

.43

.40

.39

-

1.05

.70

.31

19.41

,59

12

0.59

-

-

_

.21

-

_

-

.27-

_

-

1.82

.40

1.40

1.76

.82

.75

1.42

2.35

.28

.36

-

.35

.31

.37

_

.18

.27

.40

.50

-

.36

15.15

.46

13

-

-

-

-

-

-

-

-

_

-

1.70

.45

1.59

_

.15

-

-

-

-

-

-

-

-

_

_

_

-

-

_

-

-

3.89

.12

18

0.10

-

.05

-

.11

.01

.08

.36

-

.02

-

.10

.05

_

-

.08

.03

-

_

.02

-

-

-

-

-

_

-

-

.05

-

-

1.06

.03

' 19

0.04

-

-

_

-

-

_

-

-

_

.06

.38

.05

.37

.07

.05

-

.19

-

-

-

-

-

-

-

.04

.05

.04

-

-

-

-

1.34

.04

21

0.06

-

-

-

-

.05

.08

.04

.06

-

.15

-

.40

-

.33

.03

-

.05

-

.33

-

-

-

-

-

-

-

_

-

-

_

-

-

1.58

.05

22

0.04

-

-

-

-

-

-

-

-

-

_

.40

-

.36

.16

-

-

-

.48

-

-

-

-

-

-

-

-

-

_

-

-

1.44

.04
UNIT-HYDROGRAPH ANALYSIS OP SURFACE RUN-OFF 199

Table 50.- Storms considered in connection with unit hydrographs 

for Red River Basin above Denison, Tex. Continued

(Precipitation, in inches, measured in the afternoon except at stations 

marked *, where it was measured in the morning.)

Station

Texas: 

Canyon

Childress

Chillicothe *

Clarendon

Claude

Crowell

Dimmitt 

Dundee

Memphis

Paducah * 

Plainview

Quanah -*

Tulia

Vega *

Denison -»

Henrietta -:t

Sherman «

Oklahoma :

Ardmore

Chickasha

Mar low

Pauls Valley

A 1 4-| 10 A ±\tll&

Apache

Arapaho

Carnegie

Cloud Chief

Erick

Frederick

Hannnon

Hob art

Ho Ills

Lawton

Mangum 

Walters

Wichita

National

Forest

Average

20

0.20

-

.45

.52

1.65

-

_

.40

_

-

-

_

_

-

_

_

-

-

_

_

.10

-

_

_

_

_

_

-

_

-

-

3.32

.09

21

0.80

.95

_

-

_

.53 

2Pn. Cf\J

.55

KQ

1.10

.47

.51

-

1.60

1.55

1.14

.74

1.65

1.50

.87

-

1.40

.85

.60

1.73

1.15

.73

.90

1.05

.81 

.81

.90

27.67

.79

22

_

0.04

_

_

_

.02

.15

-

.10

.02

.04

1.70

.40

.32

.39

.15

-

.82

_

-

.10

.07

_

.10

.20

.07

.10

.05

.23

-

5.07

.14

25

_

_

-

_

_

-

_

-

_

-

-

0.20

.20

.33

_

-

-

-

_

-

-

_

-

_

_

-

-

-

-

.73

.04

Marcl26

0 1 &

.25

-

_

_

.10

.20

.08

.10 

.60

.15

.26

.05

-

_

-

_

_

-

-

_

.20

-

_

_

.08

_

'_

.06

_

-

.14

2.43

.07

i 1926

27

_

0.12

.13

_

_

-

.

.25

_

.02

.10

-

.05

.05

_

_

-

-

_

.38

-

.19

-

_

_

-

-

-

-

1.29

.03

28

_

_

0.60

_

_

.04

.10

-

.60

.49

-

-

_

.02

.14

.08

_

.02

.05

-

.15

.10

_

_

.27

.12

.05

.05

.10

-

2.98

.09

29

1

«| E

1.10

.10

.55

.40

.55

.32 

.80

1.12

.35 

T {"=;

.65

.10

.51

.30

.30

.05

_

.72

.30

.22

1.10

.95

.25

.60

.40

.58

.37

.40

.77

1.10

.44

1.10 

.48

.75

20.13

.58

30

_

0.30

_

.60

_

.40

.06

.22

.10

.15

-

.49

.28

.10

.40

.15

.14

.10

.33

on

.43

.30

.30

.40

.10

.50

.30

.40

.09

.20

.30 

IP

.20

7.66

.22

31

_

0.10

-

_

_

. -

_

-

_

-

-

.54

_

.18

_

.39

-

.05

_

-

-

.10

-

.05

_

-

.12

-

-

1.53

.04
200 RAINFALL AND ROT-OFF IK THE UNITED STATES

Table 50.- Storms considered in connection with unit hydrographs 

for Red River Basin above Deniaon, Tex. Continued

(Precipitation, in inches, measured in the afternoon except at stations 

marked *, where it was measured in the morning,)

Station

Texas:

Canyon

Childress

Chillicothe *

Clarendon

Claude

Crowell

Dimmitt

Dundee

Memphis

Paducah *

Plainview

Quanah *

Vega *

Denison *

Henrietta *

Sherman »

Oklahoma;

Ardmore 

Chickasha

Marlow

Pauls Valley

Altus

Apache

Arapaho

Carnegie

Cloud Chief

Erick

Frederick

Hammon

Hobart

Hollis

Lawton

Mangum

Walters

Wichita

National

Forest

Average

26

1.65

.07

.13

-

.25

_

_

1.90

1.50

.04

_

-

-

_

-

-

_

-

1.51

.OS

-

2.10

2.12

_

.29

-

_

.06

-

-

_

.10

11.75

.35

27

0.35

1.35

.94

2.45

1.47

1.30

1.89

-

1.65

1.85

3.21

1.20

1.15

_

.80

-

.16

err Of

.90

.35

1.80

2.87

4.96

1.65

3.10

3.14

.90

2.20

3.42

4.54

.90

1.40

.42

2.OO

54.89

1.61

M

28

_

3. SO

1.28

.40

.31

.80

.32

1.25

-

.07

1.90

.75

_

.10

-

.41

4

"7Q

. 1 «7

1.55

1.26

_

1.30

.04

-

_

.86

.66

1.35

1.87

1.05

1.70

3.5O

1.02

l.OO

32.84

.97

arch 

29

_

0.04

-

-

-

_

-

-

_

-

.04

.03

_

.27

-

_

-

.02

-

-

-

_

-

-

_

-

-

-

-

.40

.01

April

4

_

-

0.25

-

-

.20

-

.05

.10

.05

.01

-

-

-

-

_

-

-

.04

-

-

.01

-

-

-

-

-

-

-

-

.71

.02

1929

6

_

-

-

-

-

_

-

-

_

-

-

-

_

O.O2

.30

_

-

-

-

-

-

_

-

-

-

-

-

-

-

-

.32

.01

7

_

-

-

-

-

_

0.32

-

-

-

-

-

-

I

ffC

-

1.37

-

.27

_

-

_

-

-

-

-

-

1.20

4.52

.13

8

-

-

-

-

-

-

0.24

-

_

-

-

.03

-

.20

.13 

O9

.07

-

.08

-

-

-

-

-

-

-

.17

-

1.01

.03

9

-

-

-

-

-

-

-

-

-

-

-

0.04

1.67

.89

_

.49

-

-

-

-

.05

-

-

-

-

.34

-

3.48

.10
UNIT-HXDROGRAPH ANALYSIS OP SURFACE RUN-OFF 201

Table 50.- Storms considered in connection with unit hydrographa 

for Red River Basin above Denison, Tex. Continued

(Precipitation, in inches, measured in the afternoon except at stations 

marked *, where it was measured in the morning.)

Station

Texas :

Canyon

Childress

Chillicothe *

Clarendon

Claude 

Crowell

Dimmitt

Dundee

Memphi s

Paducah *

Plainview

Quanah *

Tulia

Wichita Falls

Denison *

Henrietta *

Sherman *

Oklahoma :

Ardmore

Chickasha 

Marlow

Pauls Valley

Altus

Apache

Arapaho

Carnegie

Cloud Chief

Erick

Frederick 

Hammon

Hobart

Hollis

Law ton

Man gum

Walters

Wichita

National

Forest

Average

13

_

-

_

_

-

_

_

_

_

0.02

-

_

-

_

.45

_

.13

_

_

.03

_

-

_

-

-

-

.63

.02

Jl

14

_

_

0.14

_

.25

2.95

-

_

.22

-

1.00

-

_

.26 

.90

1.60

1.83

.04

.91

.19

_

.47

_

1.05

-

3.61

.84

18.26

.52

me 19!

15

_

0.15

1.01

-

-

A C

1.40

_

1.18

.01

.60

-

.20

.88 

.20

1.18

.03

.32

.06

_

2.01

_

.55

1.20

.03

-

11.46

.33

>0

16

_

-

_

-

-

_

-

_

_

0.09

.20

-

1.06

-

1.14

_

.01

_

-

_

-

_

.05

-

_

-

2.55

.07

26

_

-

_

_

-

0.86

-

_

_

-

-

-

_

-

_

_

.13

_

_

_

-

_

-

-

.15

.36

1.50

.04

3

_

-

_

-

-

_

-

O

rfC

_

.03

.01

.30

.17

.10

-

_

-

_

.02

_

-

.86

-

-

_

-

2.24

.06

Dece

4

_

1.15

.55

.75

.30

3

CA

 zo

1.15

.20

1.00

QC

2.0O

.04

1.00

.32

.90

.33

2.03

1.35

1.70

.60

1.75

1.14

1.00

1.60 

.61

2.20

2.60

1.41

_

.68

36.05

1.03

mber 3

5

_

1.4O

1.69

_

-

_

1.00

_

1

Cf\

.31

.28

1.07

1.50

1.52

1.71

1.64 

.50

.35

.40

.92

.60

.26

_

.76

.12

.63

_

_

.75

18.91

.54

930

9

0.15

-

_

.10

-

_

-

.06

_

_

-

_

-

_

-

_

-

.05

_

_

-

_

_

.

_

-

.36

.01

10

_

0.05

.03

-

.27

.20

_

-

.11

.02

-

-

_

.04

_

-

-

_

-

_

-

_

.07 

.14

.08

.

-

_

-

1.01

.03
202 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 50.- Storms considered in connection with unit hydrographs 

for Red River Basin above Denlson, Tex. Continued

(Precipitation, in inches, measured in the afternoon except at stations 

marked *, where it was measured in the morning.)

Station

Texas :

Canyon

Childress

Chillioothe *

Clarendon

Claude

Crowell

Dimmitt

Dundee

Memphis

Paduoah *

Plainview

Quanah *

Vega *

Wiohita Falls

Denison *

Henrietta *

Sherman *

Oklahoma:

Ardmore

Chiokasha

Marlow

Pauls Valley

Altus

Apache

Carnegie

Cloud Chief

Erick

Frederick

Hammon

Hobart

Hoi 11 s

Lawton

Mangum

Walters

Wichita National

Forest

Average

January 1932

3

0.22

_

-

.30

-

.97

-

-

-

.61

-

-

-

.08

-

_

.13

.43

.07

.42

.67

.05

_

-

.05

-

_

_

.05

.77

_

-

4.82

.14

4

1.25

.45

.83

.80

_

.73

.30

1.49

~T..30

.66

.38

.71

_

1.60

2.00

1.30

1.51

2.25

1.69

2.35

2.43

.64

1.80

1.28

1.09

.38

1.55

.64

1.20

_

2.10

1.25

1.70

1.35

39.01

1.15

5

_

0.65

.56

_

.30

_

.14

_

-

_

.80

.91

1.21

.04

1.00

.60

1.15

_

.14

.07

.24

.55

.16

.50

.33

.30

.05

.48

.28

.70

.22

-

.30

.15

11.83

.35

6

_

_

_

_

_

_

-

_

-

_

_

-

0.20

_

_

_

-

_

_

-

-

_

-

-

_

_

-

_

_

.90

-

-

_

-

1.10

.03

12

_

_

_

_

_

_

_

_

_

_

_

_

_

_

0.08

.05

.94

.53

_

_

-

-

-

_

.

_

_

_

_

-

-

_

-

1.60

.05
UNIT-HYDROGRAPH ANALYSIS OF SURFACE RUN-OFF 203

Table 50.- Storms considered In connection with unit hydrographs 

for Red River Basin above Denlson, Tex. Continued

(Precipitation, in inches, measured in the afternoon except at stations 

marked », where it was measured in the morning.)

Station

Texas: 

Canyon

Childress

Chllllcothe *

Clarendon

Claude

Crowell

Dimniltt

Dundee

Memphis

Paducah -«-

Plainview

Quanah #

Tulia

Vega *

Wi chita Falls

Denison « 

Henrietta *

Sherman *

Oklahoma :

Ardmore

Chickasha

Marlow

Pauls Valley

Altus

Apache

Carnegie

Cloud Chief

Erlck

Frederick

Hammon

Hobart

Hollis

Lawton

Mangum

Walters

Wlchita

National

Forest

Average

April 1932

17

0.07

-

.07

_

-

-

_

.20

-

-

_

-

-

_

_

-

-

_

_

-

-

_

-

-

_

-

_

_

-

_

-

-

_

-

.34

.01

18

0.10

.18

.15

-

-

-

.05

.29

-

.11

-

.60

.23

-

_

_

_

-

_

.13

.08

.19

.74

.28

.20

.12

-

.55

.07

.33

1.00

.11

1.05

.25

.22

7.03^

.20

19

0.28

.36

-

_

-

-

-

-

-

-

.10

-

-

.23

.10

.15

.08

2.00

.23

.50

.53

.38

1.50

.80

.75

.45

.22

.44

.58

.13

.14

.40

.47

.47

10.29

.29

21

-

-

-

_

-

0.17

.44

-

-

_

-

-

-

_

_

-

-

_

_

-

-

_

-

-

_

_

_

-

_

-

-

_

-

.61

.02

22

0.33

_

_

.75

.70

.65

-

_

.80

.61

-

_

-

-

_

-

.02

_

_

-

-

_

-

-

_

-

_

_

.84

_

-

-

 _

-

4.70

.13

23

0.40

.51

-

-

-

_

-

-

-

.78

2.95

.65

.08

.85

.90

.30

.81

.15

.38

.49

.29

.88

.67

.25

.38

1.80

.36

1.63

_

.94

.40

1.05

.42

.24

18.56

.53

26

1.49

.35

_

.47

-

-

_

_

.30

.18

.02

_

-

-

_

_

-

_

_

_

-

_

_

-

_

-

_

_

_

_

.

-

_

-

2.81

.08

27

-

_

1.12

1.02

1.15

.74

_

1.00

.88

.49

_

.44

-

_

_

_

-

_

_

.76

-

_

.01

-

_

.15

_

.31

.87

.11

_

.10

_

-

9.15

.26
204 RAINFALL* AMD RUN-OFF IN THE UNITED STATES

Table 50.- Storms considered In connection with unit hydrographs 

for Red River Basin above Denison. Tex. Continued

(Precipitation, in inches, measured in the afternoon except at stations 

marked *, where it was measured in the morning.)

Station

Texas:

Childress 

Chillicothe »

Clarendon

Crowell 

Dimmitt

Dundee

Memphis

Paducah *

Plainview

Quanah *

Tulia

Vega *

Wichita Falls

Denis on « 

Henrietta »

Sherman »

Oklahoma:

Ardmore

Chickasha

Mar low

Pauls Valley

Altus

Apache

Carnegie

Cloud Chief

Erick

Frederick

Hammon

Hobart

Hollis

Lawton

Mangua

Walters

Wichita

National

Forest

Average

August - September 1932

30

-

O.12

1.35 

.11

.20

1.50

.04

_

.09

_

.10

_

-

_

-

_

-

-

-

-

_

-

-

_

-

-

.28

3.79

.11

31

1.90

.08

1.45

1.23

.10

.50

_

1.65

.11

.12

.58

_^

.70

-

.60

.09

.33

.07

.33

.46

.20

.07

.33

.OS

.85

.53

2.4O

.55

2.OO

_

1.07

18.38

.54

1

l.OO

1 OO««z 

.15

-

2.30

-

.20

1.10

-

.05

1.27

1.05

-

.40

_

_

-

1.93

1.43

.95

.87

.23

2.62

.36

.41

_

l.OO

.45

.87

3.OO

22.97

.68

2

O.30

 99tZtZ

-

_

.15

.06

.06

-

.03

_

.40

-

.20

.88

1.77

.50

.24

-

.70

.20

.52

.17

.17

2.4O

1.10

.05

_

-

1O.12

.30

4

-

_

0.25

-

_

_

-

-

_

_

.55

_

_

_

-

-

-

-

_

_

-

_

-

-

-

.80

.02

5

-

_

-

_

-

1.30

_

_

_

.16

_

.04

_

_

_

-

-

-

-

-

-

-

-

_

-

-

_

-

1.50

.04

6

-

_

-

0.48

_

.26

.54

-

_

.85

.02

.10

.49

.61

-

_

-

-

-

-

_

_

-

_

-

-

-

3.35

.09

7

O.28 

.07

.55 

.13

.11

-

.22

.60

.06

-

_

.16

w

.45

-

_

_

_

-

-

-

-

_

-

-

_

-

-

-

2.57

.08

8

0.04 

.05

-

_

-

_

^

.07

-

_

_

_

_

-

_

_

_

-

-

-

-

-

.04

-

_

_

-

-

-

-

.20

.01

Table 51 gives the surface run-off from the unit storms and the 

approximate precipitation that caused the run-off.
ANALYSIS OF SURFACE RUN-OFF SOS

25,000

^m

9

s

10

W/t.

^

11

'////! A

12

Si

&OOI

13

^^

crfaee

d-«at

14

1

^->

nm-ol

Mr nm15

lecodn

\

t

^ 

 oft

16 

r 19

N

17 

23

^

IB 19

1 -

20

 

21

1 -

22 23

8,000

4.000

ttt

20 21 22 24 25 26 27 28 

Maroh 1926

29 30 31

Surface run-off

£ Sroond-^ater run-off

311234567 

April 1929

89 10

35,000 

30,000 

25,000 

20,000 

15,000 

10,000 

5,000 

n

y///t

 ^n

////<

1

/

l^ 

/-

 

^\^

v

Surface run-off

=tt=.

ttrrmni -wntnr ranx

\

-off

\s

 

?7777\ Average daily rainK////I fill in inches. Bach 

rartioal interval 

represents 1 inch.

^

 .

^^

 

 - -~^

 - ^Ti~ ^^

1* 15 16 17 18 19 20

June 1930

23 24 25 26 27

Figure 67.-nnit tyixogeafba for Bed Hirer near Denison, lex.
stream flow In seoon

_x

if£5 i 3- M a

) H> JP

IE"

r ?IE

7
UHIT-HXDROIBAPH ANALYSIS OP SURFACE RUH-OFF 207

Table 51.- Surface run-off from unit atorma in 

Red River Basin above Deniaon. Tex.

Storm

Dec. 10, 1923 

Mar. 21, 1926 

Mar. 27, 1929 

June 14, 1930 

Dec. 4, 1930 

Jan. 4, 1932 

Apr. 18, 1932 

Sept. 1, 1932

Average of precipitation at stations 

(inches)

1.37 

1.02 

2.94 

.94 

1.63 

1.67 

.50 

1.63

Surface run-off 

( inches )

0.11 

.04 

.08 

.15 

.15 

.14 

.03 

.05

Ratio of 

surface runoff to average precipitation

0.08 

.04 

.03 

.16 

.09 

.08 

.06 

.03

Table 52 gives the daily percentage for the eight distribution 

graphs, and the graphs are superimposed in figure 69. The average distribution graph determined for the basin Is 1, 8, 18, 22, 18, 12, 8, 5, 3, 2, 

2, 1 percent. The first figure of each distribution graph la the percentage of surface run-off for calendar day OB which most of the rainfall 

occurred; other figures for succeeding days.

Table 52.- Distribution graphs for storms In 

Red River Basin above Denlson, Tex.

Storm

Dec. 10, 1923

Mar. 21, 1926

Mar. 27, 1929

June 14, 1930

Dec. 4, 1930

Jan. 4, 1932

Apr. 18, 19S2

Sept. 1, 1932

Storm

Dec. 10, 1923

Mar. 21, 1926

Mar. 27, 1929

June 14, 1930

Dec. 4, 1930

Jan. 4, 1932

Apr. 18, 1932

Sept. 1, 1932

1

0.4

1.7

0

a

1.0

1.0

0

0

9

4.9

7.2

7.0

4.4

1.9

2.7

3.2

4.0

2

3.5

8.4

0

.6

8.0

8.2

10.0

0

10

2.3

4.8

4.8

2.8

1.7

1.9

1.9

3.1

3

15.4

9,5

.3

10.9

17.0

17.7

18.4

10.1

11

1.5

2.3

3.6

2.1

1.1

1.0

1.0

2.5

4

18.0

13.1

11.6

19.9

26.8

23.1

18.4

25.8

12

0.7

1.1

2.6

1.7

.9

.3

.6

1.9

5

15.8

15.3

28.2

21.2

19.8

21.5

17.3

21.0

13

0.2

.4

2.0

1.1

.5

.2

.2

1,6

14

0.2

-,

1.4

.4

.4

-

_

1.1

6

14.3

14.2

16.7

18.3

11.9

13.8

13.7

13.6

15

_

-

0.8

_

.3

-

_

1.0

7

13.1

12.2

12.0

9.4

5.7

S..6

9,5

8.3

16

_

_

0.5

_

.2

-

_

.5

8

9.7

9.8

8.3

7.2

2.8

3.0

5.8

5.5

17

_

_

0.2

_

_

-

_

-

For practical application of the unit-hydrograph theory, it would 

seem that the drainage area of the Red River above Denlson (39,400 square 

miles) is too large to work with, except possibly for studying floods due 

to heavy rainfall of wide extent.
RAIKI'ALL AND RUN-OFF IN THE UNITED STATES
UNIT-HXDROGRAFH ANALYSIS OP SURFACE RUB-OFF 809

Table 55 gives the summary of the average distribution graphs 

for the eight basins. They are also plotted on figure 70 for graphic comparison.

Table 53.- Average distribution graphs, in percent

Day

1st

2d

3d

4th

5th

6th

7th

8th

9th

10th

llth

12th

Huskingum

4

15

27

21

13

8

5

3

2

1

1

-

Wabash

3

12

27

24

14

9

5

3

2

1

_

-

Embarrass

5

25

29

18

10

6

3

2

1

1

-

-

Skunk

1

32

27

18

11

5

3

2

1

_

_

-

Susquehanna

12

35

24

15

8

4

2

1

1

_

_

-

Delaware

6

43

24

13

7

4

2

1

-

_

_

-

French 

Broad

5

29

25

15

9

7

5

3

2

1

1

-

Red

1

8

18

22

18

12

8

5

3

2

2

1

The average distribution graphs as obtained for these basins reflect the time of occurrence, synchronization with the calendar day, and 

other characteristics of most of the unit storms for the respective basin. 

To the extent that these characteristics are different in the different 

basins the average distribution graphs presented in table 53 and figure 7O 

are not strictly comparable - that is, if a unit storm of the same duration and time of occurrence took place on all the basins simultaneously, 

the percentages of surface run-off on the first day from the several basins 

would probably not be the same as the percentages given in the table.

The general shape, however, of the various graphs on figure 7O 

reflects the characteristics of the different basins. No attempt has been 

made to correlate the graphs with the physical characteristics of the 

respective basins, except to note that the peak day's percentage of surface 

rtto-orf varies with the lag or time between peak rainfall and resulting 

peak run-off. The percentage of run-off on the peak day seems to be an 

Inverse exponential function of the lag, and as the lag is readily ascertainable for any basin, this feature may have significance in further 

studies.

5955 O 35 14
MI . I 

our .MO-SHH HI mi aaiim 
UNIT-HYDROGRAPH ANALYSIS OP SURFACE ROT-OFF 211

Application of the unit-hydrograph principle

In the present study the principle of the unit hydrograph has 

been applied by Merrill Bernard In storm transposition studies and reference Is made on page 118, to its use In studies of stream-flow separation. 

The principle Is also being applied by several agencies, principally In 

connection with flood problems.

The following statement, prepared in the Special Claims Division 

of the United States District Engineer Office, St. Paul, MInn., Maj. 

Dwight P. Johns, district engineer, by W. J. Parsons", under the direction 

of J. A. Grant, describes briefly the use that is being made of unlthydrograph principles In analyzing surface run-off In connection with 

operation of pools for navigation on the upper Mississippi River: 

"With the development of operating plans for the 9-foot 

channel project on the upper Mississippi River, it becomes 

apparent that complete knowledge of the clay-by-day Inflow into 

the pools created by the several dams will be desirable. Furthermore, it appears that operation would be much improved if 

flood Inflow from 2 to 5 days in advance could be estimated. 

On the main Mississippi River above Minneapolis and on the 

major tributaries there are stream gaging stations so located 

as to give sufficient warning of floods from the upper reaches, 

providing dally reports come In promptly. But the run-off 

from areas below these gaging stations and the run-off from the 

minor tributaries where no stations are maintained will be unknown, and should be estimated. Accordingly, a study has been 

made of the feasibility of predicting flood Inflow from these 

areas from the rainfall. The unit-flood (term corresponds to 

the unit hydrograph) method introduced by Mr. Leroy K. Sherman, 

which distributes the run-off from each day's rain according to 

the composite pattern observed In actual simple floods, was 

recognized as a convenient method of analysis, because of Its 

simplicity and because of Its essentially rational basis. 

The day-by-day nature of the desired predictions limited the 

study to flood flows, and no attempt was made to analyze groundwater Inflow, which varies slowly over long period of time. The 

unit-flood method appears to meet the requirements, because
212 RAINFALL AND RUH-OFF IH THE UNITED STATES

consistent unit floods have been developed for most of the 

tributary basins, and complex floods have been reproduced by 

the addition of the proper unit floods.

"Basin studies made.- Unit floods were developed for each 

river by reducing to a peak of 100 second-feet all recorded 

simple floods produced by 1-day rains and such portions of complex floods as were dominated by 1-day rains as the flood rose 

or fell away from the peak. These simple floods and portions of 

complex floods were averaged graphically, and a distribution 

diagram prepared for each stream. Although It Is admitted that 

In this territory the total flood volume Is e more uniform function of the rainfall than the peak flow (which Is materially 

Influenced by the distribution and short-time Intensity of the 

rainfall), It Is believed that this disadvantage Is more than 

overcome by the greater number of floods made available when we 

reduce floods to one peak rather than one volume. On some 

streams, where only scanty records exist, no simple 1-day floods 

have been reported, and entire reliance had to be placed on a 

unit flood built up from portions of complex floods.

"Flood run-off has been considered to be that portion of 

the hydrograph above a straight line connecting the fairly uniform flow before and after the flood. This base line for runoff generally rises on a gradual slope. Although It Is realized 

that the flood run-off under this assumption, Includes that 

portion of the Inflow from ground water, which responds quickly 

to the rainfall, sufficient information Is not available to 

segregate this Inflow, and the influence of abnormal groundwater conditions will be ignored. This study Is limited to 

periods of flood flow and no attempt has been made to extend the 

predictions Into low-flow periods, when the influence of the 

Inflow from ground water would become important.

"Within the total area under consideration there were 

available a total of 190 floods, produced by rainfall alone, for 

which dally average discharges were published by the United 

States Geological Survey and during which dally rainfall and 

temperature records were published by the United States Weather
UNIT-HYDROGRAPH ANAETSIS CP SURFACE RUN-OFF 213

Bureau. On an average there were records of about 20 floods 

per stream, but In some Instances only 5 to 10 were available.

"Rainfall-run-off relations were developed for each 

stream so that, in the large majority of floods, predicted 

values were within 20 percent of the total observed flood 

volumes. In these studies it was necessary to use complex as 

well as simple floods, the complex floods being subdivided 

into unit floods. The final rainfall-run-off relation was 

represented by a series of three curves defining a narrow belt. 

These maximum, mean, or mlT)l '"n curves should be used as indicated by the season or the record of the preceding flood.

"Data which should be available.- The proposed plan of 

operation will use 25 fairly well distributed United States 

Weather Bureau stations, which should report daily at 8 a.m. 

to a central office. In addition, these stations will make 

immediate reports of rainfall which exceeds intensities of 1 

inch in 24 hours. The stations are distributed so that at 

least three are in or adjacent to each drainage basin,

"It is planned to use 11 United States Geological Survey 

gaging stations located near the mouths of the major tributaries, which will report gage heights daily, at 8 a.m., to 

the central office,

"Daily prediction forma.- A compilation sheet has been 

prepared for each tributary basin showing all pertineut data 

and curves, such as the rainfall-run-off relation curves and 

formulae, average base flows, seasonal factors, forms for computing the average rainfall, and forms for building up flood 

flow from unit floods. One of these sheets should be filled 

out each morning during the flood season, and a predictio1 

prepared for the desired number of days In advance. This 

should be accomplished in the following order: (a) Compute 

the average rainfall over the river "basins; (b) compute the 

total volume of flood run-off, using formula and curve; (c) 

distribute the total flood volume produced by each day's rainfall according to tiie distribution diagram; (d) estimate the 

base flow from the run-off prior to the flood; and (e) obtain
214 RAINFALL AND RUN-OFF IN THE UNITED STATES

the total run-off on each day by adding the contributions from 

the several sources of supply to the base flow.

"The predicted run-off should be corrected from day to day 

in the following manner: Compare the predicted run-off for the 

beginning of the day (as computed on the preceding day) with 

the reported run-off. If these values differ by more than the 

allowable departure, compute a correction factor C from the 

formula

Observed run-off - estimated base flow 

c - Estimated run-off - estimated base flow

Daily contributions from all previous floods should then be 

multiplied by C, and the total flood run-off volume of the next 

unit-flood taken from the next higher curve if C is more than 1 

or the next lower curve if C is less than 1."

The United States District Engineer office at Zanesville, Ohio, 

and engineers of the Muskingum Watershed Conservancy District have made 

use of the unit-hydrograph principle in connection with studies in the 

Muskingum River Basin. Engineers connected with the Tennessee Valley 

Authority are using the principle in studies* relating to the determination of possible flood run-off and also for the purpose of forecasting 

run-off for a period of several days in advance. In the latter study continuous hydrologic and climatologic data are being used, whereas most of 

the other studies to date have been confined to daily averages.

The value of the unit-hydrograph principle in analyzing surface 

run-off will depend on the extent to which the principle is found applicable to areas and problems of various kinds. The principle seems especially applicable to analysis of rainfall and surface run-off that is of 

practical value where detailed knowledge of hydrology is Important, as in 

(a) manipulation of storage on large systems of river development for 

power and water supply; (b) obtaining definite knowledge of run-off characteristics of urban areas; and (c) anaivsis of potentialities of drainage 

basins for producing floods and (d) forecasting flood crestsMethod of application of the unit-hydrograpn principle.- By 

definition, a unit hydrograph is a hydrograph of surface run-off resulting 

from rainfall within a unit of time, as a day or an hour, and a distribution graph is a unit hydrograph of surface run-off modified to show the 

proportional relations of its ordinates, in percentage of the total surface run-orr.
UNIT.-HYDROGRAPH ANALYSIS OP SURFACE RUN-OFF ' 215

If a distribution graph has been prepared for a basin by methods 

described in tiie foregoing pages and if the 24-hour depth of rainfall is 

known, the problem is the determination of the hydrograph of the resulting 

surface run-off. L. K. Sherman describes the method as follows:

"First multiply the given 24-hour rainfall depth by a coefficient (or percentage) of run-off. This will give the depth d on the area 

in question. Multiply d by 26.89M (M = drainage area in square miles); 

this gives the total run-off expressed in cubic feet per second for a 24- 

hour period. The aforesaid figure, multiplied in turn by each daily percentage of the distribution graph will give the ordinates Ni, Hg, Ng, etc., 

for the average rate of run-off in cubic feet per second for each 24-hcur 

interval of the run-off period. They form the required hydrograph of runoff."

In some problems, such as that_of using the unit-nydrograph 

principle as a means of forecasting flood stages, on the basis of continuous records rather than average rates of run-off, the unit graph as presented by Sherman in his original discussion (158), seems more adaptable 

than the distribution graph. The unit graph may be defined as the unit 

hydrograph modified so that the total surface run-off of the unit graph 

represents a depth of 1 inch over the drainage basin. This is accomplished by dividing the unit-hydrograph ordinates in second-feet by the 

total surface run-off in inches.

Merrill M, Bernard (13) uses the distribution graph to distribute total rainfall expressed either as depth in inches over the area or as 

flow In second-feet, which, when presented in the form of a hydrograph, 

shows the hypothetical stream flow if all the precipitation had appeared 

as surface run-off. He designates such a hypothetical hydrograph a 

"pluviagraph." In the problem under consideration the given rainfall 

(expressed either as depth over the area or as second-feet) would have 

been multiplied in turn by each daily percentage of the distribution gra^h 

to form a pluviagraph, or graph of 100 percent rainfall and run-off. The 

pluviagraph figures are then multiplied by a coefficient of run-off to 

determine the hydrograph of surface run-off.

When the surface run-off from a rain lasting several days is 

considered the distribution-graph percentage is applied to each day's 

rainfall and the results are summed as shown in table 54.
216 RAINFALL AND RUH-QFF IN THE UNITED STATES

Regardless of whether (a) a coefficient or percentage of run-off 

la applied to the recorded rainfall, (b) a deduction is made from the 

rainfall as recorded on the basis of infiltration loss, or (c) a coefficient of run-off is applied to the pluviagraph, the accuracy of the hydrograph of surface run-off thus obtained will depend, as stated by Shennan, 

"largely on the ability of the engineer or hydrologist to determine the 

proper infiltration loss or coefficient of run-off. Until improved quantitative or mechanical procedure is established, it is important that one 

who applies the simple unit-hydrograph methods (or any rainfall method) be 

familiar with the basic factors affecting infiltration and run-off."

If Shennan's method of approach is followed the engineer or 

hydrologist must determine the coefficient of run-off or deductive factor 

to apply to the daily rainfall, so that the adjusted figures when distributed by means of the distribution graph, or unit graph will give a hydrograph of surface run-off. In Bernard's method a coefficient of run-off 

must be selected for each storm period which, when applied to the pluviagraph of total rainfall as distributed by the distribution graph, will 

givs a hydrograph of surface run-off. Only surface run-off is obtained by 

either method*

The advisory committee of the American Geophysical Union has 

recommended that steps be taken to

(1) Derive and publish a set of distribution graphs for several 

typical basins throughout the country*

(2) Derive and publish flood hydrographs compiled from possible 

hypothetical storms of known rainfall frequency upon the several basins.

(3) Continue the studies of flood run-off due to actual storms 

In these basins and also include similar studies on other basins. The 

flood-hydrograph studies should develop the different seasonal characteristics*

The Flood Protection Committee of the American Society of Civil 

Engineers has recommended that steps be taken to

(4) Compare for several basins the maximum surface run-off from 

known storms with the pluviagraph figures.

(5) Compare for one basin the maximum surfacs run-off with the 

pluviagraph figures at several gaging stations for the same storm.
OTH-HEEROGRAPH ANALYSIS OP SURFACE RUN-OFF 217

Studies in connection with recommendation No. 1 are outlined In 

the preceding discussion. The distribution graphs thus developed have 

been used by Mf» Bernard in the following section to compare the known 

surface run-off with pluviagraph figures as recommended under No. 4 and 

thus arrive at probable run-off coefficients, which he has used to make 

estimates, in accordance with recommendation No. 2, of the probable surface run-off that would have resulted if certain outstanding storms had 

centered in a critical position over certain basins.
218 RAINFALL AND RUN-OFF IN THE UNITED STATES

The unit-hydrograph memod and storm transposition

In flood problems relating to great storms In

the Eastern and Central United States

By Merrill Bernard

The Idea of superposing storms of unusual magnitude upon drainage 'basins for the purpose of estimating flood flow Is not new. The 

results have not always been satisfying because of the question whether it 

would be physically possible for the given storm to be simulated on the 

drainage basin and also because of the difficulty of taking into account 

the effect of drainage-basin characteristics on run-off when translating 

the records of a storm in one basin into terms of flood flow in another 

basin.

All flood formulas that include storm rainfall as a factor 

entail the idea of storm superpositon. Their use involves what is really 

transposition of synthetic storms to the point of application, often for 

great distances from the basin or basins on which the originator evolved 

his empirical relationships. The method herein presented involves a 

limited transposition of storms and the application of the unlt-hydrograph 

principle which, through its distribution graph, gives determinate value 

to the effect on surface run-off of such basin characteristics as area, 

shape, general slope, and arrangement of stream system.

Flood coefficients

This study utilizes the approximate proportionality between the 

ordinates of the hydrograph of flow from surface run-off and the ordinates 

of the pluviagraph, or graph of 100 percent run-off. The ratio between 

the greatest ordlnate of the hydrograph of surface run-off and that of the 

pluviagraph is taken as the "flood coefficient." Although this ratio or 

"flood coefficient" is not an average coefficient for the flood period, it. 

insures agreement between the observed and computed peak values, with only 

a slight sacrifice in agreement between the actual and computed hydrographs.
UNIT-HXDROGRAPH METHOD AND STORM TRANSPOSITION IN FLOOD PROBLEMS 219

The determination of the flood coefficient becomes largely a 

mechanical procedure after the distribution graph for the basin is made 

available through the various steps described on pages 124-133.*

The steps taken in the development of the coefficient for the 

Susquehanna River at Towanda, Pa., are illustrated in table 54. They are 

as follows:

v a) Compute, for the storm and flood period selected, the average daily rainfall depth over the basin. Where rainfall stations are comparatively numerous and well distributed, the arithmetic average is 

acceptable* Where stations are few and poorly distributed each station 

record should be weighted by geometric proportioning. Average daily rainfall is listed by date in column 2.

(b) The distribution graph of the drainage basin is listed in 

column 3.

(c) The rainfall for each day is multiplied by the items of the 

distribution graph and listed in a column. The product of the rainfall 

and the first item of the distribution graph is placed in column 4 opposite the date on which the rainfall occurred, with the following products 

opposite succeeding dates. The next day's rainfall is treated in the same 

manner and placed in column 5, and so on. If there is rain on every day 

for a long period, at least as many columns are necessary for the distribution of the rainfall as there are items in the distribution graph being 

used. This procedure is shown in columns 4 to 10.

(d) The daily increments in columns 4 to 10 are summed horizontally, and the totals are listed in column 11 as the pluviagraph values, 

or 100 percent run-off, expressed in inches on the drainage basin, and are 

converted to second-feet In column 12.

(e) Observed stream flow is listed by date in column 13.

(f) Base flow, or ground-water run-off, is estimated from a 

plotted hydrograph of observed flow (see pp. 111-119) and listed by date 

in column 14.

(g) Plow from surface run-off (column 15) is obtained by 

deducting base flow from observed stream flow.

* It Is to be noted that the distribution graphs used by the writer 

in the development of flood coefficients took slightly different daily 

percentages than those presented on pages 141, 148, 155, 163, 176, 

181, 190, 207, owing to minor changes and refinements of the distribution 

graphs In their final presentation.
RAINFALL AMD ROT-OFF IM THE UHITED STATES

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DSIT-HYCROGRAPH METHOD AHB STORM TRANSPOSITION IN FLOOD PROBLEMS 221

(h) The ratios of the surface run-off to the pluvlagraph are 

noted In column 16. The ratio of the maximum values Is taken as the flood 

coefficient.

On figures 71 to 77 are plotted for the Mn-rimum observed floods 

for selected rivers during the nonwlnter period the observed rainfall, the 

distributed rainfall in the fora of a pluvlagraph, and the hydrograph of 

surface run-off. There Is also Indicated the ratio (c) between the maximum surface run-off (maximum day) and the peak pluvlagraph value. A computed hydrograph of surface run-off la also shown, obtained by multiplying 

the pluvlagraph value by the flood coefficient.

The flood coefficients are found to change somewhat consistently 

with the seasons, indicating that temperature is an important factor. 

Other factors causing changes probably relate to differences In vegetal 

cover. The intensity and distribution of the rainfall within the storm 

period, regardless of the season, may also affect the flood coefficient.

The coefficients of the greatest floods for the different seasons are compared graphically in figure 78, and their magnitudes show, for 

each basin studied, a seasonal trend. Flood coefficients are not shown 

for the months of December, January, February, and March for basins wherethey might be materially affected by snow run-off.

It was found that In most basins the particular month of the 

year having the greatest flood within the period of record was also the 

one of greatest monthly run-off and always a month of considerable rainfall. It was also found that, with only few exceptions, the principal 

phase of the flood occurred toward the middle or end of an extended wet 

spell, Indicating a reduction of the infiltration and absorptive capacity 

of the ground. Although in many basins a higher degree of saturation of 

the ground may have been possible, the coefficients shown In figure 78 

seem the best evidence obtainable from the comparatively short records 

available as to what a mmr*«>Mi value might be in a particular month or 

season for the selected rivers.

Storm rainfall studies of the Miami Conservancy District

In March 1915 a storm that centered in western Ohio produced a 

disastrous flood on the Miami River throughout most of its length. Corrective steps were taken almost immediately after the flood to protect the
RAINFALL AND ROT-OFF IN THE UNITED STATES

'

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6 7 3 9 10 11 12 13 14 15 16 

June 1924

20 81 82 23 24 25 26 

July 1983

23 24 25 26 27 88 29 30 1 2 3 4 5 6 7 8 9 10 11 12 

Septmber-Ootober 1926

 Pluviagraph

...... Computed stream flow

___ Observed stream flow

_ _ Dally rainfall

Figure 71. Flood iydrographa and flood ooefficients (0) for Maskingum Elver at Dresden, Ohio
TJHIT-HYDROGRAPH METHOD AND STORM TRAHSPOSITION IN FLOOD PROBLEMS 223

40 

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6 7 8 9 10 11 12 13 14 

April 1926

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May 19*7

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September 1926

Explanation

. Pluviagraph

...... Computed stream flow

 Observed stream flow 

_ _ Dally rainfall

40 

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i

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Figure 72. Flood hydrographa and flood coefficients (0) for Tabash Hirer at Logansport, Ind.
RAINFALL AND RUN-OFF IN THE DHITED STATES

i

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120

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14 15 16 17 18 

September 1926

Explanation

___. Pluviagraph

....... Computed stream flow

___ Observed stream flow 

 Dally rainfall

Figure 73. Flood hjrdxographs and flood coefficients (0) for Stomk BlTer at togxata, Iowa.
OTIT-HYDROGRAPH METHOD AND STORM TRANSPOSITION IN FLOOD PROBLEMS

22 23 24 26 26 87 28 29 30 

Ingast 1933

BzplaBatlon

___ Plnviagrapti

....._ Computed stream flow

 ODserred stream flow

JL Dally rainfall

260

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ISO 

100 

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301*34567 

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Flgnre 74. Hood iydrographa and flood ooefflalerats (0) for Soaqnebaniia BlTer at Tomnda. Pa.
Dally rainfall, In Inches, and stream flow from surface run-off, 

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UHIT-HTOROGRAPH METHOD AND STORM TRANSPOSITION IN FLOOD PROBLEMS

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february 1937

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15 16 17 18 19 -20 21 22 

August 1928 

Explanation

. ^ PlUTiagraph 

..... Computed stream flow 

. _ Observed stream flow 

JL Daily rainfall

October 1929 

Figure 76. Flood hydrographs and flood ooeffioiants (0) for JTenoh Broad River at Dandridge, Tenn.
RAIBPALL AND RUB-OFF IH THE TJHITED STATES

200 

150 

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May 1933

3 300

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BOTonbor 1933

360 

300 

250 

200 

150 

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Arab 1933

13 14 15 16 17 16 19 20 21 22 

September 1925

Explanation

___ PluTiagrajh

....... Qompated atreaa flow

__. Obserred atreaa flow 

1 Bally rainfall

Figure 77.-Flood nydrograpba and flood ooefflolenta (0) fter Bed fitter near Denlaon, tax.
g 

g

Flood coefficient In peroants
230 RAINFALL AND RUN-OFF IN THE UNITED STATES

region against a recurrence of such a catastrophe. As a preliminary to 

the design of adequate flood protection works for the Miami Valley, an extensive research and analysis of rainfall data was made. This analysis, 

covering the whole of the eastern United States and complete to 1916, was 

published by the Miami Conservancy District (123). This report is now in 

the course of revision by the Conservancy District. The storms of such 

areal extent that they embraced at least five precipitation stations recording 6 inches or more of rainfall in 3 days are compared and classified 

on the basis of the fifth highest 3-day rainfall. This value is referred 

to as the storm index.

In the original report 160 notable storms were listed, plotted, 

and analyzed. The Conservancy District has since analyzed 90 storms 

occurring between 1916 and the end of 1931, making available for the present study detailed information regarding the 250 greatest storms visiting 

the eastern United States during the period 1892-1931.

A summarized classification of these storms is as follows:

Storm index (inches) Number of storms 

greater than index

16 2

15 4

12 10

11 18

10 32

9 59

8 95

7 172

6 246

There is little doubt that as time passes storms will occur that 

will tend to increase all maxima and have the effect of moving inland 

charted isohyetals of excessive rainfall depths such as are presented in 

the isopluvial maps of the report cited (123), as well as in figure 79. 

This figure shows a sufficient number of storm indexes plotted at their 

approximate storm centers to determine the position of isohyetals enveloping areas having storms of equal or greater index. This illustration Is 

noticeably similar to the isopluvial charts of the Miami Conservancy 

District report.

Storm transposition

The purpose of this study is to outline a refined method of 

estimating flood flow from storm rainfall and to direct attention to a 

.fuller use of available storm data. The superposed storms are not to be
UNIT-HXDROGRAPH METHOD AND STORM TRANSPOSITION IN FLOOD PROBLEMS 231

accepted as "limiting" storms, but as actual great storms, which, having 

visited the vicinity, could have, with reasonable likelihood, shifted 

slightly and centered in a critical position on the particular basin of 

interest.

An examination of figure 79 indicates that storms having indexes 

of 8 to 12 inches have occurred at widely different points in the central 

and upper Mississippi Valley. The superposition of certain storms on any 

basin within the region encompassed by them seems logical. Mountainous 

topography, however, creates an entirely different situation. Storms 

centering on the windward slope of great mountain barriers cannot justifiably be shifted to basins lying on the leeward side.

Without involving questions of magnitude or frequency, valuable 

information may be gained by considering the superposition of a known 

storm in a critical position on a basin. The storm selected for use 

should not have its center so far removed from the basin as to cast doubt 

on the assumption that the storm could, with reasonable probability, have 

centered on the basin.

The method followed superposes in a critical position upon a map 

of the basin the pattern of the storm, pictured as isohyetals of equal 

rainfall depth for the storm period. The selection of a critical position 

entails the assumption of the position that would produce the greatest 

average depth of rainfall on the basin. As a rule this position is 

reasonably obvious. In a more detailed study the storm is centered on one 

or more of the subbasins having characteristics highly conducive to the 

production of floods. In such a study it is necessary to deal with all 

subbasJns separately, synchronizing their flows in accordance with the 

indications of experience to the nearest practicable time unit. The 

present study considers only the position producing the greatest average 

depth over the basin.

The pattern or map of the storm having been fixed in critical 

position, the rainfall stations are treated as if the storm actually 

occurred in this locality and position. The rainfall depths are listed by 

date, properly weighted, and combined to give average daily rainfall over 

the basin throughout the storm period. All antecedent rainfall contributing surface run-off to the flood is included in the study.
RAINFALL AHD RUB-OFF IS THE UNITED STATES

figore represent! 

ijm Index 111 position of 

torn oenter.

Figure 79. Map of eastern United States snowing storm Indexes and 

geographic position of the oenters of great storms.
UNIT-HTDROGRAPH METHOD AND STORM TRANSPOSITION IN FLOOD PROBLEMS 233

Figure 49 of the Miami Conservancy report (123) shows the seasonal occurrence of the great storms embraced by the report. The 90 

storms occurring since 1916 require, to some extent, revision of the chart. 

This can also be said of figures 50 to 57 of the report, which show the 

geographic position of the storms by seasons. In the northern group there 

were certain seasons in which it would seem, from the experience disclosed 

by the record, that it was practically impossible for a storm of any considerable magnitude to develop, the possible explanation be-ing deficiency 

in air moisture occasioned by prevailing low temperatures.

Of the seven basins analyzed, the four appearing in the table 

below and shown in figure 80 were selected to demonstrate the unithydrograph method of determining flood flow. The study has used, the division of the year into seasons suggested in the Miami Conservancy report, 

the quarters beginning on November 1, February 1, May 1, and August 1. 

The quarters in which no qualifying storm has visited the locality are 

then eliminated from consideration in each basin, and it is assumed that 

the superposed storm could have occurred in any of the other seasons. The 

seasons in which, it is assumed., the superposed storm could have occurred, 

based on figures 50 to 57 of the Miami report, are as follows:

Basin Gaging station Quarters Months

Delaware River Port Jervis, N. Y. 3d and 4th May 1 to Oct. 31 

French Broad

River Dandridge, Term. 3d and 4th May 1 to Oct. 31 

Wabash River Logansport, Ind. 2d, 3d, and 4th Feb. 1 to Oct. 51 

Skunk River Augusta, Iowa 3d and 4th May 1 to Oct. 31

For each of these basins the maximum flood coefficient for the 

season in which the storm occurred is also the maximum for any other season in which it is considered possible for the storm to have occurred. 

This coefficient has been used for estimating the probable surface run-off 

of each storm in the superposed position.

Tables 55, 56, 57, and 58 give flood coefficients for the months 

of probable storm occurrence in each of the four basins.
234 RAINFALL AND RUU-OFF IN THE UNITED STATES

Table 55.- Flood coefficients for Delaware River 

at Port Jervis. N. Y.

Bate

Third quarter:

May 25, 1927 

June 6, 1928 

July 9, 1915

Fourth quarter:

Aug. 25, 1933 

Sept. 17, 1933 

Oct. 20, 1927

Maximum pluviagraph value 

(second-feet)

68,700 

55,800 

101,200

* 121,800 

77,500 

85,400

Maximum daily 

surface runoff 

(second-feet)

29,600 

29,200 

31,700

* 68,500 

23,300 

51,900

Flood 

coefficient

0.43 

.52 

.31

.56 

.30 

-::- .61

* Maxima.

Table 56.- Flood coefficients for French Broad 

River at Dandridge, Term.

Date

Third quarter:

May 4, 1932 

June 30, 1928

Fourth quarter:

Aug. 17, 1928 

Sept. 2, 1928 

Sept. 7, 1928 

Oct. 1, 1929 

Oct. 23, 1929

Maximum pluviagraph value 

(second-feet)

45,700 

88,000

* 122,000 

106,000 

79,000 

82,000 

95,000

Maximum daily 

surface runoff 

(second-feet)

25,500 

47,500

-:t 64,500 

22,000 

29,000 

30,500 

36,000

Flood 

coefficient

0.53 

* .54

.53 

.23 

.36 

.39 

.38

-:.- Maxima.

Table 57.- Flood coefficients for Wabash 

River at Logansport, Ind.

Date

Second quarter:

Mar. 22, 1927 

Mar. 31, 1924 

Apr. 8, 1926

Maximum pluviagraph value 

(second-feet)

72,600 

55,000 

54,900

Maximum daily 

surface runoff 

(second-feet)

* 51,700 

35,000 

50,800

Flood 

coefficient

0.71 

.84 

* .93

* Maxima.
TOIT-HTDROGRAPH METHOD AND STORM TRAK3POSITION IN FLOOD PROBLEMS 235

Table 57.- Flood coefficients for Wabash River 

at Loganaport, Ind.--Continued

Date

Third quarter:

May 21, 1927 

June 10, 1924 

July 6, 1929

Fourth quarter:

Aug. 3, 1926 

Sept. 3, 1926 

Sept. 25, 1926 

Oct. 7, 1926

Maximum pluviagraph value 

(second- feet)

63,700 

67,700 

61,600

69,800 

* 76,600 

50,200 

44,500

Maximum daily 

surface runoff 

(second-feet)

42,700 

38,400 

15,000

9,500 

29,300 

31,000 

32,000

Flood 

coefficient

0.67 

.57 

.24

.14 

.38 

.63 

.72

* Maxima.

Table 58.- Flood coefficients for Slomk 

River at Augusta, Iowa

Date

Third quarter:

May 4, 1919 

June 5, 1917 

June 15, 1930 

July 11, 1915

Fourth quarter:

Sept. 15, 1926

Maximum pluviagraph value 

(second-feet)

58,000 

87,500 

-::- 130,500 

50,000

78,500

Maximum daily 

surface runoff 

(second-feet)

16,500 

24,500 

* 41,000 

20,000

26,000

Flood 

coefficient

0.29 

.28 

.32 

.35

* .38

* Maxima.

Storm superposition

Figure 80 shows the outlines of the four basins and the area 

embraced by four major storms.

Delaware River Basin above Port Jervis, N. Y.

Storm A, of October 8-11, 1903, occupied the 22d position in 

order of magnitude of storms over the eastern United States and ranked 3d 

among the northern storms, with a storm index of 10.66. It centered at
236 RAINFALL ADD RUN-OFF IN THE UNITED STATES

Explanation

1 Delaware Elver Basin abore Port Jervis, N.T.

2 French Broad Elver Basin above Dandridge, 2enn.

3 Wabash Elver Basin above logansport, Ind.

4 Stank Elver Basin above Augusta, low

A Storm of October 6-11, 1903

B Storm of July 15-16, 1916

0 Storm of Karen 24-26, 1913

D Storm of August 25-26, 1903

Figure 80r-Uap of eastern Ttaited States snowing location of storm 

relative to selected drainage basins.
UNIT-HXDROGRAPH METHOD AHD STORM TRANSPOSITION IN FLOOD PROBLEMS 237

Paterson, N. J. , and enveloped the Delaware Basin above Port Jervis, N. Y. 

An average depth of about 8 Inches of rainfall fell on this basin during 

the storm, developing a flood peak at Port Jervis that is still the greatest of record (U. S. Geol. Survey Water-Supply Paper 726, p. 216, 1932). 

This storm Is considered In the two positions shown in figure 81. 

Position a is that in which the storm actually occurred. The flood pluviagraph has been constructed by applying the distribution graph for the 

basin to the weighted daily rainfall shown in figure 82. The flood hydrograph of surface run-off shown in figure 82 has been obtained by applying 

a flood coefficient of 0.61, the highest developed in the possible seasons 

(3d and 4th quarters, table 55) to the daily ordinates of the pluviagraph. 

The computed maximum daily flow is 142,800 second-feet. This figure is 

consistent with the estimated instantaneous peak of about 155,000 secondfeet for this flood (U. S. Geol. Survey Water-Supply Paper 726, p. 216, 

1932). The storm was next considered in position b, under which the 

greatest possible average depth of rainfall over the basin was developed. 

Obviously this involves the question whether it would be consistent with 

topographic and other controlling conditions for this storm to occur in 

the transposed position. By weighting the daily rainfall at the stations 

in their new positions and applying the distribution graph for the basins 

and the same flood coefficient a maximum daily discharge of 187,000 secondfeet was computed. To the extent that the various assumptions are correct, 

if the storm of October 1903 had centered 80 miles to the northwest it 

would have produced a mmr-tamm daily discharge of 187,000 second-feet at 

Port Jervis.

French Broad River Basin above Dandridge, Tenn.

Storm B, of July 15-16, 1916, centered at Altapass, N. C., with 

one of the highest single-station 24-hour rainfall depths on record. With 

a storm index of 16.77 laches, it was the 2d largest of storms over the 

eastern United States. The excessive rainfall was confined principally to 

the eastward slopes of the Blue Ridge but averaged more than 5 inches over 

the French Broad Basin above Dandridge, Tenn. The storm's position is* 

shown in figure 83. The pluviagraph was based on recorded precipitation. 

The highest flood coefficient developed within the record period for the 

seasons in which it is assumed that such a storm could have occurred was
RAINFALL AND RtJN-OFF IN THE UNITED STATES

Eainfall Total s to)

station dep

New Jersey

JJayonne

Belvidere

Dover

Flenington

Lambertrille ,

Layton

New Brunswick

Newark

Newton

Orange

Paterson

Perth inboy

Plainfield

Sussex

New Tors

Bedford Hills

Jeffersonville

Middletown

Mohonk Lake

New Yors Oity

Oneonta

Port Jervis

ith (incht

10.46

7.56

10.15 x

6.23

6.63

8.69

6.88

12.11

9.27

10.48

15.51

10.19

7.42

8.60

5.79 '

8.75

8.36

7.72

10.40

5.26

10.11 -.

Salisbury Mills 13.75 

South Eortright 5.99 

Walton 6.15 

Wappingers Balls 8.68

Pennsylvani, 

Boston 

Milford 

Point Pleasa 

10

7.23

9.91

9.39

Figure 81^-Stor 

and the Dela 

shifted so a

of October 8-11, 1903, with relative location of Weather Bureau stations 

are River Basin above Port Jervis, F.Y., in its actual position ("a") and 

to give a maximum averaga depth of rainfall on the basin (position "b").
Daily flood flow in thousands of second-feet

t-'t-'Mt-'MMIOiKN

,

$ 4

p, 4 ^

Iff

sr,

5 H1 I O- U)

O 1-J N M jp. 01 0>

Average daily rainfall in inches Aver
RAINFALL AND RUN-OFF IN THE UNITED STATES

Average distribution graph 

Day / Percent

S/ Day on which rainfall 

TOS recorded.

 Computed flood flow

Rainfall

station

north Carolina

Alta

Asheville

Banners Eli

Brevard

Oullowhee

Rendersonville

Hot Springs

Marshall 

Tennessee

Dsndridge

Johnson City

Hewport

Bogersville

!Fotal storm 

depth (indies

Figure SZ.-etorm of July 16-16, 1916, in Its actual position on French Broad BiTer Basin above 

Dandridge, Tom., and resulting plovlagraph and hydro graph of computed flood flow*
UNIT-HTOROGRAPH METHOD AND STORM TRANSPOSITION IN FLOOD PROBLEMS 241

0.54. This coefficient, applied to the pluviagraph, produced the estimated flood hydrograph of surface flow shown in figure 85, with a maximum 

of 98,400 second-feet. A stage of 21.0 feet was recorded on July 17, 1916, 

by the United States Weather Bureau. This stage corresponds to a flow of 

100,000 second-feet based on an extension of the rating curves from 16.1 

feet to 21.0 feet. Because of differences in topography it is not considered feasible to center this storm on the French Broad River Basin.

Wabash River Basin above Logansport, Ind.

Storm C, of March 24-26, 1913, centering in eastern Indiana and 

western Ohio, caused the disastrous flood on the Miami River. With a 

storm index of 8.98 inches, it is the 9th largest of the northern storms. 

This storm has been used by various investigators to estimate probable 

flood discharge for many areas. By the method outlined in this study, the 

surface flood flow that would have resulted had this storm centered critically on the Wabash River above Logansport, Ind., has been computed and is 

shown graphically in figure 84. The figure also shows the storm superposed over the basin in such a position as to produce the maximum average 

depth of rainfall. The stations listed on the basin map are located relative to the storm and not to the basin area. The high flood coefficient, 

0.95, is substantiated by those developed in this season on the Muskingum 

River above Dresden, Ohio, and a coefficient of over 0.90 was developed 

during the storm of March 1913 on the Miami River above Sidney, Ohio.

Skunk River Basin above Augusta, Iowa

Figure 85 shows storm D, of August 25-28, 1905, the SOth in 

order of magnitude of storms over the eastern United States and the 4th 

largest of the northern storms, superposed in critical position on the 

Skunk River Basin above Augusta, Iowa. The maximum flood coefficient of 

0.58 is applied to the computed pluviagraph to give the estimated flood 

hydrograph of surface run-off shown in the figure. This graph indicates a 

maximum daily discharge of 118,500 second-feet, or 28 second-feet per 

square mile.

5955 O 35 16
RAINFALL AND RtJH-OFF IN THE UNITED STATES

Average distribution graph

*/ Day on which rainfall 

was recorded.

Explanation

 Pluviagrapb

- Computed flood fid

 Kings Mills

Rainfall Total storm 

station depth (Inches)

Connersville, Ind.

Farmland

Richmond

Bellefontaine, Ohio

Dayton

Greenville

Kings Mills

Hew Bremen

Sidney

.Springfield

66

11 16

Figure 84.-Storm of March 24-26, 1913, with relative location of Weather Bureau station 

superposed on Wabash River Basin above Logsnsport, Ind., and resulting pluviagraph 

and hydrograph of computed flood flow.
OTIT-HYEROGRAPH METHOD AND STORM TRANSPOSITION IN FLOOD PROBLEMS

Lverags distribution graph 

Bay Percent

a/ Day on which rainfall 

vas recorded.

Sainfall

station

Iowa

Afton

Chariton

Corning

Corydon

Council Bluffs

Hopeville

Lacona

Lanox

Leon

Mount Ayr

Osoeola

Pacific Junction

Bed Oak

Villisoa

Woodtoorn

Explanation 

Pluviagraph

Computed flood f 1

Total storm

depth (inches)

10 37

11

11

8

12

11

6

7

7

4

10

3

7

7

15

64

87

50

18

27

20

61

50

76

01

32

37

15

64

10_____0_____10 . 20_____30____40 Miles

Figure 85.-stora of August 25-88, 1903, vlth relative location of Weather Bureau stations 

superposed on Skunk Elver Basin above Augusta, lavs., and resulting pluriagr&ph 

and hydrog^aph of computed flood flow*
244 RAINFALL AND RUN-OFF IN THE UNITED STATES

Floods influenced by snow

As previously stated the present study excludes an analysis of 

storm run-off during winter periods, when, as a result of run-off from 

melted snow, appreciable floods may be produced by light rainfall accompanied by marked rises in temperature. Under these conditions the hydrograph of stream flow may show peaks exceeding peak pluviagraph values and 

so-called "flood coefficients" exceeding unity.

The analysis of several hydrographs of run-off associated with 

melting snow, however, has disclosed an interesting and apparently significant fact. It was found that run-off from winter rainfall, augmented 

by melting snow and Ice, responded satisfactorily to the daily "proportioning" of the distribution graph developed from normal rainfalls. In 

other words, the run-off from the melted snow and ice seemed to be distributed in the same proportions as the run-off from rain.

Conclusion

This special study has been intended primarily to examine the 

possibilities of storm superposition as a means of determining flood flow, 

and It is realized that further refinements may be practical and essential to the ultimate development of this method. The study Is Intended to 

direct attention to the possibility of a fuller use of available storm 

data, rather than to indicate that such storms are to be taken conclusively as limiting storms for their respective localities. Use of such 

storms as a basis for estimating flood flow should be made with caution 

and with appreciation of their significance, and the Impression should not 

be created that the estimated results are necessarily to be accommodated 

by any contemplated design.
RAINFALL AND RUN-OFF IH THE UNITED STATES 245

Ground-water run-off

In the preceding pages some of the problems In connection with 

the separation of ground-water run-off and surface run-off are discussed, 

together with a quantitative analysis of surface run-off and its characteristics as disclosed by unit hydrographs. The following discussion relates 

to the disposal of that part of the precipitation which either is lost 

through evaporation and transpiration, is accumulated in the ground as soil 

moisture or ground water, or flows out of the basin as ground-water run-off.

The following tables show for typical basins in the United States 

and for major subdivisions of the Mississippi River Basin above Keokuk, 

Iowa, an estimate of the mean annual ground-water run-off expressed in inches 

and as a percentage of "precipitation minus surface run-off." All figures 

are, in general, 5-year annual averages and were obtained through a study of 

the plotted hydrographs of total stream flow, in part by methods described 

on pages 111-119.

As was pointed out in the discussion of the quantitative analysis 

of surface run-off, these estimates are subject to error. To the extent 

that the estimates of ground-water run-off are too large the estimates of 

surface run-off are too small, and vice versa. These estimates are rough 

approximations of the amount of infiltration that eventually reaches stream 

channels. They represent on an annual basis that part of the stream flow 

which is dependable, as compared with erratic and often destructive surface run-off.

As noted elsewhere, the figures given for the Miami River, Ohio, 

and the Pomperaug Basin, Conn., are based on a general straight-line separation, and the results may not be entirely comparable with the figures 

given for the other basins. However, where comparisons have been made 

between annual estimates of ground-water run-off based on straight_lines 

connecting the low points of hydrographs and estimates based on other methods 

the differences have generally not exceeded 10 percent on an annual basis, 

the straight-line method giving the smaller result.
246 RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 59.- Ground-water run-off 

for typical basins in the United States

Basin

Red River above 

Grand Forks, N. Dak. 

(1928-32)

Mississippi River above 

Keokuk, Iowa 

(1928-32)

Neosho River above 

lola, Kans. 

(1928-32)

Merrlmack River above 

Lawr enc e , Mass. 

(1928-32*)

James River above 

Cartersvllle, Va. 

(1928-32)

Tennessee River above 

Chattanooga, Term. 

(1901-5)

Chattahoochee River above 

West Point. Ga. 

(1928-32)

Miami River above** 

Dayton, Ohio 

(1894-1919*)

Pomperaug River above# 

Bennetts Bridge, Conn. 

(1914-16*)

Precipitation 

(Inches)

18.53

28.64

33.07

40.66

38.04

49.83

59.65

37.07

44.48

Precipitation 

minus 

Surface 

run-off 

(Inches)

18.18

25.28

29.01

30.72

31.02

34.53

48.06

29.30

32.58

Ground-water run-off

Inches

0.24

2.62

0.86

## 9.59

6.09

8.44

11.55

4.08

8.76

Percent 

of 

total 

run-off

40.7

43.8

17.5

49.1

46.4

35.6

49.9

34.4

42.4

Percent 

of 

"Precipitation 

minus 

Surface 

run-off

1.3

10.4

3.0

31.2

19.6

24.5

24.0

13.9

26.9

* Years ending September

*# Ref. 72.

# Ref. 115.

## Probably too large.

30.
GROUND-WATER RUN-OFF 247

Table 60.- Ground-water rim-off for 

major subdivisions of Mississippi River Basin above Keokuk, Iowa

Subdivision

Minnesota River above 

Mankato, Minn. 

(1930-32*)

Black River above 

Neillsville, Wis. 

(1928-32*)

Skunk River above 

Augusta, Iowa 

(1928--32*}

Zumbro River above 

Zumbro Falls, Minn. 

(1931-38*)

Yellow River above 

Sprague, Wis. 

(1928-38*)

Iowa River above 

Wapello, Iowa 

(1928-32*)

Maquoketa River above 

Maquoketa, Iowa 

(1931-32*)

Root River above 

Houston, Minn. 

(1931-32*)

Rock River above 

Afton, Wis. 

(1928-32*)

St. Croix Ri.ver above 

Rush City, Minn. 

(1928-32*)

Peoatonioa River above 

Freeport, 111. 

(1928-32*)

Kickapoo River above 

Gays Mills, Wis. 

(1928-32*)

La Crosse River above 

West Salem, Wis. 

(1928-32*)

Precipitation 

(inches)

22.22

30.99

35.85

26.35

29.09

32.83

30.64

27.98

29.62

25.32

31.95

29.67

30.35

Precipitation 

Surface 

run-off 

( inches )

21.80

23.15

30.38

24.65

24.22

28.55

27.75

25.56

25.99

21.56

27.18

26.03

27.71

Ground-water run- off

Inches

0.27

1.48

2.37

1.78

1.92

2.72

2.73

3.00

3.78

3.51

5.24

5.47

7.28

Percent 

of 

total 

run- off

39.0

15.9

30.2

51.2

28.3

38.9

48.5

55.4

51.0

48.3

52.3

60.0

73.4

Percent 

of 

"Precipitation 

minus 

Surface 

run- off"

1.2

6.4

7.8

7.2

7.9

9.5

9.8

11.7

14.5

16.3

19.3

21.0

26.2

* Years ending September 30 
248 RAINFALL AND RUN-OFF IN THE UNITED STATES

Soil moisture

As is shown In the quantitative analysis of ground-water runoff In tables 59 and 60, only a relatively small part of the "precipitation minus surface run-off" eventually appears In the stream as seepage from ground-water. Although It Is known that the portion which does 

not eventually appear as stream flow, either surface or underground, represents the amount of water that Is either evaporated or transpired, the 

exact processes involved are complex. One important phase of these hydrologic processes is, however, related to soil moisture and changes therein.

0. E. Melnzer (113) defines soil water as moisture In "the part 

of the llthosphere, immediately below the surface, from which water Is discharged Into the atmosphere in perceptible quantities by the action of 

plants or by soil evaporation."

G. E. Condra (31a) defines soil moisture as "the capillary phase 

of ground-water accumulation" and states that "because of its bearing on 

agriculture, It is perhaps our most economically important resource. There 

is drought when and where soil moisture falls during the growing season."

In addition to being one of the most important phases of the 

hydrologlc cycle from the viewpoint of the agriculturist, it Is of particular interest to the hydrologlst. Information regarding the characteristics of changes In soil moisture is desirable in connection with the 

determination of run-off coefficients for use in studies of flood, drought, 

and erosion problems, and in the application of methods, such as Meyer's, 

for computing stream flow from meterologlc information.

Field experiments by Houk in Ohio and by Taylor and others In 

California give valuable information concerning changes in soil moisture 

over small areas. Whether such information can be obtained over larger 

areas, other than through detailed field observations, presents an interesting question. Houk, ±n his study of rainfall and run-off in the Miami 

Valley (V2), made a quantitative analysis of the components of the hydrologic cycle, month by month. He presents for the Mad River Valley above 

Wright, Ohio, for the years 1915 to 1919, graphs showing by months the rainfall, flood run-off (surface run-off), ground-water run-off, soil absorption, percolation and evaporation. The method used by Houk In obtaining 

the ground-water run-off and the flood run-off Is described on page 112, 

of the present report. His so-called "retention" (storage, absorption, and
SOIL MOISTURE 249

evaporation) was obtained by subtracting the run-off from the precipitation, 

The soil absorption was estimated on the basis of plot experiments. It was 

"assumed that there is a variation of 5 inches in the amount of moisture 

during the year; that the soil reaches its driest condition sometime late 

in the summer, during August or September; that it gradually fills with 

moisture during the months of September, October, November, and December; 

and that this remains saturated until late in the spring, when it begins 

to dry out due to transpiration and increased soil evaporation. In drawing percolation curves it was assumed that percolation ceases about the 

time the soil begins tc dry out in the spring and dees not begin until 

late in the fall, about the time the surface soil becomes saturated."

A somewhat different method of approach was used in the present 

study. The "precipitation minus surface run-off" having been determined 

as an approximate representation of the amount of water which either is 

absorbed by the sell or remains on the surface in some form of storage, 

it is possible tc obtain, by the use of the Meyer curves of evaporation and 

transpiration, an approximation of the soil-moisture changes plus accretion to ground water. The objection may be raised that inasmuch as the 

evaporation, transpiration, surface run-off, and amount of accretion to 

the ground water cannot be determined accurately, the derived changes in 

soil moisture may have little relation to the facts. It is evident that 

errors in the determination of these factors may be of such magnitude as 

to cast doubt on the accuracy of the results. To the extent, however, 

that the results are demonstrated tc be reasonable, as by comparison with 

observations relating to soil-moisture conditions, they may throw some 

light en this phase of the hydrologic cycle. When the data now being 

collected in great quantity at the numerous projects being carried on by 

the Soil Conservation Service, Forest Service, United States Geological 

Survey, and other agencies become available, greater refinement in the 

methods cf quantitative analysis may be developed. A summary and brief discussion of the analyses that were made in the present study with reference 

to the investigation of soil moisture is given below.

The average precipitation and temperature were determined month 

by month over several drainage basins in the upper Mississippi Valley, from 

Weather Bureau records. The evaporation from water surfaces in the basins 

studied was assumed to be so small that it could be neglected. The evaporation from land areas and transpiration were based on curves developed by
250 RAINFALL AND ROT-OFF IN THE UNITED STATES

Adolph P. Meyer (122, 2d ed., fig. 272, p. 456, and fig. 164, p. 263), using 

the method described (idem, pp. 455-458) as follows:

"The author's evaporation curve.- The variation of 

evaporation from land areas with changes in seasons, monthly 

mean temperature, and monthly mean rainfall, based on the 

author's study of the subject, is summarized in the evaporation curve of figure 272.

"In the fall, when the monthly temperature reaches 20°, 

practically all the precipitation occurs as snow; consequently, 

evaporation for temperatures below 20° is no longer dependent 

on precipitation after the ground has been covered with 

snow, but entirely on temperature. Full evaporation, corresponding to the given monthly temperature, is usually possible 

throughout the winter. After the temperature rises above 

20°, in spring, the evaporation again depends largely on 

available moisture, as determined mainly by precipitation. 

Nevertheless, a considerable constant evaporation is still 

possible, irrespective of precipitation, because a certain 

quantity of snow and ice is almost always present on the 

ground while the monthly temperature ranges from 20° to 35°. 

After the snow has disappeared, there will still be a. 

relatively large constant evaporation, irrespective of the 

rainfall, unless the winter precipitation has been distinctly 

deficient.

"A gradual reduction in the constant evaporation has 

been assumed for the summer. It is realized, of course, 

that the constant evaporation during the summer depends, 

in a measure, on the rainfall of eae'h previous month. In 

making detailed computations of evaporation losses, the 

constant evaporation is readily varied by one or two tenths 

of an inch, in accordance with apparent variations in storage. On some watersheds, when the fall precipitation is 

very low and the temperature remains above 30°, the righthand portion of the curve is used for January and sometimes 

also for February - that is, when the storage is practicality 

exhausted and there is no snow on the ground, the constant 

of evaporation otherwise used practically vanishes, and 

the evaporation is entirely proportional to the rainfall. 

In the same way, when the fall rains are copious and the 

ground-water supply is abundant, a constant of evaporation 

one or two tenths higher than that given by the curve may 

be used to advantage.

"The portions of the limiting curve belong temperatures of approximately 35° represent evaporation from snow 

and ice surfaces. At the higher temperatures the limiting 

curve represents values somewhat less than the evaporation 

from shallow water. The quantity evaporated out of each 

inch of rainfall becomes less and less as the monthly 

precipitation increases, varying more rapidly at the lower 

than at the higher rates of precipitation.

"To the values of evaporation, in inches of depth per 

month, as taken off the curve, a coefficient must be applied to reduce these quantities to actual evaporation 

from the given watershed. This coefficient ranges from 

about 0.95 to 1.25 for most watersheds of the Northwest 

and for similar ones elsewhere. Very sandy watersheds may 

require a coefficient as low as 0.60, and very impervious 

flat watersheds may require a coefficient in excess of 1.25. 

The coefficient to be used depends on topography, vegetal 

cover, soil, subsoil, humidity, and wind. An extremely 

high coefficient of evaporation (in excess of 1.25) would 

result from flat topography devoid of vegetation, moderately pervious, shallow soil underlain with impervious subsoil or rock, low humidity, and high wind velocity. An 

extremely low coefficient (less than 0.95) would result 

from rugf?d topography, bare scanty soil underlain with 

rock, hie, humidity, and low wind velocity or extremely 

sandy soil. Between these limits the usual working values 

will be found. With a little experience, one can select 

coefficients for different watersheds with considerable 

accuracy.
SOIL MOISTURE 251

"The author's transpiration curve.- The base values 

for total transpiration, in inches of depth, during the 

growing season on any given watershed, are selected with 

reference to the character of the vegetation and the 

length of the growing season on that watershed, giving 

consideration also to available sunshine. In the following computations a normal seasonal transpiration of about 

9 inches has been assumed for small grains, grasses, and 

other agricultural crops, 8 to 12 inches for deciduous 

trees, 4 inches for evergreen trees, and 6 inches for 

small trees and brush. The normal monthly distribution 

of this total seasonal transpiration is based mainly on 

temperature. To obtain actual transpiration in any given 

month, however, the values taken from the transpiration 

curve (fig. 164, p. 263), after being multiplied by a 

coefficient, must be further modified on the basis of 

available moisture. Where precipitation minus evaporation 

for a given month is insufficient to meet the normal plant 

requirements for that month, the ground water is drawn on 

to a varying extent, depending on the character of the root 

system of the given vegetation, the depth and character of 

the soil, and the quantity of surface-soil storage, as determined by the precipitation minus losses for previous 

months. tt

Although the study covered the entire period from 1916 to 1934 

there is given in table 61 for the Skunk River Basin, Iowa, for the period 

October 1927 to September 1932, (1) observed precipitation over the basin; 

(2) observed temperature; (3) computed transpiration over the basin; (4) 

computed evaporation over the basin; (5) the surface run-off determined 

from a study of the hydrograph of total flow; (6) "Precipitation minus 

surface run-off" which in basins like this one, where the surface run-off 

is rapid, represents evaporation and transpiration, a small amount of surface storage, and the infiltration month by month. In column 7 is given 

the difference between "Precipitation minus surface run-off" and the total 

computed transpiration and evaporation. The plus sign indicates that the 

demands of transpiration and evaporation were less than the supply during 

that month and that there was either an increase in soil moisture or an 

accretion t,o the water table, or both, by about the amount indicated. The 

minus sign indicates that the current water supply was less than the combined demands of evaporation and transpiration .and that there was a draft 

either on soil moisture or on the ground water, or both, by about the 

amount indicated.

The monthly accretion to ground water (column 8) was estimated 

by applying the average ground-water depletion curve to the estimated 

hydrograph of ground-water flow at both the beginning and end of the 

month, and designating the area bounded by the hydrograph and the two depletion curves to the point of their intersection as "ground-water accretion" for the month under study. With these estimates (column 8) it is
RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 61.- Observed and estimated meteorologlc 

nd hydrologic data for Skunk River Basin above Augusta

Month

1927

Oct.

Nov.

Dec.

1328

Jan.

Feb.

Mar.

Apr.

May

June

July

Aug.

Sept.

Oct.

Nov.

Dec.

1929

Jan.

Feb.

Mar.

Apr.

May

June

July

Aug.

Sept.

Oct.

Nov.

Dec.

1930

Jan.

Feb.

Mar.

Apr.

May

June

July

Aug.

Sept.

Oct.

Nov.

Dec.

1931

Jan.

Feb.

Mar.

Apr.

May

June

July

Aug.

Sept.

Oct.

Nov.

Dec.

1932

Jan.

Feb.

Mar.

Apr.

May

June

July

Aug.

Sept.

Precipitation

(inches)

1

5.08

1.14

1.16

.18

2.18

1.66

2.61

1.95

6.81

4.71

6.54

3.59

3.93

4.32

1.17

2.42

1.25

2.07

5.30

2.13

2.70

5.06

2.70

4.01

3.34

1.41

.53

1.69

.98

.99

2.78

3.18

7.45

1.20

1.98

2.50

2.22

1.94

.97

.59

.18

2.45

3.30

3.08

4.05

3.61

3.56

7.21

4.19

5.96

2.84

1.56

.75

1.53

1.49

4.03

6.95

4.70

7.93

1.45

Temperature

(°F.)

2

57.8

41.8

24.3

26.1

31.0

40.0

46.8

64.2

66.7

76.0

74.7

62. 6

56.5

41.4

31.3

13.7

18.1

43.4

53.0

59.6

69.0

75.7

72.4

64.6

53.2

34.6

28.4

14.8

37.2

38.4

53.3

62.8

71.0

78.6

75.6

68.9

52.2

42. 8

28.0

31.4

36.8

36.2

52.3

58.4

76.5

80.2

74.6

72.4

59.0

48.8

37.1

30.0

34.0

29. 7

50.3

64.0

74.2

77.4

73.8

65.0

Transpiration

(inches]

3

1.00

0

0

0

0

.05

.40

1.30

1.50

2.30

2.10

1.40

1.00

0

0

0

0

.20

1.00

1.30

1.50

2.20

1.60

1.40

.70

0

0

0

0

0

.80

1.40

2.10

2.30

1.70

1.30

.50

0

0

0

0

0

.70

1.20

2.20

2.40

1.90

2.10

1.10

.40

0

0

0

0

.50

1.50

2.20

2.50

2.20

1.50

Evaporation

(inches)

4

2.08

.41

.38

.48

.83

.78

1.14

1.20

3.25

2.86

3.43

1.86

1.61

1.20

.30

.31

.50

.93

2.14

1.20

1.72

2.96

1.67

1.98

1.31

.36

.16

.35

.59

.59

1.35

1.75

3.74

1.04

1.35

1.46

.90

.60

.28

.54

.42

.94

1.51

1.56

2.48

2.41

2.10

3.50

1.77

1.62

.72

.70

.55

.70

.83

2.13

3.66

2.90

3.90

.85

Surface

run-off

(inches)

5

0.51

.04

.14

.21

.96

.24

.28

.09

.54

1.03

.94

.37

.36

1.28

.85

.12

.16

£.73

2.18

.29

.15

.47

.16

.07

.07

.16

.02

.01

.59

.11

.13

.21

1.99

.09

.02

.02

.04

.02

.08

.01

.03

.05

.37

.04

.38

.22

.05

.40

.29

1.55

1.07

1.53

.28

.38

.08

.41

.84

.75

.92

.01

Precipitation

minus

surface

run-off

(inches)

6

4.57

1.10

1.02

- .03

1.22

1.42

2.33

1.86

6.27

3.68

5.60

3.22

3.57

3.04

.32

2.30

1.Q9

- .66

3.12

1.84

2.55

4.59

2.54

3.94

3.27

1.25

.51

1.68

.39

.88

2.65

2.97

5.46

1.11

1.96

2.48

2.18

1.92

.89

.58

.16

2.39

2.93

3.04

3.67

3.39

3.51

6.81

3.90

4.41

1.77

.03

.47

1.15

1.41

3.62

6.11

3.95

7.01

1.44

Column 6

minus

columns

3 and 4

(inches)

7

1.49

.69

.64

- .51

.39

.59

.79

 .64

1.52

 1.48

.07

- .04

.96

1.84

.02

1.99

.59

-1.79

 .02

- .66

 .67

 .57

- .73

.56

1.26

.89

.35

1.33

- .20

.29

.50

 .18

 .38

 2.23

 1.09

- .28

.78

1.32

.61

.04

- .26

1.45

.72

.28

-1.01

- 1.42

- .49

1.21

1.03

2.39

1.05

 .67

- .08

.45

.08

 .01

.25

 1.45

.91

 .91

Total

accretion

to

ground

water

(inches)

8

0.20

0

.11

0

.27

.21

.29

0

.35

.07

.12

.07

.64

.79

0

0

.11

.86

.76

0

0

.12

0

.06

.15

.17

0

0

.44

0

.10

.25

.46

0

0

0

0

0

0

0

.08

.05

.20

0

.08

0

0

.12

.20

1.01

.30

.33

.53

.33

0

.33

.34

0

.40

0

Changes

in

soil

moisture

(inches)

9

+ 1.29

+ .69

4- .53

 .51

+ .12

 + .38

 + .50

 .64

41.17

 1.55

 .05

- .11

-1- .32

4-1.05

-f- .02

41-99

4 .48

 2.65

 .78

 .66

- .67

- .69

- .73

4 .50

41.11

+ .72

+ .35

+ 1.33

- .64

4 .29

-I- .40

- .43

- .84

 2.23

-1.09

 .28

4 .78

-hi. 32

4 .61

4 .04

 .35

4-1.41

4 .52

4 .28

 1.09

- 1.42

 .49

41.09

4- .83

41.38

+ .75

- 1.00

 .61

+ .12

-t- .08

- .34

 .09

-1.45

-h .51

- .91

Groundwater

run-off

(inches)

10

0.12

.07

.03

.09

.15

.24

.29

.13

.09

.24

.24

.17

.24

.48

.55

.21

.15

.36

.60

.55

.25

.14

.11

.07

.09

.14

.12

.07

.1$

.26

.14

.21

.23

.17

.04

.02

.02

.01

.01

.01

.04

.04

.11

.08

.08

.05

.02

.04

.16

.20

.59

.49

.45

.52

.40

.32

.30

.31

.17

.16
SOIL MOISTURE 253

possible to correct the figure shown in column 7 to show the changes in 

soil moisture only. This amount is shown in column 9. The estimated 

ground-water run-off is listed in column 10. These data show quantitatively some of the factors in the hydrologic cycle.

Figure 86 shows graphically for the Skunk River Basin for the 

period October 1926 to September 1932, by months, the rainfall, temperature, evaporation, transpiration, surface run-off, ground-water run-off, 

and changes in soil moisture. These changes have been accumulated for 

the replenishing and storage period, which has been taken as the period 

from September 1 through April 30, and for the growing period, from May 

1 through August 31. These indicated changes in soil moisture are the 

plus or minus differences between precipitation and the sum of the 

evaporation, transpiration, surface run-off, and accretion to ground 

water. The graph either represents the accumulated errors in the determination of these items or is an approximate representation of the 

changes in soil moisture*

Although various steps in the method of analysis are open to 

criticism, in that they are not subject to an exact mathematical solution, the results seem reasonable and represent, at least in a general 

way, the average magnitude of several elements of the hydrologic cycle 

in the Skunk River Basin.

A comparison was made between the computed changes in soil 

moisture and the general summary of concurrent climatologic conditions 

for this basin as reported by the Weather Bureau. A summary of the 

outstanding results is given below:

(1) Beginning about May 1, there is an indicated depletion in 

soil moisture that generally continues through August. Years in which 

the indicated depletion is more than about 4 inches, or months in which 

such depletion is excessive, are described by the Weather Bureau as 

drought periods, so far as vegetative growth is concerned.

(2) Months during the growing season when either no net change 

or an increase instead of a decrease in soil moisture is indicated are 

invariably described by the Weather Bureau as generally cool, wet months 

in which cultivation was difficult on account of wet soils and crop 

growth was generally retarded.

(3) In general, beginning with the heavy September rains, there 

is an apparent increase in soil moisture. Pall months that do not show
+ + +

Inches 

/
RUN-OFF DURING DROUGHT PERIODS 255

such trends are described by the Weather Bureau as being unusually warm 

and dry.

(4) Spring months in which an unusual amount of soil moisture 

is shown to have accumulated are described by the Weather Bureau as being cool and wet and accompanied by delayed planting.

Studies similar to that already outlined for the Skunk River 

Basin were made on the Black River and Rock River Basins, in Wisconsin. In 

figure 87 the computed changes in soil moisture for these three basins were 

plotted against the precipitation and temperature on a monthly basis, and a 

comparison showed a considerable degree of uniformity. Although no great 

amount of accuracy is claimed for these curves, they illustrate a phase of 

the hydrologic cycle that is of the greatest importance to the farmers and 

are believed to represent roughly the information that would be obtained 

if the combined experience of successful farmers in this area were translated into specific data.

These curves are especially notable as indicating that in the 

areas studied with the surface run-off taken into consideration, an average monthly precipitation of 6j to 7 inches is required during July to 

hold the soil moisture constant. An examination of the Weather Bureau 

records indicates that when this amount of precipitation occurs in July, 

the surface soil is generally too wet for satisfactory cultivation. Consequently, from the viewpoint of the farmer the most satisfactory conditions would seem to prevail when normal drafts on soil moisture occur, 

providing drying of the surface soil sufficient to permit cultivation.

Run-off during drought periods

Prom the beginning of climatic records in the United States 

until about 1930 widespread droughts were infrequent, the major droughts 

in the humid ar.eas having occurred during 1894, 1895, 1901, and 1910. 

During 1930, however, there was one of the most widespread droughts on 

record, followed by deficient precipitation over extensive areas in 

1931, 1932, and 1934. These droughts have naturally raised questions 

as to their effect and as to what can be done to provide against losses 

from their recurrence.

In conformity with the suggestions of the advisory committee 

of the American Geophysical Union, only preliminary studies have been 

made of run-off during drought periods and its relations with rainfall
RAINFALL AND RUN-OFF IN THE UNITED STATES

\

8 4

\

'4.___

60 70 80 70 60 . 50 40

Temperature in degrees Fahrenheit 

Hay June July August September October Noverabe"

Explanation

Figures on curves indicate soil-moiature changes in inches per month

 Bock Biver

 Stank Elver

 Black Biver

Figure 87.-Estimated relations between mean monthly precipitation, temperature, and soil-moisture changes 

in inches per month in Rook, Skunk, and Black Elver Basins.
ROT-OFF DURING DROUGHT PERIODS 257

or deficiency of rainfall. These studies have included (a) comparison 

of deficiencies in run-off, which during such drought periods is largely 

ground-water run-off, with deficiencies in rainfall and excesses in 

temperature, and (b) plotting of hydrographs of the annual minimum stream 

flow for periods of record on representative streams.

Comparison of deficiencies in 

ground-water run-off with deficiencies in rainfall

The study of deficiencies in ground-water run-off compared with 

deficiencies in rainfall was based on the assumption that if two severe 

droughts of equal intensity have occurred many years apart and at the 

same season of the year, the minimum flow, being supplied mainly from 

ground water, would be less and the rate of decline of the stream flow 

greater in the later drought if there had been a material lowering of the 

water table in the drainage basin during the intervening period. On ths 

other hand, it was assumed that if for fairly comparable drought conditions as respects rainfall and temperature there was an indication that 

the decline in stream flow was no more rapid and the minimum contribution of ground water to the stream no less in the later drought, the state 

of depletion of the ground-water supply was probably no more severe. 

Although during drought periods it seems well established that stream flow 

in basins with no artificial storage is supplied in a large part by seepage 

from ground water, no exact correlation seems possible between the groundwater conditions considered in detail over large areas and the seepage 

flow therefrom appearing in the stream.

Ground-water experts agree that when the water table in a 

basin is high the seepage flow from the ground water will tend to be 

greater than when it is low, and vice versa. It appears, therefore, that 

if the minimum stream flow of a region is found to be the lowest in many 

years, it may be inferred that the water table is probably also correspondingly low. As the relation between ground-water run-off and the 

ground-water conditions as marked by water levels in wells is complex 

and not well defined, deductions as to ground-water conditions from a study 

of low-water run-off are necessarily qualitative and at present, at least, 

more or less open to question. In this connection the following quotation from the report of David G. Thompson, chairman of the Committee on 

Underground Water of the Section of Hydrology of the American Geophysical

5955 O 86 17
258 RAINFALL AND RUN-OFF IN THE UNITED STATES

Union (179a), is of value in calling the attention of hydrologists and 

others to the complexities of ground water:

"Only those who have studied in detail the fluctuations of the ground-water levels and the factors producing them appreciate the errors that may result from 

inadequate observations and erroneous interpretations. 

Although much detailed information has been gathered in 

regard to fluctuations of ground-water levels, and some 

of it is in print, comparatively few hydrologists appear 

to be informed on the subject, to know the variety of 

factors that produce fluctuations or the complexity of 

the resulting ground-water movements. There is little 

realization of the magnitude or rapidity of fluctuations 

that may result from seasonal or secular differences in 

rainfall, from differences in geologic conditions, in 

relief, and depth at which the water lies, from differences in artesian and nonartesian conditions, from heavy 

pumpage in highly permeable formations or small withdrawals for domestic use in poorly permeable formations, 

and from changes in atmospheric pressure and other 

factors. The variety of fluctuations of the groundwater levels that have been revealed by automatic recorders installed on wells during the past 15 years has 

been amazing, and such records serve to emphasize the 

fact that conclusions as to secular changes in groundwater levels based on any information except actual 

measurements in wells may be quite erroneous."

A comparison has been made between the run-off, rainfall, and 

temperature during drought periods on the Red River at Grand Forks, 

N. Dak.; the Black River at Neillsville, Wis.j the Rock River at Afton, 

Wis.; the Skunk River at Augusta, lovra; and the Mississippi River at 

Keokuk, Iowa. Several different methods of analyzing the run-off and 

the precipitation, or lack of it, during drought periods were tried, and 

a comparison was made of the deficiencies in rainfall and run-off and 

excess in temperature - factors that seem to be the most illuminating.

In tables 62 to 66 are given the observed precipitation, temperature, and run-off for each month during drought periods, together 

with the averages and departures for each basin. The tables also show, 

so far as possible, the estimated ground-water flow for each period of 

drought.

Table 62 gives data for the Red River Basin for three outstanding drought periods, 1889-90, 1910-13, and 1929-31. During the first 

drought a deficiency of 5.05 inches in precipitation accumulated in 5 

consecutive months, and by the end of 14 months the accumulation had reached 

a total of 8.79 inches. In 5 consecutive months of the second drought a deficiency of 5.77 inches had accumulated, and for the remainder of the drought 

the precipitation averaged a little more than the general average. In the 

third drought a deficiency of 5.68 inches had accumulated in 4 consecutive 

months; at the end of 16 months had reached a total of 8.60 inches, and at
RUN-OFF DURING DROUGHT PERIODS

Table 62.- Drought data for Red River Basin above Grand Forks, N. Dak.

Month

1889

April

May

June

July

August

September

October

November

December

1890

January

February

March

April

May

June

July

August

September

October

November

December

1910

June

July

August

September

October

November

December

1911

January

February

March

April

May

June

July

August

September

October

November

December

1912

January

February

March

April

May

June

July

August

September

October

November

December

1913

January

February

March

April

1929

June

July

August

September

October

November

December

Temperature 

at Moorhead, Mlnn. (°F.)

For 

nonth

45.2

52.0

63.7

66.8

68.6

54.3

43.6

24.8

20.0

-.9

4.8

18.2

44.6

48.0

67.6

69.2

62.7

54.6

44.8

32.6

18.8

69.1

71.4

65.4

57.7

50.4

24.0

11.8

 .6

9.2

31.2

42.8

58.0

69.2

67.8

64.4

55.9

43.5

17.2

15.6

-6.2

11.0

20.6

46.0

56.6

63.0

68.6

64.4

54.6

46.0

32.4

17.6

1.0

7.5

19.0

47.8

64.0

71.5

69.8

54.8

47.6

24.8

12.2

Average

40.6

55.1

64.4

68.1

66.1

58.2

44.5

27.1

11.5

3.8

8.1

22.7

40.6

55.1

64.4

68.1

66.1

58.2

44.5

27.1

11.5

64.4

68.1

66.1

58.2

44.5

27.1

11.5

3.8

8.1

22.7

40.6

55.1

64.4

68.1

66.1

58.2

44.5

27.1

11.5

3.8

8.1

22.7

40.6

55.1

64.4

68.1

66.1

58.2

44.5

27.1

11.5

3.8

8.1

22.7

40.6

64.4

68.1

66.1

58.2

44.5

27.1

11.5

Departure

+ 4.6

- 3.1

.7

- 1.3

+ 2.5

- 3.9

- .9

 2.3

+ 8.5

- 4.7

- 3.3

- 4.5

4 4.0

- 7.1

4 3.2

 t 1.1

- 3.4

- 3.6

 + .3

 f 5.5

+ 7.3

4 4.7

+ 3.3

 .7

- .5

+ 5.9

- 3.1

+ .3

- 4.4

 + 1.1

+ 8.5

+ 2.2

+ 2.9

4 4.8

- .3

 1.7

- 2.3

- 1.0

- 9.9

4 4.1

 10.0

4- 2.9

- 2.1

4 5.4

4- 1.5

- 1.4

4- .5

- 1.7

 3.6

H- 1.5

+ 5.3

4- 6.1

- 2.8

 .6

- 3.7

+ 7.2

 4

4- 3!4

+ 3.7

 3.4

4- 3.1

- 2.3

4 .7

Precipitation 

over the basin (inches)

For 

month

1.09

1.89

1.18

2.32

2.11

3.68

.02

.24

.52

.32

.39

.30

.59

1.26

5.37

2.35

2.77

1.88

2.54

.24

.17

1.26

1.57

1.09

2.19

.70

.48

.51

.92

.73

.34

2.01

4.01

3.41

2.58

2.57

2.44

1.27

.96

.51

.32

.22

.38

2.36

4.02

2.25

3.82

3.93

3.87

.52

.14

.62

.47

.16

.94

1.01

1.15

1.65

1.10

1.69

2.63

.78

.81

Average

1.72

2.69

3.68

2.98

2.57

2.04

1.31

.80

.60

.56

.59

.75

1.72

2.69

3.68

2.98

2.57

2.04

1.31

.80

.60

3.68

2.98

2.57

2.04

1.31

.80

.60

.56

.59

.75

1.72

2.69

3.68

2.98

2.57

2.04

1.31

.80

.60

.56

.59

.75

1.72

2.69

3.68

2.98

2.57

2.04

1.31

.80

.60

.56

.50

.75

1.72

3.68

2.98

2.57

2.04

1.31

.80

.60

Departure

- 0.63

 .80

- 2.50

 .66

.46

+ 1.64

- 1.29

.56

- .08

.24

 .20

 .45

- 1.13

- 1.43

4 1.69

- .63

- .20

 .16

4- 1.23

- .56

- .43

 2.42

 1.41

 1.48

+ .15

 .61

 .32

 .09

4- .36

+ .14

- .41

4 .29

 + 1.32

- .27

 .40

0

 4 .40

 .04

4- .16

 .09

- .24

 .37

 .37

4 .64

-f 1.33

- 1.43

-f .84

-f 1.36

-1- 1.83

- .79

 .66

-f .02

- .09

- .43

4 .19

 .71

 2.53

 1.33

 1.47

- .35

4 1.32

- .02

4 .21

Run-off 

at Grand Forks (inches)

For 

month

0.09

.05

.03

.03

.02

.02

.02

.02

.02

.02

.02

.02

.08

.04

.06

.05

.03

.02

.03

.04

.03

.09

.04

.02

.02

.02

.02

.01

.01

.01

.03

.08

.07

.08

.03

.02

.02

.02

.02

.02

.01

0

.01

.08

.08

.05

.03

.03

.04

.06

.03

.02

.01

.01

.01

.31

.06

.04

.02

.01

.02

.02

.01

Average

0.29

.18

.14

.13

.07

.06

.06

.05

.04

.03

.03

.09

.29

.18

.14

.13

.07

.06

.06

.05

.04

.14

.13

.07

.06

.06

.05

.04

.03

.03

.09

.25

.18

.14

.13

.07

.06

.06

.05

.04

.03

.03

.09

.29

.18

.14

.13

.07

.06

.06

.05

.04

.03

.03

.09

.29

.14

.13

.07

.06

.06

.05

.04

Departure

- 0.20

- .13

- .11

- .10

 .05

- .04

- .04

 .03

 .02

- .01

 .01

- .07

 .21

- .14

- .08

- .08

 .04

- .04

- .03

 .01

 .01

- .05

 .09

 .05

 .04

 .04

 .03

- .03

 .02

 .02

- .06

- .21

 .11

 .06

- .10

 .05

- .04

 .04

 .03

- .02

- .02

 .03

- .08

- .21

- .10

 .09

- .10

- .04

- .02

0

- .02

- .02

- .02

- .02

- .08

4 .02

- .08

- .09

- .05

- .05

- .04

 .03

- .03

Estimated 

groundwater 

run-off 

( Inches '.

_

_

_

_

_

_

_

_

_

_

_

_

_

_

_

_

_

_

_

_

-

.05

.03

.02

.02

.01

.01

_

_

_

_

_

.04

.04

.02

.01

.01

.01

..

_

_

_

_

.04

.04

.04

.02

.02

.02

.03

_

_

_

_

_

-

.04

.02

.02

.01

.01

.02

.01
RAIHPALL AND RUN-OFF IN THE UNITED STATES

Table 62.- Drought data for Red River Basin above Brand Porks, H. Dak.-Contin

Month

1930

January

February

March

April

May

June

July

August

September

October

November

December

1931

January

February

March

April

May

June

July

August

September1 October

November

December

1932

January

February

March

April

May

June

Ju]y

August

September

October

November

December

1933

January

February

March

April

May

June

July

August

September

October

November

December

1934

January

February

March

April

May

June

July

August

September

October

November

December

Temperature 

at Moorhead, Minn. (°F.)

For 

month

0.3

23.0

27.0

46.3

53.4

65.0

73.6

72.2

58.8

43.6

30.4

19.8

19.6

26.2

27.7

44.6

53.2

69.0

72.5

67.6

64.9

50.5

33.0

21.2

11.4

13.2

17.8

43.6

57.0

68.9

72.1

70.7

58.8

41.2

25.3

11.5

11.9

7.4

28.0

41.4

56.8

72.8

73.7

69.5

63.2

42.6

25.4

7.2

13.8

15.4

24.2

42.4

63.6

66.2

72.5

67.5

53.5

49.6

34.2

11.0

Average

3.8

8.1

22.7

40.6

55.1

64.4

68.1

66.1

58.2

4'4.5

27.1

11.5

3.8

8.1

22.7

40.6

55.1

64.4

68.1

66.1

58.2

44.5

27.1

11.5

3.8

8.1

22.7

40.6

55.1

64.4

68.1

66.1

58.2

44.5

27.1

11.5

3.8

8.1

22.7

40.6

55.1

64.4

68.1

66.1

58.2

44.5

27.1

11.5

3.8

8.1

22.7

40.6

55.1

64.4

68.1

66.1

58.2

44.5

27.1

11.5

Departure

- 3.5

+ 14.9

=* 4.3

4 5.7

 1.7

+ -6

4 5.5

+ 6.1

+ .6

 .9

4 3.3

t- 8.3

-1- 15.8

-I- 18.1

-I- 5'.0

4 4.0

- 1.9

-|- 4.6

4 4.4

+ 1.5

+ 6.7

4 6.0

+ 5.9

4 9.7

4 7.6

4 5.1

- 4.9

4 3.0

4 1.9

+ 4.5

4 4.0

4 4.6

+ -6

- 3.3

- 1.8

0

+ 8.1

- 0.7

4- 5.3

4 0.8

4 1.7

4 8.4

4 5.6

+ 3.4

4- 5.0

- 1.9

- 1.7

- 4.3

4 10.0

7.3

1.5

1.8

8.5

1.8

4.4

1.4

 4.7

-1- 5.1

4- 7.1

 .5

Precipitation 

over the basin (inches)

For

0.32

1.48

.26

1.20

4.03

2.26

1.45

1.08

1.07

1.86

2.02

.23

.17

.31

.93

.53

2.15

3.71

3.27

2.55

1.74

2.52

1.31

.21

.49

.58

.59

2.17

2.90

2.35

1.96

2.42

1.30

2.05

.74

.19

1.07

.37

.84

1.61

3.40

2.28

1.77

1.33

1.30

.60

.89

1.36

.28

.11

.48

.BO

.91

3.96

1.66

1.73

1.27

2.08

.50

.43

Average

0.56

.59

.75

1.72

2.69

3.68

2.98

2.57

2.04

1.31

.80

.60

.56

.59

.75

1.72

2.69

3.68

2.98

2.57

2.04

1.31

.80

.60

.56

.59

.75

1.72

2.69

3.t8

2.98

2.57

2.04

1.31

.80

.to

.56

.59

.75

1.72

2.69

3.68

2.98

2.57

2.04

1.31

.80

.60

.56

.59

.75

1.72

2.69

3.68

2.98

2,57

2.04

1.31

.80

.60

Departure

- 0.24

4- .89

- .49

- .52

41. ^

 1.53

 1.49

 .97

4- .55

4 1.22

- .37

- .39

- .28

-t .18

- 1.19

- .54

+ .03

+ .29

- .02

- .30

41.21

+ .51

- .39

- .07

 .01

 .16

4 .45

4 .21

 1.33

 1.02

- .15

- .74

+ .74

- .06

- .41

4 .51

- .22

4 .09

- .11

4 .71

-1.40

- 1.21

- 1.24

- .74

 .71

h .09

4 .76

- .28

 .48

- .27

 .92

-1.78

4 .28

- 1.32

- .84

 .77

4 .77

 .30

 .17

Run-off 

at Orand Forks (inches)

For 

month

0.01

.01

.18

.37

.14

.05

.03

.01

.01

.01

.01

.01

.01

.01

.02

.05

.03

.02

.01

.01

0

.01

.01

.01

.01

.01

.05

.17

.04

.02

.01

0

0

0

0

0

0

0

.04

.10

.03

.02

.01

0

0

0

0

0

0

0

.02

.07

.02

.01

.01

0

0

0

0

0

Average

0.03

.03

.09

.29

.18

.14

.13

.07

.06

.06

.05

.04

.03

.03

.09

.29

.18

.14

.13

.07

.06

.06

.05

.04

.03

.03

.09

.29

.18

.14

.13

.07

.06

.06

.05

.04

.03

.03

.09

.29

.18

.14

.13

.07

.06

.06

.05

.04

.03

.03

.09

.29

.18

.14

.13

.07

.06

.06

.05

.04

Departure

- 0.02

- .02

4 .09

- .12

- .04

- .09

- .10

- .06

 .05

- .05

- .04

- .03

- .02

- .02

- .07

- .24

- .15

 .12

- .12

- .06

- .06

 .05

- .04

- .03

 .02

- .02

- .04

- .12

- .14

- .12

- .12

- .07

- .06

 .06

- .05

- .04

- .03

- .03

 .05

- .19

- .15

 .12

- .12

 .07

 .06

- .06

- .05

 .04

- .03

- .03

- .07

- .22

- .16

- .13

 .12

 .07

- .06

- .06

- .05

- .04

Estimated 

groundwater 

run-off 

(inches)

0.01

0

.02

.05

.04

.04

.02

.01

.01

.01

.01

.01

.01

.01

.01

.02

.02

.01

.01

0

0

0

0

0

.01

.01

.01

.02

.02

.01

.01

0

0

0

0

0

0

0

0

.01

.01

.01

0

0

0

0

0

0

0

0

0

.01

.01

0

0

0

0

0

0

0

Note.- Zero represents run-off less than 0.01 inch.
ROT-OFF DURING DROUGHT PERIODS 261

the end of 24 months the total accumulation nad reached 9.42 inches. During 

each growing season of the next 3 years, 1932, 1933, and 1934, the precipitation was deficient in amounts ranging from about 3 to 5 inches. During 

the drought of 1889-90 a deficiency in run-off of 1.45 inches had accumulated in 21 consecutive months; during the drought of 1910-13 a deficiency 

of 1.45 inches in 21 consecutive months and 1.94 inches in 34 months; and 

during the drought of 1929-31 a deficiency of 1.56 inches in 21 consecutive months and 1.88 inches in 31 months. The monthly run-off subsequent 

to March 1930 has been continuously deficient up to the end of the record 

under consideration, December 1934. The ground-water flow, exclusive of 

frozen periods, reached a minimum of practically zero during the drought 

of 1929-31. The temperature affecting the amount of transpiration (over 

40°) was on the average during 1929-31 about 0.2° a month lower than that 

during the period 1932-34, 1.2° a month higher that that of the drought 

period of 1910-13, and 3.1° a month higher than that of the drought period 

of 1889-90.

Table 63 gives data for the Black River Basin for two outstanding drought periods, 1917-18 and 1930-31. During the earlier drought a 

deficiency of 4.10 inches in precipitation accumulated in 8 consecutive 

months, although in the second and sixth months the precipitation was 

slightly more than average. In the drought of 1930-31 a net deficiency of 

5.55 inches in precipitation accumulated in 8 consecutive months, the 

fourth month having an excess of 0.85 inch, and by the end of 14 months the 

accumulated deficiency had reached 9.63 inches. During each growing season 

of the next 3 years, 1932, 1933, and 1934, the precipitation was deficient 

in amounts ranging from about 3 to 10 inches. Deficiency in run-off for 

the drought period of 1917-18 began. 2 months earlier than deficiency in 

precipitation and by the end of 10 consecutive months amounted to 3.88 inches, 

The run-off during the drought period of 1930-31 was deficient for 16 consecutive months, accumulating a total deficiency in that time of 8.48 inches, 

and in a 10-month period similar to that of the drought of 1917-18 the 

deficiency in run-off amounted to 6.85 inches. For the years 1932, 1933, and 

1934 the maximum accumulation of deficiency in run-off amounted to 3.06, 

4.47, and 2.66 inches respectively. The temperature during the period 1930- 

31 that would affect the amount of transpiration (over 40°) was on the average about 4.5° a month higher than that during the drought of 1917-18. The 

ground-water run-off, exclusive of months of freezing temperature, reached 

lower amounts in the later drought than in the earlier.
RAIMPALL AND RUN-OFF IN THE UNITED STATES

Table 63.- Drought data for Black River Basin above Nelllsvllle, Wls.

Month

1917

July

August

September

October

November

December

1918

January

February

March

April

May

June

1930

July

August

September

October

November

December

1931

January

February

March

April

May

June

July

August

September

October

November

December

1932

January

February

March

April

May

June

July

August

September

October

November

December

1933

January

February

March

April

May

June

July

August

September

October

November

December

1934

January

February

March

April

May

June

July

August

September

October

November

December

Temperature 

at Wausau, Wls. (°F.)

For 

month

68.4

61.8

56.0

36.3

34.8

10.4

4.0

13.2

34.2

39.9

56.9

62.4

71.4

70.2

60.8

46.2

36.4

20.8

22.3

27.0

30.4

45.7

54.0

68.8

72.6

66.8

65.4

51.9

40.0

28.0

21.3

18.5

21.6

42.0

55.3

67.8

70.5

69.1

58.0

43.5

28.1

17.5

23.6

12.4

27.5

42.1

57.2

73.8

73.7

66.4

63.1

43.4

29.2

18.0

22.4

14.6

27.0

43.2

64.3

70.2

74.3

66.2

53.4

50.2

37.5

16.3

Average

68.4

66.0

58.9

47.2

32.2

19.1

14.2

15.1

28.0

43.8

55.2

64.7

68.4

66.0

58.9

47.2

32.2

19.1

14.2

15.1

28.0

43.8

55.2

64.7

68.4

66.0

58.9

47.2

32.2

19.1

14.2

15.1

28.0

43.8

55.2

64.7

68.4

66.0

58.9

47.2

32.2

19.1

14.2

15.1

28.0

43.8

55.2

64.7

68.4

66.0

58.9

47.2

32.2

19.1

14.2

15.1

28.0

43.8

55.2

64.7

68.4

66.0

58.9

47.2

32.2

19.1

Departure

0

 4.2

- 2.9

 10.9

4 2.6

 8.7

-10.2

- 1.9

4- 6.2

 3.9

4- 1.7

- 2.3

+ 3.0

4 4.2

4- 1.9

 1.0

4 4.2 -

4- 1.7

4 8.1

4 11.9

4 2.4

-t- 1.9

 1.2

4 4.1

4- 4.2

4- .8

4- 6.5

 + 4.7

4 7.8

4 8.9

4- 7.1

4 3.4

- 6.4

- 1.8

4- .1

4- 3.1

4- 2.1

4 3.1

- .9

- 3.7

- 4.1

 1.6

4 9.4

- 2.7

- .5

- 1.7

4- 2.0

4 9.1

4 5.3

+ .4

4 4.2

- 3.8

 3.0

 1.1

4- 8.2

- .5

- 1.0

 .6

4 9.1

4 5.5

4 5.9

4 .2

- .5

4- 3.0

4 5.3

-~2.8

Precipitation 

over the basin (Inches)

For 

month

4.23

5.30

2.34

2.86

.23

.55

1.12

1.30

1.34

2.16

7.68

2.72

2.09

1.59

3.11

3.26

1.80

.35

.53

.60

1.46

1.12

1.40

5.98

2.25

2.95

5.76

2.70

4.70

1.06

2.64

1.87

.89

2.32

4.16

3.86

2.67

3.74

1.39

1.08

2.31

2.34

1.88

1.27

.97

3.23

4.29

2.44

1.66

1.76

2.37

1.89

.63

.98

1.30

.25

1.78

2.52

1.03

6.16

1.98

3.38

8.10

3.32

4.86

1.65

Average

3.56

3.54

3.92

2.41

2.04

.97

1.23

1.21

1.58

2.64

3.47

5.45

3.56

3.54

3.92

2.41

2.04

.97

1.23

1.21

1.58

2.64

3.47

5.45

3.56

3.54

3.92

2.41

2.04

.97

1.23

1.21

1.58

2.64

3.47

5.45

3.56

3.54

3.92

2.41

2.04

.97

1.23

1.21

1.58

2.64

3.47

5.45

3.56

3.54

3.92

2.41

2.04

.97

1.23

1.21

1.58

2.64

3.47

5.45

3.56

3.54

3.92

2.41

2.04

.97

Departure

4- 0.67

4 1.76

- 1.58

4 .45

- 1.81

 .42

 .11

4- .09

 .24

 .48

4- 4.21

- 2.73

 1.47

 1.95

- .81

4 .85

- .24

- .62

 .70

.61

- .12

 .52

- 2.07

+ .53

- 1.31

 .59

4- 1.84

4 .29

4 2.66

4 .09

4 1.41

4 .66

 .69

- .32

4 .69

- 1.59

.89

4 .20

- 2.53

- 1.33

4 .27

4- 1.37

4- .65

4 .06

 .61

4- .59

4 .82

 3.01

- 1.90

 1.78

- 1.55

- .52

- 1.41

4 .01

4 .07

- .96

4 .20

- .12

 2.44

4 .71

- 1.58

- .16

 *- 4.18

4 .91

4 2.82

+ .68

Run-off 

at Nelllsvllle (Inches)

For 

month

0.12

.11

.08

.38

.24

.07

.01

.01

1.64

1.13

2.94

1.57

.29

.05

.03

.25

.22

.09

.10

.06

.19

.65

.22

.76

.11

.02

.13

.20

1.93

.44

.80

.49

1.92

3.15

1.29

.22

.11

.07

.05

.05

.10

.22

.34

.31

1.63

2.19

1.04

.32

.02

.02

.01

.03

.05

.05

.10

.06

.23

3.10

.12

.37

.04

.04

2.02

1.07

2.66

.50

Average

0.35

.39

.46

.49

.66

.20

.15

.18

1.84

2.95

1.18

1.31

.35

.39

.46

.49

.66

.20

.15

.19

1.84

2.95

1.18

1.31

.35

.39

.46

.49

.66

.20

.15

.18

1.84

2.95

1.18

1.31

.35

.39

.46

.49

.66

.20

.15

.18

1.84

2.95

1.18

1.31

.35

.39

.46

.49

.66

.20

.15

.18

1.84

2.95

1.18

1.31 . 35

.3d

.46

.49

.66

.20

Departure

- 0.23

 .28

 .38

- .11

- .42

 .13

- .14

- .17

- .20

- 1.82

4 1.76

4 .26

 .06

 .34

- .43

- .24

- .44

- .11

- .05

- .12

- 1.65

 2.30

- .96

 .55

- .24

- .37

.33

- .29

4 1.27

4 .24

4 .65

4 .31

4 .08

4 .20

+ .11

 1.09

- .24

- .32

- .41

- .44

- .56

4 .02

4 .19

4 .13

- .21

- .76

- .14

- .99

- .33

 .37

- .45

- .46

- .61

- .15

- .05

- .12

 i.ei

4 .15

 1.06

- .94

 .31

- .35

4 1.56

4 .58

4 2.00

4 .30

Estimated 

groundwater 

run- of f 

(Inches)

0.07

.06

.06

.12

.11

.03

.01

.01

.19

.32

.18

.08

.11

.02

.02

.09

.08

.07

.05

.04

.09

.21

.14

.07

.05

.02

.05

.10

.14

.25

.24

.25

.28

.29

.23

.07

.04

.03

.04

.02

.04

.02

.04

.09

.16

.19

.12

.03

.01

.01

.01

.01

.02

.03

.04

.04

.04

.10

.09

.03

.03

.01

.04

.10

.17

.22
RUN-OFF DURING DROUGHT PERIODS

Table 64 gives data for the Rock River Basin for three outstanding drought periods, 1918-19, 1930-31, and 1933-34. During the first drought 

a deficiency of 7.24 inches in precipitation accumulated in 8 consecutive 

months, and by the end of 15 months the accumulation had reached 7.94 inches. 

In the second drought a deficiency of 7.37 inches in precipitation accumulated in a similar 8-month period, and by the end of 14 months the accumulation had reached 11.09 inches. During the drought of 1933-34 a deficiency 

of 7.48 inches in precipitation accumulated in 8 consecutive months and 

13.11 inches by the end of 15 months. The run-off during all three droughts 

was below normal for 16 consecutive months, a deficiency of 6.79 inches 

accumulating in 1933-34, 6.51 inches in 1930-31, and 4.25 inches in 1918-19. 

The temperature during drought of 1950-51 that would affect the amount of 

transpiration (over 40°) was on the average about 0.4° a month higher than 

that of 1933-34 and 2.5° higher than that of 1918-19. The flow from groundwater was less in the drought of 1933-34 than in that of the two earlier 

drought periods.

Table 65 gives data for the Skunk River Basin for three outstanding 

drought periods, 1917-18, 1930-31, and 1933-34» The three droughts were generally similar, the first accumulating a deficiency of 10.10 inches in pro*- 

cipitation in 10 consecutive months, the second a deficiency of 9.59 inches 

in 12 months, and the latest a deficiency of 18.80 inches in 15 months. The 

run-off during the drought of 1930-51 and 1933-34 was deficient for 14 and 

19 consecutive months, accumulating a deficiency of 5.76 and 8.84 inches 

respectively. In the drought of 1917-18 there was an excessive amount of 

run-off during the llth month, but the first 10 months accumulated a deficiency of 3,91 inches, and at the end of 14 months the accumulated deficiency was 4,92 inches. The greatest difference was in the temperature 

affecting the amount of transpiration (more than 40°), the earlier drought 

having temperatures about average and the last two droughts having temperatures averaging 3.5° and 4.0° a month respectively greater than the average.

Table 66 gives data for the upper Mississippi River Basin for 

three outstanding drought periods, 1894-96, 1910-11, and 1930-32, During 

the drought of 1894-96 a deficiency of 7.11 inches in precipitation accumulated in 4 consecutive months, and by the end of 22 months the accumulated 

deficiency had reached 13.88 inches. During the drought of 1910-11 a deficiency of 7»63 inches in precipitation accumulated in 5 consecutive months, 

and by the end of 16 months the accumulation amounted to 12.16 inches. In
RAINFALL AMD RUN-OFF IN THE UNITED STATES

Table 64.- Drought data for Roolc River Baaln above Afton, Wls.

Month

1918

June

July

August

September

October

November

December

1919

January

February

March

April

May

June

July

August

September

October

November

1930

July

August

September

October

November

December

1931

January

February

March

April

May

June

July

August

September

October

November

December

1932

January

February

March

April

May

June

July

August

September

October

November

December

1933

January

February

March

April

May

June

July

August

September

October

November

December

1934

January

February

March

April

May

June

July

August

September

October

November

December

Temperature 

at Madison, Wis. (°F.)

For 

month

65.9

70.3

72.6

55.9

52.9

39.4

31.4

24.1

23.7

33.2

45.8

55.2

71.2

74.8

69.0

64.2

50.2

32.6

72.8

72.5

63.8

48.1

39.0

24.4

26.1

31.4

31.7

48.0

54.9

71.4

75.8

70.8

68.4

54.9

44.8

33.0

25.9

27 !l

24.4

44.6

58.6

70.4

73.7

71.2

61.9

48. 0

32.0

22.4

30.8

18.9

31.0

44.1

57.9

76.0

73.6

69.6

67.2

49.0

34.0

23.4

26.6

18.5

29.1

45.8

65.7

73.1

75.3

69.4

60.6

53.8

41.6

20.2

Average

67.2

72.1

69.8

62.4

50.3

35.2

22.8

16.7

19.1

30.6

45.4

57.6

67.2

72.1

69.8

62.4

50.3

35.2

72.1

69.8

62.4

50.3

35.2

22.8

16.7

19.1

30.6

45.4

57.6

67.2

72.1

69.8

62.4

50.3

35.2

22.8

16.7

19.1

30.6

45.4

57.6

67.2

72.1

69.8

62.4

50.3

35.2

22.8

16.7

19.1

30.6

45.4

57.6

67.2

72.1

69.8

62.4

50.3

35.2

22.8

16.7

19.1

30.6

45.4

57.6

67.2

72.1

69.8

62.4

50.3

35. 2

22.8

Departure

- 1.3

- 1.8

+- 2.8

- 6.5

+ 2.6

4 4.2

+ 8.6

4 7.4

4 4.6

4 2.6

 + -4

- 2.4

4 4.0

4 2.7

 .8

4- 1.8

 .1

- 2.6

 + -V

4 2.7

+ 1.4

- 2.2

4 3.8

4 1.6

+ 9.4

4- 12.3

4 1.1

4 2.6

- 2.7

4 4.2

4 3.7

+ 1.0

4 6.0

+ 4.6

4. 9.6

4 10.2

-t 9.2

-t- 8.0

- 6.2

 .8

4 1.0

4 3.2

4 1.6

4 1-4

 .5

- 2.3

- 3.2

- .4

4 14.1

 .2

-1- .4

 1.3

-f .3

4 8.8

4 1.5

 .2

4- 4.8

- 1.3

- 1.2

-f -6

4 9.9

 .6

- 1.5

+ .4

4 8.1

4- 5.9

4 3.2

 .4

- 1.8

4 3.5

4- 6.4

- 2.6

Precipitation 

over the basin (inches)

For 

month

2.09

2.02

2.12

1.61

2.82

1.81

2.18

.33

1.04

2.37

3.22

3.01

3.40

3.01

1.71

6.62

5.54

E.64

2.53

1.67

3.21

2.09

.72

.63

.91

.40

1.95

1.34

2.23

3.80

2.05

3.01

6.25

3.97

5.12

1.63

1.49

1.02

1.33

.64

2.51

3.18

3.00

2.00

.42

3.83

1.60

1.58

.89

.93

2.69

3.17

8.06

2.91

3.92

2.31

3.28

1.72

.58

1.08

.76

.31

1.63

1.58

2.08

2.61

3.25

1.94

3.99

1.84

6.86

1.05

Average

3.95

2.90

3.04

4.29

3.05

2.15

1.39

1.45

1.26

2.08

2.84

3.29

3.95

2. 90.

3.04

4. 29

3.05

2.15

2.90

3.04

4.29

3.05

2.15

1.39

1.45

1.26

2.08

2.84

3.29

3.95

2.90

3.04

4.29

3.05

2.15

1.39

1.45

1.26

2.08

2.84

3.29

3.95

2.90

3.04

4.29

3.05

2.15

1.39

1.45

1.26

2.08

2.84

3.29

3.95

2.90

3.04

4.29

3.05

2.15

1.39

1.45

1.26

2.08

2.84

3.29

3.95

2.90

3.04

4.29

3.05

2.15

1.39

Departure

- 1.86

- .88

- .92

 2.68

- .23

- .34

4- .79

- 1.12

4 .68

4 .29

+ .38

- .28

 .55

4 .11

- 1.33

T 2.33

4 2.49

+ .49

- .37

- 1.37

- 1.08

- .96

- 1.43

- .76

.54

- .86

- .13

- 1.50

 1.06

- .15

- .35

- .03

4- 1.96

4 .92

- 2.97

 .24

+ .04

 .24

 .75

- 2.20

 .78

 .77

+ .10

4- 1.04

- 3.87

4- .78

- .55

4 .19

 .56

 .33

4- .61

4 .33

4- 4.77

- 1.04

+ 1.02

- .73

- 1.01

- 1.33

- 1.57

 .31

.69

- .95

- .45

- 1.26

- 1.21

 1.34

4 .35

- 1.10

 .30

- 1.21

4 4.71

- .34

Run-off 

at Afton (inchea)

For 

month

0.61

.34

.26

.25

.27

.30

.25

.25

.23

.31

.86

.79

.44

.28

.26

.28

.77

.75

.30

.22

.P2

.25

.19

.22

.22

.23

.29

.35

.S3

.16

.13

.12

.17

.29

.64

.88

.86

.61

.70

.69

.38

.24

.16

.09

.08

.14

.16

.23

.29

.31

.44

1.86

2.22

.90

.43

.27

.22

.19

.21

.20

.27

.16.

.22

.62

.25

.11

.09

.07

.13

.11

.25

.49

Average

0.64

.47

.42

.43

.51

.53

.53

.42

.56

1.35

1.54

.87

.64

.47

.42

.43

.51

.53

.47

.42

.43

.51

.53

.53

.42

.56

1.35

1.54

.87

.64

.47

.42

.43

.51

,53

.53

 '.56 4£

1.35

1.54

.87

.64

.47

.42

.43

.51

.53

.53

.42

.56

1.35

1.54

.87

.64

.47

.42

.43

.51

.53

..53

.42

.56

1.35

1.54

.87

.64

.47

,4S

.43

.51

.53

.53

Departure

 0.03

 .13

- .16

- .18

- .24

- .23

 .28

 .17

- .33

- 1.04

 .68

- .08

- .20

.19

- .16

- .15

4- .26

4- .22

- .17

- .20

- .21

 .26

 .34

.31

- .20

- .33

- 1.06

- 1.19

 .64

- .48

 .34

 .30

- .26

- .22

4 .11

4- .35

4 .44

4- .05

- .65

- .85

.49

- .40

- .31

.33

 .35

- .37

- .37

 .30

- .13

 .25

 .91

4- .32

4 1.35

4- .26

- .04

 .15

.21

 .32

 .32

.33

 .15

- .40

 1.13

 .92

.62

- .53

- .38

- .35

 .30

- .40

.28

- .04

Estimated 

groundwater 

run-off 

(inches)

0.34

.27

.24

.25

.26

.27

.25

.24

.22

.27

.38

.43

.29

.24

.22

.22

.30

.36

.22

.18

.17

.19

.15

.18

.IS

.17

.21

.21

.17

.13

.10

.09

.10

.18

.25

.41

.45

.35

.33

.31

.29

.18

.11

.07

.06

.09

.09

.12

.19

.22

.25

.38

.51

.34

.24

.18

.13

.13

.13

.13

.15

.10

.11

.25

.17

.08

.05

.04

.05

.06

.08

.20
RUN-OFF DURING DROUGHT PERIODS

Table 65.- Drought data for Skunk River Basin above Augusta, Iowa

Month

1917

July

August

Septembe

October

November

December 

1918

January

February

March

April

May

June

July

August

September

October

November

December 

1919

January

February

March

April

1930

July

August 

September

October

November 

December 

1931

January

February

March

April

May

June

July

August

September

October

Sovember

December 

193B

January 

February

March

April

May

June

July

August

September

October

Sovember

December 

1933

January 

February

March

April

May

June

July

August

September

October

Sovember

December

Temperature 

at Davenport, Iowa (°F.

For 

month

75.8

71.2

63.7

43.9

42.2

18.2

10.0

26.8

44.8

45.6

66.2

70.2

74.1

76.8

58.9

56.1

42.2

35.5

27.8

28.2

40.0

51.0

78.6

75.6 

68.9

52.2

42.8 

28.0

31.4

36.8

36.2

52.3

58.4

76.5

80.2

74.6

72.4

59.0

48.8

37.1

30.0 

34.0

29.7

50.3

64.0

74.2

77.4

73.8

65.0

51.4

35.8

26.4

36.4 

25.2

37.4

49.6

62.2

79.6

77.6

72.8

72.1

52.4

38.8

30.0

Averag

75.3

73.1

65.6

53.7

39.0

27.1

21.8

24.9

36.1

49.9

61.3

70.5

75.3

73.1

65.6

53.7

39.0

27.1

21.8

24.9

36.1

49.9

75.3

73.1 

65.6

53.7

39.0 

27.1

21.8

24.9

36.1

49.9

61.3

70.5

75.3

73.1

65.6

53.7

39.0

27.1

21.8 

24.9

36.1

49.9

61.3

70.5

75.3

73.1

65.6

53.7

39.0

27.1

21.8 

24.9

36.1

49.9

61.3

70.5

75.3

73.1

65.6

53.7

39.0

27.1

Departure

4 0.5

 1.9

 1.9

- 9.8

4 3.2

- 8.9

- 11.8

4- 1.9

4 8.7

 4.3

4- 4.9

 .3

- 1.2

4- 3.7

- 6.7

4 S.4

4- 3.2

+ 8.4

4 6.0

4- 3.3

4- 3.9

4- 1.1

4 3.3

4 2.5 

4- 3.3

- 1.5

4- 3.8 

4 .9

4 9.6

4 11.9

4 .1

 4- 2.4

- 2.9

4 6.0

4- 4.9

4 1.5

4 6.8

4 5.3

4 9.8

4 10.0

4 8.2 

4 9.1

- 6.4

4 .4

4 2.7

4- 3.7

4 2.1

4- .7

 .6

 2.3

 5.2

 .7

4 14.6 

4- .3

4- 1.3

 .3

4 .9

4 9.1

4 2.3

- .3

4- 6.5

- 1.3

- .2

4 2.9

Precipitation 

over the basin (inches)

For 

month

2.01

2.01

3.33

1.71

.20

.68

1.06

1.15

.31

2.83

7.20

6.93

2.70

3.32

2.35

3.00

2.02

1.68

.18

2.56

2.75

4.V8

1.20

1.98 

2.50

2.22

1.94 

.97

.59

.18

2.45

3.30

3.08

4.05

3.61

3.56

7.21

4.19

5.96

2.84

1.56 

.75

1.53

1.49

4.03

6.95

4.70

7.93

1.45

2.46

1.73

1.83

1.10 

.35

3.00

1.30

6.09

2.&7

1.95

3.20

4.23

1.61

.24

.88

Averag

3.44

3.78

4.76

2.63

2.07

1.21

1.04

1.10

2.11

3.25

3.48

5.18

3.44

3.78

4.76

2.63

2.07

1.21

1.04

1.10

2.11

3.25

3.44

3.78 

4.76

2.63

2.01 

1.21

1.04

1.10

2.11

3.25

3.48

5.18

3.44

3.78

4.76

2.63

2.07

1.21

1.04 

1.10

2.11

3.25

3.48

5.18

3.44

3.78

4.76

2.63

2.07

1.21

1.04 

1.10

2.11

3.25

3.48

5.18

3.44

3.78

4.76

2.63

2.07

1.21

Departure

 1.43

 l'.77

~ 1.43

- .92

 1.87

 .53

4- .02

4 .05

- 1.80

- .42

+ 3.72

4- 1.75

 .74

- .46

 2.41

4 .37

- .05

4 .47

- .86

4 1.46

i- .64

4 1.53

- 2.24

 1.80 

- 2.36

 .41

_ .13 

- .24

- .45

.92

4 .34

4- .05

.40

 1.13

4- .17

- .22

4 2.45

4 1.56

4- 3.89

4 1.63

4- .52 

 .35

 .58

- 1.76

4 .55

4 1.77

4- 1.26

4- 4.15

- 3.31

 .17

 .34

4- .62

+ .06 

- .75

4 .89

- 1.95

4- 2.61

2.51

- 1.49

- .58

- .53

1.02

- 1.83

- .33

Run-off 

at Augusta (inches)

For 

month

0.26

.10

.14

.04

.04

.03

.01

.32

.24

.12

.71

S.24

.38

.2S

.18

.05

.07

.11

.14

.23

1.35

.98

.26

.06 

.03

.06

.03 

.09

.OS

.06

.10

.48

.18

.46

.27

.07

.44

.45

1.75

1.66

2. OS 

.73

.90

.48

.73

1.14

1.06

1.09

.17

.13

.25

.93

.64 

.20

.24

.91

2.25

.51

.19

.16

.17

.04

.02

.02

Average

0.48

.35

.49

.48

.45

.34

.34

.44

.97

.87

.75

1.08

.48

.35

.49

.48

.45

.34

.34

.44

.97

.87

.48

.35 

.49

.48

.45 

.34

.34

.44

.97

.87

.75

1.08

.48

.35

.49

.48

.45

.34

.34 

.44

.97

.87

.75

1.08

.48

.35

.49

.48

.45

.34

.34 

.44

.97

.87

.75

1.08

.48

.35

.49

.48

.45

.34

Departure

 0.22

- .25

- .35

- .44

- .41

- .31

_ 3_

_ "j^g

- ^73

.75

- .04

+ 1.16

- .10

- .13

- .31

- .43

 .38

 .23

.20

 .21

+ .38

4 .11

- .22

 .29 

- .46

._ .42

- ^42 

- .25

 .32

 .38

- .87

 .39

- .63

 .62

- .21

 .28

- .05

- .03

4- 1.30

+ 1.32

4- 1.68 

+ .29

- .07

- .39

- .02

4- .06

4- i?4

- .32

 .35

- .20

4- .59

4 .30 

- .24

- .73

4 .04

4 1.50

- .57

- .29

- .19

- .32

- .44

- .43

- .32

Estimated 

groundvoter 

run-off 

( inehe s

0.15

.07

.05

.04

.03

.02

.01

.06

.14

.09

.08

.28

.17

.07

.07

.05

.04

.04

.04

.05

.33

.43

.17

.04 

.02

.02

.01 

.01

.01

 04

 04 .11

.08

.08

.05

.OS

.04

.16

.SO

.59

.49 

.45

 40

.32

.30

.31

.17

.16

.09

.08

.08

.19 

.13

.14

.32

.46

.29

.09

.05

.03

.03

.02

.02
RAIMFALL AND RUN-OFF IN THE UNITED STATES

Table 65.- Drought data for Skunk River Baain above Augusta, Iowa-Continued

Month

1934

January

February

March

April

May

June

July

August

September

October

November

December

Temperature

at Davenport, Iowa (°P.)

For

month

30.8

23.6

35.1

51. 3

70.2

79.4

80.6

73.1

63.4

58.0

45.3

23.4

Average

21.8

24.9

36.1

49.9

61.3

70.5

75.3

73 <1

65.6

53.7

39.0

27.1

Departure

 f 9.0

 1.1

- 1.0

1.4

8.9

8.9

5.3

0

2.2

4.3

6.3

 3.7

Precipitation

over the basin (inches)

For

month

0.99

.60

.90

1.52

1.14

2.74

2.93

2.05

5.71

1.25

6.05

.62

Average

1.04

1.10

2.11

3.25

3.48

5.16

3.44

3.78

4.76

2.63

2.07

1.21

Departure

 0.05

- .50

- 1.21

- 1.73

- 2.34

- 2.44

.51

- 1.73

4- .95

- 1.38

4 3.98

 .59

Run-off

at Augusta (inches)

For

month

0.04

.04

.05

.08

.02

.04

.09

.01

.03

.02

.16

.18

Average

0.34

.44

.97

.87

.75

1.08

.48

.35

.49

.48

.45

.34

Departure

0.30

- .40

 .92

.79

- .73

- 1.04

- .39

- .34

- .46

 .46

- .29

 .16

Estimated

ground -

water

run-off

( inches )

0.02

.02

.02

.03

.02

.02

.02

.01

.01

.01

.02

.07
RUB-OFF DURING DROUGHT PERIODS

Table 66.- Drought data for Mississippi River Basin above Keokuk, Iowa

Month

1894

June

July

August

September

October

November

December

1895

January

February

March

April

May

June

July

August

September

October

November

December

1896

January

February

March

April

May

June

July

August

September

October

November

December

1910

March

April

May

June

July

August

September

October

November

December

1911

January

February

March

April

May

June

July

August

September

October

November

December

1930

July

August

September

October

November

December

Temperature* 

* (°P.)

For

70.9

74.4

71.5

63.7

50.0

29.5

28.6

10.5

13.9

31.1

50.7

58.6

67.5

69.8

70.6

65.2

44.8

31.9

23.3

19.3

23.3

27.3

49.3

63.6

68.0

71.0

70.0

57.2

46.1

26.2

E5.7

48.0

49.2

53.9

69.5

73.4

69.4

60.9

53.3

29.4

19.5

15.9

24.4

37.1

44.7

62.3

71.1

71.6

67.5

60.8

46.9

26.2

26.1

74.0

73.3

62.7

47.7

37.3

23.8

Average

66.6

61.4

69.2

61.5

49.3

34.0

20.8

14.4

17.7

30.1

45. 2

57.3

66.6

71.4

69.2

61.5

49.3

34.0

20.8

14.4

17.7

30.1

45.2

57.3

66.6

71.4

69.2

61.5

49.3

34.0

20.8

30.1

45.2

57.3

66.6

71.4

69.2

61.5

49.3

34.0

20.8

14.4

17.7

30.1

45.2

57.3

66.6

71.4

69.2

61.5

49.3

34.0

20.8

71.4

69.2

61.5

49.3

34.0

20.8

Departure

+ 4.3

+ 3.0

4 2.3

-1- 2.2

+ .7

4.5

+ 7.8

- 3.9

 3.8

4 1.0

+ 5.5

4 1.3

+ .9

- 1.6

4 1.4

H- 3.7

- 4.5

- 2.1

4 2.5

-1- 4.9

4 5.6

- 2.8

4 4.1

4 6.3

4 1.4

- .4

+ .8

- 4.3

- 3.2

 7.8

+ 4.9

4 17.9

4- 4.0

- 3.4

4 2.9

4- 2.0

4 .2

 .6

4 4.0

- 4.6

 1.3

+ 1.5

4- 6.7

4 7.0

- .5

4 5.0

4- 4.5

4- .2

- 1.7

 .7

- 2.4

7.8

+ 5.3

4- 2.6

4- 4.1

4 1.2

- 1.6

4 3.3

4- 3.0

Precipitation 

over the basin (inches)

Por 

month

2.70

.67

1.17

3.17

2.84

1.15

.89

1.07

.52

.54

1.56

3.66

3.50

3.27

2.70

3.39

.44

1.55

1.28

.79

.56

1.51

5.48

5.33

3.70

3.37

2.60

3.63

2.66

2.50

.69

.18

2.20

2.46

1.36

1.82

3.11

2.84

.99

.70

.58

.94

1.68

.90

2.32

3.90

3.37

3.69

4.25

4.98

4.76

2.00

1.87

2.41

1.54

3.27

2.14

1.97

.45

Average

4.31

3.61

3.36

3.54

2.26

1.50

1.08

1.03

1.05

1.60

2.51

3.62

4.31

3.61

3.36

3.54

2.26

1.50

1.08

1.03

1.05

1.60

2.51

3.62

4.31

3.61

3.36

3.54

2.26

1.50

1.08

1.60

2.51

3.62

4.31

3.61

3.36

3.54

2.26

1.50

1.08

1.03

1.05

1.60

2.51

3.62

4.31

3.61

3.36

3.54

2.26

1.50

1.08

3.61

3.36

3.54

2.26

1.50

1.08

Departure

- 1.61

 2.94

 2.19

- .37

4- .58

- .35

.19

4- .04

- .53

- 1.06

- .95

4 .04

.81

- .34

 .66

- .15

- 1.82

H- .05

4 .20

- .24

.49

- .09

4- 2.97

4- 1.71

- .61

 .24

.76

+ .09

+ .40

-t- 1.00

- .39

- 1.42

.31

- 1.16

2.95

- 1.79

 .25

 .70

 1.27

.80

- .50

- .09

4 .63

- .70

- .19

4 .28

- .94

4 .08

4 .39

4 1.44

4 2.50

4 .50

4 .79

- 1.20

- 1.82

- .27

- .12

+ .47

.63

Run- off 

at Keokuk (inches)

For 

month

0.91

.33

.20

.25

.23

.27

.23

.16

.14

.44

.31

.43

.44

.41

.28

.22

,29

.21

.16

.14

.21

.29

.38

1.20

1.02

.51

.40

.27

.25

.35

.39

.91

.81

.63

.42

.25

.21

.23

.23

.21

.14

.17

.56

.39

.40

.42

.52

.25

.40

.36

.93

.77

.58

.45

.23

.19

.23

.20

.19

Average

0.89

.80

.47

.42

.50

.45

.32

.29

.31

.69

1.02

1.01

.89

.80

.47

.42

.50

.45

.32

.29

.31

.69

1.02

1.01

.89

.80

.47

.42

.50

.45

.32

.69

1.02

1.01

.89

.80

.47

.42

.50

.45

.32

.29

.31

.69

1.02

1.01

.89

.80

.47

.42

.50

.45

.32

.80

.47

.42

.50

.45

.32

Departure

4 0.02

- .47

 .27

- .17

.27

- .18

- .09

.13

.17

- .25

.71

.58

.45

- .39

- .19

- .20

- .21

.24

.16

.15

- .10

- .40

- .64

4- .19

4 .13

- .29

 .07

- .15

 .25

- .10

+ .07

4- .22

.21

- .38

 .47

 .55

 .26

- .19

.27

.24

.18

.12

4- .25

- .30

- .62

.59

- .37

 .55

.07

.06

4 .43

4 .32

4- .26

- .35

- .24

.23

- .27

.25

- .13'

* Stations used to compute average temperature over the basin are given in
RAINFALL AND RUN-OFF IN THE UNITED STATES

Table 66.- Drought data for Mississippi River Basin above Keokuk, Iowa-Continued

Month

1931

January

February

March

April

May

June

July

August

September

October

November

December

1932

January

February

March

April

May

June

July

August

September

October

November

December

Temperature* 

(°P«)

For 

month

25.7

31.5

31.8

48.4

55.3

71.3

75.5

70.2

67.9

54.7

42.0

31.1

22.1

23.7

23.8

45.9

59.2

69.9

73.5

71.4

60.8

46.6

30.8

19.2

Average

14.4

17.7

30.1

45.2

57.3

6C.6

71.4

69.2

61.5

49.3

34.0

20.8

14.4

17.7

30.1

45.2

57.3

66.6

71.4

69.2

61.5

49.3

34.0

20.8

Departure

4 11.3

4 13.8

4- 1.7

+ 3.2

 2.0

4 4.7

4 4.1

-c 1.0

-1- 6.4

+ 5.4

+ R.O

4 10.3

4 7.7

4 6.0

- 6.3

4- .7

4 1.9

4 3.3

4 2.1

4- 2.2

 .7

- 2.7

 3.2

 1.6

Precipitation 

over the basin (inches)

For 

month

0.44

.48

1.67

1.55

2.37

4.17

2.32

2.99

4.77

3.06

4.33

1.38

1.61

.94

1.37

1.73

3.53

3.82

3.20

4.30

1.50

1.92

1.76

1.43

Average

1.03

1.05

1.60

2.51

3.62

4.31

3.61

3.36

3.54

2.26

1.50

1.08

1.03

1.05

1.60

2.51

3.62

4.31

3.61

3.36

3.54

2.26

1.50

1.03

Departure

- 0.59

.57

4- .07

- .96

- 1.25

- .14

 1.29

- .37

4 1.23

4 .80

4 2.83

4 .30

4- .58

- .11

.23

- .78

.09

- .49

.41

4 .94

- 2.04

- .34

-4 .26

+ .35

Run-off 

at Keokuk (inches)

For 

month

0.19

.23

.23

.31

.27

.26

.33

.16

.22

.31

.45

.66

.63

.40

.59

.89

.67

.5S

.38

.28

.20

.17

.19

.22

Average

0.29

.31

.69

1.02

1.01

.89

.80

.47

.42

.50

.45

.32

.29

.31

.69

1.02

1.01

.89

.80

.47

.42

.50

.45

.32

Departure

- 0.10

- .08

- .46

- .71

- .74

- .63

 .47

- .31

- .20

.19

0

4 .34

4 .24

4 .09

.10

.13

.34

- .37

- .42

- .19

- .22

.33

- .26

.10

table 11.

» Stations used to compute average temperature over the basin are given in
GROTJHD-WATER LEVELS 269

the drought of 1930-32 a deficiency of 3.64 inches accumulated in 4 consecutive months and a total of 8.67 inches in 14 months. The run-off during the 

first drought period was deficient for 22 consecutive months, the accumulated 

total being 6.42 inches, and by the end of 29 months the accumulated deficiency amounted to 6.96 inches. During the second drought a deficiency of 

2.87 inches accumulated in 10 consecutive months, and at the end of 18 

months the accumulation amounted to 5.18 inches. In the third drought a 

deficiency of 7.15 inches in run-off accumulated in 30 consecutive months. 

The temperature affecting the amount of transpiration (over 40°) during the 

drought of 1930-32 averaged about 0.6° higher than in 1910-11 drought and 

about 0.7° higher than in 1894-96.

Ground-water levels

The advisory conmiittee of the American Geophysical Union in a report to the Water Planning Committee, dated February 12, 1935, suggested, 

among other things, "a study of the laws governing the ground-water supply to 

streams and the relation of ground-water levels to ground-water flow. This 

is important because ground water is the only source of supply to streams 

without surface storage during drought periods. Also in case of many crops, 

such as alfalfa, ground water is the principal source of moisture utilized 

by vegetation during drought periods when soil moisture is deficient."

In this connection a comparison of deficiencies in precipitation 

with decline of ground-water levels made in the Platte Valley in central 

Nebraska by Leland K. Wenzel, of the United States Geological Survey, is of 

interest. The results of this study are briefly outlined in the following 

statement prepared for the press, dated April 1, 1935. In connection with 

this statement it should be noted that water is pumped from wells for irrigation during the summer in the area east of Kearney, and hence the water-level 

fluctuations shown in the accompanying figure are not wholly caused by 

natural conditions. The part of the Platte Valley urtiere irrigation is practiced with water diverted from the Platte River is somewhat separated from 

the part of the valley east of Kearney by a restriction in the valley, and 

it is believed that the effect of surface-water irrigation west of Kearney 

on the fluctuations of the water table in the area to the east ia negligible.
270 RAINFALL AND RUN-OFF IN THE UNITED STATES

"The water levels in about 100 wells in the Platte River Valley 

between Grand Island and Cozad, in central Nebraska, have been measured 

periodically since October 1930 by the United States Geological Survey in 

cooperation with the Conservation and Survey Division of the University of 

Nebraska. In October 1934 the water levels in these wells stood from 1 to 

8 feet lower than in October 1930, thus indicating a general decline of the 

ground-water table throughout this part of the Platte Valley. It has been 

greatest in parts of the valley between Cozad and Kearney, ranging from 4 

to 8 feet in an area north of Cozad and Lexington and from 3 to 4 feet in 

an area on the north side of the valley from Lexington to and beyond Kearney. 

This decline has been caused principally by subnormal precipitation, together with the relatively small amount of surface water available for 

irrigation, and thus for seepage to the ground-water table, in the last 4 

years. N. H. Darton, of the United States Geological Survey, made an investigation in '1896 of the geology and ground-water conditions of southeastern Nebraska. The ground-water level in the vicinity of Lexington was 

then 20 to 22 feet below the land surface. At the present time it is only 

7 to 10 feet below the land surface and hence is still from 10 to 15 feet 

above the level of 1896. The net rise since 1896 doubtless has been caused 

by seepage of water diverted from the Platte River for irrigation. In years 

when only comparatively little water flows in the irrigation ditches as 

during the last 4 years the seepage is small, and therefore rather large 

declines of the water table occur. Rises of 1 to 4 feet of the water level 

in wells near Lexington were recorded in the fall of 1934, when surface 

water once more flowed in many of the canals near the city.

"East of Kearney the decline of the ground-water table has in general been less than wfljst of Kearney. From Kearney to Shelton and south of 

Alda it has in general ranged from 2 to 3 feet, and in the vicinity of Wood 

River it has been less than 2 feet. The decline east of Kearney was smaller 

chiefly because the water table had not been built up prior to 1930 to any 

great extent by surface-water irrigation and also, perhaps, because east of 

Kearney the ground-water level is sustained to a greater extent by underflow from the northwest. Such decline as occurred was due chiefly to subnormal precipitation but in small part to the considerable quantity of 

ground water that was pumped for irrigation.

"A special study was made of the fluctuation of the water levels 

in 20 observation wells between Grand Island and Kearney and their relation 

to the precipitation. The results are shown in the accompanying graphs
GROUND-WATER LEVELS 271

(figure 88). One hydrograph shows the average water level at the end of 

successive 3-month periods from January 1931 to January 1935 in 14 wells 

in which the water levels stand more than 10 feet below the land surface. 

Another hydrograph similarly shows the average water levels in 6 wells with 

water levels less than 10 feet below the surface. The wells of the second 

group are in the same stretch of the Platte Valley as those of the first 

group but are nearer the river, where the water table is not far below the 

surface. A third graph shows the accumulative departure from normal precipitation as compiled from the records at Grand Island and Kearney since 

January 1, 1931.

"The water levels in the wells of the second group in general 

rise and fall more than the water levels in the wells of the first group. 

This more active fluctuation is due to the following causest Recharge 

from precipitation occurs more frequently where the water table is shallow 

and thus larger rises of the water level result. On the other hand, the 

roots of more plants draw water directly from the zone of saturation where 

the water table is shallow, and consequently larger declines of the water 

level occur in the growing season. Changes in the -level of the Platte 

River cause similar changes in the water levels in wells close to the stream, 

but the river has small effect on the water levels in wells farther away. 

In the winter and spring of 1931, 1933, and 1934 the average rise was less 

than 1 inch in the wells with deeper water level but more than 1 foot in 

the wells with shallow water level* The decline of the water levels in 

the summer and fall was likewise greatest in the shallow-water wells. Consequently in the last 4 years the net decline was nearly the same in each 

group.

"In the first half of 1932 there were rather large rises of the 

water levels in all the wells in the Platte Valley, as Indicated by the 

hydrographs. The cause of this rise is apparent from the curve showing 

accumulative departure from normal precipitation. Prom October 1931 to 

April 1932 the average precipitation recorded at Grand Island and Kearney 

was slightly above normal, and consequently considerable water percolated 

into the ground and was added to the ground-water reservoir in this recharge period. As a result the water level did not reach as low a level
loorunulated departure of precipitation In inches 

O 
COMPARISON OP GRAPHS OP MINIMUM PLOW 273

In 1932 as it did In 1931. Since July 1932 the precipitation has been 

about 22 inches below normal a deficiency equivalent to almost one year's 

normal precipitation and the water level in the valley has suffered annual 

net declines. It may reasonably be expected that future years of greater 

precipitation will again raise the ground-water levels."

Comparison of graphs of minimum flow

The comparison of the graph of minimum flow of the major basins 

studied should be of interest, especially if the relations between general 

ground-water conditions in the basins and the seepage flow therefrom are 

eventually determined. In figure 89 is plotted (plotted points are shown 

connected for purpose of illustration) for the period of record the annual 

minimum average daily discharge for 7 consecutive days, not including the 

frozen period, for the major basins studied, except for the Merrimack River 

Basin, for which B-nrnml minimum monthly flows are plotted. The records 

have not been corrected for storage and no attempt has been made to determine the effect, if any, of storage operations or channel improvements on the

minimum flows*

Prom the records as they stard some general observations can be 

made. For the relatively short records for the Red, James, and Chattahoochee Rivers, the trend in 7-day minimum flows seems to be somewhat downward. The longer time record for the Mississippi River above Keokuk shows 

a decided downward trend in 7-day minima since 1930, but in three years - 

1894, 191O, and 1925 - the minimum was almost as low as in 1930. The 

Merrimack monthly minima have trended generally upward since 1911, with an 

early low recorded in 1883. The Tennessee River minima have trended upward since 1925, when the minimum was the lowest for the period of record, 

although approached in the earlier years 1881, 1883, and 1904. Zero flow 

was recorded on the Neosho River in 1896, 1897, 1920, and 1934.

5955 O 35 18
274 RAINFALL AND RUN-OFF IN THE UNITED STATES 

B°!°ggpin°

Figure 89. Minimum animal average daily disoharge for 7 oonseoutive days not including 

periods. Figures for llerrimaok River are minimum annual average monthly disoharge.
APPENDIX

Report of Advisory Committee of Section of Hydrology of 

the American Geophysical Union to the Water-Planning 

Committee of the National Resources Board

Gentlemen:

The Advisory Committee of the Section of Hydrology of the American Geophysical Union, which at your request has maintained an advisory 

status with the Geological Survey with regard to studies of the relations 

of rainfall and run-off, has now in hand a progress report in this matter 

which, we understand, haa been prepared for publication as a water-supply 

paper.*

The committee wishes to offer its commendation of the very useful work done by the engineers and hydrologists of the Geological Survey. 

The report ia a record of progress made in exploratory studies of certain 

phases of the relations of rainfall and run-off and the factors that; 

affect these relations. It should be understood that this report is in no 

sense to be considered a record of completed, exhaustive research into the 

subject. Many parts of the report suggest pertinent questions concerning 

aspects of the data presented, which are not answered and not answerable at 

this time.

The proposed publication offers more or less simple representations and tentative analyses of basic hydrologic data and should be of 

value to those who seek knowledge of these subjects. The compilation will 

enable students of the subjects involved to have the benefit of the information collected, and its publication offers an opportunity for hydrologists, meteorologists, and others to review and criticize the methods 

used and the results obtained. One of the principal benefits hoped to be 

derived from the report is the stimulation of such review and criticism. 

Studies such as are here described, when supplemented by other similar 

studies or when carried to a point where definite changes, trends, and 

relations can be disclosed and reasonably accurate conclusions drawn, 

should be of value in connection with the preparation of plans and measures

* Refers to this paper.- W. G. H.

275
276 RAINFALL AMD RUN-OFF IN THE UNITED STATES

for the conservation of water resources. The committee cautions readers 

against the use of any of the material apart from its accompanying text.

The Advisory Committee approves the publication of this material 

at this time. During the progress of the studies the committee has suggested items of study and also alternate methods of approach in many problems. It has recommended that some specific studies undertaken be 

abandoned, because the basic data available did not appear to be sufficiently complete or accurate for the purpose. It should be understood 

that in recommending publication of the material at this time the committee 

is not necessarilv committed to the approval of the procedures used as the 

best methods for particular studies, nor in any way committed to an 

approval of tentative conclusions which may appear to be expressed in the 

report.

Although rainfall and run-off are the most obvious and most 

widely observed factors of the hydrologic cycle, the records of reliable 

observation of these phenomena are comparatively short and afford a meager 

basis for satisfactory conclusions.

Few continuous records of precipitation and temperature and no 

records of stream flow are now available for any part of the United States 

for periods of 100 years or more.

The variations in precipitation, temperature, and run-off that 

are presented in the report cover a relatively short period of time, and 

no attempt has been made to extend the records by use of tree rings, lake 

levels, glacial changes, timber-line movements, or similar studies. No 

attempt has been made to determine whether the apparent changes are a part 

of long-time cyclic variations or are Indications of permanent changes. 

The important thing is the fact that during a period of less than 100 

years changes of sufficient magnitude to affect human occupancy have 

apparently occurred in meteorologic and hydrologic conditions in certain 

parts of the United States. Whether any part of the changes noted may 

have resulted from man's occupancy ia an open question. In one instance 

the data presented suggest that possibly conditions could be improved 

through man's efforts. The committee feels, however, that much more research will be needed before it can be definitely asserted that over the 

basins studied man's occupancy has caused measurable changes either in 

meteorologic conditions or stream flow. It is possible, however, that 

when the data presented are used in conjunction with other studies, or
REPORT OP ADVISORY COMMITTEE 277

when the present studies are carried to completion, definite reasons can 

be disclosed for the various changes, and in that event it can be definitely determined whether or not over large areas man can reasonably 

undertake remedial measures.

The Advisory Committee calls attention to the resolution of the 

American Geophysical Union at its annual meeting in Washington on April 

25, 1955. This resolution points out the fact that the study of hydrologic phenomena and its application to the conservation and utilization of 

water resources is a work that is divided among a number of different bureaus and departments of the Federal Government, and that at the present 

time there is no correlating authority or agency, for uniting in a systematic manner the work of these Federal agencies, and therefore the American Geophysical Union recommended and urged that there be established a 

permanent agency with authority to direct and correlate the work of all 

these separate agencies engaged in matters pertaining to the utilization 

of the nation's water resources.

The Advisory Committee endorses the aforesaid resolution and 

furthermore recommends that in the event of further investigations in the 

application of hydrology, all such future work be under the direction and 

supervision of such a centralized correlating agency, to be established; 

that such agency be vested with the necessary power and authority to 

insure a correlated work; and that the aforesaid correlating agency have 

authority to assign to the various bureaus and departments specific studies 

for which they may be best equipped.

In the attached supplementary notes the committee is indicating 

certain specific matters that might be restudied to advantage, and other 

methods of approach that for certain problems seem desirable.

This report was prepared and concurred in by a subcommittee consisting of Messrs. Horner, Horton, Heyer, and Sherman. The other members 

of the committee, Uessrs. Pickels, Towl, and Woermann, although cooperating 

in the studies, have not had opportunity to review the proposed watersupply paper in its present form of compilation.

Respectfully submitted.

ADVISORY COMMITTEE, 

AMERICAN GEOPHYSICAL UNION 

June 12, 1935 By Wesley W. Horner, Chairman.
278 RAINFALL AND RUN-OFF IN THE UNITED STATES

Supplementary notes 

Work of the committee

The seven members of the committee have maintained contact with 

the studies of the Geological Survey since their appointment in May 1954. 

Tcr a considerable degree discussion of material between members of the 

Advisory Committee and between them and the active staff on this project 

of the Geological Survey has been maintained by correspondence. During the 

first 6 months of the work the correspondence was supplemented by frequent 

conferences between Mr. Hoyt and others, on the one hand, and Messrs. 

Hornar and Sherman, of the committee, on the other.

In order to expedite the work of the Advisory Committee, a subcommittee was formed, consisting of Messrs. Horner, Meyer, and Sherman, 

and to this subcommittee was added Mr. R. E. Horton in January 1935. On 

January 18 three members of the subcommittee met with Mr. G. M. Matthes, 

chairman of the Committee of Flood Protection Data, for the discussion of 

certain material of common interest to the two committees; thereafter, a 

memorandum report mis rendered to the Water-Planning Committee. On April 

22, 1955, the four members of the subcommittee met with Mr. Hoyt and his 

assistants for a full-day session in Washington. At this time, the studies 

contained in the proposed water-supply paper were nearing completion. The 

material was analyzed in detail, and the members of the Advisory Committee 

offered definite suggestions as to policy, as to differences in procedure, 

and as to specific details or apparent defects in the basic data.

After the material had been assembled in final form, but prior 

to complete editing, the subcommittee met in Chicago on June 12, 1935, and 

again reviewed the results of all the studies undertaken. This report of 

the Advisory Committee will be considered its final report on the present 

exploratory studies, to be published as Water-Supply Paper 772.

Detailed comments on matter contained 

in the- water-supply paper

To amplify the statements on pages 19 and 20 it should be 

made clear that during the progress of the studies the Advisory Committee 

came to appreciate more and more the deficiencies of the fundamental data 

on which the studies undertaken had to be based. It had been hoped that
REPORT OP ADVISORY COMMITTEE 279

exploratory studies In the various fields might develop derived information of real present value, and that the results of the studies would 

permit tentative conclusions by both hydrologists and economists which 

would be useful in connection with present national planning. Although 

these hopes could not be fully realized, because of deficiencies in the 

fundamental data, the studies contained in the present report indicate 

fields for further study for which present basic data may be considered 

reasonably adequate, and they also indicate desirable modifications in 

methods of collecting basic data. With respect to the last item, the 

Advisory Committee calls attention to the report now being made to the 

Water-Planning Committee by a special committee on standards and specifications for hydrologio data, with which some of the members of the 

Advisory Committee have been associated. Because the improvement and 

standardization in the collections, compilations, and publication of 

basic data are there discussed in detail and definite recommendations are 

made with regard to them the Advisory Committee refrains in general from 

further recommendation on these subjects herein.

With regard to the material on page 19 the Advisory Committee wishes to make clear its understanding that although the studies 

contained in the main report may not be considered "broad general studies", 

yet in many phases they deal with relations of mass values, such as rainfall, run-off, and temperature on annual, 5-year, and 10-year bases. At 

the committee's suggestion, seasonal values have been developed in certain 

of the studies. To the extent that mass values are involved, detailed 

fundamental relationships are obscured, and the committee wishes at this 

point to call attention to the extreme benefit that would result from 

specific studies of the relations of rainfall and run-off with regard to 

smaller areas, high intensities, and short times of occurrence, such as 

definite storm periods. Owing to the greater simplicity of conditions and 

the possibility of their control in part, studies of run-off from small 

drainage basins are better adapted to the determination of the underlying 

laws and principles of run-off phenomena than studies of larger drainage 

basins.

In the studies of natural phenomena, such as precipitation, 

temperature, pnd run-off, 10-year progressive averages have been used 

extensively in the report. The committee believes that on the whole 5- 

year moving averages, with the result plotted for the third year, give a
280 RAINFALL AND RUN-OFF IN THE UNITED STATES

better Indication of trends than 10-year moving averages. If 10-year 

moving averages are used and are plotted on the tenth year they tend to 

obscure trends and mane the moving averages appear in conflict with the 

annual averages. If 10-year averages are used it appears best to have the 

average value plotted as the middle point of the series Instead of the end.

The material presented In table 1 (p» 21) is of great interest. 

However, In view of studies presented In other sections of the report with 

regard to changes In precipitation by geographic provinces and by baeins, 

table 1 and the statements on page 21, appear to need further analysis 

and discussion. For example, figure 1 Indicates a general downward trend 

of precipitation except In certain southern and west-central provinces and 

In a portion of the southwestern area. In view of the definite decrease 

In precipitation as indicated in figure 1 and as shown more specifically 

In certain tables, there appears to be a necessity for harmonizing the two 

studies.

The study of precipitation trends by seasons in fifteen geographic areas is a presentation of material of the first importance and 

material that may be used by hydrologlsts for further analysis. The committee considers it unfortunate that these studies have of necessity had 

to be based to so great an extent upon precipitation data collected at 

the so-called "first order stations." At many of these stations the gage; 

have been subject to change in location and exposure and in particular, to 

more than one change in height above the ground surface, generally to the 

roof of a higher building. On this account it is possible that the trend 

at some of these stations will Indicate a decreasing annual precipitation, 

when as a matter of fact the data may be affected by decreased catch of 

gage.

Much of the work on trends of hydrologlc data presented in the 

paper Is based on annual values. The committee feels that although annual 

values are useful In various ways there are certain respects In which such 

values alone are either Inadequate or may be deceptive, and that In future 

studies, involving trends or changes in conditions, a seasonal basis 

should in general be used, with the data for a growing season presented 

separately from those for the remainder of the year. Aside from the 

obvious advantage of this plan in relation to agriculture, it segregates 

the summer data which are less subject to basic errors than those for the 

winter season, and Inasmuch as the greater part of the run-off for many
REPORT OP ADVISORY COMMITTEE 281

drainage basins occurs in the winter* season, such a segregation is necessary If the results are to be applied to summer conditions.

The committee particularly commends the study of trends and of 

relationships by basins and recommends that the future studies, Insofar as 

possible, be carried out along drainage-basin lines.

The committee recommends that in future research relations between rainfall and run-off should not be studied or expressed as ratios or 

percentages, but should be Indicated by differences between rainfall and 

run-off, or so-called "water losses", which are Indicative of what is 

called the "consumptive use" characteristic of the particular basins.

The report contains tabulations showing the segregation based on 

a 5-year annual average- for certain periods noted and obtained by subtracting from the total stream flow an estimated ground-water run-off 

obtained through a study of the plotted hydrograph of stream flow, in part 

by methods discussed In the report. Certain exceptions are made as to the 

straight-line methods used on the Miami and Pomperaug Basins.

The committee calls attention to the qualification as to the 

accuracy of the results obtained, contained on page 120 where it Is stated: 

"It should be clearly recognized that the estimates given are subject to 

error. Further refinements in the methods Of determination and more exhaustive application of known factors may change the results materially." 

The committee believes that the character of the material presented in 

subsequent tables is of such importance as to Justify a further attempt 

to organize the technique of ground-water separation in accordance with 

the most scientific methods now possible, and it would suggest that the 

values presented In these tables be considered tentative only and that the 

studies on which they are based, should be renewed and revised at the 

earliest possible opportunity.

Many additional studies are in progress, and better methods for 

the separation of ground-water stream flow are being developed. When 

these methods are applied to the records for which a separation of stream 

flow was made In this report, material differences will undoubtedly be 

shown, but it is nevertheless appreciated that the existing Information 

indicates striking differences In the characteristics of the various 

drainage basins listed, and for purposes of comparison the results are believed to be of value.
282 RAINFALL AND ROT-OFF IN THE UNITED STATES

In the opinion of the committee the methods used are not subject 

to error sufficient to Invalidate their application to the separation of 

ground-water stream flow In the use of the unit-graph method.

The committee's statements with relation to the tables on pages 

120-122 apply equally to tables on ground-water run-off on pages 246 and 

247.

A considerable part of the ground-water flow Included In the 

tabulated values Is necessarily derived from flow during the winter season. 

To the extent that values of winter flow are derived from estimates and 

not from measurements, the possible error In total annual quantity Is increased. The development of winter depletion curves by the making of more 

extensive actual measurements on northern streams during periods when 

there is no surface run-off Is strongly recommended.

With regard to the statement on page 245, the committee Is of 

the opinion that quantitative values of ground-water run-off which may 

eventually be developed by scientific application of the best possible 

methods may vary from the values given on pages 246 and 247, In some instances by more than 10 percent, and that the variation may be in either 

direction.

The committee feels that the work presented by Merrill Bernard 

relating to the possibility of transposing flood producing storms by means 

of the unit hydrograph is a useful contribution In making flood estimates. 

In such applications it is necessary to be fully acquainted with the geographic and meteorologlc conditions of the areas Involved.
REFERENCES

The following list of references, largely American, to relations between rainfall and run-off and related subjects does 

not include articles on run-off of high intensity, such references being included in U. S. Geological Survey Water Supply 

Paper 771.

1. Adams, P. D., Rainfall and run-off: Science, new ser., vol. 67, 

pp. 500-501, 1928.

2. Auten, J. T., Porosity and water absorption of forest soils; Jour. 

Agr, Research, vol. 46, no. 1, June 1, 1933.

3. Babb, C. C., Rainfall and river flow: Am. Soc. Civil Eng. Trans., 

vol. 28, p. 323, 1893. Curves giving monthly run-off in 

terms of percentage of annual run-off; annual run-off computed as a percentage of annual precipitation.

4. Baker, D. M., and Conkling, Harold, Water supply and utilization,

New York, John Wiley & Sons, 1929. An outline of hydrology 

with reference to the arid section of the United States.

5. Baker, P. S., Some field experiments on evaporation from snow surfaces; Monthly Weather Rev., July 1917.

6. Barrows, H. K., Precipitation, run-off, and altitude, Connecticut 

River: Am. Geophys. Union Trans. 14th meeting, p. 396, 

Nat. Research Council, 1933.

7. Barrows, H. K., Water-power engineering, 2d ed., New York, McGrawHill Book Co., 1934. Hydrology, pp. 38-123.

8. Bartell, P. 0., and McCrory, S. H., First progress report on soilerosion experiments, North Carolina Experiment Station farm, 

West Raleigh, Wake County, N. C., U. S. Dept. Agr., 1925. 

Experiments to show run-off and soil erosion.

9. Bates, C. G., and Henry, A. J., Forest and stream-flow experiment at 

Wagon Wheel Gap, Colo.: Monthly Weather Rev., Suppl. 30, 

1928. For discussion, see Hoyt, W. G., and Troxell, H. C., 

Am. Soc. Civil Eng. Trans., vol. 99, pp. 1-94, 1934.

10. Belknap, J. B., Comparison of methods for determining the areal mean 

precipitation on drainage areas: New England Water Works 

Assoc. Jour., vol. 46, pp. 272-282, maps, 1932.

11. Bennett, C. S., Hydrological data from the Miami Conservancy District: 

Eng. News-Record, vol. 113, pp. 556-558, 11., 1934.

12. Bernard, M. M., Formulas for rainfall intensities of long duration, 

Am. Soc. Civil Eng., Trans.. vol. 96, P. 592, 1932.

13. Bernard, M.M., Approach to determinate stream flow: Am. Soc. Civil 

Eng. Proc., vol. 60, pp. 3-18, 1934. Discussion, vol. 60, 

pp. 436-438, 585-588, 764-765, 1037-1039, 1340-1351, 1934; 

vol. 61, pp. 84-88, 1935.

14. Bernard, M. M., A preliminary manual for the unit-hydrograph method 

(manuscript), U. S. Geol. Survey, August 1934.

15. Bigelow, P. H., Evaporation observations and formulae a manual for

observers in climatology and evaporation, U. S. Weather Bureau, 

1909.

285
284 RAINFALL AND RUN-OFF IN THE UNITED STATES

16. Blaney, H. P., and Taylor, C. A., Rainfall, penetration, and consumptive use: California Dept. Public Works Water-Resources 

Bull. 33, 1930.

17. Blaney, H. P., Consumptive use of water by native plants growing in 

moist areas in southern California: California i^ept. Public 

Works Water-Resources Bull. 44, pp. 1-26, 1933.

18. Boston Society of Civil Engineers, Report of committee on floods: 

Boston Soc. Civil Eng. Jour., vol. 17, pp. 293-466, 1930.

18a. Bowman, Isaiah, Our expanding and contracting deserts: Geog. Rev., 

January 1935, pp. 43-61.

19. Briggs, L. J., Losses through transpiration: U.' S. Dept. Agr., Bur. 

Plant Industry, Bull. 23O, 1912.

20. Briggs, L. J., and Shantz, H. L., Daily transpiration during the normal

growth period and its correlation with weather; Jour. Agr.

Research, vol. 7, no. 4, Oct. 23, 1916.

21. Burchard, E. D., 1925 drought breaks all records in southern Appalachians: Eng. News-Record, vol. 96, pp. 234-235., 1926. The 

average deficiency for 12 stations was 37 percent. A table 

shows monthly departure from normal rainfall at selected 

stations, and another shows comparison of monthly discharge 

of the French Broad River at Asheville for this period, v/ith 

16-year average.

22. Burgess, A. S., Safe yields of drainage areas in years of minimum 

rainfall: Eng. News-Record, vol. 89, pp. 970-971, 1922. 

Presentation and discussion of minimum, run-off in northeastern United States; mass curves to show safe yields.

23. Burr, E. W., Forests and stream flow, Herrimac River: 62d Gong.,

1st sess., H. Doc. 9, 1911; Sng. News, vol. 66, p. 100, 1911. 

No evidence of change in relation between rainfall and runoff from 1860 to 1910,

84. Cady, R. C., Fluctuations of water levels in Virginia wells: Am. 

Geophys. Union Trans. 13th meeting, p. 370, Nat. Research 

Council, 1932.

25. Chandler, E. P., What becomes of rainfall in North Dakota: North 

Dakota Univ. Quart. Jour., vol. 15, no. 2, p. 110, 1925.

26. Chittenden, H. M., Forests and reservoirs in their relation to stream 

flow, with special reference to navigable rivers: Am. Soc. 

Civil Eng. Trans., vol. 52, p. 245, 1903.

27. Church, J. E., Jr., Snow survey and stream run-off forecast in Nevada 

for 1923: Eng. News-Record, vol. 90, p. 1001, 1923.

28. Church, J. E., Jr., Precipitation and run-off at the Continental 

Divide: Eng. News-Record, vol. 94, pp. 190-195, 1925.

29. Church, J. E., Jr., High density of snow accelerates its melting and 

run-off: Eng. News-Record, vol. 99, p. 553, 1927.

30. Church, J. E., Jr., Hydrology of snow: Am. Geophys. Union Trans.

13th meeting, p. 277, Nat. Research Council, 1932. Complete

bibliography in Trans. 14th meeting, p. 342, 1933.

31. Collins, W. T., and Snyder, F. P., Run-off as a function of previous

precipitation (thesis, 1932, Ohio State University). Formulas 

for monthly run-off similar in character to Hayford's formulas for daily run-off.

31a. Condra, G. E., Relation of drought to water use in Nebraska:

Nebraska Univ., Dept. Cons, and Survey Div., Bull. 6, 1934.

Conkling, Harold. See Baker, D. M.

32. Connor, A. B., Dickson, Clarice, and Scoates, Factors influencing runoff and soil erosion: Texas Agr. Exper. Sta. Bull. 411, 1930.
REFERENCES 285

Cooley, L. E. See Johnston, T. T.

33. Crawford, E. J., Calculating run-off for water-power purposes with no 

rainfall records: Elec. World, vol. 76, pp. 1111-1112, 1920.

34. Cunningham, B., Rainfall and land drainage: Nature, vol. 105, p. 42, 

1920.

35-. Dole, R. B., and Stabler, Herman, Denudation: U. S. Geol. Survey 

Water-Supply Paper 234, pp. 78-93, 1909.

36. Eiffert, C. H., Problems in using Government data on rainfall and runoff: Eng. News-Record, vol. 113, pp. 556-558, 1934.

37. Elliott, F. C., Results of run-off experiments with muck soil: 2ng. 

and Contracting, vol. 55, pp. 363-365, abstracts, diagrams, 

1921; Eng. News-Record, vol. 87, pp. 157-158, 1921.

38. PitzGerald, Desmond, Evaporation from water surface: Am. Soc. Civil 

Eng. Trans., vol. 15, p. 581, 1886.

39. PitzGerald, Desmond, Rainfall, flow of stream, and storage: Am. Soc. 

Civil Eng. Trans., vol. 27, p. 253, 1892.

Flynt, F. L. See Horner, W. W. 

Folse, J. A. See Hayford, J. F.

40. Forecasting snow run-off of Humboldt River, Nevada: Eng. News-Record, 

vol. 109, pp. 135-136, 1932. Contains bibliography.

41. Forests and rainfall: Nature, vol. 89, pp. 662-664, 1912.

42. Forests, climate, erosion, and inundations: Nature, vol. 127, pp. 524- 

525, 1934.

43. Forests in relation to climate and floods: Sci. Am., vol. 103, p. 334, 

1910.

44. Porsling, C. L., Study of influence of herbaceous-plant cover on surface 

run-off and soil erosion, Wasatch Plateau: U. S. Dept. Agr. 

Tech. Bull. 220, 1931. For discussion see Stabler, Herman, 

Am. Soc. Civil Eng, Trana., vol. 99, pp. 80-86, 1934.

45. Frankenfield, H. C., Rainfall characteristics of the Mississippi River 

drainage basin: Am. Soc. Civil Eng. Trans., vol. 93, p. 675, 

1929. Distribution and intensity of rainfall; averages for 

different basins.

46. Gannett, Henry, Map showing mean annual run-off in the United States, 

U. S. Geol. Survey, 19O8.

47. Girand, J., Weather records projected into the future: Civil Eng., 

vol. 2, pp. 76-79, 1932.

48. Grover, N. C., Run-off characteristics of the Mississippi River drainage basin: Am. Soc. Civil Eng. Proc., vol. 53, pp. 2485- 

2491, 1927.

49. Grunsky, C. E., Rainfall and run-off near San Francisco: Am. Soc. Civil 

Eng. Trans., vol. 61, p. 496, 1908.

50. Grunsky, C. E., Run-off from rainfall and other data: Am. Soc. Civil 

Eng. Trans., vol. 79, p. 1165, 1915.

51. Grunsky, C. E., Rainfall and run-off studies: Am. Soc. Civil Eng. 

Proc., vol. 47, pp. 203-242, map, 1921.

52. Grunsky, C. E., and Horton, R. E., Hydrology of the Great Lakes:

Sanitary Dist. Chicago, Eng. Board of Review, Rept., pt. 3, 

app. 2, 1927.
286 RAINFALL AND RUN-OFF IN THE UNITED STATES

53. Hall, S. H., Stream flow and percolation water: Discussion of surface run-off and ground water run-off: Inst. Water Engineers 

Trans., vol. 23, pp. 92-127, 1918.

54. Hall, S. L., The probable variations in yearly run-off as determined 

from a study of California streams: Am. Soc. Civil Eng. 

Trans., vol. 84, p. 191, 1921.

55. Harding, S. T., Changes in lake levels in Great Basin area: Civil

Eng., vol. 5, no. 2, pp. 87-92, February 1935. Three hundred 

years of record studied to determine trend in available water 

supply.

56. Harrold, L, L.,Relation of stream flow to ground-water levels; Am.

Geophys. Union Trans. 15th meeting, pp. 414-416, Nat. Research 

Council, 1934.

57. Hayford, J. P., and Folse, J. A., A new method of estimating stream 

flow: Carnegie Inst. Washington Pub. 400, 1929. Most comprehensive study ever made to compute daily run-off.

58. Hazen, Alien, Storage to be provided in impounding reservoirs: Am. 

Soc. Civil Eng. Trans., vol. 77, p. 1539, 1914.

59. Hazen, Alien, Effect of elevation upon run-off from catchment areas: 

Eng. News-Record, vol. 89, pp. 62-64, map, 1922.

60. Horner, W. W., Rainfall and run-off studies in St. Louis: sprinkling experiments at Washington University: Municipal and 

County Eng., vol. 63, pp. 176-180, 1922.

61. Horner, W. W., and Flynt, F. L., Relation between rainfall and runoff from small urban areas in St. Louis and Dallas, Tex.: 

Am. Soc. Civil Eng. Proc., vol. 60, pp. 1135-1178, 11., 

plans, 1934.

62. Horton, R. E., Evaporation from snow: Monthly Weather Rev., vol. 42, 

p. 99, 1914.

63. Horton, R. E., Rainfall and run-off (discussion): Am. Soc. Civil Eng. 

Trans., vol. 77, p. 369, 1914.

64. Horton, R. E., Run-off from rainfall and other data: Am. Soc. Civil 

Eng. Trans., vol. 79, p. 1166, 1915.

65. Horton, R. E., Rational studies of rainfall data make possible better 

estimates of water yield: Eng. News-Record, vol. 79, pp. 

211-213, 1917.

66. Horton, R. E., Correlation of maximum rain characteristics for long and 

short time intervals: Monthly Weather Rev., vol. 49, pp. 200- 

202, 1921.

67. Horton, R. E., Determination of the mean precipitation on a drainage 

basin: New England Water Worka Assoc. Jour., vol. 38, 1924.

68. Horton, R. E., in collaboration with Grunsky, C. E., Hydrology of the 

Great Lakes: Sanitary Dist. Chicago, Eng. Board of Review, 

Rept., pt. 3, app. 2, 1927. General treatise on rainfall, 

evaporation, and run-off of Great Lakes basin.

69. Horton, R. E., Drainage-basin characteristics: Am. Geophys. Union 

Trans. 13th meeting, p. 350, Nat. Research Council, 1932.

70. Horton, R. E., Role of infiltration in the hydrologic cycle: Am. 

Geophys. Union Trans. 14th meeting, pp. 446-460, Nat. Research Council, 1933.

70a. Horton, R. E., Surface run-off phenomena, pt. 1, Analysis of the 

hydrograph: Horton Hydrol. Lab. Pub. 101, Feb. 1, 1935.

71. Houk, I. E., Rainfall, absorption, and run-off on small rural drainage areas: Eng. News-Record, vol. 82, pp. 875-876, 1919.
REFERENCES 287

72. Houk, I. E., Rainfall and run-off In the Miami Valley: Miami Conservancy Dist. Tech. Repts., pt. 8, 1921.

73. Houk, I. E., Relations between rainfall and run-off: Public Works, 

vol. 50, pp. 472-473, 1921.

74. How rainfall is absorbed: Sol. Am. Suppl., vol. 64, p. 265, 1907. 

Howson, L. R. See Thon, C. L.

75. Hoyt, J. C., Comparison between rainfall and run-off in the northeastern United States, with discussion: Am. Soc. Civil Eng. 

Trans., vol. 59, pp. 431-520, 1907.

76. Hoyt, J. C., Length of record necessary to determine run-off: Eng. 

News, vol. 59, pp. 459-60, 1908.

77. Hoyt, W. G., The effects of ice on stream flow: U. S. Geol. Survey 

Water-Supply Paper 337, 1913.

78. Hoyt, W. G., Run-off from rainfall and other data (discussion): Am. 

Soc. Civil Eng. Trans., vol. 78, p. 1173, 1915.

79. Hoyt, W. G., Erosion - watershed protection: Civil Eng., vol. 4, pp. 

81-84, 1934.

80. Hoyt, W. G., and Troxell, H. C., Forest cover and the water yield: 

Science, new ser., vol. 78, suppl., p. 6, 1933.

81. Hoyt, W. G., and Troxell, H. C., Forests and stream flow: Am. Soc. 

Civil Eng. Trans., vol. 99, p. 1, 1934.

82. Iwasaki, Tomihisi, A stream-flow study of the Tokyo water supply: 

Am. Water Works Assoc. Jour., vol. 26, pp. 163-175,1934.

83. Jarvis, C. S., Rainfall characteristics and their relation to soils 

and run-off: Am. Soc. Civil Eng. Trans., vol. 95, pp. 379- 

449, 1931.

84. Johnston, T. T., and Cooley, L. E., Data pertaining to rainfall and 

stream flow: Western Soc. Eng. Jour., vol. 1, pp. 297-404, 

1896. Daily rainfall and run-off on the Desplaines River at 

Riverside, 111., 1886-1896.

85. Jones, E. H., Precipitation and run-off at the Continental Divide: 

Eng. News-Record, vol. 94, pp. 190-195, 1925.

86. Justin, J. D., Derivation of run-off from rainfall and other data: Am. 

Soc. Civil Eng. Trans., vol. 77, p. 346, 1914. Expresses 

annual run-off by an equation consisting of a coefficient 

(which varies with slope and mean annual temperature) multiplied by the square of the annual rainfall.

87. Kincer, J. B., Is our climate changing? A study of long-time temperature trends: Monthly Weather Rev., vol. 61, no. 9, pp. 251- 

260, 1933.

88. Kincer, J. B., Study of weather records facts to reveal long range

cycles: Eng. News-Record, vol. 113, no. 2, pp. 46-47, 1934,

89. King, F. H., Principles and conditions of the movements of ground water: 

U. S. Geol. Survey 19th Ann. Rept., pt. 2, pp. 59-294, 1899. 

Discusses rates of percolation.

90. King, P. H., The soil, New York Macmillan Co., 1908. 

King, F. V. See Simons, P. T.

91. Kuichling, Emil, Forests, reservoirs, and stream flow: Am. Soo. Civil 

Eng. Trans., vol. 73, p. 368, 1911.
288 RAINFALL AND RUN-OFF IN THE UNITED STATES

92. Lapworth, H., Relation of run-off to rainfall: Engineering, vol. 112,

p. 169, 1921. 

92a. La Rue, E. C., Water power and control of Colorado River below Green

River, Utah: U. S. Geol. Survey Water-Supply Paper 556, 1925.

93. Lee, G. H., Other elements than forestation which affect stream flow: 

Eng. News, vol. 64, pp. 155-156, 191O.

94. Lee, C. H., A study of seepage losses from streams in the Owens Valley, 

Calif.: Eng. Hews, vol. 63, pp. 449-451, 191O.

95. Lee, C. H., An intensive study of the water resources of a part of Owens 

Valley, Calif.: U. S. Geol. Survey Water-Supply Paper 294,

1912.

96. Lee, C. H., Determination of the safe yield of underground reservoirs 

of the closed-basin type: Am. Soc. Civil Eng. Trans., vol.

78, p. 148, 1915.

97. Lee, C. H., Absorption and transpiration: An. Geophs. Union Trans. 

13th meeting, p. 288, Nat. Research Council, 1932. Contains 

reference to 41 papers on absorption, transpiration, and related subjects.

98. Lee, C. H., Absorption and transpiration: Am. Geophya. Union Trans.

14th meeting, p. 361, Nat. Research Council, 1933. Summary of

investigations then in progress.

99. Lippincott, J. B., Relation of rainfall to run-off in California. Eng. 

News, vol. 47, p. 467, 19O2.

100. Livingston, B. E., Transpiration from plant growth In relation to 

weight: Hot. Gaz., vol. 40, p. 31.

101. Lowdermilk, W. C., Influence of forest litter on run-off, percolation, and erosion: Jour. Forestry, vol. 27, April 193O.

102. Lynch, H. B., Rainfall cycles historically deduced: Eng. Hews-Record, 

Sept. 17, 1931. Rainfall and stream run-off In southern California since 1769. By searching records of the Spanish or 

Mexican missions and various diaries Kr. Lynch has been able 

to go far back of the rainffl.il records that were begun in a 

scattering way about 1850 and have been kept In more orderly 

and extensive fashion since the establishment of the United 

States Signal Service and its successor, the Weathe'r Bureau. 

The 162 years of rainfall and run-off in southern California 

have been pictured and valuable conclusions drawn (as commented on editorially, Eng. News-Record, Sept. 3, 1931, 

p. 358). Mr. Lynch'p leading conclusion is: "There has been 

no material change in the mean climatic conditions of southern 

California in the past 162 years."

103. Main, T. C., Water conservation in the Prairie Provinces (advance 

proof), Eng. Inst. Canada, 1935.

104. McCarthy, E. P., Forest cover as a factor in flood control: Am. Soc, 

Civil Eng. Proc., vol. 53, pp. 2511-2518, 1927.

105. McCarthy, E. P., Forest cover as a factor in flood control: Am. Soc. 

Civil Eng. Trans., vol. 93, p. 716, 1929. Forests delay runoff and prevent erosion and silting.

McCrory, S. H. See Bartell, F. 0.

106. McEwen, G. P., Our rainfall - how it is formed and what becomes of it: 

Sci. Monthly, vol. 31, pp. 385-400, diagrams, 193O.

107. McGee, W J, Percolation and evaporation: U. S. Dept. Agr. Yearbook

for 1911, Subsoil water of central United States, pp. 479-49O.

Mclntoeh, R. P. See Bartell, M. J.
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108. McLaughlin, W. W., Significant studies in hydrology on the Pacific 

coast: Am. Geophys. UnioTi Trans. 12th meeting, pp. 202- 

205, Nat. Research Council, 1931.

109. Mead, D.,W., Notes on hydrology, Chicago, Shea, Smith & Co., 1904.

Basis for an introductory study of the fundamental phenomena 

of hydrology.

110. Mead, D. W., Plow of streams and factors that modify it, with special 

reference to Wisconsin conditions: Wisconsin Univ. Bull. 425, 

1911. Discussion of factors affecting stream flow, such as 

temperature, topography, geology, storage, and surface conditions. Hydrographs of rainfall and run-off for Wisconsin 

streams.

111. Mead, D. W., Hydrology, the fundamental basis of hydraulic engineering, 

McGraw-Hill Book Co., 1919. Discussion of the most important 

facts and principles of hydrology.

112. Meinzer, 0. E., Bibliography and index of the publications of the United 

States Geological Survey relating to ground water: U. S. Geol. 

Survey Water-Supply Paper 427, 1920.

113. Meinzer, 0. E., Outldne of ground-water hydrology, with definitions: 

U. S. Geol. Survey Water-Supply Paper 494, 1923.

114. Meinzer, 0. E., Plants as indicators of ground water: U. S. Geol. 

Survey Water-Supply Paper 577, 1927.

115. Meinzer, 0. E., and Stearns, N. D., A study of ground water in the 

Pomperaug Basin, Conn.: U. S. Geol. Survey Water-Supply 

Paper 597, pp. 73-146, 1929.

116. Meinzer, 0. E., The occurrence of ground water in the United States, 

with a discussion of principles: U. S. Geol. Survey WaterSupply Paper 489, 1923.

117. Meinzer, 0. E., Outline of methods for estimating ground-water

supplies: U. S. Geol. Survey Water-Supply Paper 638, pp. 99- 

144, 1932. Numerous other reports discussing ground water in 

specific areas are given in Water-Supply Papers 256, 260, 

275, 277, 293, 343, 345, 375, 425, 467, 518, 557, 616, 638.

118. Merriam, C. P., Studies made in connection with reports of the Hydraulic Power Committee of the Pennsylvania Electric association, Harrisburg, Pa.: 1926, Relation between rainfall and 

run-off in Susquehanna Valley; 1928, Cyclic analyses of river 

flow; 1929, Comparative analysis of run-off and rainfall of 

three areas; 1930, The distribution of run-off and rainfall 

in the Susquehanna Valley; 1934, Long-range forecasting.

119. Merriam, C. P., Inconsistencies in run-off records: Am. Geophys. 

Union Rept. Libson meeting, 1933.

120. Merriam, C. P., Forecasting water supply, a report of the National 

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290 RAINFALL AND RUN-OFF IN THE UNITED STATES

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Discussion by W. W. Horner, R. H. Gay, Thorndike Saville, and 

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292 RAINFALL AND RUN-OFF IN THE UNITED STATES

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162. Silliman, H. D., Run-off records for two sewerage areas show contrasts: Eng. News-Record, vol. 79, pp. 925-926, 11., map, 

1917.

163. Simons, P. T., and King, F. V., Report on drainage arid prevention 

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164. Sleight, R. B., Evaporation from the surfaces of water and river-bed 

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167. Smart, J. R., The unit-graph method of compiling run-off applied to 

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Snyder, F. F. See Collins, W. T.

169. Sonderegger, A. L., Water supply from rainfall on valley floors: Am. 

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170. Sonderegger, A. L., Modifying the physiographical balance by conservation measures: Am. Soc. Civil Eng. Proc., vol. 59, p. 1543, 

1933.

171. Stabler, Herman, Rainfall, run-off, and erosion, grazing lands In

Utah: Am. Soc. Civil Eng. Trans., vol. 99, pp. 80-86, 1934.

172. Stabler, Herman, Sedimentation and silting: Eng. News-Record, vol. 

60, p. 649, 1908.

173. Stebbing, E. P., Influence of forests on rainfall, erosion, and Inundation: Contemporary Rev., vol. 141, pp. 359-366, 1932.

174. Straub, L. G., Dynamics of streams, discussion and literature: Am. 

Geophys. Union Trans. 14th meeting, p. 379, Nat. Research 

Council, 1933.

175. Surface yield from a hydrographical basin: Engineering, vol. 117, 

pp. 193-195, 1924.

Taylor, C. A. See Blaney, H. F.

176. Taylor, C. A., and Nickle, H. G., Investigations in Mojave River area, 

and investigations in Coldwater Canyon: California Dept. 

Public Works Water Resources Bull. 44, pp. 74-121, 1933. Discusses consumptive use of water by vegetation.
REFERENCES 293

177. Taylor, G. H., Investigations of absorption of precipitation and its

penetration to the zone of saturation: Am. Geophys. Union

Trans. 12th meeting, pp. 206-211, Nat. Research Council, 1931.

178. Terada, T., and others, On the effect of topography on the precipitation in Japan: Imp. Univ. Japan, Coll. Sci., Jour., vol. 41, 

p. 24, diagrams, tables, 1919.

179. Thompson, D. G., Consnittee report on status of ground-water investigation: Am. Geophys. Union Trans. 14th meeting, p. 366, Nat. 

Research Council, 1933.

179a. Thompson, D. G., idem., 16th meeting, Nat. Research Council, 1935.

180. Thompson, D. H», Hydrologic conditions in the chalk at Compton, West 

Sussex: Inat. Water Eng. Trans., vol. 26, pp. 228-261, 1921. 

Discussion of "depletion by underflow and replenishment by 

percolation; to ascertain the effect of ground-water storage 

and to compare each with rainfall."

181. Thon, C. L., and Howson, L. R., The yield of a Kentucky watershed:

Western Soc. Eng. Jour., p. 643, September 1913. Study of a 

26-year record.

182. Thornwaite, C. W., The climates of North America according to a new 

classification: Oklahoma Univ., reprint from Geog. Rev., 

vol. 21, 1931.

183. Tourney, J. W., Relation of forests to stream flow: U. S. Dept. Agr. 

Yearbook for 1903, pp. 279-288, 1904.

184. Troxell, H. C., Ground-water supply and natural losses in the valley 

of Santa Ana River between Riverside Narrows and the Orange 

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Bull. 44, pp. 147-172, 1933.

Troxell, H. C. See also Hoyt, W. G.

185. United States Weather Bureau, Engineering aspects of the present 

drought: Eng. News-Record, vol. 105, pp. 259-261, 1930. 

Isopluvial map shows percentage of normal rainfall over the 

United States, March 1 to July 22, 1930, and another chart 

for July only. Table showing total rainfall in June and 

July 1930 and comparison with previous low years. Effect on 

ground-water conditions.

186. Veihmeyer, P. J., The disposal of moisture from aerated portions of 

soils: Am. Geophys. Union Trans. 13th meeting, p. 330, Nat. 

Research Council, 1932.

187. Vermeule, C. C., Run-off formula for annual and monthly values: New 

Jersey Geol. Survey, vol. 3, pp. 11-108, 1894; New Jersey 

Geol. Survey Ann. Rept. for 1899, pt. 1, pp. 13-318. Vermeule 

used a constant plus a percentage for the several months of 

the year and varied this relationship with mean annual temperatures.

187a. White, B. E., A determination cf run-off in streams as a function of 

the rainfall (unpublished manuscript, Dec. 31, 1928).

188. White, W. N., A method of estimating ground-water supplies based on 

discharge by plants and evaporation from soil: U. S. Geol. 

Survey Water-Supply Paper 659, pp. 1-105, 1932.

189. Whitman, E. B., Stored water how to get, preserve, and improve it: 

Eng. News-Record, vol. 105, pp. 416-419, 1930.

190. Wilkes, J., Sun spots and river run-off records: Water Works, vol. 

66, pp. 264-265, 1927.
294 RAINFALL AND RUN-OFF IN THE UNITED STATES

191. Young, A. A., Investigation in the Santa Ana River Valley and coastal 

plain: California Dept. Public Works Water Resources Bull* 

44, pp. 26-72, 1933. Discusses consumption use of water by 

vegetation.

192. Zoch, R. T., On the relation between rainfalj. and stream flow: Monthly 

Weather Rev., vol. 62, no. 9, pp. 315-322, September 1934. 

First of a series of articles dealing with the development 

of the mathematical theory of the relation between rainfall, 

run-off, and stream flow. The application of the theory to 

flood forecasting. Relation between river stages, rain, 

evaporation, and soil capacity.

193. Zon, Raphael, Forests and water in the light of scientific investigation, U. S. Dept. Agr., Forest Service, 1927.
INDEX

Page

Acknowledgments. ......................... 15

Accuracy of precipitation, run-off and temperature data. . . . . . 92,95,96

Administration ........... ............... 12-14

Advisory Committee, American Geophysical Union, personnel. .... 14

recommendations of .............. .133,216,255,269,278-882

report to Water Planning Committee .............. 275-882

work of. ........................... 878

Advisory coordination. ...................... 14,15

Aims of present study. ...................... 19,20

Alin, A. L., work of ....................... 13

American Geophysical TJnion. See Advisory Committee. .......

Authorization. .......................... 12

Babb, C. C., cited ........................ 16

Barrows, Harlan H., member of Water Planning Committee ...... 11

Bernard, Merrill, cited. ................ 18,123,131,211,815

storm transposition. ..................... 218-844

work of. .......................... 13,218-244

Bibliography ........................... 283-294

Black River Basin above Kelllsville, Wis., drought studies .... 261,262

ground-water run-off ..................... 247

relations between temperature, precipitation, and

soil moisture. ...................... 256

surface run-off. ....................... 122

Boston Society of Civil Engineers, cited ............. 123,131

Bowker, J. Paul, work of ..................... 13

Cady, R. C., work of ....................... 13,14

Chandler, E. F., cited ...................... 62

Channel storage. ......................... 119

Chattahoochee River Basin above West Point, Ga., basin description 91 

minimum-flow graph ...................... 273,274

precipitation, annual. .................... 93

precipitation stations in. .................. 91,92

rainfall and run-off relations ......... .93,94,100,107,108-110

ruo<-off, annual. ....................... 93

run-off records, description of. ............... 91

run-off, ground-water. .................... 246

run-off, surface ....................... 121

temperature records, description of. ............. 92

temperature, mean annual ................... 93

Colllns, W. T., cited. ...................... 18

Colorado River at Lees Perry, Arlz., figure showing run-off. ... 59

Condra, G. E., cited ....................... 248

Crocker, Herbert S., member of Water Planning Committee. ..... 11

Davenport, R. W., administration of. ............... 12,15

Delaware River Basin above Port Jervis, N. Y., basin description . 176,178 

distribution graph .................... .181,185,186

flood coefficients ...................... 226,234

flood hydrographs. ...................... 226,239

flood run-off. ........................ 237

map of basin ......................... 182,238

precipitation, unit storms .................. 178-181

storm superposition. ................... .235,237-239

surface run-off from unit storms ............... 181

unit hydrographs ....................... 183-185

Depletion curves ......................... 114-116

Distribution graphs, average for selected basins ......... 209,210

Delaware River at Port Jervis, N. Y. ........... .181,185,186

Embarrass River at Ste. Marie, 111.. ............. 155,156

French Broad River at Dandridge, Term. .......... .190,195,196

Muskingum River at Dresden, Ohio ............. .129,141,142

preparation of....................... 124-209

295
296 RAINFALL AND RUN-OFF IN THE UNITED STATES

Page

Red River at Denison, Tex. .................. 207,208

Skunk River at Augusts., Iowa ................. 163,164

Susquehanna River at Towanda, Pa.. .............. 176,17V

Wabaah River at Logansport, Ind. ............... 148,149

Drought studle-s. ......................... 25B-274

Edgerton, Glen E., member Water Planning Committee ........ 11

Embarrass River Basin above Ste. Marie, 111., basin description. . 148,150 

distribution graph ...................... 155,156

map of basin ......................... 152

precipitation, unit storms .................. 150,151

surface run-off from unit storms ............... 155

unit hydrographs ............ ........... 153,154

Engineers Corps, U. S. Army, cited ................ 211-214

Essex Company, records by. .................... 76

Evaporation, determination of. .................. 250

Skunk River Basin. .................... .. 251-254

FitzGerald, Desmond, cited .................... 16

Flood bibliography, reference to Water-Supply Paper 771. ..... 283

Flood coefficients and flood hydrographs ............. 218-229

Delaware River at Port Jervls, N. Y. . . . . ......... 226,234

determination of....................... 218-221

French Broad River at Dandridge, Tenn. ............ 227,234

Muskingum River at Dresden, Ohio ............... 222

Red River at Dennison, Tex.. ................. 228

selected basins. ....................... 229

snow influence ................. ....... 244

Skunk River at Augusta, Iowa ................. 224,235

Susquehanna River at Towanda, Pa................ 225

Wabash River at Logansport, Ind. ............. .223,234,235

Flood determination, Delaware River at Port Jervis, N. Y.. . . .235,237-239

French Broad River at Dandridge, Tenn. .......... .237,240,241

Skunk River at Augusta, Iowa ................. 241,243

Wabash River at Logansport, Ind. ............... 241,242

Flood Protection Data Committee, American Society of Civil

Engineers, personnel ................... 15

recommendations of...................... 216

Flynt, F. L. , cited. ....................... 132

Foreword, Water Planning Committee ................ 9-11

Fowler, Frederick H., member Flood Protection Data Committee ... 15

French Broad River Basin above Dandridge, Tenn., basin description 186,187

distribution graphs. ................... .190,195,196

flood coefficients ...................... 227,234

flood hydrographs. ...................... 227,240

flood run-off. ........................ 240,241

map of basin ......................... 191,240

precipitation, unit storms .................. 187-190

storm superposition. ......... .......... .237,240,241

surface run-off from unit storms ............... 190

unit hydrographs ....................... 192-194

Gannett, Henry, cited. ...................... 16

Gay, Robert W., cited. ...................... 132

Grant, J. A., cited. ....................... 211

Graves, Henry S., member Water Planning Committee. ........ 11

Ground-water levels and accretion. ................ 117,118

Ground-water levels, discussion of ................ 257,258

Platte River Valley. ..................... 269-273

Ground-water run-off comparison with rainfall. .......... 257-266

quantitative analysis. .................... 245-247

Grover, N. C., administration of................. 12,15

Hall, Samuel, cited. ....................... 114

Harrold, L. L., work of. ..................... 13

Hayford, John P., cited. ..................... 17,18,96

Horner, Wesley W., chairman, Advisory Committee. ........ .14,15,277

cited. ............................ 132

Horton, Robert E., member Advisory Committees. ......... .14,15,277

cited. ......................... 18,113,115,118

Houk, Ivan E., member Flood Protection Data Committee. ...... 15

cited. ........................... 17,112,248

Infiltration capacity and storage factors. ............ 118
INDEX 297

Page

Iwasaki, Tomiahisi, cited. .................... 116

Iowa River Basin above Wapello, Iowa, ground-water run-off .... 247

surface run-off. ....................... 121

James River Basin above Cartersville, Va., basin description . . . 80,83 

minimum-flow graph ...................... 273,274

precipitation, annual. .................... 84

precipitation stations in. .................. 83

rainfall and run-off relations ......... .84,85,100,105,108-110

run-off, annual. ....................... 84

run-off records, description of. ............... 83

run-off, ground-water. .................... 246

run-off, surface ....................... 120

temperature records, description of.............. 86

temperature, mean annual ................... 84

Johns, Dwight P., cited. ..................... 211

Justin, J. D., cited ....................... 17

Kickapoo River Basin above Gays Mills, Wis., ground-water run-off. 247 

surface run-off. ................ ....... 121

Kincer, J. B., cited ....................... 15,49,57

Kings River at Piedra, Calif., figure showing, run-off. ...... 59

Kitchin, C. E., work of. ..................... 13

Kutz, C. W., member Flood Protection Data Committee. ....... 15

La Crosse River Basin above West Salem, Wis., ground-water run-off 247 

surface run-off. ....................... 121

Lake Superior altitude, figure showing changes .......... 59

La Rue, E. C., cited ....................... 58

Lynch, H. B., cited. ....................... 42

Main, T. C., cited ........................ 57

Maquoketa River Basin above Maquoketa, Iowa, ground-water run-off. 24^ 

surface run-off. ....................... 121

Markham, Edward M., member Water Planning Committee........ 11

Matthes, Gerard H., chairman, Flood Protection Data Committee. . . 15,278 

Mead, D. W., cited ........................ 17,48

Meinzer, 0. E., cited. .................. 15,112,113,119,248

Merriaack River Basin above Lawrence, Mass., basin description . . 78 

minimum-flow graph ...................... 273,274

precipitation, annual. .................... 81

precipitation stations in. .................. 79,80

rainfall and run-off relations ......... .81,82,100,104,108-110

run-off, annual. ....................... 81

run-off records, description of. ............... 78,79

run-off, ground-water. .. ........ ....... ... 246

run-off, surface ........................ 120

temperature records, description of. ............. 80

temperature, mean annual ................... 81

Meteorologic factors, ground-water separation. .......... 119

Meyer, A. P., member Advisory Committee. ............ .14,15,277

cited. ............. ............ 17,119,248-251

Miami Conservancy District, cited. ............... 17,221,230

Miami River at Dayton, Ohio, ground-water run-off. ........ 246

surface run-off. ....................... 121

Minnesota River Basin above Mankato, Minn., ground-water run-off . 247 

surface run-off. ....................... 121

Mississippi River Basin above Keokuk, Iowa, basin description. . . 65 

drought studies. ..................... .263,267-269

minimum-flow graph ...................... 273,274

precipitation, annual. .................... 72

precipitation stations in. .................. 66-71

rainfall and run-off relations ......... .72,73,100,102,108-110

run-off, annual. ....................... 72

run-off records, description of. ............... 66

run-off, ground-water. .................... 246

run-off, surface ....................... 120

temperature records, description of.............. 71,74

temperature, mean annual ................... 72

Mississippi River Power Co., records by. ............. 66

Mississippi Valley Committee, cited. ......... 10,11,12,14,15,16,19

Muskingum River Basin above Dresden, Ohio, basin description ... 134 

distribution graphs. ................... .129,141,142

flood coefficients ...................... 322
298 RAINFALL AND RUN-OFF IS THE TJ1TEPED STATES

	Page

flood hydrographs. ...................... 222

map of basin ......................... 127

precipitation, unit storms .............. .128,134-136,140

surface run-off from unit storms ............... 140

unit hydrographs ..................... .127,137-139

Muskingum Watershed Conservancy District, cited. ......... 214

Neosho River Basin above lola, Kans., basin description. ..... 74

mini nn mi-flow graph ...................... 273,274

precipitation, annual. .................... 76

precipitation stations in. .................. 75

rainfall and run-off relations ......... .76,77,100,103,108-110

run-off, annual. ....................... 76

run-off records, description of. ............... 74,75

run-off, ground-water. .................... 246

run-off, surface ....................... 120

temperature records, description of. ............. 78

temperature, mean annual ................... 76

Newell, F. H., cited ....................... 16

Parsons, W. J., cited. ...................... 211

Paul, Charlea H., member Water Planning Committee. ........ 11

Paul, D. M., work of ....................... 14

Pecatonica River Basin above Freeport, 111., ground-water run-off. 247

surface run-off. ....................... 122

Persona, Barlow S., acting chairman, Water Planning Committee. . . 11

Personnel, Advisory Committee American Geophysical Union ..... 14

Flood Protection Data Committee, American Society

Civil Engineers. ..................... 15

United States Geological Survey. ............... 12-14

Water Planning Committee, National Resources Board ...... 11

Pickels, G. W., member of Advisory Committee ........... 14,277

Platte River Valley, Nebr., ground-water levels. ......... 269-273

Pomperaug River at Bennetts Bridge, Conn., ground-water run-off. . 246

surface run-off. ....................... 121

Precipitation, accuracy of records ................ 92,95,96

at long-time Weather Bureau stations ............. 23-25

average monthly. ....................... 48,49

by basins. .......................... 60-98

by geographic provinces. ................... 22,33-43

changes, continental United States .............. 20-22

changes by basins. ...................... 96-98

Chattahoochee River Basin above West Point, Ga.. ....... 91-93

drought periods. ....................... 255-268

fall .... ......................... 45,47,48

James River Basin above Cartersville, Va.. .......... 83,84

maximum year ......................... 22,26,27

maximum 10 years ....................... 27-29

Merrimack River Basin above Lawrence, Mass.. ......... 79-81

minimum year ...... ................... 29-31

minimum 10 years ....................... 31-33

Mississippi River Basin above Keokuk, Iowa .......... 66-72

Neosho River Basin above lola, Kans. ............. 75,76

relation to run-off. ..................... 100-110

Red River Basin above Grand Forks, H. Dak. .......... 62,63

seasonal changes ....................... 43-48

storm rainfall studies .................... 221,230

summer ............................ 45,46

Tennessee River Basin above Chattanooga, Tenn. ........ 87-89

unit storms. ......................... 128-204

winter ....... ..................... 43-45

Previous studies ......................... 16-19

Rafter, George W., cited ...................... 16,17

Rainfall. See Precipitation

Recession curves ......................... 116,117

Red River Basin above Denison, Tex., basin description ...... 196

distribution graph ...................... 207,208

flood coefficients ...................... 228

flood hydrographs. ...................... 228

map of basin ......................... 197

precipitation, unit storms .................. 198-204

storm superposition. ..................... 218-243
INDEX 299

Page

surface run-off fron unit storms ............... 207

unit hydrographs ....................... 205,206

Red River Basin above Grand Porks, N. Dak., basin description. . . 61 

drought studies. ....................... 258-261

minimum-flow graph ...................... 273,274

precipitation, annual. .................... 63

precipitation stations in................... 62

rainfall and run-off relations ......... .63,64,100,101,108-110

run-off, annual. ....................... 63

run-off records, description of. ............... 61

run-off, ground-water. .................... 246

run-off, surface ....................... 120

temperature records, description ............... 65

temperature, mean annual ................... 63

Relations between rainfall and run-off, all basins combined. . . . 108-110

Chattahoochee River Basin. ........... .92-93,100,107,108-110

James River Basin. ............... .84,85,100,105,108-110

Merrimack River Basin. ............. .81,82,100,104,108-110

Mississippi River Basin. ............ .72,73,100,102,108-110

Neosho River Basin ............... .76,77,100,103,108-110

Red River Basin. ................ .63,64,100,101,108-110

Tennessee River Basin. ............. .89,90,100,106,108-110

Rock River Basin above Afton, V/is., drought studies. ....... 263,264

ground-water run-off ..................... 247

relations between temperature, precipitation, and changes

in soil moisture ............... ...... 256

surface run-off. ....................... 121

Root River Basin above Houston, Minn., ground-water run-off. . . . 247

surface run-off. ....................... 121

Run-off, accuracy of records ................... 92,95,96

at long-time gaging stations ................. 58,59

by basins. .......................... 60-99

changes by basins. .................... .58,59,97,99

Chattahoochee River Basin above West Point, Ga......... 93

drought periods. ....................... 255-274

flood coefficient, development of. .............. 218-221

floods from superposed storms. ................ 235-244

ground-water ......................... 245-247

James River Basin above Cartersville, Va.. .......... 84

Merrimack River Basin above Lawrence, Mass.. ......... 81

Mississippi River Basin above Keokuk, Iowa .......... 72

minimum-flow graphs. ..................... 273,274

Neosho River Basin above lola, Kans. ............. 76

Red River Basin above Grand Porks, N. Dak. .......... 63

relations to rainfall. .................... 100-110

surface. ........................... 120-217

Tennessee River Basin above Chattanooga, Term. ........ 89

unit-hydrograph analysis ................... 123,124

San Gabriel River near Azuza, Calif., figure showing run-off ... 59

Saville, Thorndike, administration of. .............. 14,15

Shenaan, Charles W., member Flood Protection Data Committee. ... 15

Sherman, L. K., member Advisory Committee. ........... .14,15,277

cited. ............... 18,113,123,124,131,132,211,215,216

Simons, P. T., cited ....................... 61,62

Skunk River Basin above Augusta, Iowa, basin description ..... 155,157

distribution graphs. ..................... 163,1*64

drought studies. ..................... .263,265,266

flood coefficients ...................... 224,235

flood hydrographs. ...................... 224,243

flood run-off, ........................ . 241

ground-water run-off ..................... 247

map of basin ......................... 160,243

precipitation, unit storms .................. 157-159

relation between precipitation, temperature and soilmoisture changes ..................... 256

soil-moisture changes by months. ............... 252-255

storm superposition. ..................... 241,243

surface run-off. ... .................... 122

surface run-off from unit storms ............... 159

unit hydrographs ....................... 161,162
500 RAINFALL AND RUN-OFF IN THE UNITED STATES

	Page

Smart, J. R., cited. ....................... 131

Snake River near Moran, Wyo., figure showing run-off ....... 59

Snow, influence on flood coefficients. .............. 244

Snyder, Franklin F., cited .................... 18

work of. ........................... 15

Soil moisture, definition of ................... 248

determination of....................... 248-255

relations to temperature and precipitation .......... 256

Spokane River at Spokane, Wash., figure showing run-off. ..... 59

St. Croix River Basin above Rush City, Minn., ground-water run-off 247

siirface run-off. ....................... 121

Storm areas, map showing ..................... 232,236

Storm index. ........................... 23O-232

Storm superposition. Delaware River Basin above Port

Jervis, N. Y...................... .255,237-259

French Broad River Basin above Dandridge, Term.. ..... .237,240,241

Wabash River Basin over Logansport, Ind. ........... 241,242

Skunk River Basin above Augusta, Iowa. ............ 241,245

Storm transposition. ....................... 250-244

Stream flow. See also Run-off .................. Ill

Stream-flow separation ...................... 111-119

channel storage. ....................... 119

depletion curves . ..................... 114-116

ground-water levels and accretions .............. 117,118

infiltration capacity and storage factors. .......... 118

meteorologic factors ..................... 119

recession curves ....................... 116,117

unit hydrographs ....................... *118.

Surface run-off, determination of flood coefficients ....... 218,221

quantitative analysis by basins. ............... 120-122

unit-hydrograph analysis of. ................. 125-209

Susquehanna River Basin above Towanda, Pa., basin description. . . 163,165

development of a flood coefficient .............. 219-221

distribution graphs. ..................... 176,177

flood coefficients and flood hydrographs ........... 385

map of basin ......................... 172

precipitation, unit storms .................. 165-171

surface run-off from unit storms ............... 176

unit hydrographs .................. ~ .. 173-175

Temperature, accuracy of records .. ............... 92,95,96

changes by basins. ...................... 60-98

changes over the United States ................ 49-58

Chattahoochee River Basin above West Point, Ga.. ....... 93

James River Basin above Cartersville, Va.. .......... 84

Merrimack River Basin above Lawrence, Mass.. ......... 81

Mississippi River Basin above Keokuk, Iowa .......... 72

Neosho River Basin above lola, Kans. ............. 76

Red River Basin above Grand Forks, N. Dak. .......... 63

relation to precipitation and soil moisture changes. ..... 248-256

Tennessee River Basin above Chattanooga, Tenn. ........ 89

Tennessee River Basin above Chattanooga, Tenn., basin description. 86

minimum-flow graph ...................... 275,274

precipitation, annual. .................... 89

precipitation stations in. .................. 87,88

rainfall and run-off relations ......... .89,90,100,106,108-110

run-off, annual. ........................ 89

run-off records, description of. ............... 86,87

run-off, ground-water. .................... 246

run-off, surface ....................... 121

temperature records, description of. ............. 88

temperature, mean annual ................... 89

Tennessee Valley Authority, cited. ................ 214

Thompson, D. G., cited ...................... 257,258

Thompson, D. Halton, cited .................... 115

Towl, Roy, member Advisory Committee ............... 14,277

Transpiration, determination of.................. 251

Skunk River Basin. ...................... 251-254

Unit hydrographs, analysis of surface run-off. .......... 125-209

application of ........................ 211-244

Delaware River at Port Jervis. N. Y. ............. 182-185
INDEX 501

	Page

Embarrass River at Ste. Marie, 111.. ............. 155,154

French Broad River at Dandridge, Tenn. ............ 192-194

Muskingum River at Dresden, Ohio ............. .127,137-159

preparation of ........................ 124-209

Red River near Denison, Tex. ................. 205,206

Skunk River at Augusta, Iowa ................. 161,162

Susquehanna River at Towanda, Pa................ 173-175

stream-flow separation .................... 118

Wabash River at Logansport, Ind. ............... 146,147

Vermeule, C. C., cited ...................... 16

Wabash River Basin above Logansport, Ind., basin description . . . 141

distribution graphs. ..................... 148,149

flood coefficients .................... .225,234,235

flood hydrographs. ...................... 223,242

map of basin ......................... 145,242

flood run-off. ........................ 241,242

precipitation, unit storms ........... ....... .143,144

storm superposition. ..................... 241,242

surface run-off from unit storms ............... 148

unit hydrographs ....................... 146,147

Walser, Daniel C., member Flood Protection Data Committee. .... 15

Water Planning Committee, National Resources Board, cited.11,14,15,16,19,20

personnel of ......................... 11

Wenzel, Leland K., cited ................ ..... 269-273

White, Byron E., cited ...................... 117

Willamette River at Albany, Oreg., figure showing run-off. .... 59

Woerman, J. W., member Advisory Committee. ............ 14,277

Woodward, Sherman W., administration of. ............. 14,15

member Water Planning Committee. ............... 11

Yellow River above Sprague, Wis., ground-water run-orf ...... 247

surface run-off. ..... .................. 122

Zumbro River above Zumbro Falls, Minn., ground-water run-off . . . 247

surface run-off. ............. ........ 121