UNITED STATES DEPARTMENT OF THE INTERIOR

J. A. KRUG, Secretary

GEOLOGICAL SURVEY 

W. E, Wrather, Director

Water-Supply Paper 915

MAJOR WINTER AND NONWINTER FLOODS 

IN SELECTED BASINS

IN NEW YORK AND PENNSYLVANIA

BY

WALTER B. LANGBEIN AND OTHERS

Prepared in cooperation with the 

FEDERAL EMERGENCY ADMINISTRATION 

OF PUBLIC

UNITED STATES

GOVERNMENT PRINTING OFFICE 

WASHINGTON : 1947

For sale by the 

Superintendent of Documents, Government Printing Office, Washington 25, D. C.
NOTE. This report was prepared in 1939 and 1940. Conditions 

arising out of the war have delayed its publication.

ii
CONTENTS

Page

Abstract ............................... . 

Introduction ..........,......................... 

Utility of flood-control data ............................ ^............... 1

Scope of the present report ........................ . . 2

Methods of analysis ................................ . « 4

Rainfall .............................................................. 4

Snow cover ................................ .. .. . 5

.Direct runoff .................................... . "

Ground-water runoff and recharge .......................... ..- 7

Lag interval ........................................... 9

Infiltration index ..................... .................................. H

Winter floods ............................................................. 13

Floods of March 1936 .................................................. 14

Sacandaga River near Hope, N. Y. ................................. 14

East Branch of Delaware River at Fishs Eddy, N. Y. ............... 23

Chemung River at Chemung, N. Y. ................................ 39

Susquehanna River at Wilkes-Barre, Pa. ........................... 48

Susquehanna River at Harrisburg, Pa. ............................. 55

West Branch of Susquehanna River at Williamsport, Pa. ............ 63

Flood of March 1920, Genesee River at St. Helena, N. Y................. 70

Snow-runoff studies ................................................... 81

Nonwinter floods ......................................................... 85

Flood of July 1921, Sacandaga River near Hope, N. Y.................... 87

Storm of July 1935 .................................................... 91

Floods of July 1935 ................................................... 94

Chemung River at Chemung, N. Y.................................. 94

Susquehanna River at Wilkes-Barre, Pa............................. 97

Storm of August 21-25, 1933 .......................................... 100

Floods of August 1933 ................................................ 101

East Branch of Delaware River at Fishs Eddy, N. Y................. 101

Susquehanna River at Marietta, Pa................................. 107

Flood of May 1894, Susquehanna River at Harrisburg, Pa............... 112

Flood of April-May 1909, West Branch of Susquehanna River at Williamsport, Pa. ............................................................ us

Flood of May 1916, Genesee River at St. Helena, N. Y................... 125

Rates of flood discharge .:................................................. 134

Index .................................................................... 139

ILLUSTRATIONS

Page

PLATE 1. Map of Susquehanna River and East Branch of Delaware River 

basins showing lines of equal precipitation, August 20-25, 1933

facing 114 

2. Map of Susquehanna River basin showing lines of equal precipitation,

May 17-23, 1894 .........................................facing 114

III
IV ILLUSTRATIONS

Page 

FIGURE 1. Average ground-water depletion curve, Sacandaga River near Hope,

N. Y. ......................................................... 8

2. Relation between the rate of ground-water discharge and volume 

of available ground-water storage, Sacandaga River near Hope, 

N. Y. ......................................................... 9

3. Graph showing relation between rainfall and rainfall excess, in 

terms of infiltration index, at recording rain gage near East Branch 

of Delaware River basin, storm of. August 20-25, 1933. .......... 12

4. Map of Sacandaga River basin above Hope, N. Y., showing depth, 

in inches, of water content of snow on the ground, March 8, 

1936 .......................................................... 16

5. Map of Sacandaga River basin showing depth, in inches, of watef

content of snow on the ground, March 15-16, 1936 ............... 17

6. Map of Sacandaga River basin showing depth, in inches, of water

content of snow on the ground, March 22, 1936. ................. 18

7. Map of Sacandaga River basin above Hope, N. Y., showing lines of

equal precipitation, March 8-22, 1936. ........................... 19

8. Hydrograph of Sacandaga River near Hope, N. Y., showing discharge, March 1936 ............................................ 20

9. Map of basin of East Branch of Delaware River above Fishs 

Eddy, N. Y., showing lines of equal precipitation, March 9-22, 

1936 .......................................................... 27

10. Hydrograph of East Branch of Delaware River at Fishs Eddy,

N. Y., showing discharge, March 1936.......................... 28

11. Map of Susquehanna and upper Delaware River basins, showing

lines of equal precipitation, March 9-22, 1936.................... 40

12. Hydrograph of Chemung River at Chemung, N. Y., showing discharge, March 1936 ............................................ 42

13. Hydrograph of Susquehanna River at Wilkes-Barre, Pa., showing

discharge, March 1936 ........................................ 50

14. Hydrograph of Susquehanna River at Harrisburg, Pa., showing

discharge, March 1936 ........................................ 57

15. Hydrograph of West Branch of Susquehanna River at Williamsport, Pa., showing discharge, March 1936. ...................... 66

16. Map of Genesee River basin above St. Helena, N. Y., showing lines

of equal precipitation, March 11-14, 1920 ........................ 71

17. Hydrograph of Genesee River at St. Helena, N. Y., showing discharge, March 1920 ........................................... 73

18. Relation between cumulative snow runoff and degree-days above 

freezing, Driftwood Branch of Sinnemahoning Creek at Sterling 

Run, Pa., February-March 1936. ............................... 82

19. Relation between volume of supply and runoff...................... 86

20. Map of Sacandaga River basin above Hope, N. Y., showing lines of

equal precipitation, July 8-12, 1921 ............................. 87

21. Hydrograph of Sacandaga River near Hope, N. Y., showing discharge, July 1921, and precipitation, July 8-12, 1921.............. 88

22. Map of eastern United States showing position of storm, 8 a.m.

(E.S.T.), July 8, 1935 ......................................... 91

23. Map of upper Susquehanna River basin showing lines of equal precipitation, noon July 6 to noon July 10, 1935......................... 92

24. Curves showing- average depth of rainfall over indicated areas during periods of maximum intensity, storm of July 6-10, 1935. ...... 94
ILLUSTRATIONS V

Page

FIGURE 25. Hydrograph of Chemung River at Chemung, N. Y., showing discharge, July, and precipitation, July 6-10, 1935................... 95

26. Hydrograph of Susquehanna River at Wilkes-Barre, Pa., showing

discharge, July, and precipitation, July 6-10, 1935. ............... 98

27. Map of eastern United States showing position of storm, 8 a.m.

(E.S.T.), August 24, 1933 ..................................... 100

28. Hydrograph of East Branch of Delaware River at Fishs Eddy, 

N. Y., showing discharge, August-September, and precipitation, 

August 21-25, 1933 ............................................ 104

29. Hydrograph of Susquehanna River at Marietta, Pa., showing discharge, August-September, and precipitation, August 21-29, 1933. . 110

30. Map of United States showing position of storm, 8 a.m. (E.S.T.),

May 20, 1894 .................................................. 113

31. Hydrograph of Susquehanna River at Harrisburg, Pa., showing

discharge, May-June, and precipitation, May 16-26, 1894. ........ 114

32. Map of United States showing position of storm, 8 a?m. (E.S.T.),

April 30, 1909 ................................................. 119

33. Map of basin of West Branch of Susquehanna River above Williamsport, Pa., showing lines of equal precipitation, April 27- 

May 1, 1909 ................................................... 120

34. Hydrograph of West Branch of Susquehanna River at Williamsport, Pa., showing discharge, April-May, and precipitation, April 

26-May 10, 1909 .............................................. 122

35. Map of United States showing position of storm, 8 a.m. (E.S.T.),

May 16, 1916 ................................................. 126

36. Map of Genesee River basin above St. Helena, N. Y., showing lines

of equal precipitation, May 14-20, 1916 ......................... 127

37. Hydrograph of Genesee River at St. Helena, N. Y., showing discharge, May, and precipitation, May 12-21, 1916. ................ 128

38. Concentration of direct runoff in relation to concentration of net

supply ........................................................ 135

TABLES

Page 

TABLE 1. Summary of rainfall and runoff data for winter floods.............. 14

2. Observations of snow cover, Sacandaga River near Hope, N. Y.,

March 1936 ................................................... 15

3. Precipitation, in inches, for 12-hour periods, at stations in and near

Sacandaga River Basin near Hope, N. Y., March 8-22, 1936...... 21

4. Daily mean areal precipitation and temperatures, Sacandaga River

near Hope, N. Y., March 7-22, 1936............................ 22

5. Hydrologic data observed at Wanakena, N. Y., March 1936........ 22

6. Daily mean temperature, Sacandaga River near Hope, N. Y., February 8 to March 8, 1936...................................... 23

7. Gage height and discharge of the Sacandaga River near Hope, N. Y.,

during flood of March 1936.................................... 24

8. Computation of volume of direct runoff associated with precipitation period March 8-14, 1936, Sacandaga River near Hope, N. Y... 25

9. Computation of time of center of mass of net supply and lag intervals,

Sacandaga River near Hope, N. Y., March 8-14, 1936............ 25
VI TABLES

Page

TABLE 10. Computation of volume of direct runoff associated with precipitation period March 15-22, 1936, Sacandaga River near Hope, 

N. Y. ...............................................'. . ..t -> 26

11. Computation of time of center of mass of net supply, and lag intervals, Sacandaga River near Hope, N. Y., March 15-22, 1936.... 26

12. TPrecipitation, in inches, for 6-hour periods, at stations in and near 

East Branch of Delaware River at Fishs Eddy, N. Y., March 

1936 .......................................................... 29

13. Daily mean temperature, East Branch of Delaware River at Fishs

Eddy, N. Y., February 8 to March 8, 1936...................... 30

14. Daily mean areal precipitation and temperatures, East Branch of

Delaware River at Fishs Eddy, N. Y., March 8-22, 1936.......... 30

15. Gage height and discharge of the East Branch of Delaware River at

Fishs Eddy, N. Y., during flood of March 1936.................. 31

16. Computation of volume of direct runoff associated with precipitation period March 8-15, 1936, East Branch of Delaware River 

at Fishs Eddy, N. Y. .......................................... 32

17. Computation of time of center of mass of net supply, and lag 

intervals, East Branch of Delaware River at Fishs Eddy, N. Y,, 

March 8-15, 1936 .............................................. 32

18. Computation of volume of direct runoff associated with precipitation period March 15-21, 1936, East Branch of Delaware River 

at Fishs Eddy, N. Y. .......................................... 33

19. Computation of time of center of mass of net supply, and lag intervals, East Branch of Delaware River at Fishs Eddy, N. Y., 

March 15-22, 1936 ............................................. 34

20. Hourly precipitation, in inches, at recording gages in and near

Susquehanna River basin, March 9-22, 1936..................... 35

21. Reported snowfall, in inches, at selected cooperative Weather Bureau stations, Susquehanna River basin, March 9-22, 1936........ 39

22. Daily precipitation, in inches, at rain gages in and near Chemung

River basin above Chemung, N. Y., March 8-21, 1936............ 44

23. Daily mean temperature, Chemung River at Chemung, N. Y., February 8 to March 8, 1936....................................... 45

24. Daily mean areal precipitation and temperatures, Chemung River

basin, March 8-22, 1936 ........................................ 45

25. Gage height and discharge of the Chemung River at Chemung,

N. Y., during flood of March 1936............................. 45

26. Computation of volume of direct runoff associated with precipitation period March 9-14, 1936, Chemung River at Chemung, N. Y. 47

27. Computation of time of center of mass of net supply, and lag intervals, Chemung River at Chemung, N. Y., March 8-14, 1936.... 47

28. Computation of volume of direct runoff associated with precipitation period March 15-22, 1936, Chemung River at Chemung, 

N. Y. .......................................................... 47

29. Computation of time of center of mass of net supply, and lag intervals, Chemung River at Chemung, N. Y., March 15-21, 1936.... 48

30. Daily precipitation, in inches, at rain gages in and near Susquehanna River basin at Wilkes-Barre, Pa., March 9-21, 1936........ 51

31. Daily mean temperature during 30-day period preceding storm 

period March 9-21, 1936, Susquehanna River at Wilkes-Barre, 

Pa. ........................................................... 52
TABI.ES "vn

Page 

TABLE 32. Daily mean areal precipitation and temperatures, Susquehanna River

at Wilkes-Barre, Pa., March 9-22, 1936.......................... 52

33. Gage height and discharge of the Susquehanna River at WilkesBarre, Pa., during flood of March 1936......................... 53

34. Computation of volume of direct runoff associated with precipitation period March 9-15, 1936, Susquehanna River at WilkesBarre, Pa. .................................................... 54

35. Computation of time of center of mass of net supply, and lag intervals, Susquehanna River at Wilkes-Barre, Pa., March 9-15, 

1936 .......................................................... 54

36 Computation of volume of direct runoff associated with precipitation period March 16-21, 1936, Susquehanna River at WilkesBarre, Pa. .................................................... 55

37. Computation of time of center of mass of net supply, and lag intervals, Susquehanna River at Wilkes-Barre, Pa., March 16-21, 

1936 .......................................................... 55

38. Daily precipitation, in inches, at stations in and near lower Susquehanna River basin, March 9-21, 1936............................ 58

39. Daily mean areal precipitation and temperatures, Susquehanna River

at Harrisburg, Pa., March 9-21, 1936........................... 59

40. Gage height and discharge of the Susquehanna River at Harrisburg,

Pa., during flood of March 1936................................ 60

41. Computation of volume of direct runoff associated with precipitation period March 9-15, 1936, Susquehanna River at Harrisburg, 

Pa. ........................................................... 61

42. Computation of time of center of mass of net supply, and lag 

intervals, Susquehanna River at Harrisburg, Pa., March 9-15, 

1936 .......................................................... 61

43. Computation of volume of direct runoff associated with precipitation period March 16-21, 1936, Susquehanna River at Harrisburg, 

Pa. ........................................................... 62

44. Computation of time of center of mass of net supply, and lag 

intervals, Susquehanna River at Harrisburg, Pa., March 16-21, 

1936 .......................................................... 62

45. Daily precipitation, in inches, at stations in and near West Branch 

of Susquehanna River basin at Williamsport, Pa., March 9-21, 

1936 .......................................................... 65

46. Daily mean areal precipitation and temperatures, West Branch of

Susquehanna River at Williamsport, Pa., March 9-21, 1936...... 67

47. Daily mean temperature, West Branch of Susquehanna River at

Williamsport, Pa., February 8 to March 8, 1936.................. 67

48. Gage height and discharge of the West Branch of the Susquehanna

River at Williamsport, Pa., during flood of March 1936.......... 68

49. Computation of volume of direct runoff associated with precipitation period March 9-15, 1936, West Branch of Susquehanna River 

at Williamsport, Pa. ........................................... 69

50. Computation of time of center of mass of net supply, and lag 

intervals, West Branch of Susquehanna River at Williamsport, 

Pa., March 9-15, 1936 ......................................... 69

51. Computation of volume of direct runoff associated with precipitation period March 16-21, 1936, West Branch of Susquehanna 

River at Williamsport, Pa. ................................... 69
TABLES

Page

TABLE 52. Computation of time of center of mass of net supply, and lag 

intervals, West Branch of Susquehanna River at Williamsport, 

Pa., March 16-21, 1936 ........................................ 70

53. Daily precipitation, in inches, at stations in and near Genesee River

basin above St. Helena, N. Y., March 11-14, 1920................ 74

54. Daily precipitation, in inches, at stations in and near Genesee River

basin above St. Helena, N. Y., March 10-14, 1920................ 74

55. Hourly precipitation, in inches, at recording gages in and near

Genesee River basin, March 8-20, 1920.......................... 75

56. Daily mean areal precipitation and temperatures, Genesee River at

St. Helena, N. Y, March 9-15, 1920............................ 77

57. Daily mean temperature, Genesee River at St. Helena, N. Y.,

February 9 to March 9, 1920.................................... 77

58. Snow depth and snowfall at Weather Bureau stations in and near

Genesee River above St. Helena, N. Y., March 7-17, 1920........ 78

59. Gage height and discharge of Genesee River at St. Helena, N. Y.,

during flood of March 1920.................................... 79

60. Computation of volume of direct runoff associated with precipitation period March 10-14, 1920, Genesee River at St. Helena, 

N. Y. ......................................................... 80

61. Computation of time of center of mass of net supply, and lag

intervals, Genesee River at St. Helena, N. Y., March 9-14, 1920. .. 80

62. Rates and depths of snow melt.................................... 84

63. Summary of rainfall and runoff data for nonwinter floods. ......... 86

64. Precipitation, in inches, for 12-hour periods, at rain gages near

Sacandaga River basin above Hope, N. Y., July 8-12, 1921...... 89

65. Gage height and discharge of Sacandaga River near Hope, N. Y.,

during flood of July 1921...................................... 89

66. Computation of volume of direct runoff associated with precipita- .

tion period July 8-12, 1921, Sacandaga River near Hope, N. Y.... 90

67. Precipitation, in inches, for 12-hour periods, at stations in and near

Chemung River basin, July 6-10, 1935.......................... 95

68. Gage height and discharge of Chemung River at Chemung, N. Y.,

during flood of July 1935...................................... 96

69. Computation of volume of direct runoff associated with precipitation period July 7-10, 1935, Chemung River at Chemung, N. Y.... 96

70. Daily precipitation, in inches, at stations in and near Susquehanna

River basin above Wilkes-Barre, Pa., July 6-10, 1935............ 97

71. Gage height and discharge of Susquehanna River at Wilkes-Barre,

Pa., during flood of July 1935.................................. 99

72. Computation of volume of direct runoff associated with precipitation period July 6-10, 1935, Susquehanna River at Wilkes-Barre, 

Pa. ........................................................... 99

73. Hourly precipitation, in inches, at recording rain gages in and near 

Susquehanna and upper Delaware River basins, August 20-25, 

1933 .......................................................... 102

74. Daily recorded rainfall, in inches, at stations in and near East 

Branch of Delaware River at Fishs Eddy, N. Y., August 20-25, 

1933 .......................................................... 105

75. Precipitation, in inches, for 6-hour periods, at stations in and near 

East Branch of Delaware River at Fishs Eddy, N. Y., August 

20-25, 1933 .................................................... 105
TABLES 1X

Page

TABLE 76. Gage height and discharge of East Branch of Delaware River at

Fishs Eddy, N. Y., during flood of August 1933................ 106

77. Computation of volume of direct runoff associated with precipitation period August 21-25, 1933, East Branch of Delaware River 

at Fishs Eddy, N. Y. ........................................... 107

78. Precipitation, in inches, at rain gages in and near Susquehanna

River basin above Marietta, Pa., August 21-31, 1933............ 108

79. Gage height and discharge of Susquehanna River at Marietta, Pa.,

during flood of August 1933.................................... HI

80. Computation of volume of direct runoff associated with precipitation period August 21-25, 1933, Susquehanna River at Marietta, 

Pa. ........................................................... H2

81. Precipitation, in inches, at stations in and near Susquehanna River

basin above Harrisburg, Pa., May 16-26, 1894.................. 115

82. Hourly precipitation, in inches, at recording Weather Bureau rain

 gages near Susquehanna River basin, May 16-24, 1894............ 116

83. Gage height and discharge of Susquehanna River at Harrisburg, Pa.,

during flood of May 1894...................................... 117

84. Computation of volume of direct runoff associated with storm

period May 17-23, 1894, Susquehanna River at Harrisburg, Pa.... 118

85. Daily precipitation, in inches, at stations in and near West Branch 

of Susquehanna River basin above Williamsport, Pa., April 27 

to May 10, 1909 .............................................. 123

86. Daily mean areal precipitation and temperatures, West Branch of 

Susquehanna River at Williamsport, Pa., April 27 to May 4, 

1909 .......................................................... 124

87. Gage height and discharge at indicated time, West Branch of

Susquehanna River at Williamsport, Pa., April-May 1909........ 124

88. Computation of volume of direct runoff associated with precipitation period April 27 to May 4, 1909, West Branch of Susquehanna River at Williamsport, Pa. ............................. 125

89. Computation of time of center of mass of net supply, and lag 

intervals, West Branch of Susquehanna River at Williamsport, 

Pa., April 27 to May 4, 1909................................... 125

90. Daily precipitation, in inches, at rain gages in and near Genesee

River at St. Helena, N. Y., May 13-19, 1916.................... 129

91. Hourly precipitation, in inches, at recording Weather Bureau gages

near Genesee River basin, May 13-24, 1916...................... 130

92. Gage height and discharge of Genesee River at St. Helena, N. Y.,

during flood of May 1916...................................... 132

93. Computation of time of center of mass of net supply, and lag

intervals, Genesee River at St. Helena, N. Y., May 13-19, 1916.... 133

94. Computation of volume of direct runoff associated with precipitation of May 13-19, 1916, Genesee River at St. Helena, N. Y...... 133

95. Concentration of rainfall and runoff during major winter and nonwinter floods .................................................. 137

MAJOR WINTER AND NONWINTER FLOODS

IN SELECTED BASINS 

IN NEW YORK AND PENNSYLVANIA

By W. B. LANGBEIN AND OTHERS

ABSTRACT

The scientific design of flood-control works is based on an evaluation of the 

hydrologic factors basic to flood events, particularly how rainfall and snow runoff, 

soil conditions, and channel influences can combine to produce greater or lesser 

floods. For this purpose an analysis of the pertinent hydrologic data is needed. 

The methods of analysis adopted should conform as closely as possible to those 

already in use and must be adapted to the quality of the available information.

Maximum floods in 8 basins in New York and Pennsylvania during the winter 

and nonwinter months were studied, a total of 21 floods.

The most outstanding winter flood of record in the North Atlantic region was 

that of March 1936. Rainfall plus snow melt in the basins studied ranged between 

3.04 and 6.87 inches, and associated volumes of direct runoff from 1.88 to 5.63 

inches. Winter floods have a common characteristic in their relation to freezing 

temperature. The antecedent periods, representing a period of snow accumulation 

and frost penetration, are below freezing, and the flood itself is contemporaneous 

with a period of above-freezing temperatures, usually associated with rain, during 

which the previously accumulated snow is melted. A second common characteristic 

of major winter floods is their tendency to be associated with widespread causal 

meteorologic conditions. There was a more complete conversion of rainfall and 

snow melt into runoff during the winter storms studied than during the wettest 

nonwinter flood. Snow melt during winter floods ranged from 0.04 to 0.07 inch 

per degree-day above 32° F.

The depth of mean areal rainfall produced by the nonwinter storms studied 

ranged from 3.05 to 4.96 inches. The maximum 24-hour quantity at single stations 

was 14 inches, which was measured during the storm of July 1935 in New York. 

The volume of direct runoff ranged between 1.39 and 3.41 inches. The portion of 

rainfall that was converted into runoff varied in accordance with the rate of 

antecedent base flow, expressed in second-feet per square mile, and emphasized 

the influence of antecedent conditions.

The average volume of direct runoff during winter floods was 4.24 inches, and the 

average during nonwinter floods was 2.44 inches. The latter, however, were more 

concentrated as to time, tending to compensate for large volume of runoff in 

winter, so that the crest rates of direct runoff averaged 0.056 inches per hour during 

the winter and 0.051 inches during the nonwinter period.

INTRODUCTION 

UTILITY OF FLOOD-CONTROL DATA

In recent years nearly all parts of the country have experienced recordbreaking floods that have caused much damage and suffering, yet this
2 FLOODS IN NEW YORK AND PENNSYLVANIA

damage has not discouraged the continued occupancy and use of lands 

so situated as to be almost predestined to recurrence of flooding. Instead, 

demands have been made that the floods be controlled, so that damages 

in the future can be avoided or at least mitigated. The scientific design 

of public works for the control of floods is based on the study and 

evaluation of the hydrologic factors basic to floods, such as rate and 

amount of rainfall and snow melt, soil conditions, and channel influences. 

The first step in such an evaluation is the marshaling of all available 

climatologic and stream-flow data in an orderly array, convqgflient and 

accessible for thorough investigation. The United States Geological 

Survey in several recent reports on floods has presented comprehensive 

data in considerable detail. These essential data are not, however, in a 

form suitable for direct application to flood-control problems. For such 

purposes there is need for the computation of basic rates, volumes, and 

interrelations and for explanation of the processes involved in the correlation of rainfall and runoff. This report is directed to that end; it 

presents results of computations and analyses of basic data in publications and files of the Geological Survey and the Weather Bureau.

A further objective is the presentation of tested procedure for the 

analysis of flood data. The section on Methods of analysis outlines 

techniques that are of wide utility. The application of computed results 

to practical problems is dependent to a large extent on the method by 

which they were derived, as results derived by one procedure are not 

necessarily comparable with those derived by another. The advantages 

of uniform procedure are many. This report, therefore, explains in more 

detail than heretofore the methods used by the Geological Survey for 

evaluating the basic rates and volumes needed in considering water 

problems. The computations are presented in form suitable for use in 

other similar studies.

SCOPE OF THE PRESENT REPORT

The work presented in this report had its inception in a project for 

"Surveys of floods and droughts" for which funds were provided by the 

Federal Emergency Administration of Public Works. The compilation 

of basic data on major winter and nonwinter floods according to outlines 

prepared by the senior author was assigned to the district offices of the 

Geological Survey at Albany, N. Y., and Harrisburg, Pa. The work 

at Albany was performed by H. W. Fear, assisted by L. A. Wiard, 

G. E. Cook, D. Myers, and J. McGrath, under the direction of A. W. 

Harrington, district engineer; and that at Harrisburg by Geo. Weber, 

assisted by M. I. Rorabaugh and T. H. Hake, under the direction of 

J. W. Mangan, district engineer. The coordination of the work and the 

preparation of this report were conducted by W. B. Langbein, division 

of water utilization, under the direction of R. W. Davenport, chief.
INTRODUCTION 3

Early hydrologic analysis in the United States was directed largely 

toward the study of the annual yield of rivers and the relations between 

this yield and such climatic factors as annual precipitation and temperature. General conclusions reached by such men as Rafter, Vermeule, and 

others who carried on these early studies still find wide application and 

utility.

As the demands for water for power, irrigation, and municipal use 

increased, the irregularly varying rates of flow of rivers became of 

greater economic consequence, and it was desirable to ascertain the 

nature of stream flow during short periods of time. Thus, Mead1 in 

1908 and Meyer 2 in 1915 discussed certain principles underlying the 

relations between monthly climatic conditions and associated runoff and 

showed that such analysis required the maintenance of a distinction 

between surface and ground-water runoff and the study of their relation 

to soil moisture.

Analysis of the March 1913 flood in Ohio by the Miami Conservancy 

District and the subsequent design and construction of a system of 

detention reservoirs in the Miami River Basin served to emphasize that 

much of the yield of many streams occurs as flood flow associated with 

identifiable heavy rainfall. Intensive studies of the nature of stream flow 

in times of flood for use in the design of protective or control works are 

now directed, among other things, toward answering the question of 

how much runoff will result from a given storm and' what will be its 

time distribution.

The conclusion has generally been reached that stream flow is the 

integrated result of the many separate but generally identifiable meteorologic factors and the indirectly related but important soil, geologic, and 

biologic factors. Search is in progress for methods for evaluating the 

runoff in a given area in terms of the associated edaphic and physiographic conditions. Records of stream flow have been collected by the 

Geological Survey at some places for over 40 years. These include many 

floods, representing many different combinations of meteorologic and 

hydrologic conditions. Such records, in conjunction with the climatologic 

records of the Weather Bureau, provide a basis for solution of the 

rainfall-runoff equation.

The present report is essentially a presentation of basic hydrologic 

conditions underlying major winter and nonwinter floods of record 

in selected areas in New York and Pennsylvania, followed by derivation 

of certain fundamental factors. In its preparation search has been made 

for all existent information on rainfall, snow cover, and temperature

1 Mead, D. W., Water-power engineering, pp. 111-197, New York, McGraw Publishing Co., 

1908.

2 Meyer, A. F., Computing runoff from rainfall and other physical data: Am. Soc. Civil Eng. 

Trans., vol. 79, pp. 1056-1224, 1915.
4 FLOODS IN NEW YORK AND PENNSYLVANIA

not generally available in regularly published reports of the Weather 

Bureau or the Geological Survey. Data heretofore published are not 

included in this report, except where deemed necessary for completeness 

or for explanation. Acknowledgment is made to the Weather Bureau 

for furnishing results of measurements and observations of rainfall and 

temperature, and to other persons and agencies, as indicated in the 

appropriate places, who have furnished helpful information.

Besides these basic data, the report presents mean areal storm precipitation ; mean areal precipitation during short periods of time; snow cover 

and snow melt; mean areal temperature; volume of direct and groundwater runoff; and retention, infiltration index, and time interval between 

the occurrence of rainfall plus snow melt and the associated direct runoff, 

as derived by computation. Methods of deriving these results are explained in the following section.

METHODS OF ANALYSIS

The analytical methods followed in this report are, in general, those 

already described in other flood reports of the Geological Survey. They 

conform as closely as practicable to standard procedures already in use 

and described in other published works. Some departures seemed to be 

required by the quality of the available information and the time available for its compilation. In order that the adequacy of the computed 

results may be evaluated, the methods actually employed are described 

below.

Rainfall. Thorough search was made for rainfall records in published reports and files of the Weather Bureau and other organizations. 

All data so compiled for areas in or near the respective basins were used 

to compute the mean areal precipitation.

The mean areal precipitation during the storms studied was computed 

by the ThiessenS method, the lines being drawn by the use of perpendicular bisectors, as described by Horton. 4 This method assumes that the 

precipitation at any point in the basin during a given interval is the same 

as that recorded at the nearest rain gage. The ratio between the area 

so assigned to a given rain gage and the total basin area is its Thiessen 

weight. The recorded total storm precipitation at each rain gage was multiplied by its Thiessen weight. The sum of the products equals the mean 

areal precipitation. In order to show the areal distribution of total storm 

rainfall, isohyetal maps also have been prepared. In general, these maps 

have not been used for determining mean areal precipitation, tests having 

demonstrated that in the areas under consideration the Thiessen method 

was adequate for the purpose. The Thiessen weights were convenient

8 Thiessen, A. H., Precipitation average for large areas: Monthly Weather Rev., Vol. 39, p. 

1083, July 1911. 

* Horton, R. E., Rational study of rainfall data: Eng. News-Record, pp. 211-213, Aug. 2, 1917.
METHODS OF ANALYSIS 5

also for use in determining mean areal precipitation during selected 

portions of the storm, as described below.

Besides the total amount of storm rainfall, information as to its time 

distribution is of interest, as well, particularly with respect to computation of infiltration rates and detailed time comparisons of rainfall and 

runoff. For this purpose the mean areal precipitation was computed for 

specified intervals of time throughout the storm period. The length of 

the interval was chosen on the basis of the accuracy of the available 

records and the size of the particular basin. Thus, 6-hour intervals were 

chosen for the Sacandaga River Basin above Hope, N. Y., with an area 

of 491 square miles, and 24-hour intervals for the basin of West Branch 

of Susquehanna River above. Williamsport, Pa., area 5,682 square miles. 

The longest interval used was 24 hours.

Most of the rain gages available for this purpose were read only once 

daily, either in the morning or in the evening, but two or more recording 

gages also were available within the storm areas and within or near 

the basins studied.

The records of hourly rainfall at the automatic rain gages were used 

to establish a rainfall distribution pattern for the given basin. Allowance 

was made for the estimated time of travel of the storm between the point 

of observation and the basin or the group of rain gages. Time of travel 

was estimated by comparison of the times of rainfall at the available 

automatic rain gages and inspection of the weather map. Measurements 

of the daily catch at each nonautomatic rain gage were then distributed 

over the 24-hour period preceding the time of observation so as to conform to the pattern established by the automatic rain gages.

In this manner the precipitation between selected clock hours was 

computed at each rain gage, regardless of the time of reading. These 

computed amounts are shown in the tables accompanying the account of 

each flood. The contemporaneous amounts at the several rain gages were 

averaged in accordance with the Thiessen method to obtain the mean 

areal precipitation during the respective periods of time, and the mean 

areal amounts are given in the tables.

Snow cover. Extensive search was made for information regarding 

snowfall and antecedent snow cover. With respect to the flood of March 

1936> this phase was, in general, satisfactorily covered by the data given 

in Geological Survey Water-Supply Papers 798, 799, and 8005. Additional information is included in this report. The available data on snow 

cover, however, were inadequate to account for the behavior of streams. 

These data, therefore, were supplemented by an approximation of the 

water content of the initial snow cover, obtained by subtracting the

6 The floods of March 1936, pt. 1, New England rivers; pt. 2, Hudson River to Susquehanna 

River region; pt. 3, Potomac, James, and upper Ohio Rivers: U. S. Geol. Survey Water-Supply 

Papers 798, 799, and 800, 1937.
6 FLOODS IN NEW YORK AND PENNSYLVANIA

runoff from the precipitation during that part of the winter or subfreezing season preceding the flood and considering the difference as an 

indication of the maximum amount of water on the ground in the form 

of snow just before the thaw. There were indications that some snow 

remained in parts of the basins after the flood period. Estimates of water 

content of this snow were made by computing the difference between 

direct runoff and precipitation during a thawing period immediately 

following the flood, and using the results, where positive, as an indication 

of the minimum contribution to runoff during the subsequent thawing 

period from snow left on the ground after the main flood period. These 

differences between total precipitation and observed runoff during the 

flood periods described gave information that was useful in supplementing and interpreting measurements of snow cover and in making estimates of the probable snow cover preceding the flood and that remaining 

on the ground after the flood and from these to compute the amount of 

snow melt contributed to the flood. The computations for each flood 

are described in appropriate detail as a part of the discussion of that flood.

Direct runoff. Computations of the amount of direct runoff during 

the several floods were made by the methods described in other flood 

reports of the Geological Survey, particularly Water-Supply Paper 867. 6 

In brief, the method used is as follows: Hydrographs of discharge during 

the flood period, as well as during a substantial period preceding and 

following the flood were plotted, as shown, for example, on figure 8, 

page 20, which applies to Sacandaga River near Hope, N. Y., during the 

flood of March 1936.

Fluctuations in stream flow suggest two classifications as to time: 

direct and base runoff. Direct runoff is that runoff which is directly 

associated as to time with causative rainfall or melting of snow. It forms 

the bulk of the hydrograph and is responsible for the destructive flood 

flows. Base runoff on the other hand is represented by the sustained or 

fair-weather flow, and in the basins studied in this report, may be considered as composed largely of ground-water effluent. Direct runoff in 

these basins may be considered to include superficial wash or sheet flow 

and such shallow perched-water effluent wet-weather seeps and springs 

 that reaches the streams during and promptly after the occurrence of 

rainfall or the melting of snow.

The total area under the hydrograph on figure 8 represents the runoff 

that reached the streams from both surface and ground-water sources 

resulting from the storms of March 1936 plus the flow that would have 

been maintained if there had been no increment of supply after March 10. 

On figure 8 a graph has been drawn representing the estimated discharge

8 Hurricane floods of September 1938: U. S. Geol. Survey Water-Supply Paper 867, pp. 421- 

423, 1940.
METHODS OF ANALYSIS 7

from ground-water sources. The area enclosed within the hydrograph 

and above the estimated base-flow line is equivalent to the direct runoff 

associated with the flood. This area has been further subdivided, where 

necessary to determine the portion of the direct runoff attributable to 

discrete or separate periods of precipitation. The method of making this 

subdivision is also shown on figure 8. Table 8, page 25, shows the steps 

used in computing the volume of direct runoff of Sacandaga River near 

Hope, N. Y., associated with the precipitation period, March 8-14, 1936.

The mean river discharge during successive equal intervals of time 

are tabulated through the flood rise, following the estimated recession 

shown on figure 8, for March 16-19, when the normal recession from 

the first flood rise was interrupted by succeeding rainfall and snow 

melt. The estimated base runoff (including any direct runoff remaining 

from a preceding flood that had not drained from the channel system 

before the beginning of the flood in question) as read from figure 8 

is then tabulated for corresponding intervals and subtracted from the 

mean discharge previously listed. The differences represent the direct 

runoff during the selected intervals. The sum of the differences, converted into inches over the drainage area, represents the total direct 

runoff associated with the indicated flood.

Ground-water runoff and recharge. The approximate amount of 

ground-water runoff and net recharge to ground water may also be 

computed from the hydrograph and the estimated graph of base flow. 

The method of computation used is as follows: Again referring to figure 

8 showing a hydrograph of discharge of Sacandaga River near Hope, 

N. Y., during March 1936, it was estimated that as a result of the 

climatologic events of March 9-21, ground-water discharge rose from 

300 second-feet on March 9 to about 1,750 second-feet on March 28. 

During this time the total discharge from ground-water sources was 

estimated as 22,500 second-foot-days. Studies of hydrographs of 

Sacandaga River during fair-weather periods, when river flow is assumed 

to consist entirely of ground-water discharge, indicate that the normal 

rate of depletion of this discharge is as shown on figure 1. This depletion 

hydrograph was then integrated to determine the volume of flow remaining in the ground-water body that is available for runoff in relation to 

the rate of ground-water discharge. The ground-water storage curve, as 

the result of the integration is known, is shown on figure 2. Since the 

depletion curve shown on figure 1 does not extend below 0.09 second-foot 

per square mile, the volumes of storage shown in figure 2 refer to the 

volume of 0.09 second-foot per square mile as an origin.7 As previously 

stated, the estimated ground-water flow between March 9-28 was about 

22,500 second-foot-days. On the last-mentioned day there was an estir Report of cooperative hydrologic investigations: Pennsylvania Dept. Forests and Water, pp. 

59-64, processed report, August 1939.

689521 47 2
8 FLOODS IN NEW YORK AND PENNSYLVANIA

IU.VJ

9.0

e.o

7.0 

6.0 

5.0

4.0 

3.0

2.0

1.0 

.9 

.6 

.7 

.6 

.5 

.4

.3 

.2

. 1 

0

\

\

\

\

\

\

\\

>

^

\

\

^

\

X

x^ \

^"\ *^^

) 5 10 15 20 25 30 33 40 45 50 5!

Doys

FIGURE 1. Average ground-water depletion curve, Sacandaga Eiver near Hope, N. Y.

mated rate of discharge of 1,750 second-feet (3.56 second-feet per 

square mile), which, according to figure 2, indicated that the volume 

in storage to be yielded to the streams regardless of whether there is any 

additional rainfall or not was 20,000 second-foot-days. The total flow and 

potential flow was therefore 42,500 second-foot-days. But on March 9 

there was a flow of 300 second-feet (0.61 second-foot per square mile), 

which indicated, according to figure 2, that 4,000 second-foot-days would 

be delivered as stream flow after that date in addition to that produced 

by subsequent events; accordingly, of the total of 42,500 second-footdays, 4,000 must be subtracted as being attributable to events prior to 

March 9. The ground-water runoff produced solely by the events of 

March 8-21 is therefore 37,500 second-foot-days or 2.8 inches over the 

491 square miles.

Separate determinations of the ground-water runoff associated with 

each of the two separate flood rises between March 9-22, 1936, were not 

made due to the uncertainties of determining the ground-water storage 

at the end of the first storm while the streams continued in flood.
METHODS OF ANALYSIS 9

6.0 

5.0

3.0

a 2.0

1.0

5,000 10,000 15,000 20,000 25,000 30,000

Ground-water storage in cond-foot dayt

FIGURE 2. Relation between the rate of ground-water discharge and volume of available groundwater storage, Sacandaga River near Hope, N. Y.

Lag interval. Recent writers 8 have pointed out that the time difference between supply and the associated direct runoff bears a general 

relation to the shape of the unit hydrographs. This time difference, 

called the lag interval, is denned herein as the time interval between the 

center of mass of supply rain and snow melt effective in producing 

runoff and the center of mass of direct runoff. As described by Langbein,9 

the lag interval as so defined not only is inversely proportional to the 

ordinates of maximum discharge hydrographs of equal volume but also 

is equal to the slope of the discharge-storage curve applicable to the 

basin, and so provides two useful measures.

Computations have been made of the lag interval for each of the floods 

studied in this report, and comparisons have been made between the 

lag intervals thus computed for different floods in a given basin, and in 

a section. Rates of flood discharge comparisons are made between concentration of rainfall and runoff during the floods studied in the several 

basins in terms of their lag intervals.

»Hoyt, W. G., and others, Studies of rainfall and runoff in the United States: Geol. Survey 

Water-Supply Paper 772, pp. 209-210, 1936. Snyder, F. F., Synthetic unit graphs: Am. Geophys. 

Union Trans., 19th Ann. Meeting, pp. 447-454, 1938. Langbein, W. B., Some channel-storage 

and unit-hydrograph studies: Am. Geophys. Union Trans. 21st Ann. Meeting, pp. 620-627, 1940.

' Langbein, W. B., op. cit.
IQ FLOODS IN NEW YORK AND PENNSYLVANIA

In the computation of the lag interval as defined above, the graph 

of effective supply is not generally available, particularly with respect 

to snow melt. Estimates based on available rneteorologic data are therefore necessary. The basins studied in this report are large and have 

relatively long lag intervals and therefore errors of a few hours in the 

estimates of the time of net supply are not important. However, the 

volume of net supply, being equal to the volume of direct runoff, is known.

Table 9, on page 25, illustrates the method employed to determine the 

time of center of mass of net supply as applied to the flood of March 

8-14, 1936, on the Sacandaga River near Hope, N. Y. The second 

column lists the mean areal precipitation as taken from table 3 during 

the 12-hour periods indicated in the first column. The third column lists 

the estimated snow melt during the indicated periods. These estimates 

were made by distributing the known total snow-melt during the flood 

period proportionately on the basis of the thawing temperatures during 

the selected periods. The total snow melting, determined by the difference 

between the initial and final snow cover, as previously discussed, plus 

the water content of any additional snowfall during the storm, as indicated by Weather Bureau observations, and supplemented by reference 

to temperature readings, was divided by the total degree-days above 

32° F. during the storm period. The ratio so derived was multiplied by 

the degree-days above 32° F. during each interval, and the product 

reported as the melting during that interval. During some of the intervals, 

the indicated snowfall exceeded the snow melt so computed. Such conditions are indicated by a minus sign in column 3.

The total supply, as reported in the fourth column of table 9, is the 

sum of the precipitation plus the snow melt. This supply was then 

diminished by amounts sufficient to account for the infiltration or other 

retention of water by the ground, so that the total net supply equaled the 

measured direct runoff. The total retention (total supply minus total 

direct runoff) was distributed among the several periods as follows: 

One-half of the retention of 1.16 inches in the example used for illustration was distributed uniformly with respect to time among the several 

periods and the remaining portion was distributed proportionately on 

the basis of amount of total supply. These amounts of retention were 

then readjusted so that the retention during any interval did not exceed 

the supply during that interval and so that net supply did not begin 

until the stream flow at the gaging station had begun to rise. In general, 

the amount by which the net supply was reduced at the beginning of the 

storm period to allow for the latter adjustment was added to the net 

supply in the latter part of the storm period, since the portion of supply 

converted into runoff, other things being the same, tends to increase as the 

storm continues. The seventh column of table 9 lists the time lever (time 

from origin) of the indicated masses of net supply from the selected
METHODS OF ANALYSIS 11

origin, 6 p.m. of March 8; and the last (eighth) column lists the product 

of the separate amounts of net supply and their corresponding time 

levers. The quotient of the sums of the last column and the sixth column 

(net supply) equals the time corresponding to the center of mass of 

volume of supply with reference to the origin. The final computations 

are made below the table, with appropriate explanation.

Infiltration index. The progress of precipitation into infiltration and 

runoff is a complex process not clearly apparent. It is quite likely that 

some of the precipitation becomes runoff at the surface of the ground, 

and that as the remaining infiltrated water encounters more impervious 

soil horizons, additional volumes are induced to flow laterally through 

the upper stratum of greater permeability by relatively short routes to 

the stream channels, and so also become part of the direct runoff. There 

may be a wide zone of gradation between distinct surface runoff and 

distinct ground-water runoff. In the absence of definite information as 

to the relative amounts of the surface and subsurface flow that combine 

to make up the flood hydrograph, it is convenient to classify their sum 

as direct runoff. Similarly, it is convenient to use a single measure of 

the retentive capacity of the ground regardless of the differing rates of 

infiltration or percolation existing at different places in the basin or at 

different soil horizons.

It might be conceived that the rates at which water can pass below 

the ground surface and through lower strata are limited by the 'given 

soil, vegetal, and moisture conditions and that the supply in excess of 

these rates becomes direct runoff. Consequently a measure of these 

resultant rates might be defined by the average rate of rainfall such that 

the volume of rainfall at greater rates equals the total direct runoff and 

the volume at lesser rates equals the volume of retention. This average 

rate has been termed the infiltration index and does not necessarily refer 

to the rate of infiltration at the ground surface or the rate of percolation 

of water through subsurface strata.

The infiltration index for a given storm was determined by the following method: Tabulations were prepared of the volume of rainfall that 

fell in excess of trial infiltration indices of 0.01, 0.05, 0.10, 0.20, and 0.30 

inch per hour at each available, recording rain gage. Graphs were then 

prepared showing the computed rainfall excess for each gage against the 

total storm rainfall at the particular gage, in terms of the infiltration 

index, and lines of equal infiltration index were drawn so as to conform 

to the plotted points. Figure 3 shows the results of these computations for 

the East Branch of Delaware River Basin above Fishs Eddy, N. Y., 

applicable to the storm of August 20-25, 1933. Four recording rain 

gages were available as follows: Scranton, Pa., Binghamton, N. Y., 

Kingston, N. Y., and Voorheesville, N. Y. Although none of these were 

in the basin, they were well enough arranged around it to indicate the
12 FLOODS IN NEW YORK AND PENNSYLVANIA

storm characteristics. The points plot close enough to the trend lines 

shown to justify the assumption that the rainfall distribution at any 

point in the area is related to the total precipitation. The maximum 

precipitation at any of the recording rain gages was 4.72 inches at 

Scranton, Pa., and since the mean precipitation over the basin is 6.22 

inches extrapolation was needed. The precipitation in the basin during 

the storm varied between a maximum and a minimum of about 12.0 

inches and 4.4 inches, respectively, but the curves of equal infiltration 

index within this range were considered as straight lines and the mean 

areal precipitation as adequately indicating the mean infiltration index. 

Figure 3 was based on rainfall records at individual rainfall stations 

and the rainfall distribution indicated for the mean areal precipitation

JO /

/

/"

^

,

'

/

/

/"»

?o /I

JO/

/

/*> /L

^

.ao

x"

X'

O ^xiOS

.5$^^

^s

» 

^

/

s'**s

/ T

/'

x^

^s

x-"*^

Eoet Bronch of Deknrore River boein

Precipitation^ £.22 inches

Direct run-off » 3.46 Inch**

Infiltration kwiex » 0.09 inche* per hour

 .05 

jOO /S'

3 1 2 34 5 6 7

Romfdl e*ees« in inches

FIGURE 3. Graph showing relation between rainfall and rainfall excess, in terms of infiltration 

index, at recor-ling rain gage near East Branch of Delaware River basin, storm of August 

20-25, 1933.

is that for a station having precipitation equal to the mean areal precipitation and does not indicate the distribution of rainfall of a graph showing 

contemporaneous hourly values of mean areal precipitation. However, 

the generation of runoff is considered a local event and is therefore 

determined by the local or unit-area rainfall distribution rather than by 

the mean of the contemporaneous rainfall over a whole basin, although 

the resultant discharge at the gaging station is the integration of the 

runoff as generated from the several localized areas composing the basin. 

On this basis, the mean areal infiltration index, according to figure 3, 

corresponding to mean areal precipitation of 6.22 inches and direct runoff
WINTER FLOODS 13

of 3.46 inches, is 0.09 inch per hour. The value of the index so computed 

is intended to serve as a measure of the hydrologic conditions affecting 

the generation of runoff from rainfall that is independent of the effects 

of amount and time distribution of rainfall. The index does not necessarily represent a rate of infiltration or retention that existed for any 

appreciable length of time or over any appreciable area.

Difficulties with respect to rate and distribution of snow melt are such 

as to prohibit the computation of infiltration index during winter storms.

WINTER FLOODS

The most outstanding winter flood of record in the North Atlantic 

region occurred as a result of the widespread extratropical storm and 

thaw of March 9-22, 1936. Records of river discharge and flood heights 

of the March 1936 floods, as well as studies of the basic hydrologic 

conditions, are presented in a series of three volumes published by the 

Geological Survey. 10 In all but one of the basins studied in this report, 

the March 1936 flood was the greatest winter flood of record. The 

present study has for its purpose a more detailed inquiry into the 

hydrologic background and features of these events than was given in 

the earlier reports and a comparison of these winter floods with the major 

nonwinter floods in the same basins, which have not hitherto been 

undertaken.

Major winter floods have a common characteristic in their relation 

to freezing temperatures. Thus, each of the floods summarized in table 1 

was preceded by a 30-day period during which the average temperature 

was well below freezing, but each was contemporaneously associated 

with temperatures markedly above freezing. At the termination of the 

subfreezing periods the ground surface was covered with an accumulated 

snow cover and the ground was frozen to a depth dependent on the 

opportunity for frost penetration, which may be influenced by the 

presence of snow cover. Rising temperature releases this snow mantle 

at a rate dependent on the intensity and duration of the thawing temperature, and the snow melt almost invariably finds its absorption by the 

ground impaired by the presence of frost. The snow melt contributed 

to each of the major floods listed in table 1 was augmented by contemporaneous rainfall which, as during the March 1936 flood, generally 

exceeded the amount of antecedent snow cover.

Possibly a second common characteristic of major winter floods is 

their tendency to be associated with the widespread extent of the causal 

meteorological conditions. Thus, during March 1936, record-breaking 

floods occurred as a result of two widespread storms, each of which

10 The floods of March 1936, pt. 1, 2, and 3: U. S. Geol. Survey Water-Supply Papers 798, 

799, and 800, 1937.
14 FLOODS IN NEW YORK AND PENNSYLVANIA

extended over nearly all of New England, New York, Pennsylvania, 

and New Jersey, and parts of Maryland and Virginia. The storms 

occurred over ground covered by snow, which was melted by a general 

rise in temperature contemporaneous with the storm rainfall. Winter 

floods, unless caused by an ice jam are definitely not a local condition, 

because they depend largely on temperature, which tends to be uniform 

over wide areas. Another common characteristic, as illustrated by the 

data in table 1, is the tendency of floods throughout the area covered 

by this report to occur most frequently during March and April, the 

spring "break-up" months, which mark the termination of the winter's 

accumulation of snow and the beginning of the thaw. The season's 

accumulation of snow represents the integration of many different snowstorms of various intensity and areal extent; it therefore tends to be 

uniform over wide areas, but is affected by local altitude and exposure. 

The flood-producing potentialities of the snow cover, however, depend 

not only upon its depth but also upon how rapidly and to what extent 

the temperature rises above the freezing point. During the outstanding 

floods listed herein, the rise was abrupt and very marked.

Figure 19 included in the section on nonwinter floods, presents the 

results of a study of the relation between rainfall plus snow melt and 

the associated total runoff for the various storms listed in tables 1 and 63. 

The winter floods lay close to the line indicating 100 percent runoff, 

and generally there was a more complete conversion of supply into runoff 

than took place during the wettest nonwinter flood studied.

Table 1 summarizes selected hydrologic data with respect to the winter 

floods. In the following pages there is presented more detailed information 

concerning each of the major winter floods in the basins studied, with 

appropriate discussion. The volumes of snow cover, rainfall, and runoff 

for the floods of March 1936 given in this report, being based on more 

detailed analysis, may differ in some respects from those given for the 

same basins in Water-Supply Papers 798 and 799.

FLOODS OF MARCH 1936

SACANDAGA RIVER NEAR HOPE, N. Y.

During the winter of 1935-36 there were prolonged periods of subfreezing temperature with heavy snowfall. Records of the depth of snow 

on the ground at points in and near this basin just prior to the beginning 

of the storm of March 1936 were probably the most adequate of any 

section of the State, since there were a number of well-distributed 

stations at which snow surveys were made regularly. These stations were 

generally at elevations between 800 and 2,000 feet in second-growth 

woodlands, typical of a great part of this mountainous drainage basin. 

Measurements made early in February showed an average snow depth
TABIJE 1. Summary of rainfall and runoff data for winter floods

Drainage 

basin

Sacandaga River near Hope, 

N. Y.

East Branch Delaware River 

at Fishs Eddy, N. Y.

Chemung River at Chemung,

N. Y.

Susquehanna River at WilkesBarre, Pa.

Susquehanna River at Harrisburg, Pa.

West Branch Susquehanna 

River at Williamsport, Pa.

Qenesee River at St. Helena, 

N. Y.

Drainage 

area 

(sq. ml.)

1 491

} 783 

} 2, 530 

} 9,960 

j 24, 100

} 5, 682 

1,017

Precipitation 

period

/Mar. 8-14, 1936 

\Mar. 16-22, 1936

/Mar. 9-15, 1936 

\Mar. 15-21, 1936

/Mar. 9-14, 1936 

\Mar. 15-21, 1936

/Mar. 9-15, 1936 

\Mar. 16-21, 1936

/Mar. 9-14, 1936

\Mar. 16-21, 1936

/Mar. 9-15, 1936 

\Mar. 16-21, 1936

Mar. 10-14, 1920

Total 

precipitation 

(inches)

1.86 

3.37

1.87 

4.36

1.89 

4.71

1.51 

4.15

1.74 

4.69

1.99 

6.02

.88

Water content 

of snow at 

beginning of 

flood period 

(inches)

7.35 

6.17

4.7. 

2.15

2.85 

.8

3.0

.9

3.2 

1.2

3.8 

1.5

3.0

Estimated 

net snow 

melt 

during 

flood 

(Inches)

1.18 

2.07

2.55 

2.15

2.05 

.0

2.1 

.45

2.0

.8

2.3

.85 1

2.2

Approximate 

duration of 

measurable 

rainfall 

(hours)

54 

96

42 

96

45 

80

39 

55

24

Maximum 

precipitation in ' 

24 hours 

(inches)

 1.23 

M.30

 3.00 12.86

 1.70 

«2. 25

 1.70 

 2.25

«2.10 

"4.47

1 .80

Maximum rate of 

discharge

Secondfeet

10, 200 

23,900

33, 900 

46. 000

92, 300 

83,000

186,000 

232, 000

436, 000 

740, 000

165, 000 

264, 000

39,600

Inches 

per hour

0.032 

.075

.066 

.091

.058 

.051

.029 

.Oi6

.028 

.048

.045 

.072

.060

Volume 

of' direct 

runoff 

(inches)

1.88 

5.23

3.08 

5.45

2.39 

4.00

2.83 

4.38

2.92 

4.53

3.10 

5.63

2.08

Difference 

between 

precipitation 

plus snow 

melt and 

direct runoff 

(inches)

1.16 

.21

1.34 

1.06

1.55 

.71

.78 

.22

.82 

.96

1.19 

1.24

1.00

Approximate groundwater 

runoff 

(Inches)

| 2.8

} »

} 1.80 

| 1.25

1 »

} 2.0 

.80

Temperature 

during 

storm 

period (°F)

/ 35 

1 39

f 40 

1 46

I 37 

\ 36

/ 39 

1 40

f 40 

1 41

/ 39 

I 39

36

Temperature 

during 

30-day 

antecedent 

period (°F)

16

20

22

22

23

23 

28

24 

29

19

Precipitation 

during 

30-day 

antecedent 

period 

(Inches)

2.30

1.20

1.13

1.50 

1.85

1.70 

2.27

1.30 

2.50

1.10

Ratio of 

maximum 

24-hour 

runoff 

to total 

direct 

runoff 

(percent)

35 

27

43 

32

49 

27

23 

17

, 20 

21

32 

27

55

Time interval from center 

of mass of net supply to 

Center of 

mass of 

direct runoff 

(hours)

52 

45

34 

36

33 

30

67

70

86 

83

49 

50

32

Time of 

peak 

discharge 

(hours)

25 

2

14 

13

32 

31

40 

43

39 

32

27 

19

26

» Recorded at Speculator, N. Y., at 8 a.m. March 12, for preceding 24 hours.

 Recorded at Speculator, N. Y., at about 8 a.m. March 18, for preceding 24 hours.

 Recorded at Slide Mountain, N. Y., at 8 a.m. March 12, for preceding 24 hours, 

a Recorded at Slide Mountain, N. Y., at 8 a.m. March 18, for preceding 24 hours.

 Recorded at Burdett, N. Y., at 8 a.m. March 12, for preceding 24 hours.

* Recorded at Elmira, N. Y., at midnight March 17, for preceding 24 hours.

« Recorded at Weikert, Pa., in the afternoon of March 11, for preceding 24 hours.

h Recorded at Kylertown, Pa., at midnight March 17, for preceding 24 hours.

1 Recorded at Bolivar, N. Y., during late afternoon of March 12, for preceding 24 hours.

Face p. 14

FLOODS OF MARCH 1936, SACANDAGA RIVER 15

of at least 21 inches, with a water content of about 4.3 inches. By 

March 1, the snow cover had increased to an average of approximately 

27 inches, with a water content of over 6 inches, and by March 8, as 

indicated in table 2, to nearly 30 inches, with an average water content 

of about 7.35 inches. The distribution of the snow cover on March 8 

is shown in figure 4. The snow blanket on that day represented potential 

runoff of considerable magnitude.

Measurements made during the storm are given in table 2 and shown 

graphically on figures 5 and 6. The measurements indicate a water 

content of 6.17 inches over the basin on March 15, or a net melting of 

1.18 inches during the first storm period. Measurements of snow cover 

in the period March 22-25 indicate a mean areal depth of 4.1 inches water 

content, or a total snow runoff during the storm of 3.25 inches.

Precipitation during the storm at 12-hour intervals at five rainfall 

stations in and near the basin is given in table 3. Precipitation occurred 

on every day, the greatest amount being on March 17. The total storm 

precipitation over the basin, shown graphically on figure 7, was 5.23 

inches, of which 1.86 inches fell during the first period, March 8-14, 

and 3.37 inches fell during the second period, March 15-22.

Daily mean precipitation is given in table 4, with daily maximum, 

minimum, and average temperatures. The temperature averaged 4° F.

TABLE 2. Observations of snow cover, Sacandaga River near Hope, N. Y.,

March 1936

["T" indicates a trace; "P" indicates patches of snow]

Place of 

observation 

(New York)

Griffin. __ ...................

Wells... ................... ...

Altitude

(feet)

1,700

800

800 

1,100 

1,700 

1,300

1,860 

900

1,650 

1,800 

1,700 

1,500

1,700 

800

1,000 

800

Prior to storm 

period »

Snow 

depth 

(inches)

27.0

23.0

25.8 

34.2 

25.3 

25.0 

38.0 

25.2

34.0 

33.3 

33.3

31.2 

24.0 

34.5

25.8 

25.0

Water 

content 

(inches)

"6.21

5.75

5.84 

8.43 

5.80 

d6. 25 

a 9. 5 

5.27

as 5 

8.20 

8.17

7.77 

5.23 

d8. 6

5.40 

6.28

March 15-17

Snow 

depth 

(inches)

12.0

18.5

18.5 

23.3 

13.0 

14.0 

31.0 

14.3 

14.3 

27.0 

210 

23.7

28.8 

16.0 

19.5 

12.0 

14.3 

17.9

Water 

content 

(inches)

3.0

4.65

5.36 

6.67 

4.67 

a 3. 5 

d7.75 

5.50 

3.6 

d6.75 

8.20 

7.50

9.50 

4.90 

4.9

d 3.0

5.80 

5.58

March 22-25

Snow 

depth 

(inches)

b!2

T

1.0 

P 

T 

15

10 

25

8.7

15 

12

«10 

17

3

Water 

content 

(inches)

t3. 2

a. 25

5.4

2.5 

a 6. 2 

3.4

as. 75 

4.8

= .34 

6.2

d.75

aBased on snow surveys between Feb. 28 and Mar. 2, 

to March 9.

b80 percent of ground covered. 

cComputed from observations at nearby points. 

dOn basis of estimated 25 percent water density. 

*10 percent of ground covered.

1936, and other measurements prior
16 FLOODS IN NEW YORK AND PENNSYLVANIA

SCALE IN MILES

FIGURE 4. Map of Sacandaga River basin above Hope, N. Y., showing depth, in inches, of 

water content of snow on the ground, March 8, 1936.
FLOODS OF MARCH 1936, SACANDAGA RIVER 17

SCALE IN HILCS

FIGURE 5. Map of Sacandaga River basin showing depth, in inches, of water content of snow 

on the ground, March 15-16, 1936.
18 FLOODS IN NEW YORK AND PENNSYLVANIA

FIGURE 6. Map of Sacandaga River basin showing depth, in inches, of water content of snow 

on the ground, March 22, 1936.
FLOODS OF MARCH 1936, SACANDAGA RIVER 19

0tndlon Lok«

SCALE IN MILES

FIGURE 7. Map of Sacandaga River basin above Hope, N. Y., showing lines of equal precipitatation, March 8-22, 1936.
20 FLOODS IN NEW YORK AND PENNSYLVANIA

above freezing during the period, and there was some effective thawing 

temperature on each day. Table 5 gives a record of observations at 

Wanakena, N. Y., of air and soil temperatures and precipitation during 

the month of March. Although Wanakena is not in the basin, the record 

is of interest for its completeness and for illustrating the march of events 

during this month in the Adirondack Mountains. The record indicates 

that frost was present until March 15 at 6-inch depth, but that there 

was no frost during the month at 24-inch depth.

Daily mean temperatures during the 30-day antecedent period, February 8 to March 8, are given in table 6. The average for 30 days was 

16° F., and on only 2 days was the average above freezing. Active thawing did not begin until March 9.

Discharge from the basin is given in table 7, and variations in discharge 

in graphic form are shown on figure 8. Direct runoff during the first 

period as delineated on figure 8 and as computed in table 8 was 1.88 

inches. The lag interval between the rainfall and snow runoff and the 

direct runoff (table 9) was 52 hours. The flood peak followed the center 

of mass of net supply by 25 hours.

14,000

tlJJOO

15,000

It .000

V>00

«,ooo

1000

\

\

\

EttiiratMt rteMtion

J--I-4-

 ^riwot«d 9« "" i horj i

K> II 12 IS 14 li 16 IT 18 19 20 21 22 2S 2« 25 26 2T 28 29 SO Si I 2 S 4 9 

March I9SC »Bf» »M

FIGT-RE 8. Hydrograph of Sacandaga River near Hope, N. Y., showing discharge, March 1936.
TABLE 3. Precipitation, in inches, for 12-hour periods, at 

Sacandaga River Basin near Hope, N. Y., Marc

Station

(New York)

North Creek. .........

Altitude

(feet)

1,860

900

1,020

1,770

1,550

Weight 

(percent)

11.4

17.8

11.2

51.3

8.3

100.0

12-hour 

period

ending

12m.

12m.

12 p.m.

12m.

12 p.m.

12m.

12m.

12m.

12 p.m.

8

0.08

.16

0

.08

.02

.04

0

0

.17

.34

0.02

.07

9

0.06

0

.17

.36

.02

0

0

0

.23

.14

0.06

.07

10

0

0

.55

.28

0

0

0

0

.07

0

0.11

.05

11

0.18

.38

0

.28

.20

.40

.31

.62

.09

.18

0.21

.47

12

0.28

.18

.56

.34

.27

.15

.30

0

.18

.16

0.33

.11

13

0.10

.20

.10

.11

.10

.05

.08

.16

.16

.16

0.10

.15

14

0.10

0

.13

.09

.03

0

.08

0

.09

.06

0.09

.02

M
22 FLOODS IN NEW YORK AND PENNSYLVANIA

TABLE 4. Daily mean areal precipitation and temperatures, Sacandaga River near 

Hope, N. Y., March 7-22, 1936

March

7........... .......

8. .................

9..................

10..................

11....... .. ........

12..... .............

13..................

14..................

15..................

16............... ...

17..................

18............. ....

19......... .........

20.... ...............

21..................

22..................

8-22......... .......

Mean areal

precipitation 

(inches)

0.09

.13

.16f-Q

.44

9?

.11

.15

.81

1.10

.62

.19

.28

.16

.06

5.23 

Maximum 

(°F.)

30

36

38

42

43

48

49

40

43

45

48

53

52

51

45

44

45

Temperature

Minimum 

(°F.)

 2

22

30

32

36

26

21

18

32

31

37

38

30

32

29

27

Mean b 

(°F.)

17

30

36

38

42

34

30

30

38

40

45

45

40

38

36

36

* Average of readings at Gloversville and Indian Lake, N. Y. 

b Average of maximum and minimum.

TABLE 5. Hydrologic data" observed at Wanakena, N. Y., March 1936

[In this table "T" indicates a trace, "B" shows blown snow, and "P" indicates patches of snow]

March

1.. _._

2........

3 __

4----....

5

6

9

10.. 

12........

13 

14........

15- ..-.

16 .

17.. ..

18........

19.. ...

20 _

21........

22 

23 

24........

25........

26........

27 

28. ...

29........

30........

31.. ......

Time 

of observation 

(a.m. )

9:50 

9:35 

9:40 

9:10 

9:15 

9:15 

9:15 

9:15 

9:25 

9:15 

9:15 

9:30 

10:05 

10:20 

9:30 

9:25 

9:40 

9:15 

9:15 

9:20 

9:15 

9:55 

9:50 

9:15 

9:15 

9:15 

9:15 

9:15 

9:15 

9:15 

9:15

Air temp. (°F.)

Observed

11 

20 

30 

41 

22 

6 

13 

21 

37 

42 

49 

43 

29 

21 

38 

35 

46 

33.5 

51.5 

32 

36 

29.5 

36 

51 

49 

39 

44 

35 

47 

44 

29.5

Maximnm

21 

38 

43 

52 

30 

14 

29 

44 

44 

60 

52 

44 

32 

39 

56 

47 

57.5 

55 

56 

41 

42 

38 

52 

66 

57 

. 55 

55.5 

48 

63.5 

60 

31

Minimum

 12 

 21 

20 

20 

7 

2.5 15

__ O

21 

27 

32 

41 

24 

16 

14 

29 

30 

31 

31 

29 

27 

27 

' 10 

34 

43 

22 

23 

30 

22 

26 

29

Soil temperature in °F. 

at depth of

1 

inch

31.0 

22.0 

30.0 

30.0 

27.0 

27.5 

20.5 

21.5 

31.5 

31.5 

32.0 

32.5 

32.0 

32.0 

32.0 

32.0 

32.0 

37.0 

47.5 

32.0 

32.0 

32.0 

32.0 

47.0 

50.5 

33.0 

40.0 

42.0 

32.5 

52.5 

37.5

6 

inches

31.4 

24.4 

30.0 

30.2 

28.4 

29.0 

24.2 

24.6 

31.0 

31.4 

31.8 

31.8 

32.0 

32.2 

31.8 

32.0 

32.2 

32.6 

35.8 

32.2 

32.2 

32.2 

32.2 

35.4 

42.6 

32.6 

36.4 

34.6 

32.8 

39.4 

39.2

12 

inches

31.5 

31.5 

32.0 

32.0 

32.5 

31.5 

31.5 

31.5 

31.5 

31.5 

32.0 

32.0 

31.5 

32.0 

32.0 

32.0 

32.5 

32.0 

33.0 

32.0 

32.5 

32.0 

32.5 

33.0 

33.0 

32.5 

32.5 

32.5 

33.0 

33.5 

34.5

24 

inches

32.0 

32.0 

32.0 

32.0 

32.0 

31.5 

32.0 

32.0 

32.0 

32.0 

32.5 

32.0 

32.0 

32.0 

32.5 

32.0 

32.5 

32.5 

33.0 

32.0 

32.5 

32.0 

32.5 

33.0 

33.0 

32.5 

32.5 

32.5 

33.0 

34.0 

36.0

Precipitation (inches)

Rain

0.11

.04 

T

T

.18

.10 

.37 

.20 

T 

.16 

.52 

.22 

.04 

.09 

.24 

.30 

T

.09

T

.39

.04 

.32

Snow

1.0

.4

.4

1.5

4.5 

4.0

1.0

T

B

Snow 

on 

ground

14.5 

13.5 

12.5 

12.5 

10.5 

10.0 

10.0 

10.0 

10.5 

9.5 

6.0 

P 

5.5 

9.5 

5.5 

1.5 

2.5 

P 

P 

P 

P 

6.6 

4.5 

1.0

P 

P 

P 

P 

P 

P

 Data furnished by the State Rangers School, central-station record.
FLOODS OF MARCH 1936, EAST BRANCH DELAWARE RIVER 23

TABLE 6. Daily mean tempera-hire*, Sacandaga River near Hope, N. V., 

February 8 to March 8, .1936

Feb. 

8 ..................

9 ..................

10 ..................

11 ..................

1?

13 ..................

14 ..................

IS ..................

16 ..................

17 ..................

18 ..................

19 ..................

20 ..................

21 .................. ">")

Mean temperature 

(°F.)

6

19

19

5

5

7

IS

26

16

90

1 ft

4

3

4

3

Feb. 

91

94

25 ...................

26 ...................

27 ...................

28 ...................

?Q

1 ...................

2 ...................

3 ...................

g

7 ...................

8 ...................

Mean temperature 

(°F.)

8

13

v>

34

\&.

26

14

IS

8

28

97

12

20

11

17

16

^Average of recorded daily maximum and minimum temperatures at Indian Lake and Gloversville, N. Y.

Direct runoff associated with the second period, as computed in 

table 10, was 5.23 inches. There was an elapsed time intervaj of 45 hours 

between the centers of mass of supply and direct runoff.

The direct runoff totaled 7.11 inches. Total precipitation was 5.23 

inches and snow melt was 3.25 inches making a total supply of 

8.48 inches, indicating a retention of 1.37 inches. However, ground-water 

runoff approximated 2.8 inches, pointing to an underestimation of the 

gross areal supply of at least 1.43 inches.

At a point some 30 miles below the gaging station, the flow of the 

Sacandaga River was impounded in the Sacandaga Reservoir, the level 

of which rose over 20 feet during the storm period. The storage of this 

large volume of water materially diminished the flood damage created 

by the Hudson River below Hadley, N. Y., and saved the city of Albany 

from destruction like that wrought by the flood of March 1913.

EAST BRANCH OF DELAWARE RIVER AT FISHS EDDY, N. Y.

The snow cover in this basin seemed to become depleted more rapidly 

than it did in any of the other basins studied herein. The initial quantity 

estimated at 4.7 inches water content, entirely disappeared during the 

storm period. This rapid melting probably resulted from the higher 

temperatures prevailing over the area, the average during the storm 

being 42.5° F., with an average below freezing on only one day.

The above estimate of snow cover is an average between that of 4.8 

inches given in Water-Supply Paper 799, and 4.6 inches derived as 

follows: Precipitation between December 1, 1935, and March 8, 1936, 

was about 8.8 inches, while associated runoff totaled 4.2 inches leaving 

an indicated retention of 4.6 inches, mostly as snow. Runoff associated

689521 47 3
24 FLOODS IN NEW YORK AND PENNSYLVANIA

TABLE 7. Gage height and discharge of the Sacandaga River near Hope, N. Y., 

during flood of March 1936

MEAN DISCHARGE, IN SECOND-FEET, 1936

Day

1 

2 

3.....

4.....

5.....

6... ._

7.....

8 

9.....

10.. 

Feb.

260

260

240

240

260

240

240

240

220

220

Mar.

300

260

260

280

340

420

360

320

300

340

Apr.

4,970

4,200

4,080

3,340

2,920

8,020

7,630

5,300

4,080

3,480

Day

11 

12 

13 

14 

15 

16 -.

17 ..

18 -.

19.....

20 ..

Feb.

220

200

200

200

240

220

200

200

190

190

Mar.

460

6,000

8,420

5,000

3,720

3,550

7,840

19,400

15,400

11, 800

Apr.

3,340

3,500

3,270

2,960

2,960

3,150

3,060

2,670

2,380

2,110

Mean monthlv discharse. in second-feet

Runoff, ir

Day

21.....

22.....

23 

24 

25.....

26 

27 

28.....

29 

30 

31 

Feb.

180

180

170

170

160

220

300

380

340

227

0.50

Mar.

8,720

7,690

5,620

5,250

7,470

7,480

8,960

9,620

6,930

6,120

6,120

5,315

12.47

Apr.

2,170

2,190

1,960

1,780

1,600

1,500

1,400

1,300

1,260

1,400

3,133

7.12

GAGE HEIGHT3, IN FEET, AND DISCHARGE, IN SECOND-FEET, AT INDICATED TIME, 1936

Hour

2--. . .......

6...........

8. .....

10- 

12m. 

2.... .... ....

4.. ....... ...

6.L . ......

8... .....

10. . 

12 p. m .......

2.... ........

4_ 

6.... ....

8... .... -

10. 

12m ...... .

2 __ ........

4............

6....... .....

8. 

10. 

12 p. m .......

2. ..

4-. ....

6.. ...... ....

8. .......

10-.. .-.

12m ....

2,. ....

4.... ... .....

6...... ..... .

8.. ...

10 

Feet Sec.-ft.

March 8

3.56

3.73

3.81

b320

March 14

5.47 

5.36 

5.24 

5.15 

5.11 

5.06 

5.04 

4.98 

4.94 

4.91 

4.87 

4.83

6,030 

5,700 

5,360 

5,110 

5,000 

4,860 

4,810 

4,650 

4,540 

4,470 

4,370 

4,270

March 20

7.66 

7.58 

7.47 

7.32 

7.16 

7.02 

6.88 

6.80 

6.73 

6.66 

6.57 

6.45

14,300 

13,900 

13,400 

12,800 

12,100 

11,600 

11,000 

10,700 

10,400 

10,100 

9,790 

9,330

Feet 8ec.-ft.

March 9

3.81 t>300

March 15

4.79 

4.76 

4.71 

4.69 

4.62 

4.60 

4.56 

4.48 

4.42 

4.40 

4.38 

4.36

4,180 

4,110 

3,990 

3,950 

3,790 

3,750 

3,670 

3,500 

3,380 

3,340 

3,300 

3,260

. March 21

6.33 

6.22 

6.15 

6.07 

6.08 

6.14 

6.23 

6.32 

6.37 

6.39 

6.39 

6.37

8,890 

8,490 

8,240 

7,960 

8,000 

8,210 

8,530 

8,850 

9,030 

9,100 

9,100 

9,030

Feet Sec.-ft.

March 10

3.96 b340

March 16

4.32 

. 4.29 

4.29 

4.29 

4.32 

4.39 

4.48 

4.58 

4.66 

4.78 

4.90 

5.12

3,190 

3,130 

3,130 

3,130 

3,190 

3,320 

3,500 

3,710 

3,880 

. 4,150 

4,440 

5,030

March 22

6.33 

6.27 

6.20 

6.12 

6.01 

5.95 

5.90 

5.84 

5.80 

5.73 

5.67 

5.60

8,890 

8,670 

8,420 

8,140 

7,760 

7,550 

7,380 

7,180 

7,050 

6,830 

6,640 

6,420

Feet Sec.-ft..

March 11

4.07

4.30

b460

819

March 17

5.42 

5.58 

5.72 

5.82 

5.87 

5.78 

5.95 

6.05 

6.25 

6.53 

6.79 

7.10

5,880 

6,360 

6,790 

7,120 

7,280 

6,990 

7,550 

7,900 

8,600 

9,520 

10,700 

11,900

March 23

5.45

5.30

5.24

5.28

5.29

5.26

5,970

5,530

5,360

5,470

5,500

5,420

Feet Sec.-ft.

March 12

5.11

5.20

5.86

6.20

6.39

6.68

1,870

5,250

6,990

8,180

9,100

10, 200

March 18

7.39 

7.69 

8.10 

8.70 

9.53 

9.38 

9.27 

9.23 

9.07 

8.85 

8.66 

8.45

13,100 

14,400 

16,500 

19,700 

22,100 

23,800 

23,100 

22,900 

21,900 

20,600 

19,500 

18,200

March 24

5.20

5.14

5.07

5.16

5.30

5.45

5,250

5,080

4,890

5,140

5,530

5,970

Feet Sec.-ft.

March 13

6.67 

6.60 

6.57 

6.45 

6.32 

6.19 

6.05 

5.96 

5.84 

5.76 

5.66 

5.59

10,200 

9,900 

9,790 

9,330 

8,850 

8,380 

7,900 

7,580 

7,180 

6,920 

6,610 

6,390

March 19

8.29 

8.13 

8.00 

7.91 

7.80 

7.72 

7.72 

7.73 

7.74 

7.78 

7.77 

7.73

17,400 

16,600 

16,000 

15,600 

15,000 

14,600 

14,600 

14,600 

14, 700 

14,900 

14,800 

14,600

March 25

5.59 

5.68 

5.72 

5.76 

5.77 

5.79 

5.89 

6.03 

6.20 

6.28 

6.32 

6.30

6,390 

6,670 

6,790 

6,920 

6,950 

7,020 

7,350 

7,820 

8,420 

8,710 

8,850 

8,780

 Supplemental records: Mar. 12, 5 a.m., 10.08 ft. (backwater from ice); 6:50 a.m., 8.74 ft. 

(backwater from ice); 6:20 p.m., 7.40 ft. (backwater from ice); Mar. 18, 12:30 p.m., 9.40 ft., 

23,900 sec.-ft.

bMean for the day.

LOCATION. Water-stage recorder, lat. 43°21'10", long. 74°16'1S", V/2 miles below junction of 

East and West Branches of Sacandaga River and 4H miles above Hope, Hamilton County. 

DRAINAGE AKEA. 491 square miles. 

REMARKS. Records published in Geol. Survey Water-Supply Paper 799.
FLOODS OF MARCH 1936, EAST BRANCH DELAWARE RIVER 25

TABLE 8. Computation of volume of direct runoff associated ivith precipitation 

period March 8-14, 1936, Sacandaga River near Hope, N. Y.

March

10 ..............

11 ..............

19

13 ..............

14 ..............

IS ..............

16 ..............

17 ..............

18 ..............

19 ..............

Total

12-hour period 

ending 

12 m.

12 p.m.

12 p.m. 

12 m

12 p.m. 

12 m.

12 p.m. 

i f\

12 p.m. 

12 m.

12 p.m. 

12 m.

12 p.m. 

12 m.

12 p.m. 

12m.

12 p.m.

Daily mean 

di?char<?e 

(second-feet)

3 SO

S10

3,610 

8,700 

9,620

7,220 

5,580

4,500 

3,930

3,520 

 3,000

"2,600 

*° 300

»2,OSO 

"1.8SO

M.650 

 1,550

 1,450

64,400

32,200

Estimated recession from 

preceding storm 

ati'l base runoff 

(second-feet)

350

370

390 

410

430 

480

530 

sun

630 

700

770

QA A

920 

1,000

1,090 

1,180

1,270 

1,360

1,450

14,750

7,375

Direct runoff 

(second-feet)

0

40 

120

3,200 

8,270

9,140

6,690

5,000

3,870

3,230 

2,750 

2,160

1,680 

1,300

960 

670

380 

190

0

49,650

24,825 (-

1.88 inches)

 Estimated recession under subsequent rise.

TABLE 9. Computation of time of center of mass of net supply, and lag intervals, 

Sacandaga River near Hope, N. Y., March 8-14, 1936

March

8 ........

9 ........

10 ........

11 ........

12 ........

13 ........

14 ........

Total .......

12-hour 

period 

ending

12m.

12 p.m. 

12m.

12 p.m. 

12 m.

12 p.m. 

12 m.

12 p.m. 

12m.

12 p.m. 

12 m.

12 p.m. 

12m.

12 p.m.

Mean 

areal 

precipitation 

(inches)

0.02

.07 

.06

.07 

.11

.05 

.21

.47 

.33

.11 

.10

.15 

.09

.02

1 Q/C

Estimated 

snow 

melt 

(inches)

 0.02

 .0 

 .04

.07 

.07

.15 

.11

.24 

.14

.38 

 .05

.15 

 .07

.05

1.18

Precipitation plus 

snow 

melt 

(inches)

0

.07

no

.14 

.18

.20 

.32

.71

.47

.49 

.05

.30 

.02

.07

3 04

Net 

supply 

(inches)

0

0

0

.05 

.10

.11

.20

.50 

.32

.34 

.02

.21 

0

.03

1.88

Time from 

origin 

(days)

0

.5

1 

1.5

2

2.5

3 

3.5

4 

4.5

5 

5.5

6

Product 

(inchdays)

0 

0

.05 

.15

.22

.50

1.50 

1.12

1.36 

.09

1.05 

0

.18

6.22

 Estimated result of snowfall and thawing.

£ f\e\

Center of mass of net supply occurred l.S = 3.31 days after 6 p.m. of March 8 = March

12.06 ( =8.75 + 3.31).

Time of center of mass of direct runoff was at March 14.21 or 2.15 days (52 hours) after 

center of mass of net supply.

Peak discharge occurred at 1 a.m. March 13 or 1.05 days (25 hours) after center of mass 

net supply.
26 FLOODS IN NEW YORK AND PENNSYLVANIA

TABLE 10. Computation of volume of direct runoff associated with precipitation 

period March 15-22, 1936, Sacandaga River near Hope, N. Y.

March

16 ..................

17 ..................

1 Q

19 ..................

20 ..................

91

22 .................

93

24 ..................

25 ..................

26 ..................

97

28 ..................

29 ..................

Total:

Daily mean discharge 

(second-feet)

3,150

3,950 

6,670

9,010 

17,200

21,600 

16,100

14,700 

13,200

10,400

8 30ft

8,880 

8,390

6,990 

5,760

 4,700 

 4,050

 3,550 

'3 200

 2,900 

 2,600

 2,350 

 2,150

 2,000 

 1,850

 1,750

185,490

92,745

Estimated recession 

from preceding storm

and base runoff 

(second-feet)

3,000

2,600 

2,300

2,050 

1,850

1,650 

1,550

1,450 

1,500

1,550 

1,600

1,600 

1,650

1,700 

1,750

1,800 

1,800

1,800 

1,800

1,800 

1,750

1,750 

1,750

1,750 

1,750

1,750

47,300

23,650

Direct runoff 

(second-feet)

150

1,350 

4,370

6,960 

15,250

19,950 

14,550

13,250 

11,700

8,850 

6,790

7,280 

6,740

5,290 

4,010

2,900 

? ?So

1,750 

1,400

1,100 

850

600 

400

250 

100

0

138,190

69,095 ( =

5.23 inches)

"Estimated recession under subsequent rise.

TABLE 11. Computation of time of center of mass of net supply, and lag intervals, 

Sacandaga River near Hope, N. Y., March 15-22, 1936

March

15 .......

16 .......

17 .......

18 .......

19 .......

20 .......

21 .......

22 .......

I? 99

12-hour 

period 

ending

12m.

12 p.m. 

12m.

12 p.m. 

12m.

12 p.m. 

12m.

12 p.m. 

12m.

12 p.m. 

12m.

12 p.m. 

12m.

12 p.m. 

12m.

12 p.m.

Mean 

areal 

precipitation 

(inches)

0.05

.10

90

.52 

.56

.54 

.40

.22 

.14

.05 

.11

.17 

.11

.05 

.04

.02

3.37

Estimated 

snowmelt 

(inches)

0.00

.05 

.08

.16

.04

.21 

.18

.31 

.16

.28 

.08

.18

.07

.14 

.04

.09

2.07

Precipitation plus 

snowmelt 

(inches)

0.05

.15

37

.68

.60

.75 

.58

.53 

.30

.33 

.19

.35 

.18

.19 

.08

.11

5 44

Net 

supply 

(inches)

0.05

.15

.36

.65 

.59

.72

.55

.51 

.29

.32 

.18

.34 

.18

.18 

.08

.10

Z 9?

Time from 

origin 

(days)

0

.5 

1.0

1.5 

2.0

2.5 

3.0

3.5 

4.0

4.5 

5.0

5.5 

6.0

6.5

7.0

7.5

Product 

(inchdays)

0

.08 

.36

.98 

1.18

1.80 

1.65

1.78 

1.16

1.44 

.90

1.87 

1.08

1.17 

.56

.75

16.76

Center of mass of net supply occurred 16.76

5.25 = 3.20 days after 6 a.m. of March 15 =

March 18.45.

Time of center of mass of direct runoff was at March 20.23 or 1.88 days (45 hours) after 

center of mass of net supply.

Peak discharge occurred at 12:30 p.m. March 18 or 2 hours after center of mass of net 

supply.
FLOODS OF MARCH 1936, EAST BRANCH DELAWARE RIVER 27

with meteorologic events of March 26-31, after the flood period, was 

less than precipitation, indicating little, if any, contribution from melting 

snow.

There was a total rainfall of 6.23 inches over the hasiri distributed 

geographically as shown in figure 9 and distributed with respect to time

0Pleoiont tit

woo1

SCALE IN MILES 

10 £0

FIGURE 9. Map of basin of East Branch of Delaware River above Fishs Eddy N. Y., showing 

lines of equal precipitation, March 9-22, 1936.

as shown in table 12, which gives precipitation in 6-hour intervals at 

the indicated rain gages. Daily mean areal precipitation is given in 

table 14 together with daily maximum, minimum, and mean temperatures. Daily mean temperatures during the 30-day antecedent period are
28 FLOODS IN NEW YORK AND PENNSYLVANIA

given in table 13. The average temperature was 20° F., with an average 

above freezing on only 6 days.

Discharge at Fishs Eddy is given in table 15 and shown graphically 

on figure 10. The volume of direct runoff associated with the first flood 

period, as computed in table 16, was 3.08 inches. The total supply in the 

form of precipitation and melted snow was 4.42 inches leaving a retention 

of 1.34 inches. During the second flood period, the direct runoff was

50,000

24 25

Morch 1936

FIGURE 10. Hydrograph of East Branch of Delaware River at Fishs Eddy, N. Y., showing

discharge, March 1936.

5.45 inches from a total supply of precipitation, and estimated snow melt 

was 6.51 inches, leaving a retention of 1.06 inches. The total flood retention was therefore 2.40 inches. Ground-water runoff associated with the 

flood period, as computed by methods previously explained, was 2.1 

inches, indicating net field-moisture increment and evaporation losses of 

only 0.3 inch, which is very low in view of the total quantity of water,
TABLE 12. Precipitation, in inches, for 6-hour periods, a

East Branch of Delaware River at Fishs Eddy, N. 

Station 

(New York)

Delhi . .. -.-. _ .. _ . 

Jeffersonville ___ . ____ ..-.. _ _-.

Pine Hill..............................

Prattsville- ------------- - . . ....

Slide Mountain-.. ___________

Weight 

(percent)

0.6

25.8

8.3

0.4

26.0

18.4

0.5

12.4

7.6

100. 00

6-hour 

period 

ending

6a.m. 

12m. 

6 p.m. 

12 p.m. 

6a.m. 

12m. 

6 p.m. 

12 p.m. 

6a.m. 

12m. 

6 p.m. 

12 p.m. 

6a.m. 

12m. 

6p.m. 

12 p.m. 

6a.m. 

12m. 

6p.m. 

12 p.m. 

6 a.m. 

12m. 

6 p.m. 

12 p.m. 

6a.m. 

12m. 

6 p.m. 

12 p.m. 

6 a.m. 

12m. 

6p.m. 

12 p.m. 

6a.m. 

12m. 

6p.m. 

12 p.m.

6a.m. 

12m. 

6p.m. 

12o.m.

8

0.00 

.00 

.00 

.13 

.00 

.00 

.00 

.02

.00 

.00 

.00 

.08 

.00 

.00 

.00 

.16 

.00 

.00 

.00 

.01 

.00 

.00 

.00 

.04

.00 

.00 

.00 

.12 

.00 

.00 

.00 

.01 

.00 

.00 

.00 

.09

0.00 

.00 

.00 

.03

9

0.00 

.11 

.19 

.11 

.00 

.08 

.15 

.05 

.00 

.05 

.08 

.05 

.00 

.02 

.03 

.02

.01 

.03 

.04 

.00 

.00 

.01 

.01 

.00 

.00 

.00 

.01 

.00 

.00 

.07 

.10 

.00

.00 

.01 

.01 

.01

0.00 

.05 

.07 

.01

10

0.02 

.00 

.00 

.00 

.02 

.00 

.00 

.00

.01 

.02 

.03 

.02 

.00 

.01 

.01 

.01 

.00 

.00 

.00 

.00 

.00 

.06 

.06 

.05 

.00 

.01 

.00 

.01

.00 

.00 

.00 

.00 

.00 

.06 

.06 

.06

0.01 

.02 

.02 

.01

11

0.00 

.01 

.05 

.06 

.00 

.00 

.00 

.11 

.03 

.13 

.48 

.57 

.02 

.03 

.11 

.13 

.00 

.05 

.16 

.14 

.05 

.12 

.44 

.53 

.01 

.04 

.15 

.18

.00 

.09 

.31 

.12 

.07 

.17 

.63 

.75

0.02 

.07 

.25

.28

12

0.13 

.07 

.26 

.13 

.21 

.04 

.16 

.20 

1.09 

.00 

.02 

.01 

.26 

.03 

.11 

.05 

.29 

.05 

.23 

.06 

1.01 

.06 

.26 

.13 

.33 

.04 

.16. 

.08 

.24 

.04 

.19 

.17 

1.45 

.04 

.18 

.09

0.55 

.04 

.19 

.13

13

0.05 

.00 

.00 

.06 

.08 

.00 

.00 

.00 

.00 

.00 

.00 

.01 

.02 

.00 

.00 

.10 

.04 

.00 

.00 

.00 

.05 

.00 

.00 

.01 

.03 

.00 

.00 

.00 

.08 

.00 

.00 

.04 

.04 

.00 

.00 

.04

0.05 

.00 

.00 

.01
30 FLOODS IN NEW YORK AND PENNSYLVANIA

10.93 inches, involved. The following is an inventory of the rainfall and 

runoff during the winter season of 1935-36 in this basin:

Period

December 1, 193S to March 8, 1936.... 

March 9-22 .........................

March 23-31 ........................

Total .........................

Rainfall and runoff (inches)

Precipitation

8.8 

6.2 

1.6

16.6

Runoff

4.2 

10.6 

1.4

16.2

Difference

4.6

 4.4 

.2

0.4

Although the above inventory shows a positive balance to allow for 

evaporation losses and soil-moisture accretion, it seems too low to be

TABLE 13. Daily mean temperature*. East Branch of Delaware River at 

Fishs Eddy, N. Y., February 8 to March 8, 1936

Day

Feb. 

8 .................

9 .................

10 .................

11 .................

12 .................

13 .................

14 .................

15 .................

16 .................

17 .................

18 .................

19 .................

20 .................

21 .................

22 .................

Mean .........

Mean temperature 

(°F.)

17

7

9

14

7

24

30

20

33

19

2

3

7

8

Day

Feb. 

21

24 ..................

9S

26 ..................

27

OQ

9Q

Mar.

1 ..................

3 ..................

4 ..................

5 ..................

6 ..................

7 ..................

Mean temperature 

<°F.)

8

18

39

38

40

00

22

24

 16

31

36

36

20

20

22

20

"Average of recorded daily maximum and minimum temperatures at Delhi, Jeffersonville, and 

Roxbury, N. Y.

TABLE 14. Daily mean arcal precipitation and temperatures, F,ast Branch of 

Delaware River at Fishs Eddy, N. Y., March 8-22, 1936

March

8. .............

9..............

10..............

11..............

12..............

13..............

14..............

15..............

16..............

17..............

18..............

19..............

20..............

21..............

99

Mean areal 

precipitation 

(inches)

0.03

.13

.06

.62

.91

.06

.04

.02

.98

.77

1 37 '

.44

.04

.76

0

6.23

Maximum* 

(°F.)

40

47

59

51

52

34

44

60

55

62

58

55

57

49

46

51

Temperature

Minimum8 

(°F.)

4

31

31

35

32

9S

2S

30

38

36

45

39

33

37

31

31

Meanb 

(°F.)

22

39

45

43

42

29

35

45

46

49

51

47

45

43

38

41

 Average of readings at Delhi, Jeffersonville, and Roxbury, N. Y. 

bAverage of maximum and minimum.
FLOODS OF MARCH 1936, EAST BRANCH DELAWARE RIVER 31

TABLE 15. Gage height and discharge of the East Branch of Delaware River 

at Fishs Eddy, N. Y., during flood of March 1936

MEAN DISCHARGE, IN SECOND-FEET, 1936

Day Feb.

550

500

500

500

480

480

460

460

460

460

Mar.

1,100

1,000

900

900

1,100

1,300

1,000

800

850

1,700

Apr.

3,570

3,500

3,970

3,500

3,240

7,930

8,110

5,870

4,570

4,300

Day

11

12

13

14

15

16

17

18

19

20

Feb.

460

440

440

460

500

550

550

550

500

480

Mar.

9,000

29, 000

15, 800

7,890

6,020

7,090

23, 200

38, 600

23,100

12, 800

Apr.

4,220

4,240

5.880

6,490

6,270

5,650

4,820

4,050

3.520

3,030

Day

21

22

23

24

25

26

27

28

29

30

31

Mean monthly discharge, in second-feet .

Runoff, in inches

Feb.

460

440

440

440

160

550

850

1,100

1,200

542

0.75

Mar.

11, 100

9,740

6,600

5,100

4.350

3,660

3,950

6,300

5,090

4,350

3,970

7,979

11.75

Apr.

2,850

3,310

2,660

2,410

2,210

2,050

1,890

1,690

1,590

1,480

3,962

5.64

GAGE HEIGHT*, IN FEET, AND DISCHARGE, IN SECOND-FEET, AT INDICATED TIME, 1936

Hour

2 

4 

6 

8 

10 

12 m. 

2 

4 

6 

8 

10 

12p.m.

2 

4 

6 

8 

10 

12m. 

2 

4 

6 

8 

10 

12p.m.

2 

4 

6 

8 

10 

12m. 

2 

4 

6 

8 

10 

12p.m.

Feet Sec.-'ft.

March 8

i>6.53 b800

March 14

9.04

8.67

8.37

' 8.07

7.86

7.71

9.140

8,340

7,750

7,200

6,820

6,550

March 20

11.40

10.84

10.32

9.87

9.50

9.16

15, 600

13, 900

12, 300

11,200

10, 200

9,420

Feet Sec.-ft.

March 9

t>6. 54 i>850

March 15

7.54

7.37

7.18

7.13

7.48

7.96

6,240

5,940

5,620

5,530

6,130

7,000

March 21

8.97

9.26

10.04

10.45

10.62

10.36

8,980

9,660

11, 600

12, 700

13, 200

12,400

Feet Sec.-ft.

March 10

6.82

7.10

7.43

7.96

1,220

1,550

2,090

2,920

March 16

8.01

7.92

7.85

7.88

8.01 

8.32 

8.82

7,090

6,930

6,800

6,850

7,090 

7,660 

8,650

March 22

9.96

9.57

9.24

8.91

8.60

8.36

11, 400

10, 400

9,620

8,850

8,200

7,730

Feet Sec.-ft.

March 11

8.16 

8.67 

8.92 

9.18 

9.89 

14.30 

16.25 

9.98 

11.37 

13.64 

13.60 

13.94

3,310 

3,770 

4,260 

4,890 

5,520 

6,270 

7,420 

8,790 

13, 400 

18, 300 

21, 600 

23, 600

March 17

9.76 

11.40 

12.94 

14.04 

14.59 

14.83 

14.85 

14.79 

14.78 

14.98 

15.28 

15.55

10, 900 

15, 600 

20, 200 

24,000 

25, 900 

26, 800 

26, 900 

26, 700 

26, 600 

27,400 

28,600 

29, 700

March 23

8.01

7.72

7.46

7.23

7,090

6,570

6,100

5,700

Feet Sec.-ft.

March 12

14.89 

15.90 

16.59 

16.61 

16.46 

16.01 

15.57 

15.13 

14.86 

14.63 

14.31 

13.90

27, 100 

31, 100 

33, 900 

33, 900 

33, 300 

31, 500 

29, 800 

28, 000 

26, 900 

26, 100 

24,900 

23,500

March 18

15.88 

16.31 

17.17 

18.13 

18.84 

19.19 

19.07 

18.61 

18.10 

17.51 

16.86 

16.13

31,000 

32, 700 

36, 300 

40, 600 

44, 200 

46, 000 

45, 400 

43, 000 

40, 500 

37, 800 

34, 900 

32, 000

March 24

7.03

6.86

6.68

6.55

5,360

5,080

4,790

4,580

Feet Sec.-ft.

March 13

13.01

12.20

11.31

10.59

10.00

9.49

20, 400

18, 000

15, 300

13, 100

11, 500

10, 200

March 19

14.90

14.28

13.65

13.12

12.53

11.96

27, 100

24,800

22,600

20, 800

19, 000

17, 200

March 25

6.46

6.41

6.31

6.15

4,440

4,360

4,220

3,980

 Supplemental records: Mar. 11, 3 p.m., 16.61 ft., 8,090 sec.-ft.; 5 p.m., 9.44 ft., 10,100 sec.-ft.; 7 p.m. 

14.96ft., 16,300sec.-ft. Mar. 12, 7:30a.m., 16.62ft., 34,000sec.-ft. Mar.,15 3 p.m., 7.11 ft., 5,5 Osec.-ft. Mar18, 12:30 p.m., 19.21 ft., 46,000 sec.-ft.

b Mean for the day.

LOCATION. Water-stage recorder, lat. 41°58'00", long. 75°10'SO", at railroad bridge in Fishs 

Eddy, Delaware County, 4l/2 miles below mouth of Beaver Kill. Zero of gage is 950.84 feet 

above mean sea level. 

DRAINAGE AREA. 783 square miles. 

REMARKS. Records published in Geol. Survey Water-Supply Paper 799.
32 FLOODS IN NEW YOUK AND PENNSYLVANIA

TABLE 16. Computation of volume of direct runoff associated with precipitation 

period March 8-15, 1936, East Branch of Delaware River at Fishs Eddy, N. Y.

March

8...............

9...............

10...............

11...............

19

13...............

14...............

IS...............

16...............

17...............

18...............

Total

12-hour 

period 

ending

12 m.

12 p.m. 

12 HL

12 p.m. 

12 m.

12 p.m. 

12 m.

12 p.m.

12 p.m. 

12 m.

12 p.m. 

12 m.

12 p.m. 

12 m.

12 p.m. 

12 m.

12 p.m. 

12 m.

12 p.m. 

12 m.

12 p.m.

Daily mean 

discharge 

(second-feet)

800

800

ft95

875 

1 ??5

2,162 

4 390

14,070 

31 140

27,200

in ->7n

12,450

ft ft1 ft

7,057 

6,088

 5,200 

 4,500

 3,800 

 3,300

 3,000 

 2,700

 2,500

162,170

81,085

Estimated 

recession from 

preceding storm 

and base runoff 

(second-feet)

800

800 

800

800

fl9 5

850 

900

1,100 

1,200

1,300 

1,350

1,400 

1,600

1,650 

1,700

1,800 

1,900

2,100 

2,200

2,300 

9 Ann

2,500

 tf O7S

16,138

Direct runoff 

(second-feet)

0

0

9C

75

400

1,312 

3,490

12,970

9O Q4fl

25,900 

17,920

11,050

7 91ft

5,407 

4,388

3,400 

2,600

1,700 

1,100

700 

300

0

129,890

ftA 045 =

3.08 inches

 Estimated recession under subsequent rise.

TABLE 17. Computation of time of center of mass of ne

East Branch of Delaware River at Fishs Eddy, N.

1 supply, and lag intervals, 

Y., March 8-15, 1936

March

9........

10........

11. .......

1?

13........

14........

15........

6-hour 

period 

ending

12 p.m.

12 m. 

6 p.m. 

12 p.m.

12 m. 

6 p.m. 

12 p.m.

12 m. 

6 p.m. 

12 p.m.

12 m. 

6 p.m. 

12 p.m.

12 m. 

6 p.m. 

12 p.m.

12 m. 

6 p.m. 

12 p.m. 

6 a.m.

Mean 

areal 

precipitation 

(inches)

0.00

.03 

.00

.05 

.07 

.01 

.01

.02 

.02 

.01

f!9

.07 

.25 

.28 

.55

.04 

.19 

.13 

.05

.00 

.00 

.01 

.02

.00 

.01 

.01 

.02

1.87

Estimated 

snow 

melt 

(inches)

0.00

.05

(\±

.09 

.13 

.10 

nft

.21 

.35 

.21 

.10

.16 

.22 

.17 

.08

.14 

.20 

.08 

.00

.00 

.00

a.01 

a.02

.03 

.09 

.05 

.00

2.55

Precipitation plus 

snow 

melt 

(inches)

0.00

.08 

.04

.14 

.20 

.11 

.09

.23 

.37 

.22 

19

.23 

.47 

.45 

.63

.18 

.39 

.21 

.05

.00 

.00 

.00 

.00

.03 

.10 

.06 

, .02

4.42

Net 

supply 

(inches)

0.00

.00 

.00

.04 

.06 

.04 

.05

.17 

.30 

.16 

.08

.17 

.38 

.37 

.53

.13 

.30 

.17 

.02

.00 

.00 

.00 

.00

.00 

.07 

.04 

.00

3.08

Time from 

origin 

(days)

0.00

.25 

.50

.75 

1.00 

1.25 

1.50

1.75 

2.00 

2.25 

9 cn

2.75 

3.00 

3.25 

3.50

3.75 

4.00 

4.25 

4.50

4.75 

5.00 

5.25 

5.50

5.75 

6.00 

6.25 

6.50

Product 

(inchdays)

0.000

.000 

.000

.030 

.060 

.050 

.075

.298 

.600 

.360 

.200

.468 

1.140 

1.203 

IB<;C

.488 

1.200 

.722 

.090

.000 

.000 

.000 

.000

.000 

.420 

.250 

.000

9.509

"Estimated result of thawing and snowfall.

9 509 Center of mass of net supply occurred ' .. 0 = 3.

3.08

Time of center of mass of direct runoff was at 

center of mass of net supply.

Peak discharge occurred at 7:30 a.m. March 12 

of net supply.

09 days after 3 p.m. March 8 = March 11.72. 

March 13.15 or 1.43 days (34 hours) after 

or 0.59 day (14 hours) after center of mass
FLOODS OF MARCH 1936, EAST BRANCH DELAWARE RIVER 33

acceptable. There is some indication here that rainfall data during this 

flood in the mountainous region drained by the East Branch of the 

Delaware River were inadequate and that the gross water supply was 

probably greater than was indicated by available records.

Tables 17 and 19 give mean areal precipitation at 6-hour intervals 

and the estimated snow melt during concurrent intervals. The estimates 

of snow melt were made by distributing the total amount through the 

flood period on the basis of temperature, reducing the rate somewhat as 

the snow cover diminished. Snow was assumed to have been entirely 

gone by March 21. The total supply listed in tables 17 and 19 was converted into net supply by the methods previously explained, and the time 

of center of mass computed for each flood period. The lag interval 

between the center of mass of net supply and center of mass of direct 

runoff for each flood period as computed in tables 17 and 19 was 34 hours 

and 36 hours for the first and second periods, respectively. The lag 

interval from the center of mass of net supply to the flood peak was 14 

hours and 12 hours for the first and second periods, respectively.

TABLE 18. Computation of volume of direct runoff associated with precipitation 

period March 15-21, 1936, East Branch of Delaware River at Fishs Eddy, N. Y.

March

IS...............

16...............

17...............

18...............

19...............

20...............

91

2?

23......... . ..

24...............

25...............

26...............

27...............

Total

12-hour 

period 

ending

12 m.

12 p.m. 

12 m.

12 p.m. 

12 m.

12 p.m. 

12 m.

12 p.m. 

12 m.

12 p.m. 

12 m.

12 p.m. 

12 m.

12 p.m. 

12 m.

12 p.m.

19 «*

12 p.m.

1 O .M

12 p.m.

19 «M

12 p.m. 

12 m.

12 p.m. 

12 m.

Daily mean 

discharge 

(second-feet)

£. noo

5,970 

6,970

7,185 

19,050

27,400 

37,100

40,100 

26,400

19,730 

14,750

10,750 

9,715

12,630 

10,940

8,575 

7,120

6,120 

 5,100

 4,350 

 3,610

 3,000

 2,550

 2,300 

 2,100

299,613

149,806

Estimated 

recession from 

preceding storm 

and base runoff 

(second-feet)

£ f»QQ

5,200 

4,500

3,800 

3,300

3,000 

2,700

2,500 

2,500

2,500 

2,400

2,400 

2,400

2,400 

2,300

2,300 

2,300

2,300 

2,200

2,200

9 9ftQ

2,200 

2,100

2,100 

2,100

69,988

34,994

Direct runoff 

(second-feet)

0

770 

2,470

3,385 

15,750

24,400

 tA A-\e\

37,600

23,900

,17,230 

"l2,350

8,350 

7 315

10,230 

8,640

6,275 

4,820

3,820 

2,900

2,150 

1,410

800 

450

200 

0

229,645

114,822 =

5.45 inches

 Estimated recession under subsequent rise.
34 FLOODS IN NEW YORK AND PENNSYLVANIA

TABLE 19. Computation of time of center of *mass of net supply, and lag intervals, 

East Branch of Delaware River at Fishs Eddy, N. Y., March 15-22, 1936

March

15........

16... .. ...

17........

18........

19.......

9(\

21. .......

22. .......

6-hour 

period 

ending

12m.

6 p.m. 

' 12 p.m.

12 m. 

6 p.m.

12 p.m.

12m. 

6 p.m. 

12 p.m.

12 m. 

6 p.m. 

12 p.m.

12m. 

6 p.m. 

12 p.m.

12m. 

6 p.m. 

12 p.m.

12 m. 

6 p.m. 

12 p.m.

Mean areal 

precipitation 

(inches)

0

0 

0 

0

.13

.20 

.65

91

.07 

.16 

.33 

' .90

.28 

.08 

.11

90

.05 

.14 

.05 

.00

.00 

.00 

.04

.45

.11 

.16 

.04 

.00

4.36

Estimated 

snow 

melt 

(inches)

0.11

.20 

.14 

.09

.15

.22 

.13 

.05

.12 

.19 

.14 

.09

.11 

.13 

.07 

.03

.04 

.05 

.03 

.00

.02

.02 

.02

2.15

Precipitation plus 

snow melt 

(inches)

0.11

.20 

.14 

.09

.28

.42 

..78

.19 

.35 

.47 

.99

..39 

.21 

.18

93

.09 

.19 

.08

.00

.02 

.02 

.06 

.45

.11

.16 

.04 

.00

6.51

Net 

supply 

(inches)

0.07

.15 

.10 

.06

.23 

.37 

.70 

99

..16 

.30 

.42 

.90

.35 

.18 

.15 

in

.06 

.15 

.05 

.00

.00 

.00

.02 

.40

.08 

.13 

.02

.00

5.45

Time 

from origin 

(days)

0

.25 

.50 

.75

1.00 

1.25 

1.50

1.75

2.00 

2.25 

2.50

9 7?

3.00 

3.25 

3.50 

3 75

4.00 

4.25 

4.50 

4.75

5.00 

5.25 

5.50 

5.75

6.00 

6.25

6.50 

6.75

....

Product 

(inchdays)

0

.038 

.050 

.045

.230 

.362 

1.050

3QC

.320 

.675 

1.050

1.050 

.585 

.525 

.679

.240 

.637 

.225 

.000

.000 

.000 

.110 

2.300

.480 

.812 

.130 

.000

14.458

Center of mass of net supply occurred ^-rz = 2.65 days after 9 a.m. of March 15 = March )»45 

18.03.

Time of center of mass of direct runoff was at March 19.52 or 1.49 days (36 hours) after 

center of mass of net supply.

Peak discharge occurred at March 18.52 or 0.49 day (12 hours) after center of mass of 

net supply.
TABLE 20. Hourly precipitation, in inches, at recording gages in and near Sus

[In this table, "a" indicates no record, "T" indicates a trace of precipitation, "leaders" indicate zero 

been included in the following measurement

Station

Arnot Forest, N. Y- ____ ......

U. 8. Soil Conservation Service.

U. 8. Weather Bureau. 

China, N.Y.........................

U. 8. Geological Survey.

Day

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22

9

10 

11 

12 

13 

14 

15 

16

a.m.

1

....

0.03 

.03

.04 

.26 

.05 

.02

~.~03

.01 

.02

.06

.01 

.20 

.06

 rp

.01

.01

2

....

0.03 

.03

.04 

.18 

.11 

.02

T 

T

.06

*

.02 

.47 

.12

T 

T

.01

.04 

01

3

6" 01

.03 

.02 

01

01

08

.04 

.15 

.18 

.02

T 

.01

.01 

.02 

.01

.02 

.32 

.13

.09

.02

.07

01

4

67oi

.03

.12

.03 

.02 

.06

.06

T

.01

.07 

.13 

.17

.06

.08 

.03

5

 

0.01

.06

.04

.23

.15

T

T

.01 

T 

.12 

.07

.12

.04

6

 

0 06

.04

.23

.22

T

T 

T 

.08 

T

.14

.02

7

....

0.06

.04

.08

.10

T

.04 

.01 

.03

.08

.01

.04

8

....

0 08

.03

.04

.10

T

T

.05 

.01 

T

.01

01

02

9

....

0.02

.04

.10

.01

.02

.14 

T

T

.02

05

,05

10

....

0.02

,01

.15

.01

.04

.02

T 

T

.16 

.02

T

04

.01

.10

11

0.02

.02

,07

.03

.01

.03

T 

.01

.04 

.01

T

05

01

 -

07

12

0.02

.02

,06

.03 

01

.01

.03

.01 

.01

T

T

.04

.04

.01 

01

1

0.02

.02 

.03

.03

.01

T

.01 

.01 

T

.01

.05

01

.01

.01

.01

2

0.02

.02 

.10

.03

T

T 

.02

T

.05

.06

.01

01

....

0.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0
TABLE 20. Hourly precipitation, in inches, at recording gages in and near Susquehann

Station

China, N. Y. (Con.).. - - -

Clarion, Pa. (Piney). _ ........ __ .

Pennsylvania Electric Co.

U. 6. Soil Conservation Service.

U. 8. Weather Bureau.

Day

17 

18 

19 

20 

21 

22

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22

9

10 

11 

12 

13 

14

a.m.

1

.04

.05

....

.01

.02

.06 

.10 

.05 

.08

.01

.02

.04

~."08 

.03

....

.02 

.01

2

.06 

.09 

,05

....

....

.02

.14 

.20 

.06 

.01

T6I 

.02 

.05

 -

T

3

.02 

.08 

07

.06

.01

.03

.16 

.25 

.04

.03

01

.03 

.05 

.04 

.13

.01

4

.04 

.19 

0?

.03

.01

.01

.04 

.21 

.04 

,01

05

.01

.13 

.07 

.05 

.10

.02

T 

.01

» 5

.03 

.20 

02

.13

....-

01

02

01

.05 

.14 

.06

05

01

.07 

.02

.16

.06

T 

.01

6

.02 

.18 

.01

.14

 

01

.06 

.26 

.06

03

02

.02 

.12

.18

.14

T 

.01

T

7

.02 

.09

.12

.01 

01

02

01

.05 

.26 

.07 

0?

04

.02 

.29 

01

.20

.19

T 

T 

.02

8

.03 

.03

.04

.05 

01

,01

.03 

.17 

.07 

.02

.03

.01

.02

.06

T 

T 

.01

9

.02 

.05

01

.01 

01

.02

01

.01

.01

.01 

.23 

.08

03

~."6i

....

T 

.01

10

.02 

.03 

01

.01

"oi

.01

09

.02 

.26 

.10 

.01

03

.01 

.06

.04

.04

.04 

.01

11

~.~6i

,07

.01 

.01

,02

.04

01

01

.05 

.14 

.13

.05

.01 

.04

.04

.01

.

.08 

.13

12

....

11

.01 

01

.01

05

01

.02 

.27 

.11

05

.01

.02 

.15

....

.14 

.10

1

"oi

,02

.01

....

.03

,01

02

.06 

.36 

.12 

,01

,06

.02

.02 

.10

.01

.12 

.10

2

....

.11

04

02

.02 

.10 

.07 

.01

01

.06

.01 

.11

....

.28 

.10

3

....

.16

.01

.05

.11

01

.02 

.11 

.03

.02

"."16

....

.10 

.08
Rochester, N. Y __ ........ ......

16

17

10

19

20

21

OO9

10

11

12 

13

14

15

16

17 

in

19 

20

21

229

10

11

12

13

14

15

16

17

18

19

20

21

229

10

11

12 

13

14

15

16 

17

18

19

20

21

22

T

,09

.05 TT

.04 

05

T TT

08*TT

08

.08

13TTT

.01

.10

"oi

,03

.14

04

.01 

.01

.06 

05

.02 TT

06TT

01

,09

09

05T

.03

.02

....

.03

02

01

03

0?

.09

.01 T

.06 

05

.07TT

.02TT

.17

,10

10T

02

.01 

.01

"04

.07

01

01

,18T

.01T

.06

06

.08

01T

01

11

08

09

.05

.02 

02

,02 

,02

.20

01

02

01

08

.01T

.05 

,05

.09TTT

12T

10

.03

"02

.05

.10

02

04

T

11

,02T

.09 

.04

.10TT

07

03

.02

"oi

.05 

03

09

04

,01

,08

.01

.01

.10 

04

.10

 01T

03

.02T

,03

"oi

.10 

02

.06

.02

02T

.07T

.07 

02

.12

O4TT

O4

,01

,01

.01 

,01

.05

.04

,02

T

10

.01

.05 

,01

.11

.10TT

,03TT

.05

.01

.21 

.01

f\A

T

.01

"T

.03 T

.01

.06

01T

,05

....

.31

03

01

01

T

01T

T T

.02 T

.01

05T

01

05

....

.04

02

10

01

T

01

.01TT

.02T

04TTTT

,07

04

.02

....

02

,02

,01

TTT

,05

.01 T

.03T

06T

02T

04T

,08

.01

....

01

,04

TT

,05T

02

.05 

01

.04

.01

.06T

,03TTT

,06

.07

.03

.07

01
TABLE 20. Hourly precipitation, in inches, at recording gages in and near Susgueha

Station

U. S. Weather Bureau. 

Truxton, N. Y._.._. .................

U. 8. Geological Survey.

Day

9

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22

9

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22

a.m.

1

*

*

*

.08 

.02 

.02

.03 

.09

.01 

~.~6l

2

\

*

,05

.10 

.01

.18 

.01

.01

~.~6i

3

.12 

.01

*

*

03

.07 

.01

.01

.16

.^

~.~6i

4

.10

*

.01

.04

.01

.11 

03

.16 

,09

~."02

5

*

.11

,02

.18 

.Ofi

~."03

6 

.09

*

.25

.09

.06

12

.09

7

* 

T

.07

.12

,04

.09

8

.08 

T

.22

.60 

.24

.27

.02

.07

,13

.08 

,02

.09

9

*

T

T

03

01

.03 

.11

.05 

01

.04

10

T

T

T

T

*

02

02

.03 

,0?

.04

01

.05

11 

T

T 

.01

T

.10

,01

.04 

01

.05

.04

12

* 

*

.01

T

.02

.03

.01

1

*

T

01

....

....

2

.03

*

*

.04

.03

05

....

3

 

.0

.0

.0

0

...
FLOODS OF MARCH 1936, CHEMUNG RIVER 39

TABLE 21. Reported snowfall, in inches, at selected cooperative Weather Bureau

stations, Susquehanna River basin, March 9-22, 1936

[In this table "T" indicates a trace]

Station

New York: 

Alfred.. ..............

Cooperstown ___ ...

Elmira......

Franklin. . .........

Hammondsport _ . _

Woodhull.. ....... ..

Pennsylvania:

Bellefonte. _ . ___ ..

Cleat-field.. .. ....

Hanover..... . __ .

Lawrenceville

Morris Run ___ .

Wellsboro ....

March

9

T

10 11

*

1.5

12

8 

6 

2

3.5 

4

8

1

3

1

4

6

3 

2 

4.5 

T

5.5

13

4 

3 

5 

2 

3.5

2

5.5 

2

2.5

6

3 

0.5

2 

2

4 

3

1.5

14

1 

T

1 

2

2

2 

2

1

T 

T

15

-----

-----

.....

16

1

1

3

T

T

17

5 

4

2

2

2

T

18

4 

3

-----

T

19

1.5 

2 

3

2

T

T

4

T

T

T 

2

1

.5

20

1

2

2.5 

1

2

1

.5

21

3.5 

4 

2

1

3

1

5 

3

1

4

6

4

3

.5

5 

T

4

22

""T

T

.....

T

CHEMUNG RIVER AT CHEMUNG. N. Y.

Table 22 lists the computed calendar-day precipitation at all rain gages 

in and near the Chemung River Basin, for the period March 8-21, 1936. 

The indicated calendar-day amounts at the nonrecording rain gages were 

computed by the methods previously explained on the basis of time 

distribution of rainfall registered at the autographic rain gages, as 

published in table 20. The daily mean areal precipitation was computed 

by averaging the precipitation at the several rain gages on the basis of 

the indicated weights, of which the rain gage at Woodhull, N. Y., has 

the greatest, controlling 560 square miles of the total basin area of 

2,530 square miles. In table 22 are listed 11 rain gages, an average of 

230 square miles per rain gage. The areal distribution of the total precipitation is shown by the isohyetal map in figure 11.

The computed calendar-day precipitation is also listed in table 24 

together with the maximum, minimum, and average temperatures. These 

temperatures were computed on the basis of observations at Alfred, 

N. Y., Elmira, N. Y., Woodhull, N. Y., and Lawrenceville, Pa. Maximum daily temperatures were above freezing during the entire period 

and averaged below freezing only during 3 days. Daily mean temperatures during the 30-day period preceding the March 1936 floods are 

given in table 23. With the exception of those on 5 days, the temperatures were consistently below freezing.

689521 47 4
40 FLOODS IN NEW YORK AND PENNSYLVANIA

FIGURE 11. Map of Susquehanna and upper Delaware River basins showing lines of equal 

precipitation, March 9-22, 1936.
FLOODS OF MARCH 1936, CHEMUNG RIVER 41

Estimates of snow cover on March 9 and that remaining on March 25 

were based on observations given in Water-Supply Paper 799 supplemented by inventories of the total precipitation and runoff during the 

winter season of 1935-36. Temperatures from December 1935 through 

February 1936, were substantially below freezing. During this period 

precipitation over the basin averaged about 5.9 inches, and runoff to 

March 8 totaled 2.2 inches, leaving a retention of 3.7 inches, which 

represents the maximum possible snow cover on March 9. Records of 

snow depths from March 9-12, 1936, at places in and near the basin, 

as reported in Water-Supply Paper 799, ranged from a trace at Lawrenceville, Pa., to 30 inches measured at C. C. C. Camp 155, 13 miles west of 

Wellsboro, Pa. The available measurements are inadequate in number and 

distribution to give accurate indications of the snow cover, but if supplemented by an assumed water content of 25 percent they indicate a mean 

areal snow cover equivalent to about 2 inches water content. This 

estimate, which is unduly influenced by measurements made in towns 

where the cover is not representative, tends to be low and is probably 

near the minimum possible snow cover. The actual amount was probably 

within the range of 2.0 inches so determined and 3.7 inches determined 

as the maximum from an inventory of the precipitation and runoff during 

the preceding subfreezing season. For the purpose of this analysis the 

snow cover has been estimated as the average of these two determinations, or 2.85 inches.

The estimate of the amount remaining on March 23 at the conclusion 

of the flood precipitation period was similarly made. Temperatures after 

the flood averaged above freezing. During the period March 23 to 

April 2 the precipitation totaled about 0.3 inch whereas the runoff associated with events of that period totaled 1.45 inches pointing to a contribution of 1.15 inches from snow remaining on March 23. Many 

observations at Weather Bureau stations, as reported in Water-Supply 

Paper 799, indicate negligible snow after March 23; snow 2 inches deep 

was reported at Morris Run, Pa., on March 22. At various Civilian 

Conservation Corps camps outside the basin, heavier snow cover was reported. Based on this evidence, a net snow cover of 0.8 inch water content 

on March 23 was estimated. Following is a summary of the precipitation 

and runoff during the winter season of 1935-36:

Period

Dec. 1, 1935 

Mar. 9-22 

Mar. 23 to

Total.

to Mar. 6, 1936. .........

Rainfall and runoff (inches)

Precipitation

5.9 

6.6 

.3

12.8

Runoff

2.2 

8.2 

1.45

11.85

Difference

3.7 

 1.6 

 1.15

0.95

In the first period listed there was substantial snow accumulation, 

while in the last two the snow cover was depleted. Although some of the
42 FLOODS IN NEW YORK AND PENNSYLVANIA

CL
FLOODS OF MARCH 1936, CHEMUNG RIVER 43

precipitation of March 9-22 fell as snow, there was an apparent minimum net thawing of 1.6 inches. The total snow runoff during the flood 

period reported in table 27 is 2.05 (2.85 0.8) inches, which allows 

0.45 inch of the total seasonal retention of 0.95 inch for soil-moisture 

accretion and evaporation losses during the flood period only a small 

portion of the total amount of water involved.

Discharge at Chemung, N. Y., during the floods of March 1936, is 

given in table 25 and shown as a hydrograph in figure 12. The amount 

of direct runoff associated with the first part of the flood period (precipitation period March 9-14, 1936) has been computed as shown in table 26 

based on the discharge records in table 25. The total direct runoff was 

2.39 inches in comparison with 1.89 inches of precipitation and an estimated snow melt of 1.9 inches, leaving 1.40 inches available for infiltration, ground-water recharge, and evaporation losses. Ground-water runoff 

during this separate period has not been computed. In contrast to most 

other parts of the Susquehanna River Basin in March 1936, the Chemung 

River reached its highest stage during the first storm period, and its 

peak discharge on March 12 was the highest during the entire record.

The lag interval from center of mass of net supply to the peak discharge and to the center of mass of direct runoff has been computed as 

shown in table 27. Mean areal precipitation is for the calendar day and 

is taken from table 24. Estimated daily snow melt has been computed by 

distributing the total net amount for the flood (2.05 inches) on the basis 

of the daily excess in temperature above freezing. On certain days 

temperature and records, as shown in table 21, indicate that some of the 

precipitation fell as snow and remained as such at midnight of that day. 

This snowfall has been indicated in table 27 as minus snow melt, as 

previously explained. On March 13 the snowfall exceeded the thawing 

but on the following day the reverse was true. The net supply has been 

estimated on the basis of the total precipitation plus estimated snow 

melt. The computed lag intervals are 33 hours to the center of mass 

of direct runoff and 32 hours to the flood peak.

Direct runoff associated with the second precipitation period, March 

15-21, as computed in table 28, was 4.00 inches over the basin. This 

runoff was the result of 4.71 inches of precipitation, some of which fell 

as snow, and snow melt during the period. Most of the precipitation on 

March 17, 18, and 19 was in the form of snow because of the localized 

drop in temperature on those days. By the consequent alleviation of 

flood stages, this drop in temperature was a saving feature in many 

areas.

The lag intervals during the second period computed on table 29 

were 30 hours to the center of mass of direct runoff and 21 hours to the 

flood peak. The lag interval to the center of mass of direct runoff agrees 

closely with that computed for the first part of the flood.
TABLE 22. Daily precipitation, in inches, at rain gages in a

basin above Chemwng, N. Y., March 8-21,

Station

New York: 

Alfred.. __ .. _______ . ____ . _ ...

Cohocton. _________________ .

Elmira ___________________ .

Hammondsport *>. _____________

Haskinvttle... ______ ________ . Woodhull.....................1.............

Pennsylvania:

Altitude 

(feet)

1,840 

1,920 

1,030 

1,290 

863

1,300 

1,620 

1,825

1,000 

1,700

Weight 

(percent)*

0.082 

.017 

.021 

.055 

.146 

.055 

.055 

.079 

.223

.177 

.090

1.000

8

0 

0 

.10 

.08 

0 

.05 

.10 

0 

0

0 

0

0.02

9

0.12 

.17 

.03 

.0 

.22 

.07 

0 

.12 

.12

0 

.12

0.09

10

0.01 

.01 

.23 

0 

0 

0 

.09 

0 

.03

.01 

.04

0.02

11

0.26 

1.33 

1.36 

1.35 

1.05 

.60 

.66 

.17 

1.06

.46 

1.19

0.83

12

0.42 

.63 

.94 

.78 

.50 

.50 

.63 

.50 

.81

.77 

1.06

0.71

13

0.22 

.22 

.12 

.20 

.37 

.07 

.15 

.30 

.34

.08 

.05

0.21

1

0

.

0 

.

0 

.

.

.

0

0

0

 Percent of total Chemung River drainage area, determined by Thiessen method.

 > Recording gage.
FLOODS OF MARCH 1936, CHEMUNG RIVER 45

TABLE 23. Daily mean temperature9, Chemung River at Chemung, N. Y., 

February 8 to March 8, 1936

Day

Feb. 

8. ...................

9....................

10....................

11....................

12....................

13....................

14....................

IS....................

16....................

17....................

18....................

19....................

20....................

21....................

22....................

Mean 

temperature 

(°F.)

IS

op

9

13

IS

27

77

77

71

12

1

6

9

9

Day

Feb. 

23... .................

7J.

75

26....................

27....................

28....................

29....................

Afar.

1....................

2....................

3....................

4. ...................

S. ...................

6....................

7....................

8....................

Mean 

temperature 

(°F.)

12

26

AA

38

38

25

26

21

19

31

40

33

19

24

28

23

* Average of recorded daily maximum and minimum temperatures at Alfred and Elmira, 

N. Y., and Lawrenceville, Pa.

TABLE 24. Daily mean areal precipitation and temperatures, Chemung River basin,

March 8-22, 1936

March

..................

10.................

11.................

12.................

13.................

14.................

15.................

16.................

17.................

18.................

19.................

20.................

21.................

22.................

precipitation 

(inches)

0.02

.09

.02

ft*

.71

.21

.01

.06

1.17

1.19

.94

.81

.03

.51

0

6.60

Maximum * 

<°F.)

39

42

SO

48

45

34

44

56

49

34

36

37

50

42

44

43

Temperature

Minimum b 

<°F.)

16

14

32

38

77

22

24

28

33

29

30

30

25

30

29

29

Mean« 

(°F.)

28

38

41

43

38

28

34

42

41

31

33

34

37

36

36

36

 Midnight to midnight

b Average of readings at Alfred, Elmira, and Woodhull, N. Y., and Lawrenceville, Pa.

c Average of maximum and minimum.

TABLE 25. Gage height and discharge of the Chemung River at Chemung, N. Y., 

during flood of March 1936

MEAN DISCHARGE, IN SECOND-FEET, 1936

Day

1

2

3

4

5

6

7

8

9

10

Feb.

440

440

420

420

440

420

420

400

380

380

Mean mo

Mar.

4,660

3,800

2,970

2,830

10, 500

10,000

5,570

4,560

4,560

7,740

nthlv dis<

Runoff, in inches

Apr.

8,930

8,130

9,710

6,290

5,070

6,000

9,580

6,550

5,490

5,280

jharge, in

Day

11

12

13

14

15

16

17

18

19

20

second

Feb.

380

380

360

360

360

380

380

380

380

340

 feet---

Mar.

19, 400

74, 900

51, 200

15, 700

13, 300

32, 000

43,200

72, 200

61, 900

48, 100

Apr.

5,830

7,580

10,700

8,930

7,630

6,390

5,070

4,360

3,890

3,510

Day

21

22

23

24

25

26

27

28

29

30

31

Feb.

320

320

300

300

400

950

2,600

10, 000

6,360

1,014

.43

Mar.

27, 400

17,200

15,200

14,200

26,000

30, 500

19, 400

21, 100

13, 400

10, 000

11,300

22,410

10.22

Apr.

3,140

3,420

3,140

2,560

2,200

2,000

1,860

1,680

1,680

2,000

5,287

2.33
46 FLOODS IN NEW YORK AND PENNSYLVANIA

TABLE 25. Gage height and discharge of the Chemung River at Chemung, N. Y.t 

during flood of March 1936 Continued

GAGE HEIGHT, IN FEET, AND DISCHARGE, IN SECOND-FEET, AT INDICATED TIME, 1936

Hour

2 

4 

6 

8 

10 

12m. 

2 

4 

6 

8 

10 

12p.m.

2 

4 

6 

8 

10 

12m. 

2 

4 

6 

8 

10 

12 p.m.

2 

4 

6

8 

10 

12m. 

2 

4 

6 

8 

10 

12p.m.

2 

4 

6 

8 

10 

12m. 

2 

4 

6 

8 

10 

12p.m.

Feet Sec.-ft.

March 8

8.38

6.17

5.31

5.41

 4,560

March 14

10.40 

10.13 

9.90 

9.60 

9.43 

9.JL8 

8J93 

8.70 

8.52 

8.43 

8.38 

8.37

20,200 

19, 100 

18, 200 

17, 000 

16, 300 

15,300 

14,300 

13, 400 

12, 900 

12,600 

12, 400 

12,400

March 20

16.13 

16.27 

16.32 

16.24 

15.66 

15.43 

14.70 

14.05 

13.45 

12.95 

12.57 

12.28

58,200 

59,400 

59,900 

59,200 

56,600 

51, 900 

46,100 

40,900 

36, 700 

33, 700 

31, 400 

29,700

March 26

12.37 

12.50 

12.67 

12.81 

12.90 

12.91 

12.82 

12.60 

12.28 

11.87 

11.42 

11.02

30, 200 

31, 000 

32, 000 

32,900 

33, 400 

33, 500 

32, 900 

31, 600 

29,700 

27, 400 

25,100 

23,100

Feet Sec.-ft.

March 9

5.33

5.23

5.24

5.62

 4,560

March 16

8.38 

8.40 

8.42 

8.46 

8.51 

8.53 

8.63 

8.63 

8.67 

8.90 

9.28 

9.56

12,400 

12,500 

12,600 

12, 700 

12, 800 

12, 900 

12,900 

12, 900 

13,300 

14, 200 

15, 700 

16, 800

March 21

12.15 

12.13 

12.21 

12.28 

12.29 

12.18 

12.02 

11.81 

11.66 

11.27 

10.97 

10.65

28,900 

28,800 

29,300 

29,700 

29,700 

29,100 

28,100 

27, 000 

25, 800 

24,400 

22, 800 

21,200

March 27

10.68 

10.42 

10.28 

10.20 

10.15 

10.09 

10.02 

9.93 

9.92 

9.97 

10.02 

10.22

21,400 

20,300 

19,700 

19, 400 

19, 200 

19, 000 

18, 700 

18,300 

18,300 

18, 500 

18, 700 

19, 500

Feet Sec.-ft.

March 10

5.94

6.37

6.73

7.04

7.40

7.66

6,800

6,800

7,710

8,640

9,530

10, 300

March 16

10.00 

10.55 

11.20 

11.80 

12.43 

12.95 

13.42 

13.66 

13.88 

14.12 

14.33 

14.49

18,600 

20, 800 

24,000 

27, 000 

30, 600 

33, 700 

36, 600 

38, 100 

39, 700 

41, 500 

43,100 

44, 400

March 22

10.40 

10.20 

10.04 

9.89 

9.70 

9.47 

9.26 

9.17 

9.16 

9.18 

9.24 

9.29

20,200 

19, 400 

18, 800 

18, 200 

17,400 

16,500 

15,600 

15,300 

15,200 

15,300 

15,600 

15,800

March 28

10.42 

10.64 

10.82 

10.95 

11.00 

11.01 

10.92 

10.73 

10.51 

10.25 

9.93 

9.68

20, 300 

21,200 

22,100 

22,800 

23,000 

23,000 

22, 600 

21, 600 

20,600 

19, 600 

18, 300 

17,300

Feet Sec.-ft.

March 11

7.80 

7.95 

8.33 

8.60 

9.25 

9.87 

10.25 

10.73 

11.25 

11.90 

12.80 

14.10

10,700 

11, 200 

12,300 

13, 100 

15, 600 

18, 100 

19,600 

21,600 

24,200 

27,500 

32, 800 

41,300

March 17

14.68 

14.63 

14.64 

14.60 

14.53 

14.40 

14.20 

13.99 

13.86 

13.92 

14.17 

14.60

45, 100 

45,600 

45, 600 

45, 300 

44, 700 

43,700 

42, 100 

40,400 

39, 500 

39, 900 

41,900 

45, 300

March 23

9.35 

9.46 

9.57 

9.61 

9.55 

9.39 

9.15 

8.92 

8.68 

8.55 

8.48 

8.41

16, 000 

16, 400 

16, 900 

17,000 

16, 800 

16, 200 

15, 200 

14,300 

13, 300 

13,000 

12,700 

12, 500

March 29

9.23

8.87

8.61

8.34

8.08

7.86

15, 500

14, 100

13, 100

12,300

11, 500

10, 900

Feet Sec.-ft.

March 12

15.00 

16.00 

16.75 

17.30 

17.77 

18.20 

18.65 

10.00 

19.30 

19.50 

19.57 

19.43

48,500 

87,000 

63,800 

69,000 

73,700 

78,000 

82,600 

86,000 

89,300 

91,600 

92,300 

90,700

March 18

15.30 

16.20 

16.90 

17.48 

17.86 

18.10 

18.28 

18.43 

18.55 

18.70 

18.69 

18.63

60,900 

68,800 

65, 100 

70,800 

74,600 

77, 000 

78,800 

80,300 

81, 500 

83, 000 

82, 900 

81, 300

March 24

8.39 

8.42 

8.46, 

8.64 

8.65 

8.77 

8.90 

9.04 

9.19 

9.36 

9.60 

9.95

12,500 

12,600 

12, 700 

12,900 

13, 200 

13, 700 

14, 200 

14,800 

15,400 

16,000 

17,000 

18, 400

March 30

7.69

7.57

7.53

7.52

7.50

7.47

10, 400

10, 000

9,900

9,870

9,810

9,730

3 

Feet Sec.-ft.

March 13

19.10 

18.60 

17.70 

16.80 

15.80 

14.70 

13.75 

12.90 

12.20 

11.63 

11.15 

10.75

87, 100 

81,000 

73,000 

64,200 

55, 200 

46,100 

38,800 

33,400 

29,200 

26,200 

23,800 

21, 800

March 19

18.23 

17.77 

17.26 

16.77 

16.41 

16.05 

15.80 

15.66 

15.60 

15.64 

15.76 

16.94

78,300 

73, 700 

68,600 

63,900 

60, 700 

57,400 

55,200 

53,900 

63,400 

63,800 

54,800 

56, 500

March 25

10.31 

10.75 

11.22 

11.52 

11.77 

11.94 

12.02 

12.05 

12.09 

12.12 

12.19 

12.28

19,800 

21, 800 

24,100 

25,600 

26,800 

27,700 

28,100 

28,300 

28,500 

28,700 

29,100 

29,700

March 31

7.51 

7.63 

7.76 

7.89 

8.09 

8.25 

8.32 

8.30 

8.21 

8.13 

8.03 

7.90

9,840 

10,200 

10,600 

11,000 

11.600 

12,000 

12, 300 

12, 200 

11,900 

11, 700 

11,400 

11,000

 Mean for the day. 

LOCATION. Water-stage recorder, lat. 42°00'10", long. 76'38'00", just below highway bridge

three-quarters of a mile southwest of Chemung, Chemung County. 

DRAINAGE AREA. 2,530 square miles. 

REMARKS. Records published in Geol. Survey Water-Supply Paper 799.
FLOODS OF MARCH 1936, CHEMUNG RIVER 47

TABLE 26. Computation of volume of direct runoff associated with precipitation 

period March 9-14, 1936, Chemung River at Chemung, N. Y.

March

9...................

10...................

11...................

12...................

13...................

14......... ..........

IS...................

16...................

17...................

18...................

Total

Daily mean 

discharge 

(second-feet)

4,560

7 740

19 400

74,900

e i Onn

»15,000

»9,000

'6,800

»5,800

 5,400

199 800

Estimated 

recession from 

preceding storm 

and base runoff 

(second-feet)

4,150

2,750

2,500

9 onn

3,300

3,700

4,000

4,300

4,600

5,000

37,200

Direct runoff 

(second-feet)

410

4,990

16,900

72,000

47,900

11,300

5,000

2,500

1,200

400

162,600 ( =

2.39 inches)

 Estimated recession under subsequent rise.

TABLE 27. Computation of tvme of center of mass of net supply, and lag intervals, 

Chemung River at Chemung, N. Y., March 8-14, 1936

March

8............

9.............

10.............

11.............

12.............

13.............

14.............

Mean areal 

precipitation 

(inches)

0.02

.09n9

.83

.71

.21

.01

1.89

Estimated 

snow 

melt 

(inches)

0.09

.35

.53

.65

.35 ».14

».22

2.05

Precipitation plus 

snow melt 

(inches)

0.11

.44

.55

1.48

1.06

.07

93

3.94

Net 

supply 

(inches)

0

fit

.30 i n?

.70

M

.09

2.39

Time 

from 

origin 

(days)

0

1

 j

3

4

5

6

Product 

(inch-days)

0

.26

.60

3.06

2.80

.10

54

7.36

a Estimated result of snowfall and thawing. 

Center of mass of net supply occurred 7.36

2.39 = 3.08 days after 12 noon of March 8 = ^. j*# March 11.58.

Time of center of mass of direct runoff was at March 12.96 or 1.38 days (33 hours) after 

center of mass of net supply.

Peak discharge occurred at 10 p.m. March 12 or 1.34 days (32 hours) after center of mass of 

net supply.

TABLE 28. Computation of volume of direct runoff associated with precipitation 

period March 15-22, 1936, Chemung River at Chemung, N. Y.

March

15...................

16...................

17...................

18...................

19...................

20...................

21................... ??

23...................

24...................

25....................

26....................

Total

Daily mean 

discharge 

(second-feet)

13,300

32,000

43,200

7O OAA

48,100

27,400

 16,500

 10,700

"8,200

 6,900

 6,300

346,700

Estimated 

recession from 

preceding storm 

and base runoff 

(second-feet)

9,000

6,800

5,800

5,400

5,500

5,900

6,100

6,100

£ AAA

6,000

5,900

5,800

74,300

Direct runoff 

(second-feet)

4,300

25,200

37,400

66,800

56,400

42,200

21,300

10,400

4,700

2,200

1,000

* 500

272,400 ( =

4.00 inches 

over basin)

1 Estimated recession under subsequent rise.
48 FLOODS IN NEW YORK AND PENNSYLVANIA

TABLE 29. Computation of time of center of mass of net supply, and lag intervals, 

Chemung River at Chemung, N. Y., March 15-21, 1936

March

15.............

16.............

17.............

18.............

19.............

20.............

21.............

Mean areal 

precipitation 

(inches)

0.06

1.17

1.19

.94

81

.03

.51

4.71

Estimated 

snow 

melt 

(inches)

.41

».67

a. 25

MS

.15

».05

0

Precipitation plug 

snow melt 

(inches)

n ??

1 CQ

?7

.69

.66

.18

.56

0.71

Net 

supply 

(inches)

0.42

1.40

.42

.57

.57

.12

.50

4.00

Time 

from 

origin 

(days)

0

1

2

3

4

5

6

Product 

(inch-days)

0

1.40

.84

1.71

2.28

.60

3.00

9.83

9.83

4.00

= 2.46 days after 12 noon of March 15 =

 Estimated result of snowfall and thawing.

Center of mass of net supply occurred 

March 17.96

Time of center of mass of direct runoff was at March 19.21 or 1.25 days (30 hours) after 

center of mass of net supply.

Peak discharge occurred at 8 p.m. March 18 or 0.87 days (21 hours) after center of mass of 

net supply.

SUSQUEHANNA RIVER AT WILKES-BARRE, PA.

Calendar-day precipitation during the flood of March 1936 at rain 

gages in and near the Susquehanna River Basin above Wilkes-Barre, 

Pa., listed in table 30, was computed from daily readings at the indicated gages, which were adjusted to a midnight-to-midnight, or calendarday, basis using as a guide the autographic records of hourly precipitation at Binghamton and Ithaca, N. Y., and at Clarion and Scranton, Pa. 

For the purpose of combining these daily amounts to compute daily 

mean areal precipitation, the several stations were assigned the Thiessen 

weights indicated in table 30. In this table, 25 rain gages are listed, an 

average of 1 for each 400 square miles of the area, although the gage 

at Towanda, Pa., covers an area of 890 square miles. However, since the 

storm rainfall, as shown in figure 11, was fairly uniform, the basin 

average may not be greatly in error, being 5.65 inches, of which the 

greatest daily amount, 1.13 inches, fell on March 17.

Daily mean precipitation and daily maximum, minimum, and mean 

temperatures during the flood period are summarized in table 32. The 

temperature over the basin averaged 39° F., being below freezing only 

on 1 day, March 13. It should be noted, however, that the Susquehanna 

River Basin above Chemung, N. Y., averaged 36.5° F. (2.5° colder) 

during the period March 9-22, and that temperatures on March 17-19 

in the Chemung River Basin were substantially lower than in the 

remainder of the basin above Wilkes-Barre.

Temperatures during the 30-day antecedent period, February 8 to 

March 8, as shown in table 31, averaged 10° F. below freezing, although 

during the latter part of this period there were 6 days that averaged
FLOODS OF MARCH 1936, SUSQUEHANNA RIVER 49

above freezing. No specific information about frost penetration is 

available.

Fragmentary observations of snow depth made on or about March 9, 

as reported in Water-Supply Paper 799, indicate a depth of snow over 

the basin equivalent to 2.6 inches average water content. However, 

during the subfreezing period December 1 to March 8, there was a total 

precipitation of 7.4 inches and a total runoff of 3.65 inches, indicating 

a retention of 3.75 inches, of which a large part probably remained as 

snow cover, which on March 9 was estimated as 3.0 inches, intermediate 

between the two limits above defined.

Many observations at Weather Bureau stations in the basin reported 

negligible snow remaining at the conclusion of the storm period, 

although several Civilian Conservation Corps camps there reported snow 

depths ranging as high as 9 inches (water content unknown), and some 

outside the basin reported even heavier cover. However, during the 

period March 23 to April 5 while temperatures were generally above 

freezing, precipitation amounted to 0.6 inch and runoff was 0.7 inch 

indicating a minimum contribution from remaining snow of 0.1 inch, 

which from available evidence, was estimated at 0.45 inch water content. 

The snow-runoff contribution to the flood was therefore 2.55 inches 

(3.0-0.45).

The following is a summary of rainfall and runoff during the winter 

season of 1935-36:

Period

Dec. 1, 1935, to Mar. 8, 1936. ...........

Mar. 9-22 ............................

Rainfall and runoff (inches)

Precipitation

7.4 

5.65 

.6

13.65

Runoff

3.65 

8.45 

.70

12.80

Difference

3.75 

 2.8 

 .1

0.85

A hydrograph of river discharge at Wilkes-Barre, Pa., during the flood 

period, based on data given in table 33, is shown on figure 13. Direct 

runoff associated with the first precipitation period, March 9-15, as 

computed in table 34 was 2.83 inches. Precipitation during this period 

was 1.51 inches, and snow melt as indicated in table 35, was estimated 

at 2.10 inches, leaving a residual of 0.78 inch available for ground-water 

recharge, soil-moisture accretion, and evaporation losses. The estimated 

daily snow melt given in tables 35 and 37, was computed by distributing 

the amount on the basis of the degree-days above 32° F. and deducting 

the snowfall as a negative snow melt so that the total net result equaled 

2.55 inches. The snowfall was estimated by reference to data in table 21 

and by inspection of the temperature and precipitation records. On 

March 13 and 17 the snowfall over the basin exceeded the snow melt.
50 FLOODS IN NEW YORK AND PENNSYLVANIA
TABLE 30. Daily precipitation, in inches, at rain gages in 

River basin at Wilkes-Barre, Pa., March 9-

Station

New York: 

Alfred ---------------------

Delhi..---........ --_- 

Pennsylvania:

Weight

(percent)

3.23

.04

3.95

7.98

6.80

5.77

.83

7.07

5.50

3.15

3.49

3.92

3.64

3.61

.15

1.79

6.00

6.27

3.99

.79

3.52

5.12

8.94

1.45

3.00

100. 00

9

0.12

.22

.35

.34

.83

.34

.32

.22

.12

.16

.17

.75

.63

.34

.09

.14

.12

.01

.13

.06

0.24

10

0.01

.11

.03

.09

.09

.01

.04

.02

.05

.03

0.02

11

0.26

.29

.19

.17

08

.21

.13

1.05

.17

.57

.15

.15

.11

.26

.17

1.54

.46

35

1.19

.78

.93

.26

.70

.93

.46

0.44

12

.46

.44

.48

.37

.78

.53

.50

.50

.54

.25

.46

.41

.34

.71

.42

.77

.58

1.06

1.20

.53

.40

.75

.76

.44

0.56f

13

.11

.04

OQ

.31

.14

.37

.30

.15

.15

.20

.12

.16

.31

.10

.08

.15

.05

.14

.13

.05

.04

.09

.11

0.15

14

0.03

.02

.08

.02

no

.11

.08

.07

.13

.05

.07

.04

.11

.02

.06

.05

.12

.05

.04

.03

0.06

15

0.02

.03

.05

.04

.04

.10

.05

.05

.05

.07

.04

.02

.04

.03

.02

.04

.10

0.03

M
52 FLOODS IN NEW YORK AND PENNSYLVANIA

Direct runoff during the second period totaled 4.38 inches, as a result 

of 4.15 inches of precipitation and 0.45 inch of snow melt leaving a 

retention of 0.22 inch.

Ground-water runoff from the entire storm period was approximately 

1.25 inches in comparison with a total retention of 1.0 inch, indicating 

an inconsistency in basic data of at least 0.25 inch.

The lag intervals between center of mass of net supply and center of 

mass of direct runoff, as computed in tables 35 and 37, were 67 and 

70 hours for the first and second flood periods, respectively.

TABLE 31. Daily mean temperature* during 30-day period preceding storm period 

March 9-21, 1936, Susquehanna River at Wilkes-Barre, Pa.

Day

Feb.

8

-

9...................

10...................

11...................

1 9

13...................

14...................

15...................

16...................

17................... 1ft

19...................

20...................

21

9?

Mean. .........

Mean 

temperature 

<°F.)

11

91

6

9

13

14

oe

97

24

97

15

3

11

19

Day

Feb. 

2*

yd

2">

26....................

27...., .............

28...................

29....................

Mar.

1. ..................

2...................

3...................

4...................

5. ..................

6...................

7...................

8...................

Mean 

temperature 

(°F.)

14

29

46

40

19

26

30

7O

21

33

42

34

20

25

30

22

a Average of recorded daily maximum and minimum temperatures at Binghamton and Elmira, 

N. Y., and Scranton and Towanda, Pa.

TABLE 32. Daily mean areal precipitation, and temperatures, Susquehanna River 

at Wilkes-Barre, Pa., March 9-22, 1936

March

9................. 10.................

11.................

12.................

13.................

14.................

15.................

16.................

17.................

18.................

19. ................

20.................

21.................

22. ................

Mean areal

precipitation 

(inches)

A f)A

.02

.44

.56

.15

.06

.03

.90

1 1 8

.97

.48

.01

.61

0

5. 65

Maximum b 

(°F.)

49

50

49

4777

43

CO

H9

50

45

42

53

46

47

47

Temperature

Minimum b 

(°F.)

31 *9

40

33

or

77

30?d

i?

33

33

28 ji

30

31

Average c 

(°F.)

37

41

44

40

31

35

44

43

41

39

7ft

40ift

7ft

39

 Midnight to midnight.

b Average of readings in Chemung River Basin and at Norwich, N. Y., and at Mt. Pocono and 

Towanda, Pa. 

c Average of maximum and minimum.
FLOODS of MARCH 1935, SUSQUEHANNA RIVEH

TABLE 33. Gage height and discharge of the Susquehanna River at Wilkes-Barre, 

Pa., during flood of March J936

MEAN DISCHARGE, IN SECOND-FEET, 1936

Feb.

5,700

5,600

5,400

5,300

5,200

5,100

5,000

4,900

4,750

4,700

Mar.

17, 700

16, 100

14, 300

12, 900

14, 000

17, 600

30, 100

17, 700

17, 100

19, 900

Apr.

33, 000

29,200

29,800

32, 500

28,200

28,200

32, 000

37, 100

33, 600

30,300

Day

11

12

13

14

15

16

17

18

19

20

Feb.

4,600

4,500

4,400

4,300

4,500

4,200

4,400

4,400

4,200

4,000

Mar.

48,800

129, 000

182,000

150, 000

99,400

80, 200

125, 000

192. 000

229, 000

221, 000

Apr.

29, 200

31,400

34, 700

45,200

41, 300

37, 100

32, 000

27, 200

23,800

21, 500

Day

21

22

23

24

25

26

27

28

29

30

31

Mean monthly discharge, in second-feet _ Runoff, in inches

Feb.

3,900

' >4, 100

3,900

3, 800

'3, 700

4,200

; 6,000

12,000

15,000

5,233

.57

Mar.

184,000

144,000

99,000

72, 300

59, 000

63,500

62, 200

52, 800

51, 700

41, 200

33, 900

80, 560

9.33

Apr.

19, 700

18, 900

18, 500

17, 700

15, 700

14,000

12, 600

11,600

10, 700

10, 100

26, 230

2.93

Day

GAGE HEIGHT, IN FEET, AND DISCHARGE, IN SECOND-FEET, AT INDICATED TIME, 1936

Hour

2

4

6

8

10

12m.

2

4

6

8

10

12p.m.

2

4

6

8

10

12m.

2

4

6

8

10

12p.m.

2

4

6

8

10

12m.

2

4

6

8

10

12p.m.

Feet Sec.-ft.

March 8

7.84

7.78

7.68

7.55

7.48

7.48

7.40

7.30

7.24

7.24

7.26

7.32

18, 900

18, 900

18, 500

18, 100

17, 700

17, 700

17,300

16, 900

16, 500

16, 500

16, 900

16, 900

March 14

28.02

27.62

27.13

26.55

25.92

25.30

24.68

24.09

23.52

23.00

22.50

22.06

178, 000

173, 000

168, 000

163,000

156, 000

150,000

144, 000

138, 000

132, 000

128,000

123,000

119,000

March 20

33.07

33.00

32.90

32.75

32.57

32.34

32.10

31.81

31.44

31.12

30.85

30.55

232,000

240,000

229,000

228,000

226,000

223,000

221, 000

218,000

213, 000

210,000

207,000

206,000

Feet 8ec.-ft

March 9

7.40

7.45

7.43

7.42

7.40

7.38

7.34

7.30

7.29

7.30

7.33

7.40

17, 300

17,300

17, 300

17, 300

17, 300

17,300

16, 900

16, 900

16, 900

16, 900

16, 900

17, 300

March 15

21.61

21.20

20.84

20.48

20.11

19.78

19.47

19.16

18.82

18.52

18.23

17.98

115,000

111,000

107, 000

105, 000

101, 000

98, 600

96,000

93, 500

90, 200

87, 700

85, 200

83,600

March 21

30.28

30.03

29. 7d

29.38

28.95

28.63

28.25

27.86

27.52

27.18

26.89

26.61

202, 000

198,000

195,000

192,000

188,000

184,000

180, 000

176,000

172,000

169, 000

166,000

163,000

Feet Sec.-ft.

March 10

7.47

7.55

7.62

7.69

7.74

7.80

7.90

8.03

8.24

8.55

8.94

9.38

17, 700

18, 100

18, 100

18, 500

18, 500

18, 900

19, 300

19, 700

20,600

22, 400

23, 750

26,200

March 16

17.78

17.59

17.45

17.35

17.30

17.25

17.25

17.26

17.33

17.52

17.88

18.40

82, 000

80, 400

78, 900

78, 900

78, 100

77, 300

77, 300

7S, 100

78, 100

79, 600

82, 800

86, 900

March 22

26.35

26.08

25.80

25.51

25.20

24.84

24.45

24.04

23.59

23.09

22.62

22.15

161, 000

158, 000

155, 000

152, 000

149,000

145, 000

141, 000

137,000

133, 000

129,000

124, 000

120,000

Feet Sec.-ft.

March 11

9.96

10.64

11.13

11.56

11.93

12.55

13.72

14.70

15.35

15.78

16.29

17.12

29,200

32, 500

35, 300

38, 300

40, 100

44,500

51, 800

58, 700

63, 700

66, 600

70, 400

76, 500

March 17

19.13

20.08

20.91

21.74

22.48

23.09

23.64

24.17

24.65

25.03

25.32

25.67

92, 600

101, 000

108, 000

115,000

123, 000

129, 000

133,000

139, 000

143, 000

147, 000

150,000

154,000

March 23

21.70

21.23

20.77

20.35

20.00

19.61

19.31

19.03

18.75

18.48

18.24

18.01

115,000

111,000

107, 000

104, 000

100, 000

96, 900

94, 400

91, 800

90, 200

87, 700

85, 200

83, 600

Feet Sec.-ft.

March 12

18.27

19.55

20.65

21.73

22.72

23.56

24.35

25.08

25.74

26.30

26.78

27.24

86,100

96, 900

106, 000

115,000

125,000

133,000

141,000

148, 000

154,000

160, 000

165, 000

169, 000

March 18

26.16

26.59

27.19

27.95

28.78

29.54

30.36

31.00

31.54

32.10

32.42

32.62

169. 000

163, 000

169,000

178, 000

186, 000

193,000

203,000

209,000

214,000

221,000

224,000

226,000

March 24

17.78

17.54

17.29

17.04

16.76

16.52

16.24

15.98

15.75

15.54

15.35

15.17

82,000

79, 600

78, 100

75, 700

74, 200

71,900

69, 600

68,100

66,600

64,400

63, 700

62, 300

Feet Sec.-ft.

March 13

27.68

27.98

28.20

28.35

28.52

28.66

28.75

28.80

28.80

28.73

28. 58

28.35

174,000

178, 000

180, 000

182,000

183,000

185,000

186,000

186,000

186,000

185, 000

184,000

182,000

March 19

32.75

32.78

32.77

32.77

32.78

32.80

32.85

32.90

32.97

33.00

33.05

33.06

228,000

228,000

228,000

228,000

228,000

228,000

228,000

229,000

230,000

230,000

230,000

232, 000

March 25

15.04

14.91

14.81

14.74

14.66

14.61

14.56

14.53

14.53

14.57

14.68

14.83

60,800

60, 100

59, 400

58, 700

58, 700

58,000

58, 000

57,300

57, 300

58,000

58, 700

59,400

LOCATION. Water-stage recorder, lat. 41° IS'00", long. 75°53'10", at Market Street Bridge at

Wilkes-Barre, Luzerne County. Zero of gage is 511.94 feet above mean sea level. 

DRAINAGE AREA. 9,960 square miles. 

REMARKS. Records published in Geol. Survey Water-Supply Paper 799.
54 - FLOODS IN NEW YORK AND PENNSYLVANIA

TABLE 34. Computation of volume of direct runoff associated with precipitation 

period March 9-15, 1936, Susquehanna River at Wilkes-Barrre, Pa.

March

9................... 10...................

11...................

12...................

13...................

14............... ....

l^,. ...................

16...................

17...................

18...................

19...................

20...................

71

22......... .......... o-t

24...................

Total

Daily mean 

discharge 

(second-feet)

17,100

19,900

48,800

129,000

182,000

150,000

99,400

 69,000

 50,000

»37,000

 25,000

»20,500

 19,000

 15,500

"14,500

926,700

Estimated 

recession from

preceding storm 

and base runoff 

(second-feet)

15,000

12,500

11,000

9,000

8,000

8,000

9,000

9,000

9,000

10,000

10,000

11,000

13,000

14,000

169,500

Direct runoff 

(second-feet)

2,100

7,400

37,800

119,000

174,000

142,000

91,400

60,000

41,000

28,000

20,000

15,000

9,500

7,000

2,500

500

757,200 ( =

2.83 inches)

Estimated recession under subsequent rise.

TABLE 35. Computations of time of center of mass of net supply, and lag intervals, 

Susquehanna River at Wilkes-Barre, Pa., March 9-15, 1936

March

9.............

10.............

11............:

12.............

13.............

14..... ........

15.............

Mean areal 

precipitation 

(inches)

n 7d

02

.45

.56

.15

.06

.03

1.51

Estimated 

snow 

melt 

(inches)

0.20

.48

.69 «.29

» .04

a 05

a 43

2 10

Precipitation plus 

snow melt 

(inches)

0.44

.50

1.14

QC

.11

.11

.46

3.61

Net 

supply 

(inches)

n 39

39

.95

.71

.05

.04

.37

2.83

Time 

from 

origin 

(days)

0

1

3

4

5

6

Product 

(inch-days)

0

.39

1.90

2.13

.20

.20

2.22

7.04

a Estimated result of snowfall and thawing.

Center of mass of net supply occurred = 2.49 days after noon of March 9 = March2.83 

11.99.

Time of center of mass of direct runoff was at March 14.79 or 2.80 days (67 hours) after 

center of mass of net supply.

Peak discharge occurred at March 13.67 or 1.68 days (40 hours) after center of mass of 

net supply.
FLOODS OF MARCH 1936, SUSQUEHANNA HIVER 55

TABLE 36. Computation of volume of direct runoff associated with precipitation 

period March 16-21, 1936, Susquthanna River at Wilkes-Barre, Pa.

March

16...................

17...................

1 ft

19...................

20...................

21...................

99

9^

24...................

25...................

26...................

27...................

28...................

29...................

30...................

31...................

Total

Daily mean 

discharge 

(second-feet)

80,200 

125,000 

192,000 

229,000 

221,000 

184,000 

144,000 

99,000 

72,300 

 52,000 

 42,000 

»33,000 

 27,000 

 22,500 

 18,500 

 16,000

1,557,500

Estimated 

recession from 

preceding storm 

and base runoff 

(second-feet)

69,000 

50,000 

37,000 

30,000 

25,000 

20,500 

19,000 

15,500 

14,500 

15,000 

15,000 

15,000 

15,000 

15,000 

14,000 

14,000

383,500

Direct runoff 

(second-feet)

11,200 

75,000 

155,000 

199,000 

196,000 

163,500 

125,000 

83,500 

57,800 

37,000 

27,000 

18,000 

12,000 

7,500 

4,500 

2,000

1,174,000 ( = 

4.38 inches)

 Estimated recession under subsequent rise.

TABLE 37. Computation of time of center of mass of net supply, and lag intervals, 

Susque-hanna River at Wilkes-Barre, Pa., March 16-21, 1936

March

16.............

17.............

18.............

19.............

20.............

21.............

Mean areal 

precipitation 

(inches)

0.90

.97

.01

.61

4 15

Estimated 

snow 

melt 

(inches)

0.33

». 04

».oo

».10

».03

0 45

Precipita. 

tion plus 

snow melt 

(inches)

1 91

1.14

.97

.51

.11

.64

4.60

Net 

supply 

(inches)

1.17

1.10

.09 

.61

4.38

Time 

from 

origin 

(days)

' 01-

3

4

5

Product 

(inchdays)

0

1.10

I Of

1.44

.36

3.05

7.81

a Estimated result of snowfall and thawing.

7 81 Center of mass of net supply occurred ' = 1.78 days after noon of March 16 = 18.28.

Time of center of mass of direct runoff was at March 21.20 or 2.92 days (70 hours) after 

center of mass of net supply.

Peak discharge occurred at March 20.08 or 1.80 days (43 hours) after center of mass of 

net supply.

SUSQUEHANNA RIVER AT HARRISBURG, PA.

Calendar-day precipitation at rain gages in an near the lower Susquehanna River Basin below Williarasport and Wilkes-Barre, Pa., is given 

in table 38. Average daily precipitation has been averaged with the 

precipitation for corresponding days over the basin above WilkesrBarre 

and Williamsport. During the first storm period, March 9-15, precipitation averaged 1.74 inches over the basin, the greater part falling on 

March 11 and 12. During the second storm period, March 16-21, 4.69 

inches fell over the basin, the greater part falling on March 17 and 18.

689521 47 5
56 FLOODS IN NEW YORK AND PENNSYLVANIA

Daily mean precipitation over the basin, taken from table 38, is summarized in table 39 together with the daily maximum, minimum, and 

mean temperatures. The temperatures listed were computed by averaging 

readings at a number of places. The daily mean temperature is the 

average of the daily maximum and minimum. The average temperature 

for the flood period is 41° F. and each day shown averaged above freezing 

temperature, although as previously noted there were great variations 

in temperature, notably in the upper West Branch and Chemung River 

Basins, where subfreezing temperatures on March 13, 17-19,. turned 

much rainfall into snow with important effects on river stages.

Depth of snow cover on March 9 was estimated as being intermediate 

between that given in Water-Supply Paper 799, which was based 

principally upon available measurements of snow depth supplemented 

by estimates of its density, and that given in the analysis below. Precipitation during the subfreezing period, December 1 to March 8, amounted 

to about 8.4 inches, and runoff equaled 4.7 inches; the retention of 

3.7 inches is indicative of the water content of the maximum possible 

average snow cover on March 9. Available fragmentary observations 

reported in Water-Supply Paper 799 indicate an approximate snow cover 

on March 9 of 3.0 inches. This determination is probably low because 

of the general lack of representative measurements in rural places, more 

especially in the mountains. Therefore for the purposes of this analysis 

an estimate of 3.2 inches was used, intermediate between the limits 

above defined.

After the flood period, from March 24 to April 5, there was a total 

rainfall of 0.65 inch over the basin and resultant runoff of 0.6 inch, 

indicating a minimum contribution from snow remaining on March 23 

of essentially zero. It is found, however, that the 0.6-inch runoff at 

Harrisburg had its origin from the basin above Williamsport and WilkesBarre, the lower basin producing negligible runoff. This seems to indicate 

that there was little, if any, snow remaining in the lower basin. Accordingly, that in the Susquehanna River Basin above Harrisburg was taken 

as equal to the volume estimated as above Wilkes-Barre and Williamsport converted into inches over the basin above Harrisburg. This 

amounts to 0.4 inch. The total snow melt during the period was, therefore, 2.8 inches.

The following table contains a summary of the rainfall and runoff 

amounts, in inches, during the winter season of 1935-36:

Period

Dec.

Mar. 

Mar.

1, 1935 to Mar. 8, 1936... ......

9

97

24 to Apr. 5 ...................

Rainfall and runoff (inches)

Precipitation

8.4 

6.4

.65

15.45

Runoff

4.7 

9.0 

.6

14.3

Difference

3.7

 2.6 

.05

1.15
 OQPOO

rrntt-t a a 4 9«rt»K>iiiaaMi9iei7i8!»*o

FIGURE 14. Hydrograph of Susquehanna River at Harrisburg, Pa., sho
TABLE 38. Daily precipitation, in inches, at stations in an

hanna River basin, March 9-21, 1936

Station

(Pennsylvania)

Bedford........................

State College.. -.--...--.... ...

"\\TAilrArt

Wilkes-Barre

Average or total above WilkesBarre (»). .....--... ___ ..

Average or total above Williamsport ( b). .... _ ..

Average or total over basin

Altitude

(feet)

1,615

1,442

1,060

1,050

467

520

isn

553

337

650

1,637

469

500

1,045

420

540

1,217

507

754

750

540

521

Weight 

(percent)

1.23

1.84

2.52

.24

1.75

3.06

1.53

.03

.92

4.04

.02

.10

.16

3.17

3.11

.94

1.52

2.60

.03

2.80

1.86

1.62

41.33

23.58

100.00

9

0.10

.03

.31

.03

.07

.06

.02

.02

.03

.13

.07

Tr.

.04

0.24

0.08

0.13

10

0.07

.09

.24

.10

.12

.17

.10

.11

.09

.24

.09

.05

.08

.24

.12

.25

.03

.05

0.02

0.09

o'.oe

11

0.51

.75

.48

1.00

1.16

1.08

.41

1.00

1.65

.72

.66

1.50

.52

.76

.87

1.88

1.01

.67

.70

2.00

.46

1.46

0.44

0.92

0.74

12

0.35

.45

.40

.43

.80

.81

.63

.87

.59

.55

.56

.36

.11

1.16

.78

.45

.53

.54

.75

.50

.44

1.07

0.56

0.62

0.60

13

0.21

.02

.04

.02

.02

.11

.17

.17

.01

.11

.04

.11

.19

0.15

0.11

0.11

14

0.08

.04

.07

.17

.06

.10

.04

.03

.09

0.06

0.08

0.06

15

0.08

.13

.02

.07

.07

Tr.

.05

.05

.02

.06

.05

.04

.10

0.03

0.09

0.04

M

T

9

(») From Table 30. 

(>>) From Table 45.
FLOODS OF MARCH 1936, SUSQUEHANNA RIVER 59

Discharge at 2-hour intervals during the flood period is given in 

table 40, and figure 14 shows the discharge in graphic form. The figure 

also shows the methods used in separating the total stream flow into 

ground-water and direct runoff and the division of the total flood period 

into its two distinct rises.

The volume of direct runoff associated with 1.74 inches of precipitation during the period, March 9-15, as computed in table 41, was 2.92 

inches. The total snow melt during this period was figured at 2.0 inches 

and was estimated to have occurred in daily amounts, as indicated in 

tables 42 and 44. These estimates have been made by distributing the 

total snow melt of 2.8 inches on the basis of effective thawing temperatures, making allowance for snowfall in certain parts of the basin as a 

negative snowfall (see p. 10). Considering the basin as a whole, snow 

melt exceeded snowfall on all but one day, March 13.

As computed in table 43, direct runoff, associated with 4.69 inches of 

precipitation during the second period March 16-21, was 4.53 inches. 

An estimated snow melt of 0.80 inch was contributed to runoff during 

this period.

As a quantitative index of basin characteristics, the lag intervals 

between center of net supply and direct runoff have been computed in 

tables 42 and 44. These values, 86 hours during the first period and 83 

during the second, are a measure of the average time required for the 

collection of flood waters at Harrisburg.

Ground-water runoff during the entire flood period was computed as 

1.5 inches, which is 0.28 inch less than the difference between total 

precipitation (6.43 inches) plus snow melt (2.8 inches) and total 

direct runoff (7.45 inches). The 0.28-inch difference, although subject 

to considerable percentage error, is indicative of small field-moisture 

accretion and evaporation losses, considering the total amount of water 

involved in the flood.

TABLE 39. Daily wean areal precipitation, and temperatures, Susquehanna River 

at Harrisburg, Pa., March 9-21, 1936

March

9.................

10.................

11.................

12.................

13.................

14.................

IS.................

16.................

17.................

18.................

19.................

20.................

21.................

Mean areal

precipitation 

(inches)

0.13

.06

.74

.60

.11

.06

.04

.91

1.67

1.00

co

.06

.53

6.43

Maximum 

<°F.)

45

54

51

49

36

47

60

53

52

50

43

52

46

49

Temperature

Minimum 

(°F.)

34

35

' 42

32

26

27

35

36

34

35

33

29

32

33

Mean 

(°F.)

39

44

46

40

31

37

45

44

43

42

38

40

39

41

* Midnight to midnight.
60 FLOODS IN NEW YORK AND PENNSYLVANIA

TABLE 40. Gage height and discharge of the Susquehanna River at Harrisburg, 

Pa., during flood of March 1936

MEAN DISCHARGE, IN SECOND-FEET, 1936

Day

1

2

3

4

5

6

V

8

9

10

Feb.

18, 000

18, 000

17, 000

16,000

16, 000

15, 500

15, 000

14, 500

14, 000

13, 500

Mar.

75, 000

81,000

78, 000

78, 000

78, 000

82,000

95, 000

140, 000

91, 000

93,200

Apr.

84, 000

75, 800

71, 600

68,800

67,300

80, 200

114,000

119,000

112, 000

101, 000

Day

11

12

13

14

15

16

17

18

19

20

pi

Feb.

13, 000

12, 500

12, 000

12, 000

12,500

13, 000

14,000

15, 000

16, 000

15, 500

Mar.

130, 000

304, 000

424, 000

368,000

267, 000

203, 000

219, 000

414, 000

691, 000

614, 000

Apr.

94,500

91,900

89, 300

86,700

91, 900

86, 700

75, 800

65, 800

58, 300

52, 000

Day

21

22

23

24

25

26

27

28

29

30

31

Mean monthly disnharefi. in sflfinnrl-fap.t ------

Bunoff, in inches

Feb.

15, 000

14, 000

13,500

13, 000

13,000

15, 000

23,000

38, 000

53,000

16, 910

.76

Mar.

440, 000

342, 000

258, 000

193, 000

157, 000

138, 000

146, 000

146, 000

132, 000

121,000

99,600

216, 100

10.34

Apr.

47,600

43,300

40,600

39, 200

36,600

34, 000

31,600

28,400

26,700

25,300

68,000

3.15

GAGE HEIGHT, IN FEET, AND DISCHARGE, IN SECOND-FEET, AT INDICATED TIME, 1936

Hour

2 

4 

6 

8 

10 

121m. 

2 

V 4 " 6

m s

10 

12p.m.

2 

4 

6 

8 

10 

12m. 

2 

4 

6 

8 

10 

12p.m.

2 

4 

6 

8 

10 

12m. 

2 

4 

6 

8 

10 

12p.m.

Feet Sec. -ft.

March 8

14.30 

13.05 

12.20 

11.50 

11.00 

10.40 

9.94 

9.52 

9.25 

9. 10 

9.00 

8.95

 140, 000

March 14

20.85 

20.68 

20.44 

20.15 

19.85 

19.52 

19.20 

18.87 

18.56 

18.18 

17.87 

17.50

406, 000 

403, 000 

394, 000 

388, 000 

377, 000 

369, 000 

361, 000 

352, 000 

345, 000 

334, 000 

326,000 

316, 000

March 20

29.40 

28.90 

28.40 

27.90 

27.38 

26.90 

26.50 

25.95 

25.50 

25.00 

24.55 

24.10

705, 000 

686,000 

667,000 

648,000 

629,000 

611, 000 

596, 000 

578,000 

560,000 

542,000 

528, 000 

510, 000

Feet Sec.-ft.

March 9

8.90

8.87

8.83 

8.78 

8.70

8.65 

8.60 

8.57

8.50

8.45

8.38

8.25

»91,000

March 15

17.17 

16.80 

16.43 

16.05 

15.70 

15.36 

15.00 

14.70 

14.35 

14.10 

13.78 

13.50

309,000 

299,000 

290,000 

280,000 

273, 000 

266, 000 

257, 000 

250, 000 

243,000 

236,000 

229,000 

223,000

March 21

23.70 

23.25 

22.90 

22.50 

22.10 

21.75 

21.40 

21.15 

20.80 

20.50 

20.30 

20.20

497, 000 

480,000 

470, 000 

458, 000 

445, 000 

436,000 

423, 000 

417, 000 

406,000 

397, 000 

391, 000 

388, 000

Feet Sec.-ft.

March 10

8.12 

8.00 

7.90 

7.80 

7.76 

7.73 

7.72 

7.74 

7.78 

7.82 

7.90 

7.98

98, 300 

96, 000 

93, 700 

91, 400 

91, 400 

89, 100 

89, 100 

89,100 

91, 400 

91, 400 

93,700 

96, 000

March 16

13.32 

13.15 

12.95 

12.78 

12.64 

12.50 

12.40 

12.30 

12.20 

12.15 

12.10 

12.05

218, 000 

216, 000 

211, 000 

207, 000 

202, 000 

200,000 

198, 000 

195, 000 

193, 000 

193, 000 

191, 000 

189, 000

March 22

20.05 

19.80 

19.45 

19.10 

18.75 

18.42 

18.18 

17.80 

17.50 

17.23 

16.92 

16.70

383, 000 

377, 000 

366, 000 

358, 000 

350, 000 

339, 000 

33*, 000 

324, 000 

316, 000 

309,000 

302,000 

297, 000

Feet Sec.-ft.

March 11

8.10 

8.22 

8.38 

8.58 

8.77 

9.00 

9.24 

9.58 

10.00 

10.60 

11.20 

11.90

98,300 

101, 000 

105, 000 

110,000 

115, 000 

119,000 

124,000 

133, 000 

143, 000 

156, 000 

170, 000 

186, 000

March 17

12.02 

12.04 

12.08 

12.20 

12.40 

12.78 

13.18 

13.70 

14.30 

14.90 

15.55 

16.25

189, 000 

189, 000 

191, 000 

193, 000 

198, 000 

207, 000 

216, 000 

227, 000 

241, 000 

255, .000 

271,000 

285,000

March 23

16.40 

16.17 

15.90 

15.65 

15.30 

15.00 

14.78 

14.43 

14.18 

13.95 

13.62 

13.18

290, 000 

285, 000 

278, 000 

271, 000 

264,000 

256,000 

252, 000 

243,000 

238,000 

234,000 

225,000 

216, 000

Feet Sec.-ft.

March 12

12.70 

13.60 

14.62 

15.60 

16.55 

17.35 

18.05 

18.70 

19.30 

19.78 

20.20 

20.65

204, 000 

225,000 

248, 000 

271, 000 

294, 000 

314, 000 

329,000 

347, 000 

363, 000 

377, 000 

388, 000 

400,000

March 18

16.90 

17.60 

18.30 

19.00 

19.78 

20.60 

21.50 

22.40 

23.28 

24.20 

25.15 

26.00

302, 000 

319, 000 

337, 000 

355, 000 

377, 000 

400, 000 

426, 000 

454, 000 

484, 000 

514, 000 

549, 000 

578, 000

March 24

12.96 

12.82 

12.70 

12.50 

12.30 

12.10 

11.96 

11.80 

11.70 

11.60 

11.45 

11,38

211, 000 

207,000 

204,000 

200,000 

195, 000 

191, 000 

189,000 

184,000 

182,000 

180,000 

175,000 

175, 000

Feet Sec.-ft.

March 13

21.08 

21.38 

21.58 

21.70 

21.76 

21.76 

21.71 

21.65 

21.56 

21.38 

21.22 

21.08

414, 000 

423,000 

429, 000 

432,000 

436, 000 

436,000 

432, 000 

429,000 

429, 000 

423, 000 

417, 000 

414, .000

March 19

26.95 

27.50 

28.20 

28.70 

29.30 

29.75 

30.05 

30.25 

30.33 

30.20 

30.00 

29.75

614,000 

637, 000 

659, 000 

678, 000 

701, 000 

721, 000 

729,000 

736, 000 

740, 000 

736, 000 

729,000 

721, 000

March 25

11.22 

11.10 

10.96 

10.80 

10.68 

10.56 

10.44 

10.35 

10.25 

10.18 

10.10 

10.00

170, 000 

168, 000 

166, 000 

161, 000 

159, 000 

156,000 

152,000 

152, 000 

147, 000 

147, 000 

145, 000 

143, 000

 Mean for the day. 

LOCATION. Chain gage, lat. 40° 15'35", long. 76"53'Q5", at Walnut Street Bridge, Harrisburg,

Dauphin County. Zero of gage is 290.04 feet above mean sea level. 

DRAINAGE AREA. 24,100 square miles. 

REMARKS. Records published in Geol. Surrey Water-Supply Paper 799.
FLOODS OF MARCH 1936, SUSQUEHANNA RIVER 61

TABLE 41. Computation of volume of direct runoff associated with precipitation 

period, March 9-15, 1936, Susguehanna River at Harrisburg, Pa.

March

9................... 10...................

11...................

12...................

13. .............. .....

14...................

15...................

16...................

17...................

18...................

19...................

on

21...................

22...................

23...................

24....................

25...................

26...................

27...................

Total

Daily mean 

discharge 

(second-feet)

91,000 

93,200 

130,000 

304,000 

424,000 

368,000 

267,000 

»19S,000 

 150,000 

 120,000 

 100,000 

 85,000 

"73,000 

 63,000 

 55,000 

 50,000 

 45,000 

 42,000 

 39,000

2,694,200

Estimated 

recession from 

preceding storm 

and base runoff 

(second-feet)

91,000 

69,000 

57,000 

50,000 

44,000 

40,000 

37,000 

35,000 

34,000 

32,000 

31,000 

32,000 

33,000 

34,000 

35,000 

36,000 

37,000 

37,000 

37,000

801,000

Direct runoff 

(second-feet)

0 

24,200 

73,000 

254,000 

380,000 

328,000 

230,000 

160,000 

116,000 

98,000 

69,000 

53,000 

40,000 

29,000 

20,000 

14,000 

8,000 

5,000 

2,000

1,893,200 (.- 

2.92 inches)

 Estimated recession under subsequent rise.

TABLE 42. Computation of time of center of mass of net supply, and lag intervals, 

Susquehanna River at Harrisburg, Pa., March 9-15, 1936

March

9. ......... ...

10.............

11.............

12.............

13.............

14.............

15.............

Mean areal 

precipitation 

(inches)

0 1 \

.06

.74

.60

.11

.06

.04

1.74

Estimated 

snow 

melt 

(inches)

n ?<»

.51

.63

a OC

».05\*>

*> nn

Precipitation plus 

snow melt 

(inches)

A OQ

57

1 V3

SR

.07

.11

.36

3 74

Net 

supply 

(inches)

f\ ofl

44

1.14

.73

n?

.06

oe

2.92

Time 

from 

origin 

(days)

0

1

2

3

4

5

6

Product 

(inch-days)

0

.44

2.28

? 10

.08

.30

1.50

6.79

 Estimated result of snowfall and thawing.

Center of mass of net supply occurred ' = 2.33 days after noon of March 9 = 

March 11.83.

Time of center of mass of direct runoff was at March 15.41 or 3.58 days (86 hours) after 

center of mass of net supply.

Peak discharge occurred at March 13.46 or 1.63 days (39 hours) after center of mass of 

net supply.
62 FLOODS IN NEW YORK AND PENNSYLVANIA

TABLE 43. Computation of volume of direct runoff associated with precipitation 

period March 16-21, 1936, Susquehanna River at Harrisburg, Pa.

Day

Mar. 

16...................

17....................

18....................

19....................

20...................

21.................... 9"?

23....................

24...................

25

26...................

27...................

28................... > »

30....................

31...................

Apr. 

1. ..................

2...................

3...................

Total

Daily mean 

discharge 

(second-feet)

203,000

219,000

414,000

691,000

614,000

440,000

342,000

258,000

193,000

157,000

130,000

108,000

n» ftflfl

80,000

70,000

60,000

52,000

45,000

40,000

4,209,000

Estimated recession 

from preceding 

storm and base 

runoff 

(second-feet)

195,000 

150,000

120,000

100,000

QC AAA

73,000

63,000 

55,000

50,000

45,000

42,000

39,000

38,000

38,000

37,000

37,000

36,000

35,000

35,000

1,273,000

Direct runoff 

(second-feet)

8,000

69,000

294,000

591,000

529,000

367,000

279,000

203,000

143,000

112,000 oQ nnn

69,000

55,000

42,000

33,000

23,000

16,000

10,000

5,000

2,936,000 ( =

4.53 inches)

TABLE 44. Computation of time of center of mass of net supply, and lag intervals, 

Susquehanna Rvver at Harrisburg, Pa., March 16-21, 1936

March

16 ...........

17 ............

18 ...........

19 ............

20 ............

21 ............

Mean 

areal precipitation 

(inches)

0.91

1

6.1

1.00

5?

.06

.53

4.69

Estimated 

snow 

melt 

(inches)

MO

M7 .08

.15 .05

0.80

Precipitation plus 

snow 

melt 

(inches)

1.16

1.77

1.17

.60

.21

.58

5 49

Net 

supply 

(inches)

0.97

1 52

.98

.47

.13

.46

4 53

Time from 

origin 

(days)

0

1

2

3

4

5

Product 

(inch -days)

0.97

1.52

1.96

1.41

.52

2.30

8.68

 Estimated result of snowfall and thawing.

Center of mass of net supply occurred ' = 1.92 days after noon of March 16 = March

4.5*5

18.42

Time of center of mass of direct runoff was at March 21.88 or 3.46 days (83 hours) after 

center of mass of net supply.

Peak discharge occurred at March 19.75 or 1.33 days (32 hours) after center of mass of net

supply.
FLOODS IN NEW YORK AND PENNSYLVANIA 63

WEST BRANCH OF SUSQUEHANNA RIVER AT WILLIAMSPORT, PA.

Daily precipitation at the several stations in and near the basin, computed on the basis of distribution at nearby recording rain gages so as 

to conform with the calendar day, is given in table 45. In combining 

the several records to obtain the average over the basin, they have been 

assigned the Thiessen weights indicated. In table 45, 15 rain gages are 

listed, about one for each 380 square miles of the area. The rain gage 

at Clearfield, Pa., has the greatest weight, being alone in an area of 

about 930 square miles. Precipitation over the basin during the storm 

averaged 8.01 inches, of which 1.99 inches fell during the period, March 

9-15 and 6.02 inches fell from March 16-21. The areal distribution, 

shown on figure 11, indicates that the West Branch Basin received 

greater precipitation than did any other part of the Susquehanna River 

Basin, the amount exceeding 10 inches locally. This excess was largely 

due to the precipitation in the second storm period.

Table 46 lists daily mean precipitation and the daily maximum, minimum, and mean temperatures in the basin. Temperatures listed are the 

average of those observed at Williamsport, Clearfield, and Lawrenceville, Pa. The average temperatures for all but one day, March 13, were 

above freezing, the general average being 39° F. The most significant 

variation in temperature occurred on March 16, 17, 18, and 19, the 

records of which follow:

Station

Williamsport... __ _____ ......

Clearfleld ....... .................

Variation in temperature (° F.) on 

March 16

Max.

48 

45 

55

49

Min.

40 

35 

32

36

March 17

Max.

63 

41 

34

45

Min.

36 

28 

30

31

March 18

Max.

60 

40

38

46

Min.

39 

31 

31

34

March 19

Max.

56 

38 

39

44

Min.

34 

32 

31

32

The above records show that on 3 of the 4 days in question a difference 

in temperature of 15° to 30° F. existed between the observed maxima at 

Williamsport and Lawrenceville, with temperatures at Clearfield not 

widely different from those at Lawrenceville. The drop in temperature 

that occurred over parts of the basin on March 17 was the result of the 

migration of a cold air mass, whose front stagnated along a line over the 

basin. This drop in temperature, although a part of the meteorologic 

factors that were in the background of the flood, was also of direct 

consequence on the intensity of the flood in this area in that, during the 

3 days of heavy precipitation, it caused much snow instead of rain, and 

thus temporarily kept much water out of stream channels.
64 FLOODS IN NEW YORK AND PENNSYLVANIA

Daily mean temperatures during the 30 days antecedent to the storm 

period are given in table 47. The average during the 30 days was 24° F., 

remaining below freezing until February 25, although active thawing 

did not begin until March 9. The effect of thawing temperatures during 

the preliminary period appears to settle the snow cover, that is, to increase its density or "ripen" it.

The water content of the snow cover on March 9 is given in WaterSupply Paper 799 as 4.0 inches, based on fragmentary observations of 

depth of snow in and near the basin, and estimates of the density. The 

West Branch Basin not only had the greatest precipitation of any of 

the tributaries of the Susquehanna River Basin but also contained much 

of the region with greatest snow depth. The subfreezing season, during 

which snow accumulated, began on December 1 and continued until 

March 8. Precipitation during this season averaged 8.4 inches and runoff 

equaled 4.6 inches, indicating that the maximum possible snow cover on 

March 8 would be 3.8 inches, which value was adopted for use in this 

analysis.

The following method was used to estimate the amount of snow remaining after the termination of the storm period on March 22: Precipitation during March 24-31 totaled 0.65 inch and the runoff was 1.15 

inches, indicating a minimum possible contribution from melting snow 

of 0.5 inch. Based on this indication and limited available observations 

reported in Water-Supply Paper 799, the amount of snow on March 22 

was estimated as 0.65 inch water content, and the net snow melt as 3.15 

inches (3.8-0.65).

A hydrograph of flood discharge based on data given in table 48 is 

shown on figure 15. In common with other streams there were two 

separate stream rises, associated with the two periods of precipitation. 

Figure 15 shows the manner of separation into direct runoff and groundwater flow and the division between the storm rises. As given in table 49 

the volume of direct runoff associated with the first storm period March 

9-15 was 3.10 inches. The precipitation during March 9-15 was 1.99 

inches and net snow melt as shown in table 50 was estimated at 2.30 

inches, the total being 4.29 inches. Snowfall occurred on March 12-15, 

but only on March 13 did it exceed the amount of thaw.

The volume of direct runoff associated with the second precipitation 

period March 16-21 as given in table 51, equaled 5.63 inches. Precipitation from March 16-21 was 6.02 inches and snow melt as shown in 

table 52, was estimated at 0.85 inch. Snowfall exceeded snow melt on 

March 17. The greatest amount of snow melt during the flood was estimated to have occurred on March 11 (0.78 inch), the day with greatest 

average temperature, while the snow cover was still generally plentiful 

over the entire basin.
TABLE 45. Daily precipitation, in inches, at stations in an

Sttsquehanna River basin at Williams port, Pa,, M

[In this table "T" indicates a trace]

Station 

(Pennsylvania)

State College... .. ..

TWiuturt'

Altitude 

(feet)

1,650

1,050

800

1,120

2,000

1,325

1,637

1,750

1.045

672

1,500

1,217

750

1,419

521

Weight

(percent)

3.58

6.69

10.72

16.33

3.10

9.31

11.29

3.05

.14

14.36

7.64

3.38

1.29

3.72

5.40

100.00

9

0.10

.09

.16

.17

.14

.07

.12

.10

.01

.03

.07

.06

.04

0.08

10

0.07

.10

.05

.10

.17

.09

.04

.02

.07

.12

.25

.05

.05

0.09

11

0.51

1.00

1.28

,63

.32

1.54

.66

1.19

.78

.49

.22

1.01

2.00

.93

1.46

0.92

12

0.35

.43

1.02

.36

.40

.42

.56

1.06

1.20

.64

.12

.53

.50

.76

1.07

0.62

13

0.21

.23

.16

.06

.10

.11

.05

.14

.19

.02

.01

.09

.19

0.11

14

0.08

.07

.13

.12

.11

.17

.05

.04

.20

.04

.04

.09

0.08

15

0.08

.07

.22

.10

.09

.07

T

.04

.03

.09

.25

.05

.10

.10

0.09
66 FLOODS IN NEW YORK AND PENNSYLVANIA

mi pm»n m I«JO«MIO
FLOODS OF MARCH 1936, WEST BRANCH SUSQUEHANNA RIVER 67

Ground-water runoff associated with the storm period March 9-22 

was 2.0 inches, which, added to the total direct runoff of 8,73 inches, 

makes a total runoff of 10.73 inches from a total precipitation and snow 

melt of 11.16 inches leaving indicated balance of only 0.43 inch for 

field-moisture accretion and evaporation losses.

The lag interval between the occurrence of precipitation and snow 

melt and the passage of the resultant direct runoff at Williamsport was 

49 hours for the first storm period and 50 hours for the second.

TABLE 46. Daily mean a/real precipitation, and temperatures, West Branch of 

Susquehanna River at Williamsport, Pa., March 9-21, 1936

March

9 ...............

10 ...............

11 ...............

12 ...............

13 ...............

14 ...............

15 ...............

16 ...............

17 ...............

18 ...............

19 ...............

20 ...............

21 ...............

Mean

areal 

precipitation* 

(inches)

0.08

.09

0?rf\

.11

ftQ

.09

1.20

2.36

1 17

.64

1?

ca

8.01

Maximum* 

<°F.)

43

1?

49

48

37

43

56

49

45

46

44

51

46

47

Temperature

Minimumb 

(°F.)

34

34

41

31

24

25

90

36

31

?d

32

28

31

32

Mean0 

(°F.)

oo

A^

45

40

30

34

42

42

38

40

38

39

39

39

 Midnight to midnight.

bAverage of observations at Clearfield, Lawrenceville, and Williamsport, Pa.

'Average of maximum and minimum.

TABLE 47. Daily mean temperature*, West Branch of Susquehanna River at 

Williamsport, Pa., February 8 to March 8, 1936

Day

Feb. 

8 .................

9 .................

10 .................

11 .................

1?

13 .................

14 .................

IS .................

16 .................

17 .................

18 .................

19 .................

?n

21 .................

99

Mean 

temperature 

<°F.)

13">">

14

11

13

17

30

31

24

30

17

5

5

19

13

Day

Feb. 

93

24 .................

25

26 .................

?7

28 ..................

29 .................

1 .................

3 ..................

4 ..................

5 ..................

6 ..................

7 ..................

8 ..................

Mean 

temperature 

(°F.)

12

30

40

37

40

29

29

28

20

32

39

39

25

27

29

24

"Average of recorded daily maximum and minimum temperatures at Qearfield, Lawrenceville, 

and Williamsport.
68 FLOODS IN NEW YORK AND PENNSYLVANIA

TABLE 48. Gage height and discharge of the West Branch of the Susquchanna 

River at Williamsport, Pa., during flood of March 1936

MEAN DISCHARGE, IN SECOND-FEET, 1936

Day

1

2

3

4

5

6

7

8

9

10

Feb.

2,500

2,400

2,300

2,200

2,100

2,050

2,000

1,950

1,900

1,850

Mar.

23,000

24,000

19, 000

17, 000

22, 000

31, 000

32, 000

23,000

20, 000

22, 000

Apr.

23,900

20, 900

20, 400

19, 000

17, 100

19, 800

30, 200

32, 300

26, 400

23,400

Day

11

12

13

14

15

16

17

18

19

20

Feb.

1,800

1,750

1,750

1,700

1,700

1,650

1,700

1,800

2,100

2,000

Mar.

45, 000

145, 000

137, 000

74, 600

47, 100

48, 400

107, 000

218, 000

225, 000

' 153, 000

Apr.

21, 900

22, 400

22, 900

21, 400

19, 000

17, 100

15,300

13,600

11,900

11, 200

Day

21

22

23

24

25

26

27

28

29

30

31

Mean monthly discharge, in second-feet _ _ .

Runoff, in inches

Feb.

1,900

1,850

1,750

1,700

1,650

1,700

3,000

8,000

15, 000

2,612

.50

Mar.

94, 200

64,600

46, 500

40, 100

39, 100

45, 500

44, 900

44, 500

40, 000

31, 900

27, 800

62, 970

12.80

Apr.

10, 000

9,500

8,080

7,970

7,320

6,690

6,230

5,930

5,640

5,780

16,140

3.17

GAGE HEIGHT, IN FEET, AND DISCHARGE, IN SECOND-FEET, AT INDICATED TIME, 1936

Hour

2 

4 

6 

8 

10 

12m. 

2 

4 

6 

8 

10 

12p.m.

2 

4 

6 

8 

10 

12m. 

2 

4 

6 

8 

10 

12p.m.

2 

4 

6 

8 

10 

12m. 

2 

4 

6 

8 

10 

12p.m.

Feet Sec.-ft.

March 8

....... >>23,000

March 14

16.86 

16.30 

15.76 

15.27 

14.78 

14.30 

13.88 

13.50 

13.15 

12.81 

12.52 

12.25

97,000 

91, 000 

86, 100 

81, 300 

76, 500 

71, 800 

68, 200 

64, 600 

62, 000 

58, 600 

56, 200 

53,900

March 20

25.48 

24.88 

24.28 

23.67 

23.13 

22.55 

21.95 

21.32 

20.70 

20.07 

19.47 

18.88

183, 000 

177, 000 

171, 000 

165, 000 

159, 000 

154, 000 

148, 000 

141, 000 

135, 000 

129, 000 

123, 000 

117,000

Feet Sec.-ft.

March 9

....... b20, 000

March 15

12.00 

11.78 

11.59 

11.41 

11.26 

11.12 

11.00 

10.88 

10.78 

10.67 

10.60 

10.55

52, 400 

50, 900 

49, 500 

48, 100 

47, 400 

46, 100 

45, 400 

44, 800 

44, 100 

43,500 

42, 800 

42, 800

March 21

18.10 

17.65 

17.29 

16.97 

16.68 

16.41 

16.21 

16.01 

15.78 

15.55 

15.31 

15.05

109, 000 

104, 000 

101, 000 

98, 000 

95, 000 

92, 000 

90, 000 

88, 100 

86, 100 

84, 200 

81, 300 

78, 400

Feet Sec.-ft.

March 10

b22, 000

March 16

10.58 

10.61 

10.66 

10.73 

10.86 

10.99 

11.13 

11.36 

11.72 

12.23 

12.87 

13.62

42, 800 

42, 800 

43,500 

43,500 

44,800 

45, 400 

46, 100 

48, 100 

50,200 

53, 900 

59,400 

65,500

March 22

14.79 

14.51 

14.25 

13.98 

13.70 

13.45 

13.20 

12.90 

12.67 

12.41 

12.17 

11.99

76,500 

73,700 

70,900 

69, 100 

66,400 

63,700 

62, 000 

59, 400 

57, 800 

55, 400 

53, 900 

52, 400

Feet Sec.-ft.

March 11

H5, 000

March 17

14.38 

15.21 

16.05 

16.83 

17.50 

18.11 

18.63 

19.15 

19.62 

20.18 

20.85 

21.78

72, 800 

80, 300 

88,100 

96, 000 

103, 000 

109,000 

114, 000 

120, 000 

124, 000 

130, 000 

136, 000 

146, 000

March 23

11.81 

11.66 

11.52 

11.38 

11.26 

11.12 

11.00 

10.87 

10.73 

10.63 

10.51 

10.41

50, 900 

50,200 

48, 800 

48, 100 

47, 400 

46, 100 

45, 400 

44,800 

43,500 

42, 800 

42, 200 

41, 600

Feet Sec.-ft.

March 12

17.58 

19.22 

20.72 

21.85 

22.67 

23.07 

23.32 

23.45 

23.56 

23.66 

23.56 

23.42

104, 000 

120, 000 

135, 000 

146, 000 

155, 000 

159, 000 

161, 000 

162, 000 

164, 000 

165, 000 

164, 000 

162, 000

March 18

23.08 

24.00 

25.38 

26.78 

28.63 

30.25 

31.42 

32.47 

33.30 

33.54 

33.56 

33.32

159, 000 

168, 000 

182, 000 

196, 000 

214, 000 

230, 000 

242, 000 

253, 000 

261, 000 

263, 000 

264, 000 

261, 000

March 24

10.34 

10.26 

10.20 

10.17 

10.16 

10.15 

10.13 

10.11 

10.07 

10.03 

9.97 

9.92

41, 000 

41, 000 

40, 400 

40, 400 

40, 400 

40,400 

39, 800 

39, 800 

39, 800 

39, 200 

39, 200 

38, 600

Feet Sec.-f.

March 13

23.27 

23.03 

22.67 

22.27 

21.80 

21.25 

20.67 

20.07 

19.43 

18.73 

18.08 

17.47

161, 000 

158, 000 

155, 000 

151, 000 

146, 000 

140, 000 

135, 000 

129, 000 

122, 000 

115, 000 

109, 000 

103, 000

March 19

32.81 

32.20 

31.57 

31.00 

30.35 

29.72 

29.12 

28.48 

27.85 

27.25 

26.70 

26.08

256, 000 

250, 000 

244,000 

238,000 

232, 000 

225, 000 

219, 000 

213, 000 

206, 000 

200, 000 

195, 000 

189, 000

March 25

9.86 

9.85 

9.85 

9.87 

9.90 

9.93 

9.97 

10.01 

10.05 

10.09 

10.16 

10.27

38, 600 

38, 000 

38, 000 

38, 600 

38, 600 

38, 600 

39, 200 

39, 200 

39, 200 

39, 800 

40,400 

41, 000

' Supplemental records: Mar. 18, 9 p.m., 33.57 ft., 264,000 sec.-ft.

b Mean for the day.

LOCATION. Water-stage recorder, lat. 41° 14'15", long. 76°59'S5", at highway bridge at Williamsport, Lycoming County. Zero of gage is 494.55 feet above mean sea level. 

DRAINAGE AREA. 5,682 square miles. » 

REMARKS. Records published in Geol. Survey Water-Supply Paper 799.
FLOODS OF MARCH 1936, WEST BRANCH SUSQUEHANNA RIVER 69

TABLE 49: Computation of volume of direct runoff associated with precipitation 

period March 9-15, 1936, West Branch of Susquehanna River at Williamsport, Pa.

March

9 .................

10 ..................

11 ..................

19

13 ..................

14 ..................

IS ..................

16 ..................

17 ..................

18 ..................

19 ..................

20 ..................

Total

Daily mean 

discharge 

(second-feet)

20,000

22,000

45,000

145,000

137,000

74,600

47,100

 32,000

"25,000

"21,000

"18,000

"16,500

603,200

Estimated recession 

from preceding storm 

and base runoff 

(second-feet)

16,000

12,500

10,000

8,000

7,500

7,500

O DAA

10,000

11,000

12,000

13,000

14,000

130,300

Direct runoff 

(second-feet)

4,000

9,500

35,000

137,000

129 500

67,100

38,300

22,000

14,000

9,000

5,000

2,500

472,900 ( =

3. 1 0 inchest

 Estimated recession under subsequent rise.

TABLE 50. Computation of time of center of mass of net supply, and lag intervals, 

West Branch of Susquehanna River at Williamsport, Pa., March 9-15, 1936

March

9 ...........

10 ...........

11 ...........

12 ...........

13 ...........

14 ...........

15 ...........

Mean 

areal 

precipitation 

(inches)

0.08

.09

.92

£*)

.11

no

.09

1.99

Estimated 

snow 

melt 

(inches)

0 29

.6970

 OQ

« .05

".01

».30

2.30

Precipitation 

plus snow 

melt 

(inches)

70

1.70

.90

.06

.09

.39

4.29

Net 

supply 

(inches)

0.21£*y

1.37

64

.01

.01

.24

3.10

Time 

from 

origin 

(days)

0

1

3

4

5

6

Product 

(inch-days)

0

.62

2.74

1.92

.04

.05

1.44

6.81

"Estimated result of snowfall and thawing. 

Center of mass of net supply occurred 6.81

3.10 = 2.20 days after noon of March 9 = March

11.70.

Time of center of mass of direct runoff was at March 13.73 or 2.03 days (49 hours) after 

center of mass of net supply.

Peak discharge occurred at March 12.83 or 1.13 days (27 hours) after center of mass of net 

supply.

TABLE 51. Computation of volume of direct runoff associated with precipitation 

period March 16-21, 1936, West Branch of Susquehanna River at Williamsport, Pa.

March

15 .................

16 ..................

17 ..................

18 ..................

19 .................

20 ..................

21 ..................

2?

23

24 .................

9<

26 .................

27 ..................

28 ..................

29 ..................

30 ..................

Total

Daily mean 

discharge 

(second-feet)

47,100

48,400

107,000

218,000

225,000

153,000

QA OAn

64,600

46,500

"36,000

"29,000

"25,000

"21,500

"18,000

"16,000

 12,800

1,162,100

Estimated recession 

from preceding storm 

and base runoff 

(second-feet)

47,100

32,000 

25,000

21,000 

18,000

16,500

16,000

16,000

15,500

15,000

14,500

14,000

13,500

13,000

i 9 flrtn

12,500

302 400

Direct runoff 

(second-feet)

0

16,400

oo nnn

197,000

207,000

. 136,500

78,200

48,600

31,000

21,000

14,500

11,000

8,000

5,000

3,200

300

859,700 ( =

5.63 inches)

"Estimated recession under subsequent rise.
70 FLOODS IN NEW YORK AND PENNSYLVANIA

TABLE 52. Computation of time of center of *mass of net supply, and lag intervals, 

West Branch of Susquehanna River at Williamsport, Pa., March 16-21, 1936

March

16 ...........

17 ...........

18 ...........

19 ...........

20 ...........

21 ...........

Mean 

areal 

precipitation 

(inches)

i 9f>

O 1£

1 19

.64

19

ca

£ rt/>

Estimated 

snow 

melt 

(inches)

0.33 "-.01

99

.17 «.14

 0

ft fi<:

Precipitation 

plus snow 

melt 

(inches)

1.53

o oe

SI

o<c

C9

6.87

Net 

supply 

(inches)

1 98

9 ft9

1.11

.63

.14

.45

S.63

Time 

from 

origin 

(days)

0

1

3

4

5

Product 

(inch-days)

0

2 02

9 99

1.89

.56

2.25

8.94

 Estimated result of snowfall and thawing. 

Center of mass of net supply occurred 8.94

5.63 = 1.59 days after 12 noon of March 16 =

March 18.09.

Time of center of mass of direct runoff was at March 20.16 or 2.07 days (SO hours) after 

center of mass of net supply. 

Peak discharge occurred at March 18.88 or 0.79 day (19 hours) after center of mass of net 

 upply.

FLOOD OF MARCH 1920, GENESEE RIVER AT ST. HELENA, N. Y.

The Genesee River Basin was the only one studied in which the maximum winter flood of record did not occur in March 1936. The maximum 

flood was that of March 1920 and was the result of rapid melting of a 

heavy snow cover during a few days of high temperature, together with 

a very moderate rainfall. The occurrence of so small an amount of rainfall with a flood of the magnitude of that of March 1920 in the Genesee 

River Basin is very unusual.

Records of precipitation at all Weather Bureau stations in and near 

the basin are given in table 53. Three of these stations are within the 

drainage basin and three others are not far from it, so that the determination of rainfall was probably fairly reliable. More than half the 

total storm precipitation of 0.88 inch fell on March 12. The daily precipitation listed in table 54 is that which was estimated to have fallen 

within the indicated calendar day on the basis of the regular daily 

records and of hourly records at Buffalo and Rochester, N. Y. Available records of hourly precipitation are given in table 55. The maximum 

total storm precipitation recorded was 2.03 inches at Bolivar just off 

the western watershed, and the minimum was 0.26 inch at Lauterbrunnen at the lower end of the basin. Figure 16 shows an isohyetal 

map of total storm rainfall.

Daily mean areal precipitation together with daily temperature is 

shown in table 56. Temperatures were highest on March 10, 11, and 12, 

during which period they ranged between 59° and 29° and averaged 

43° F. The temperature on the morning of March 13 dropped to 12° F., 

and the temperatures on March 14 were continuously below freezing. 

Most of the precipitation on those days fell as snow. At the recording
FLOOD OF MARCH 1920, GENESEE RIVER 71

FICDM 16. Map of Genesee River basin above St. Helena, N. Y., showing lines of equal precipitation, March 11-14, 1920.

689521 47 6
72 FLOODS IN NEW YORK AND PENNSYLVANIA

rain gages listed in table 55, the Weather Bureau reported all the 

precipitation falling on March 13 and 14 as snow.

Little is known of the extent of frost in the ground at the beginning 

of the storm period. Table 57 indicates that temperatures averaged 

freezing or below each day during the 30-day antecedent period February 9 to March 9. The average 30-day temperature was 19° F. which 

was 5° below normal. This evidence would suggest that frost was present 

in the ground where not insulated by snow cover sufficiently to prevent it.

The only direct information on snow cover is that given in table 58, 

which lists measurements of the depth of the snow on the ground made 

by observers of the Weather Bureau. No data are available concerning 

its water content. Substantial amounts of snow were measured at several 

places on March 8 and 9, which were rapidly depleted until March 13 

when there was additional snowfall.

The storm period ended March 14 with some snow still on the ground, 

less deep than that on March 9 but of unknown water content. The data 

given in table 58 are generally inadequate for determining water equivalent of the snow cover on March 9 or on March 14, so the analysis below 

was used to supplement them.

The temperatures of the period December 1919 to March 10, 1920, 

were generally subfreezing. During this time there was a total precipitation of 6.4 inches over the basin, and runoff totaled 1.9 inches, leaving 

a retention of 4.5 inches, of which the greater part was probably snow. 

The estimate of average water content on March 9 was placed at 3 

inches, since that is the maximum that seemed consistent with the data 

given in table 58.

An estimate of the snow remaining after the close of the storm period 

was similarly made. The total precipitation from March 15 to March 20 

was 0.15 inch and the total direct runoff associated with the events of 

the same period was 0.76 inch, indicating a minimum contribution to 

runoff from snow of 0.61 inch. Based on measurement on March 15 at 

Alfred and Angelica, N. Y., and West Bingham, Pa., and an estimated 

water content of 50 percent, the snow cover remaining after the storm 

was estimated at 0.8 inch, the net snow melt from March 10-14 being 

of 2.2 inches (= 3.0-0.8 as entered in table 61).

Discharge during the flood period is given in table 59 and plotted 

as a hydrograph on figure 17. The total direct runoff associated with the 

period March 10-14 as computed in table 60 was 2.08 inches. Precipitation and estimated snow melt totaled 3.08 inches, indicating a retention 

of 1.0 inch. Ground-water runoff was computed, however, as equal to 

0.80 inch, leaving an indicated 0.20 inch for soil-moisture accretion and 

evaporation losses.

Table 61 shows the procedure of computing the lag interval between 

net supply and direct runoff. Twelve-hourly precipitation was computed
FLOOD OF MARCH 1920, GENESEE RIVER 73

 10 II 12 13 14 15 16 17 16 19 20 21

10

FIGURE 17. Hydrograph of Genesee River at St. Helena, N. Y., showing discharge, March 1920.
74 FLOODS IN NEW YORK AND PENNSYLVANIA

.from daily and hourly records of rainfall. Snow melt was computed 

by distributing the estimated snow melt of 2.2 inches on the basis of 

daily temperatures above freezing, snowfall being treated as negative 

snow melt. The total supply was reduced to net supply and the time 

of its center of mass computed as shown.

The time interval between the net supply and the center of mass of 

direct runoff was 32 hours, and that between the net supply and the peak 

discharge was 26 hours.

TABLE 53. Daily precipitation, in inches, at stations in and near Genesee River

basin above St. Helena, N. Y., March 11-14, 1920

[Measured in afternoon except as noted]

Station

New York: 

Alfred .......

Angelica .....

York .........

Pennsylvania:

11

0.16

.02

.75

1?

.10

.03

.13

-11

.10

12

0.17

.45

DA

.12

.07

.30

T)

43

.27

1?

.35

March

13

0.31

.40 

.48

.28

.45

.28

.11

.12

.28

.11

.50

14

0.05

.16

.20

f)4

Total 

11-14

0.69

1.03 

2.03

.40

.64

.68

.26

.88

.59

.34

.95

"Measured in the morning, the amount then recorded being for the preceding 24 hours.

TABLE 54. Daily precipitation, in inches, at stations in and near Genesee River 

basin above St. Helena, N. Y., March 10-14, 1920

Station

New York: 

Alfred-.-- 

Hunt- ..

Pennsylvania:

Altitude

(feet)

1,840 

1,420 

1,800 

1,150 

1,260

1,171

Weight (percent)

12.7 

33.1 

8.0 

11.4 

16.8

18.0

100.0

' March

10

0.04 

0 

.19 

.03 

0

.03

0.03

11

0.12 

.02 

.56 

.07 

.03

.07

0.09

12

0.28 

.59 

.97 

.40 

.16

.52

0.48

13

0.22 

.34 

.31 .18' 

.07

.33

0.26

14

0.03 

.08 

0 

0 

0

0

0.03

Total 

10-14

0.69 

1.03 

2.03 

.68 

.26

.95

0.88
TABLE 55. Hourly precipitation, in inches, at recording gages in and near 

[!D this table "T" indicates a trace]

Station

Buffalo, N. Y.. ......................

U. 8. Weather Bureau. 

Ithaca, N. Y.. ......................

U. 8. Weather Bureau.

U. 8. Weather Bureau.

Day

8

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20

8

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20

8

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

10 

20

a.m.

1

0.02

T

T

~.~02 

~~T

T

....

.01 

T

.03

.01

2

0.02

T

T

~.~02

"T

T

....

.01 

T

T

.02

.01

3

0.02

.01 

.03 

T

T

~.~03

T

T

.01

,01

.01

T

4

0.02

.02 

.07 

.01

T

~.~03 

T

T

T

.01

T

.03

T

.01

09!

5

T 

0.02

.02 

.07 

T

.01

T

T 

.02 

.01

T

T

.02

.09

03

04

6

T 

0.01

.01 

.06 

.01

T

.01 

.02 

.02

.01

T

.02

T 

.02

06

7

0.01 

.01

T 

.02 

T

T

.02 

.01 

.02

.01

T

.03

T

T 

.03

T

T

04

8

T

T

T

T 

T

T

.02 

T 

.02

.01

T

.04

T

.01 

.04 

T

04

0

T

T

T

T

.03 

T 

.03

T

T

.03

.01

.01 

T 

.02

02

10

T

0.01

T

.04 

T 

.04

T

.02

T

T 

T 

.01

01

11

T

0.01

T

T

.04

.04

T

.01

.01

.02

01

12

T

0.01

.04

.04

.04

.01

T

.02

T

1

T

0.01

08

.01

.04

.01

.03

T

T 

.01

2

T

0.02

08

.04

.01

.04

T

.01 

T

o

.

.

.

.

.

.
76 FLOODS IN NEW YORK AND PENNSYLVANIA

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FLOOD OF MARCH 1920, GENESEE RIVER IT

TABLE 56. Daily mean areal precipitation and temperature, Genesee River 

at St. Helena, N. Y., March 9-15, 1920

March

9 ...............

10 ...............

11 ...............

19

13 ...............

14 ...............

IS ...............

Mean. 10-14 ......

Mean areal 

precipitation" 

(inches)

0

.03

.09

AQ

f\f

.03

0

0.89

Maximum6 

(°F.)

41

SO

47

59

50

9ft

47

47

Minimum1* 

(°F.)

20

35

9O

42

19

8

6

2$

Mean0 

(°F.)

30

42

38

SO

31

18

26

36

 Midnight to midnight.

bAverage of reading at Alfred, Angelica, Bolivar, Hunt, Lauterbrunnen, N. Y., and West 

Bingham, Pa.

°Average of maximum and minium.

TABLE 57. Daily mean temperature, Genesee River at St. Helena, N. Y., 

February 9 to March 9, 1920

Day

Feb. 

9 .................

10 .................

11 .................

12 .................

13 .................

14 .................

IS .................

16 .................

17 .................

18 .................

19 .................

90

21 .................

?9

23 .................

94.

Mean temperature" 

(°F.)

20

28

26

28

31

30

18

3

16

99

7

10

11

26

20

27

Day

Feb.

25

26 ..................

97

28 ..................

?o

Mar.

2

3 ..................

4 ..................

S ..................

6 ..................

7 ..................

9 ..................

Mean temperature" 

(°F.)

15

7

3

10

1 Q

12

24

32

32

28

11

8

16

30

19

'Average of recorded daily maximum and minimum temperatures at Alfred, Angelica, Bolivar, 

Lauterbrunnen, N. Y., and West Bingham, Pa.
TABLE 58. Snow depth and snowfall at Weather Bureau 

Genesee River above St. Helena, N. Y., March 7-1

[In this table "T" indicates a trace]

Station

New York: 

Alfred. 

Buffalo. _ ...

Elmira ___ ...

Haskinville. 

Lauterbrunnen..

Pennsylvania: 

West Bingham..

Time 

of 

observation

6p.m. 

5p.m. 

p.m. 

8p.m.

0:30 a.m. 

p.m. 

6p.m. 

8p.m. 

8p.m.

6p.m.

March

T

Snowfall

0.3 

0 

0 

T

0 

0 

T 

.6 

2

0

Snow 

cover

14.0 

10.0

7.0 

3

5.0

 7.0 

12.0 

20.0

8

Snowfall

0 

0 

0

.1

0 

0

0 

0 

0

0

Snow 

cover

13.0

7.6

3 

A

5.0

7.0 

11.0 

20.0

0

Snowfall

0 

0

1

1.8

0 

.4

T 

1.5 

T

0

Snow 

cover

12.0

6.6

5.0

T 

11.0 

18.0

10

Snowfall

0 

0

0

0

0 

0

0 

0 

0

0

Snow 

cover

»9.0

4.0

2.0

T 

8 

13.5

11

Snowfall

0 

0

0

0

0 

0

0 

0 

0

Snow 

cover

4.0

3.0

1.0

T 

5.0 

12.0

12

Snowfall

0 

0

0

0

0 

0

0 

0 

0

Snow 

cover

1.0

2.0

T

T 

T 

4

 End of sleighing weather, continuous since December 25,1910.
FLOOD OF MARCH 1920, GENESEE RIVER 79

TABLE 59. Gage height and discharge of Genesee River at St. Helena, N. Y., 

during flood of March 1920

MEAN DISCHARGE, IN SECOND-FEET, MARCH 1920

Day

1... ..

2. .......

3........

4........

5........

Me 

Rui

Sec.- 

ft.

220 

220 

220 

260

440

an monl 

aofl, in i

Day

6 ....

7 _

8-... ...

9.... ...

10 

hly discha 

nches....

Sec.- 

ft.

1.500 

1,900 

1,300 

1,000 

950

irge, in s

Day

11......

12......

13 ...

14. _ ..

15. _ ..

«cond-feet

Sec.- 

ft.

2,000 

18,600 

28,800 

7,050 

4,240

Day

16 

17 

18 

19 

20 

Sec.-

ft.

6,640 

11, 390 

4,770 

3,490 

2,640

Day

21 

22 

23 

24. _ ..

25 

See.- 

ft.

2,140 

2,140 

3,130 

3,900 

4,100

Day

26 

27 

28......

29 

30 

31......

Sec. 

ft.

4,530 

4,310 

2,890 

2,290 

2,000 

1,600

4,215

4.78

GAGE HEIGHT, IN FEET, AND DISCHARGE, IN SECOND-FEET, AT INDICATED TIME, 1920

Hour

3... ..........

6 ..........

9 ..........

12m...........

3... ..

6 ....

9....... . 

12p.m.. .

Feet Sec.-ft.

March 10

5.87

5.82

5.80

5.79 

5.80 

5.82

5.86 

6.05

»950

.......

Feet Sec.-ft.

March 11

6.20

6.33

6.43

6.61 

6.64 

7.51

7.76 

8.71

»2,000

"4266"

Feet Sec.-ft.

March 12

10.37 

9.29

8.91 

9.33 

10.12 

10.64 

11.27 

11.85

6,630

15,400 

17,400 

21, 800 

25,500 

30,500 

35,600

Feet Sec.-ft.

March 13

12.27 

12.25 

11.90 

11.31 

10.65 

9.75 

8.86 

8.25

39, 400 

39, 200 

36,100 

30,800 

25,600 

19,600 

15, 100 

12, 400

Feet Bec.-ft.

March 14

7.70 

7.24 

6.87 

6.59 

6.35 

6.23 

6.18 

6.11

10, 200 

8,370 

7,070 

6,190 

5,560 

5,270 

5,150 

4,990

Feet Sec.-ft.

March 15

6.04 

5.86 

5.68 

5.65 

5.52 

5.63 

5.73 

5.90

4.840 

4.440 

4,060 

4,000 

3,740 

3,960 

4,160 

4,530

Hour

3....

6 ..........

»- .. . .

12m....... ..

3...............

6.....

9..... .

12p.m...... .....

Feet Seo.-ft.

March 16

6.05 

6.14 

6.16 

6.21 

6.41 

7.02 

7.86 

8.48

4,860 

5,060 

5,110 

5,220 

5,720 

7,540 

10, 800 

13, 300

Feet Sec.-ft.

March 17

8.73 

8.66 

8.42 

8.06 

7.76 

7.44 

7.15 

6.84

14,400 

14,100 

13, 100 

11,600 

10,400 

9,160 

8,020 

6,940

Feet Sec.-ft.

March 18

6.51 

6.25 

6.04 

5.84 

5.74 

5.68 

5.65 

5.66

5,980 

5,320 

4,840 

4,400 

4,180 

4,060 

4,000 

4,020

Feet Sec.-ft.

March 19

5.60 

5.53 

5.46 

5.37 

5.30 

5.25 

5.19 

5.14

3,900 

3,760 

3,620 

3,450 

3,320 

3,220 

3,110 

3,020

Feet Sec.-ft.

March 20

5.06 

5.02 

4.98 

4.91 

4.86 

4.82 

4.78 

4.76

2,880 

2,810 

2,740 

2,620 

2,540 

2,470 

2,410 

2.380

 Mean for the day. 

LOCATION. Water-stage recorder, lat. 42°37'20*, long. 77'59'20", at highway bridge in St.

Helena, Wyoming County, 1% miles downstream from Wolf Creek. 

DRAINAGE AJZEA. 1,017 square miles. 

REMARKS. Records supersede those published in Water-Supply Paper 504.
80 FLOODS IN NEW YORK AND PENNSYLVANIA

TABLE 60. Computation of volume of direct runoff' associated with precipitation 

period March 10-14, 1920, Genesee River at St. Helena, N. Y.

March

10 ...............

11 ...............

12 ...............

13 ...............

14 ...............

15 ...............

16 ...............

17 ...............

18 ...............

Total 

Sec. -ft. -days. .....

12-hour period 

ending

12 m.

12 p.m. 

12 m.

12 p.m. 

12 m.

12 p.m. 

12 m.

12 p.m. 

19 M

12 p.m. 

12 m.

12 p.m. 

1 *) « 

12 p.m. 

12 m.

12 p.m.

1 O « 

12 p.m.

Daily mean 

discharge 

(second-feet)

900

1,000 

1,200

2,800 

10,900

26,000 

37,200

20,400 

8,700

5,380 

4,460

 3,700 

 3,200

 2,800 

 2,600

 2,300 

 2,100

 1,950

68,795

Estimated 

recession from 

preceding storm 

and base runoff ' 

(second-feet)

900

' 800 

800

750 

800

900 

950

1,100 

1,250

1,400

1,550 

1,700 

1,800

1,900

1,950 

1,900

1,850 

1,800

12,050

Direct runoff 

(second-feet)

0

200 

400

2,050 

10,100

25,100 

36,250

19,300 

7,450

3,980 

7 oin

2,000 

1,400

.105 

650

400 

7^n

150

56,745 ( =

2.08 inches)

 Estimated recession under subsequent rise.

TABLE 61. Computation of time of center of mass of net supply, and lag intervals, 

Genesee River at St. Helena, N. Y., March 9-14, 1920

March

9.........

10......... 

11.........

12.........

13.........

14.........

12-hour 

period 

ending

12m........ 

12p.m...... 

12m........

12m........

12m........

12m........

Mean areal 

precipitation 

(inches)

0.00

0.00 

.03 

.06 

.03

.35 

.13

.16

.09

.03 

nn

n 8a

Estimated 

snow 

melt 

(inches)

0.12

.20 

.40 

.10 

.29

.42 

.68

».08 

MO

».03 

.00

"> on

Precipitation plus 

snow melt 

(inches)

0.12 

.20 

.43 

.16

32

.77

Q 1

.08 

.19

0 

0

 S fkQ

Estimated 

net supply 

(inches)

0.00

.11

.30

.08 

22

.59

.63

.03

.12

.00 

.00

"> na

Time 

from 

origin 

(days)

0.0

.5

1.0

1.5 

2.0

2.5 

3.0

3.5 

4.0

4.5 

5.0

Product 

(inchdays)

0.000

.055 

.300 

.120 

.440

1.470 

1.890

.105 

.480

.000 

.000

4.860

 Estimated result of snowfall and thawing.

Center of mass of net supply occurred 

= March 12.05.

= 2.30 days after 6 p.m. of March 9 (origin)

..

Time of center of mass of direct runoff was at March 13.40 or 1.3S days (32 hours) after 

center of mass of net supply.

Urred ^ 3 a' m> Mar°h 13 °f L°8 dayS (26 h°Urs) after Center of mass of
FLOODS IN NEW YORK AND PENNSYLVANIA 81

SNOW-RUNOFF STUDIES

Flood-crest discharge rates are the result of two factors, the volume 

of runoff and its concentration with respect to time. The maximum 

volume of direct runoff associated with the nonwinter floods in table 63 

is 3.47 inches, whereas the maximum volume of runoff for the winter 

floods is 5.63 inches. The characteristically greater volume of runoff 

during winter floods in the northeast is attributable to contributions 

from snow as well as to decreased retentive capacity of the ground during the winter season.

However, inspection of the ratio between the volume of direct runoff 

during the maximum 24 hours and the total volume of direct runoff 

for both the winter and nonwinter floods, discloses that the higher ratios 

prevailed during the nonwinter season, indicating more sharply concentrated runoff. The greater volumes and decreased concentration characteristic of winter floods are partially compensating factors.

The concentration of runoff during winter floods is affected by the 

intensity of rainfall and by the rate of melting of the snow cover. The 

rate of melting is related primarily to the magnitude of the thawing 

temperatures and in a secondary way to the amount of snow remaining 

on the ground. It seems to approach a limit lower than observed rates 

of rainfall. Rate of wind movement and relative humidity are other 

factors of more indirect influence.

In the absence of continuous measurements of snow cover, the difference between measured runoff and precipitation has provided a basis 

for approximating the amount of water released from the snow cover 

to stream flow as melt or slush, which has been studied in relation to 

temperature. The following procedure was adopted for this purpose: 

Beginning with the end of a sub freezing period, a graph of stream flow 

was plotted upon which was drawn the estimated position of the line 

representing base flow. A table was prepared listing daily values of the 

total discharge and the estimated apportionment in base flow and direct 

runoff. A cumulative table of total discharge was prepared, which gave 

the total discharge in second-foot days past the gage from the end of 

the subfreezing period until midnight of each indicated day. These 

values of total discharge were adjusted for the estimated ground-water 

storage and channel storage based on the daily rates of base flow and 

direct runoff. In general the ground storage on any day in second-footdays was determined from the rate of base flow in second-feet using 

appropriate ground-water storage curves as shown in figure 2 and the 

channel storage, on any day, as equal to the average lag interval, in 

days, times the concurrent rate of direct runoff, in second-feet.

These volumes of storage were added to the total discharge to obtain 

the total runoff into the stream channels from the beginning of the 

thaw up to the indicated day. From the total runoff, converted into
82 FLOODS IN NEW YORK AND PENNSYLVANIA

equivalent depths in inches, was subtracted the cumulative precipitation 

over the basin as indicated by available rain gages. The difference 

equaled the runoff from snow, less the amounts that were added to field 

moisture and the amount that evaporated. The excess in temperature 

above 32° F. was computed for each day on the basis of daily recorded 

maximum and minimum temperatures, at two or more Weather Bureau 

stations. Account was taken for thawing temperature during those days 

when part of the day was above and part below 32° F. The daily degreeday excess above 32° F. was cumulated over the same period as the computed snow runoff. Figure 18 shows a plot of the computed cumulative

s

I

I '

t.

Avtrog*

-Mar 6

relation » 0.0! 19 inch ftr da )r*«-4ay

r. ZS

Mar. 91

40 60 120 160 

r**-doy« obov* fr«

200 240

FIGURE 18. Relation between cumulative snow runoff and degree-days above freezing, Driftwood 

Branch of Sinnemahoning Creek at Sterling Run, Pa., February-March 1936.

snow runoff against the measured cumulative degree-day excess above 

32° F. during March 1936 at Sterling Run, Pa., for Driftwood Branch
SNOW-RUNOFF STUDIES 83

of Sinnemahoning Creek, a tributary of the West Branch of the Susquehanna River.

The thaw began on February 25, but there was no apparent snow 

melt until February 29 or until about 25 degree-days had been accumulated. From then until March 15, snow runoff continued to increase 

steadily in a manner approximately proportionate to the cumulative 

degree-day thawing temperature. Snow runoff continued after March 15 

until the end of the month but at a decreasing rate. Apparently March 15 

marked the end of the most favorable snow exposure, and the subsequent decreasing rate of snow runoff was an indication that the quantity 

of snow was decreasing. After the snow was gone, the curve flattened 

and, as there was precipitation in excess of runoff, turned downward.

The general trend of relation, as indicated on figure 18, between 

computed snow runoff and thawing temperatures during the period ending March 15, when the heat was most efficient in producing snow 

runoff, shows 0.059 inch of snow runoff per degree-day. The indicated 

rate is not the absolute maximum for the period, as is clearly shown by 

examination of the figure, which also suggests that for a given drainage 

basin and a given extent of snow cover there is no uniform rate per 

degree-day at which water is released from the snow cover. Possibly 

the melt that is produced by thawing temperatures first accumulates in 

the snow as capillary water, a process known as ripening, and may be 

suddenly released as runoff by the application of even a small quantity 

of additional thawing heat, when it may, under some circumstances, carry 

with it some of the unmelted snow that had become sodden. However, 

it would seem that the volumes that can be so stored and released are 

limited to a portion of the total volume of snow cover on the ground.

In an areal sense snow melting over basins may be conceived to occur 

normally. At a given time the highest northerly slopes may be in their 

original state, perhaps with absorbed rain; lower down, in more exposed 

positions, snow is ripening, and still lower in the basin and on southerly 

slopes there may be active thawing and release of snow melt perhaps 

with some slush. In the lowest and most exposed parts of a basin the 

snow may be all gone and the ground bare. Basin-wide averages therefore may not indicate the rate of melting and release of snow within 

the area in which active thawing is taking place. This normal behavior 

also suggests that simultaneous basin-wide ripening and thawing may 

produce critical rates of snow runoff.
84 FLOODS IN NEW YORK AND PENNSYLVANIA

The following is a tabulation of the results of the studies of the rate 

of snow melt for essentially complete snow cover:

TABLE 62. Rates and depths of snow welt

Stream

New York:

Genesee River at St. Helena...

Sugar River at Talcottville. . . . 

Sacandaga River near Hope....

Little Beaver Kill near LivingPennsylvania :

Driftwood Branch of Sinnemahoning Creek at Sterling Run

Period

March 1920

April 1928 

March 1936

.....do......

.....do......

Rate

(inches per

degreedays 

above 

32 8F.)

0.06

.05

.04

.07

.06

at indicated rates 

(inches)

2.5

6.0 

6.0

2 S

4.0

Approx.

water

content 

of initial 

depth 

(inches)

3.5

9.5 

8.0

7.0

7.5

The above determinations do not take account of snow or rainfall 

added to field moisture or evaporated, and therefore may be low. Moreover, the computed rates may be in error to the extent that the determination of the temperature factor was not sufficiently refined because 

of incomplete records and inadequate allowance for variations over the 

area. No adjustments were made for any difference in altitude between 

the thermometers and the drainage basin. For these reasons the computed degree-day excess seems subject to a large percent of error for 

temperature near freezing point. The results, however, are fairly consistent and compare with the results of other investigators.

Clyde11 found the rate of melting of snow cover in Gooseberry Creek 

in Utah during 1928 to average 0.09 inch per degree-day above 32° F., 

for an initial depth of snow of 17.2 inches water content. He also found 

the rate of melting of snow cores in the laboratory to vary between 

0.046 and 0.083 inch per degree-day of thawing heat. Using the temperature and runoff data given by Clyde on figure 6 of his report12 a 

maximum rate of melting of 0.083 inch per degree-day was obtained 

by the methods used in the present study. Clyde's studies indicate greater 

rates of melting than for those here recorded, perhaps because the 

Gooseberry Creek area had a greater initial depth of snow cover than 

had any of the basins listed in table 62. The amount of snow melted 

in Gooseberry Creek Basin at the rate of 0.083 inch of snow cover was 

4 inches or about a third of the total initial depth. The maximum rate 

per degree-day applicable to two-thirds of the initial depth of about 

12 inches of water content, was 0.062 inch.

Preliminary studies of the rate of snow melting reported in WaterSupply Paper 799 indicated that runoff from snow at a mean temperature of 31° F., during the 14-day period March 9-22, was negligible

"Clyde, G. D., Snow-melting characteristics: Bull. 231, Utah Agri. Expt. Sta., August 1931. 

» Clyde, G. D., op. cit, p. 17.
NONWINTER FLOODS 85

and that for each degree-day above this temperature the runoff from 

melting snow increased between 0.03 and 0.05 inch. This, however, was 

a general average from which there were notable local variations. Snow 

melt associated with the flood period of March 17-20, 1936, in the 

upper Pemigewasset River Basin in New Hampshire amounted to 8.2 

inches. Temperature in the basin during the flood period totaled about 

52 degree-days above freezing, indicating that melting in this basin 

averaged 0.16 inches per degree-day.

NONWINTER FLOODS

A summary of rainfall and runoff data for the major floods of record 

for eight different basins during the nonwinter seasons are listed in 

table 63. The depth of rainfall that produced these floods ranged from 

an average of 3.0 inches in 4 days over the Sacandaga River Basin 

above Hope, N. Y., to an average of 4.96 inches in 6 days over the 

Susquehanna River Basin above Harrisburg, Pa. The duration of rainfall of 0.01 inch or more per hour, based on available records of hourly 

rainfall, ranged between 34 and 63 hours, in a manner that was generally proportional to the length of the storm period. Because of the 

sparsity of recording rain-gage stations, information regarding hourly 

intensities in the area of heaviest rainfall is generally deficient, but daily 

rainfall figures afford some clue to possible intensities. The maximum 

24-hour amount for the storms listed in table 63 was 14 inches, which 

was measured in the center of the storm of July 1935 in New York. 

The next highest amount, 8.48 inches, fell in 24 hours at York, Pa., 

from August 22-23, 1933. These high 24-hour rainfall figures suggest 

the occurrence of local runoff intensities on small areas, which probably 

greatly exceeded that observed from the larger drainage areas reported 

in table 63.

Maximum observed rates of discharge, which are the principal flood 

characteristics, are given in table 63 expressed in second-feet and in 

inches per hour from the' indicated drainage areas. These rates are 

related to the integration of the difference between rates of rainfall and 

retention as smoothed and modified by transmission through the numberless converging routes of the stream system and by the action of 

channel storage.

The volumes of direct runoff associated with the floods listed in 

table 63 varied between 1.39 and 3.44 inches, and the volume of groundwater runoff between 0.30 and 1.10 inches. Total runoff ranged between 

1.75 and 4.22 inches. The amount of runoff that will result from a given 

volume of rainfall during nonwinter conditions is influenced by the 

antecedent moisture conditions. The rate of base flow prior to the flood 

has been used by some investigators as an index of such moisture conditions. Figure 19 shows a study of the volumes of rainfall and runoff

FLOOD OF JULY 1921, SACANDAGA RIVER 87

existed in the West Branch of the Susquehanna River before the storm 

of April 27 to May 4, 1909.

The ratio between the volume of direct runoff during the maximum 

24-hour period and the total volume of direct runoff for the flood rise 

is a measure of the concentration of runoff with respect to time. Its value 

is affected by the variable durations of the storms as well as the more 

uniform influence of storage and other channel characteristics of the 

basins. However, it affords a convenient way of expressing the resultant 

effects of the latter factors. The computed ratios varied between 27 and 

60 percent, being generally near the lower limit for the larger drainage 

basins, and the upper limit for the smaller drainage basins. The lag 

intervals between center of mass of net supply to center of mass of direct 

runoff as listed in table 63 are a measure of the channel characteristics 

of the different basins and as such are inversely related to the concentration ratios. The product of the concentration ratio in percent and the 

lag, in hours, ranged between 1,700 and 2,600, having less variation than 

either the values of the concentration ratio or the lag interval, thus 

demonstrating to some degree this inverse relationship. Further study of 

this subject is presented in the section "Rates of flood discharge."

FLOOD OF JULY 1921, SACANDAGA RIVER NEAR HOPE, N. Y.

The flood of July 11, 1921, at Hope, N. Y, was probably the result

T»»00*

44*0*

T**00*

FIGURE 20. Map of Sacandaga River basin above Hope, N. Y., showing lines of equal precipitation, July 8-12, 1921.

689521 47 7
88 FLOODS IN NEW YORK AND PENNSYLVANIA

of heavy local downpours in the basin. There were no rainfall measurements within the basin. The river-gage observer at Hope, however, 

reported a cloudburst on July 11. The lack of competent quantitative 

rainfall information removes most of the force of any analysis of the 

rainfall and runoff relation of this storm and flood.

The prevalent temperature around July 11 was above normal and the 

weather was notable for thunderstorms. Thus, the United States Weather 

Bureau reports that thunderstorms were observed at 31 stations in New 

York on July 8, at 28 stations on July 9, 32 stations on July 10, 17 

stations on July 11, and 11 stations on July 12. It is likely that the intensity of these storms was confined to small areas and was not associated 

with any frontal action between air masses of different character.

The isohyetal map shown on figure 20 is based on available published 

records of the United States Weather Bureau in the region, but may 

be unreliable for the Sacandaga River Basin because of deficient information. The average rainfall for the basin, according to the map is 3.0 

inches, which seems unlikely to have been great enough to produce the

t 7 » 10 II « 13 14 IS W 17 l> 19 80 81 22 23 24 85

FIGUKE 21. Hydrograph of Sacandaga River near Hope, N. Y., showing discharge, July 1921, 

and precipitation, July 8-12, 1921.
FLOOD OF JULY 1921, SACANDAGA RIVER 89

TABLE 64. Precipitation, in inches, for 12-hour periods, at rain gages 

Sacandaga River basin above Hope, N. Y., July 8-12, 1921

Station (New York)

Glovers villfi

Altitude 

(feet)

850

1,860

1,660

Weight (percent)

8

51

41

100

12-hour

period 

ending

12m.

12 p.m.

12m.

12 p.m.

12m.

12 p.m.

12m.

12 p.m.

8

0

.48

.60

1.78

0

.27

0.10

.46

9

0

1.27

.80

0

.03

.30

0.15

.23

Jt]

10

0.05

.05

.21

.42

.60

.62

0.36

.47

dy

11

0.05

.03

.54

.69

.65

.34

0.55

.49

12

0

0

.35

0

.03

.02

0.19

.01

Total 

8-12

1 1.93

f O. otf

1 2.86

j 3.01

TABLE 65. Gage height and discharge of Sacandaga River near Hope, N. Y., 

during flood of July 1921

MEAN DISCHARGE, IN SECOND-FEET, JULY 1921

Day

1_ ......

2.......

3.......

4.......

5.......

M 

Ri

Sec. -ft.

910 

820 

700 

525 

320

ean moi 

mofi, in

Day

6.......

7.......

8 

9.......

10 

ithly disc 

inches

Sec.-ft.

202 

161 

150 

139 

1,230

large, in

Day

11......

12......

13......

14...... 

15......

second-fe

Sec.-ft.

14,600 

6,130 

3,080 

1,780 

1,590

et

Day

16 

17 

18 

19 

20 

Sec.-ft.

1,470 

1,380 

1,380 

1,560 

1,440

Day

21......

22......

23......

24......

25......

Sec.-ft.

1,110 

910 

660 

525 

438

Day

26 

27 

28......

29 

30 

31 

Sec.-ft.

380 

340 

310 

305 

295 

322

1,457 

3.42

GAGE HEIGHT/ IN FEET, AND DISCHARGE, IN SECOND-FEET, AT INDICATED TIME, 1921

Hour

2.............

4............. 

6.. ........

8 ......

10 .........

12m..... ......

2............ T

4.............

6 

8 ... . ......

10 ... .......

12p.m. ........

Hour

7a.m. .........

Feet Sec.-ft.

JulyS

......

1.80

Feet

.......

147

Feet Sec.-ft.

July 9

......

1.75

1.80

Sec.-ft.

July 14

3.95 

3.80

1,880 

1,680

........

132

147

Feet

Feet Sec.-ft.

July 10

.......

1.95 

2.20 

2.5 

2.85 

3.25 

3.75 

4.45 

5.20 

5.85

Sec.-ft.

July 15

3.75 

3.70

1,620 

1,560

........

202 

310 

465 

700 

1,060 

1,620 

2,650 

4,230 

5,930

Feet

Feet Sec.-ft,

July 11

6.55 

7.15 

7.70 

8.20 

8.60 

8.95 

9.20 

9.20 

8.85 

8.45 

7.95 

7.45

8,000 

10, 100 

12,300 

14,500 

16,500 

18,400 

19,800 

19,800 

17, 800 

15, 700 

13, 400 

11,200

Sec.-ft. Feet

Feet Sec.-ft.

July 12

6.85 

6.40 

6.05

5.75

5.50

5.25

9,000 

7,530 

6,500

5,660

4,990

4,360

Sec.-ft.

July 16 July 17

3.65 

3.60

1, 500 3. 55 

1, 440 3. 55

1,380 

1,380

Feet Sec.-ft.

July 13

......

4.30

Feet

.......

2,390

Sec.-ft.

July 18

3.50 

3.60

1,330 

1,440

 Supplemental records: July 8, 7 a.m., 1.82 ft., 154 sec.-ft. July 9, 7 a.m., 1.78 ft., 141 sec.-ft. July 10, 

7 a.m., 1.85 ft., 164 sec.-ft. July 11, 3 p.m., 9.30 ft., 20,400 sec.-ft. July 13, 7 a.m., 5.00 ft., 3,760 sec.-ft. 

LOCATION. -Inclined staff gage, lat. 43°21'10", long. 74°16'13", V/t miles below junction of 

East and West Branches of Sacandaga River and 4V6 miles above Hope, Hamilton County. 

DRAINAGE AREA. 491 square miles. 

REMARKS. Records supersede those published in Geol. Survey Water-Supply Paper 521.
90 FLOODS IN NEW YORK AND PENNSYLVANIA

maximum nonwinter flood of 28 years' record in that river, particularly 

where it followed a period of subnormal precipitation and excess temperature. No information is available concerning rates of rainfall.

Table 64 lists the estimated time distribution of rainfall at the indicated rain gages near the basin during the storm period, based on observers' notations of the beginning and ending of rainfall.

The river discharge at Hope during the flood is given in table 65, 

and is graphically shown on figure 21. The volume of direct runoff as 

computed in table 66 was 1.94 inches, leavifig an apparent retention of 

1.06 inches. Ground-water runoff accounted for 0.65 inch of this retention, leaving 0.41 inch for field-moisture accretion and evaporationtranspiration losses.

The sharp concentration of the rainfall may be discerned from the 

fact that 57 percent of the direct runoff occurred during 24 hours, compared with 35 and 27 percent during the two winter floods of March 

1936 as reported in table 1. The interval between the centers of estimated 

effective rainfall and direct runoff was 38 hours. This interval is about 

10 hours less than for the March 1936 floods and may indicate that the 

storm centered near the lower part of the basin as suggested by the river 

observer's notation of a cloudburst on July 11. The interval between the 

center of effective precipitation and the peak discharge was 25 hours.

TABLE 66. Computation of volume of direct runoff associated with precipitation 

period July 8-12, 1921, Sacandaga River near Hope, N. Y.

July

9.................

10.................

11......... ........

12 ....

13.................

14........... ......

15......... ........

16..... ............

17.................

18, ................

Sec. -ft.-% days....

12-hour 

period 

ending

12 p.m.. ......... 

12m.............

12m.............

12m.......... ...

12 p.m.. .........

12m.............

12m.............

12m.......... ...

12m.............

12p.m.. .........

12m.............

12m.............

Daily mean 

discharge 

(second-feet)

135 

210

2,250

12,270

16,910

7,260

5,000

3,760

2,390

 1,880

'1,550

"1,280

 1,080

"900

»800

"700

"630

 600

59,605

29,802

Estimated 

recession from 

preceding storm 

and base runoff 

(second-feet)

135 

165

200

?Sn

310

370

440

510

590

610

620

610

600

600

600

ff\t\

600

600

8,410

4,205

Direct runoff 

(second-feet)

f\

45

2,050

12,020

16,600

6,890

4,560

3,250

1,800

1,270

930

670

480

300

200

100

30

0

51,195

25,597 ( =

1.94 inches)

 Estimated recession under subsequent rise.
FLOODS IN NEW YORK AND PENNSYLVANIA 91

STORM OF JULY 1935

Hollister Johnson has described the storm and flood of July 1935 in 

New York State in a report 13 that lists the records of available rainfall 

and maximum flood discharges, with discussion of the meteorology of 

the storm. Johnson says, "A series of extraordinarily severe thunderstorms during the night of July 7 and the morning of July 8, 1935, 

speedily brought many small streams to destructive heights before the 

inhabitants could realize the situation in which they were caught." Thus 

the storm causing the flood consisted of several more or less localized 

electrical storms during the period July 7 to 10.

13 Johnson, Hollister, The New York State flood of July 1935: Geol. Survey Water-Supply 

Paper 773E, 1936.

FIGURE 22. Map of eastern United States showing position of storm, 8 a.m. (E.S.T.),

July 8, 1935.
92 FLOODS IN NEW YORK AND PENNSYLVANIA
STORM OF JULY 1935 93

The storm originated in a meteorological disturbance that centered 

over Minnesota on July 5. (See fig. 22.) The normal eastward movement 

was blocked by the presence of a high-pressure area of cold air centering 

over Hudson Bay. By 8 a.m., July 8 (see fig. 22), the low-pressure area 

centered over western New York, and the cold front lay in an east-west 

position over southern New York close to the 70° isothermal line shown 

on figure 22. Wind directions on the surface weather map of July 8 

indicate the movement of warm air from the South Atlantic and the 

movement of cold air from the northeast towards the frontal region in 

New York. The weather map therefore suggests that the heavy rainfall 

was the result of pressure contrasts that created a condition in which a 

continuous stream of warm moist air was being rapidly carried aloft over 

a wedge of colder air and which resulted in condensation of the moisture contained in the warm air mass.

The flood was particularly disruptive on the smaller streams in 

southern New York, some of which reached discharge rates exceeding 

2,000 second-feet per square mile (3.1 inches per hour), thus indicating 

very high rates of precipitation over local areas that were greatly in 

excess of the capacity of the land to absorb it. Measurements indicate 

that 1-day rainfall on these areas exceeded 14 inches. Figure 23 shows 

an isohyetal map of the rainfall from noon of July 6 to and including 

July 10, based upon records of rainfall published by Johnson, and one 

additional record as reported below.

Rainfall at Cohocton, N. Y. (lat. 42°30/10//, long. 77°29'50") as observed by the United States Soil Conservation Service at 8 a.m. of the 

indicated days:

July

6...................................

7...................................

8...................................

9...................................

10...................................

11...................................

Rainfall (inches)

0

.61

6.70

.91

.05

0

The New Jersey State Water Policy Commission has prepared a 

series of maps showing the areal distribution of rainfall at intervals 

during the storm, and from these maps the maximum rainfall during 

6-hour, 12-hour, 18-hour, 24-hour, and 36-hour periods have been determined. The area enclosed within the isohyetal lines on these maps has 

been measured, and the mean precipitation computed. The results are 

shown on figure 24.

The storm of July 1935 produced the greatest flood on record in many 

of the smaller streams in central New York, and produced the greatest 

summer flood of record on the Chemung River at Chemung, N. Y., and 

on the Susquehanna River at Wilkes-Barre, Pa.
94 FLOODS IN NEW YORK AND PENNSYLVANIA

8 * * g 8 8 g 8

" o wwwowg o X X 8 ff 8 K

Arto in Muort rallM

FIGURE 24. Curves showing average depth of rainfall over indicated areas during periods of 

maximum intensity, storm of July 6-10, 1935.

FLOODS OF JULY 1935

CHEMUNG RIVER AT CHEMUNG, N. Y.

Rainfall for 12-hour periods during the storm at several rain gages 

in and near the basin is given in table 67. The total storm rainfall, from 

July 6-10, averaged 4.90 inches over the basin, of which about 3.5 inches 

fell in the 24-hour period between noon of July 7 and noon of July 8. 

As shown in figure 23, the storm centered over the valley of the Cohocton 

River where local precipitation exceeded 14 inches and small tributary 

streams reached record-breaking heights. However, the precipitation 

averaged only about 2 inches over the upper Tioga River which drains 

the southerly part of the basin. The Tioga River Basin above Lindley, 

N. Y. (770 square miles), contributed a relatively negligible runoff.

The discharge during the flood is given in table 68 and is plotted as 

a hydrograph on figure 25. Direct runoff associated with the 4.90 inches 

of precipitation from July 6-10 was 1.91 inches, leaving a retention of 

2.99 inches. Ground-water runoff accounted for about 0.3 inch, indicating 

that field-moisture accretion and evaporation losses averaged 2.69 inches 

over the basin.

As computed by methods previously explained, the infiltration index 

was 0.17 inch per hour. The time interval between center of mass of
FLOODS OF JULY 1935, CHEMUNG RIVER 95

 0,000

 0,006

TO.OOO

 0,000

I

30.000

4 O.OOO

50,000

20000

10,000 \7\

6 8 10 II 12 13 15 16 17 18 19 20 21 22 23 24

July 1939

FIGURE 25. Hydrograph of Chemung River at Chemung, N. Y., showing discharge, July, 

and precipitation, July 6-10, 1935.

TABLE 67. Precipitation, in inches, for 12-hour periods, at stations in and near 

Chemung River basin, July 6-10, 1935

Station

New York: 

Alfred... ....... .........

Elmira. _________

Haskinville _______

Woodhull... -.. 

Pennsylvania: «**

12-hour period ending

July 6

12p.m.

0.06 

.42 

2.00 

1.12 

.10 

1.90 

.75 

.16

.63 

.00

0.64

July 7

12m.

0.00 

.00 

.00 

.00 

.00 

.00 

.00 

.00

.00 

.00

0.00

12p.m.

1.86 

1.22 

4.66 

3.62 

.56 

3.34 

2.66 

.75

.39 

.07

1.64

JulyS

12m.

3.20 

1.07 

4.08 

3.92 

.79 

2.94 

2.77 

.89

.52 

.92

1.82

12p.m.

0.70 

.65 

.32 

.68 

.21 

.26 

.53 

.30

.16 

.65

0.40

July 9

12m.

0.14 

.43 

.04 

.19 

.08 

.18 

.00 

.22

.12

.28

0.16

12p.m.

0.32 

.15 

.00 

.07 

.03 

.08 

.43 

.08

.06 

.06

0.12

July 10

12m.

0.36 

.13 

.02 

.04 

.00 

.05 

.52 

.06

.08 

.03

0.12

12p.m.

0.00 

.00 

.04 

.00 

.00 

.00 

.00 

.00

.00 

.00

0.00

Total

6.64 

4.07 

11.16 

9.64 

1.77 

8.75 

7.66 

2.46

1.94 

2.01

4.90
96 FLOODS IN NEW YORK AND PENNSYLVANIA

TABLE 68. Gage height and discharge of Chemung River at Chemung, N. Y 

during flood of July 1935

MEAN DISCHARGE, IN SECOND-FEET, JULY 1935

Day

M

R

Sec.-ft.

555 

511 

471 

444 

431

ean moi 

unofif, in

Day

6... ...-

7 ....

y

10 

ithly disc 

inches ...

Sec.-ft.

431

520 

16, 040 

68, 800 

24,740

large, in

Day

11 .

13 

14......

15 

second-fe

Sec.-ft.

13, 790 

7,380 

7,570 

5,800 

3,683

et

Day

16

17

18......

19 .

20 

Sec.-ft.

4,170

3,380 

2,320 

1,850 

1,560

Day

21 .

22. ..

23 

24 

25 

Sec.-ft.

1,270 

1,140 

1,200 

1,070 

1,390

Day'

26 

27-. _ .

28 

29 ...

30 

31......

Sec.-ft.

4,320 

2,240 

1,490 

1,310 

1,500 

1,140

5,888 

2.86

GAGE HEIGHT, IN FEET, AND DISCHARGE, IN SECOND-FEET, AT INDICATED TIME, 1935

Hour

2. 

4___. ..... ....

6...... 

8-.... ........

10 ... .

12m. 

2

4. . ........

6 .. .

8.- .... 

10 - 

Hour

2

4-_ _-_-.._

6- ...... ...

8.. .. -.

10-...... .

12m....---..-.

2. ........

4....... ..

6.. ...

8. ....... .

10- 

12p.m.........

Feet Sec.-ft.

July 7

2.22 

2.22 

2.24 

2.27 

2.29 

2.30 

2.32 

2.34 

2.40 

2.45 

2.50 

2.57

Feet

444 

444 

457 

477 

490 

497 

511 

526 

569 

607 

645 

701

Feet Sec.-ft.

JulyS

2.70 

2.81 

2.85 

2.90 

3.15 

7.50 

10.0 

11.55 

12.85 

14.05 

15.1 

16.0

Sec.-ft.

July 13

5.90 

6.05

a is

6.20 

6.24 

6.41 

6.74 

7.18 

7.53 

7.55 

7.31 

,7.01

5,710 

6,040 

6,340 

6,390 

6,490 

6,900 

7,730 

8,920 

9,900 

9,960 

9,280 

8,460

810 

910 

950 

1,000 

1,260 

9,810 

17, 700 

23,700 

29, 800 

36, 400 

43,800 

51, 000

Feet

Feet Sec.-ft.

July 9

16.8 

17.6 

18.5 

19.2 

19.45 

19.35 

18.9 

18.25 

17.5 

16.65 

15.85 

14.95

Sec.-ft.

July 14

6.74 

6.50 

6.29 

6.11 

5.94 

5.81 

5.68 

5.58 

5.48 

5.40 

5.32 

5.24

7,730 

7,120 

6,610 

6,180 

5,800 

5,510 

5,240 

5,030 

4,820 

4,660 

4,500 

4,350

58,200 

66, 000 

75, 50'0 

83,200 

86, 000 

84,800 

79,900 

72,800 

65,000 

56, 800 

49, 800 

42, 600

Feet

Feet Sec.-ft.

July 10

14.15 

13.3 

12.6 

11.95 

11.35 

10.95 

10.8 

10.7 

10.58 

10.49 

10.39 

10.25

Sec.-ft.

July 15

5.18 

5.12 

5.04 

4.99 

4.92 

4.86 

4.80 

4.76 

4.71 

4.69 

4.67 

4.66

4,230 

4,120 

3,970 

3,870 

3,740 

3,620 

3,510 

3,430 

3,340 

3,300 

3,270 

3,250

37,000 

32, 100 

28,600 

25,400 

22, 900 

21,300 

20, 700 

20, 300 

19,800 

19, 500 

19, 100 

18, 600

Feet

Feet Sec.-ft.

July 11

10.04 

9.77 

9.54 

9.30 

9.03 

8.78 

8.52 

8.28 

8.05 

7.83 

7.65 

7.46

17,800 

16, 900 

16, 100 

15, 200 

14,400 

13,600 

12,900 

12, 100 

11,400 

10,800 

10, 200 

9,700

Sec.-ft.

July 16

4.66 

4.70 

4.84 

4.95 

5.04 

5.13 

5.26 

5.44 

5.59 

5.59 

5.49 

5.37

3,250 

3,320 

3,590 

3,800 

3,970 

4,140 

4,380 

4,740 

5,050 

5,050 

4,840 

4,600

 I* 

Feet

W4»H

Sec.-ft.

July 12

7.29 

7.13 

6.97 

6.82 

6.67 

6.52 

6.39 

6.28 

6.18 

6.09 

6.01 

5.93

Feet

9,220 

8,780 

8,350 

7,940 

7,550 

7,170 

6,850 

6,580 

6,340 

6,140 

5,950 

5,780

Sec.-ft.

July 17

5.22 

5.08 

4.95 

4.84 

4.74 

4.68 

4.60 

4.52 

4.45 

4.40 

4.34 

4.30

4,310

4,040 

3,800 

3,590 

3,400 

3,280 

3,140 

3,000 

2,880 

2,800 

2,700 

2,640

LOCATION. Water-stage recorder, lat. 42°00'10", long. 76°38'00", just below highway bridge

three-quarters of a mile southwest of Chemung, Chemung County. 

DRAINAGE AREA. 2,530 square miles. 

REMARKS. Records supersede those published in Geol. Survey Water-Supply Paper 781.

TABLE 69. Computation of volume of direct runoff associated with precipitation 

period July 7-10, 1935, Chemung River at Chemung, N. Y.

July

7. ................ ..

9................... 10...................

11. ...... ............

17

13...................

14. ..................

15. .............. ....

16....................

17...................

Total

Daily mean 

discharge 

(second-feet)

520

16,040

68,800

24,740

13,790

7,380

 4,300

 2,750

 1,800

 1,350

 1,150

142,620

Estimated 

recession from 

preceding storm 

and base runoff 

(second-feet)

500

600

900

1,300

1,500

1,450

1,400

1,350

1,300

1,250

1,150

19 inn

Direct runoff 

(second-feet)

15,440 

67,900

1 t'tan

5,930

1,400 inn

100

0

ion oon / 

1.91 inches)

« Estimated recession under subsequent rise.
FLOODS OF JULY 1935, SUSQUEHANNA RIVER 97

effective rainfall to the center of mass of direct runoff was 45 hours 

and that to the peak discharge rate 30 hours.

SUSQUEHANNA RIVER AT WILKES-BARRE, PA.

The total precipitation over the basin of the Susquehanna River above 

Wilkes-Barre, Pa., as shown on figure 23 averaged 4.66 inches for the 

period July 6-10. The daily amounts at several gages in and near the 

basin are listed in table 70. Of the total rainfall, 75 percent fell on 

July 7 and 8.

The discharge during the flood is given in table 71 and plotted las a 

hydrograph on figure 26. Direct runoff associated with the precipitation 

period July 6-10 as computed in table 72 was 1.52 inches, indicating a 

retention of 3.14 inches. Ground-water runoff was 0.38 inch leaving a 

net retention of 2.76 inches as field-moisture accretion and evaporation 

losses.

The infiltration index as computed by methods previously explained 

was about 0.17 inch per hour, the same as that for the Chemung River 

Basin during this storm. The interval between centers of mass of effective rainfall and direct runoff was 77 hours and the interval between 

the center of mass of effective rainfall and the peak rate of discharge 

was 54 hours.

TABLE 70. Daily precipitation, in inches, at stations in and near Susquehanna 

River basin above Wilkes-Barre, Pa., July 6-10, 1935

[In this table "T" indicates a trace]

Station

New York:

Alfred... . ......-.. .........

Delhi........ ................

Elmira.. ... _ . _ ...........

Pennsylvania:

Altitude 

(feet)

1,420

1,840

1,006

858

1,200

1,129

1,460

863

1,620

872

1,000

1,325

1,015

1,112

1,037

400

1,325

1,750

1,045

1,820

746

754

1,419

540

Weight (percent)

0.04

3.23

3.95

10.18

6.80

5.77

.83

7.07

5.50

3.15

6.00

3.49

3.92

3.65

3.61

.15

1.79

3.99

.79

4.91

5.88

10.81

1.45

3.04

100.0

6

0.26

.05

0

.27

.28

.57

0

.10

.76

1.12

.62

1.03

1.10

.49

.16

19

0

.13

0

"1.68

.18

0

0

7

1.85

1.97

2.73

.07

2.06

3.69

2.84

.56

2.90

3.62

.42

2.88

4.01

2.73

2.52

2.05

.58

.28

.55

0

0

.39

.30

.28

Ju

8

2.82

3.80

2.20

1.02

3.03

5.70

5.73

1.00

3.10

4.60

.67

1.70

4.23

3.57

1.88

1.25

1.10

1.35

.98

.82

1.39

.97

.65

1.72

2.09

iy

9

1.13

.38

.56

.31

.44

1.32

.36

.11

.43

.26

.16

.32

.37

.21

.47

.13

.22

.35

.75

1.63

2.60

.39

.10

2.' 86

0.67

10

0

.44

.19

.22

.71

.26

.52

0

.52

.04

.07

23

.08

.12

.06

T

.03

0

0

0

T

1.03

0.15

Total 6-10

5.80

6 64

5.56

1 QQ

a eo

11 54

9 1*

1.77

7.71

9 fid

1 94

6.16

Q 70

7.12

5.09

3.62

1 94

2 m

2 4.1

2.45

3 QQ

1 93

1.05

5

QQ

4.66

' Very local rainfall, not included in average.
I6QPOO

IZOpOO

IOQPOO

80,000

60000

4OPOO

«VOOO

\

29 K Zl 28 29 30 I 2 3 4 9 6 7 8 » IO II 12 13 14 IS 16 IT 18 19 

Jun* 1939 July 1939 

FIGURE 26. Hydrograph of Susquehanna River at Wilkes-Barre, Pa,, showing- discha
FLOODS OF JULY 1935, SUSQUEHANNA RIVER 99

TABLE 71, Gage height and discharge of Susquehanna River at Wilkes-Barre, Pa.,

during flood of July 1935

MEAN DISCHARGE, IN SECOND-FEET, JULY 1935

Day

l. ......

2.......

3 .

4.......

5. ___ .

M 

Ri

Sec.-ft.

3,780 

3,380 

3,190 

2,930 

2,680

ean moi 

moff , in

Day

6 _

7 

8 

9 

10-.-.

ithly disc 

inches

Sec.-ft.

2,520 

2,600 

2,600 

43, 900 

142, 000

jharge, in

Day

11..... 

12..... 

13 

14.....

15...-.

second-f

Sec.-ft.

115,000 

56, 200 

31,600 

25, 200 

22,000

eet

Day

16. 

17 

18 

19 

20 

Sec.-ft.

17, 300 

14, 600 

13, 600 

11,900 

10, 700

Day

21 

22 

23 

24......

25...-.

Sec.-ft.

9,200 

8,080 

7,540 

7,540 

7,280

Day

26 

27 

28 

29 

30 

31 ...

Sec.-ft.

9,420 

14, 600 

12, 900 

10, 100 

8,360 

7,540

20, 330 

2.3S

GAGE HEIGHT, IN FEET, AND DISCHARGE, IN SECOND-FEET, AT INDICATED TIME, 1935

Hour

6_ _

12m.........

6-. . ........

6....-. -.

12m. __ ....

6. ..........

6-.. .-.-.

6. .......

Feet Sec.-ft.

July?

2.24 

2.17 

2.15 

2.16

2,680 

2,520 

2,520 

2,520

July 12

15.80 

14.15 

12.80 

11.77

66,640 

55, 200 

45, 820 

39, 500

July 17

6.79 

6.66 

6.60 

6.60

15, 000 

14, 650 

14, 300 

14, 300

Feet Sec.-ft.

JulyS

2.18 

2.21 

2.19 

2.19

2,600 

2,600 

2,600 

2,600

July 13

10.98 

10.30 

9.88 

9.37

34, 700 

30, 850 

28,700 

26, 200

July 18

6.56 

6.41 

6.22 

6.06

14, 300 

13, 600 

12, 900 

12, 550

Feet Sec.-ft.

July 9

2.79 

6.51 

18.80 

22.44

3,670 

13, 950 

90, 160 

122, 000

July 14

9.10 

9.12 

9.31 

9.20

24,700 

24,700 

25,700 

25,200

July 19

5.94 

5.88 

5.80 

5.72

11,900 

11,900 

11,600 

11,300

Feet Sec.-ft.

July 10 »

24.30 

25.20 

25.18 

24.15

140,000 

149, 000 

149, 000 

139, 000

July 15

8.77 

8.44 

8.14 

7.88

23,300 

21, 500 

20, 150 

19, 300

July 20

5.59 

5.45 

5.32 

5.19

11,000 

10, 400 

10, 100 

9,800

Feet Sec.-ft.

July 11

22.50 

20.75 

19.16 

17.48

123, 000 

107, 000 

93, 500 

79, 650

July 16

7.64 

7.44 

7.23 

7.00

18, 100 

17,300 

16, 500 

15, 700

July 21

5.03 

4.93 

4.82 

4.72

9,200 

8,920 

8,640 

8,360

a Peak discharge: July 10, 2i:30 p.m., 151,000 sec.-ft. 

LOCATION. Water-stage recorder, lat. 41° 15'00", long. 75°53'10", at Market Street Bridge at

Wilkes-Barre, Luzerne County, 116 miles above mouth of Toby Creek. Zero of gage is

511.94 feet above mean sea level. 

DRAINAGE AREA. 9,960 square miles. 

REMARKS. Records of daily mean discharge published in Geol. Survey Water-Supply Paper 781.

TABLE 72. Computation of volume of direct runoff associated with precipitation 

period July 6-10, 1935, Susquehanna River at Wilkes-Barre, Pa.

July

8....................

9.......... ....... 10....................

11................... 19

13...................

14.................... is....................

16....................

17....................

18....................

19....................

Total

Daily mean 

discharge 

(second-feet)

2,600

43,900

142,000

115,000

c^c ofirt

31,600

 21,000

 14,200

 9 800

 6,700

 4,800

 4,000

451,800

Estimated 

recession from 

preceding storm 

and base runoff 

(second-feet)

2,600

3,000

3,400 

3,800

4,000 

4,000

4,000

4,000 

4,000

4,000

4,000

4,000

44 '800

Direct runoff 

(second-feet)

0

40,900

138,600

111,200

52,200

O« rfCAA

17,000

10,200

5,800

2,700

800

0

407,000 ( 

1.52 inches)

 Estimated recession under subsequent rise.
100 FLOODS IN NEW YORK AND PENNSYLVANIA

STORM OF AUGUST 21-25, 1933

The storm of August 21-25 was of the tropical hurricane type that 

originated in the vicinity of the Leeward Islands and appeared off.the 

coast of the Carolinas on August 23. As shown on figure 27, the center

FIGURE 27. Map of eastern United States showing position of storm, 8 a.m. (E.S.T.),

August 24, 1933.

of the low-pressure area followed a northwesterly path and crossed the 

length of the Susquehanna Valley during the afternoon of August 23 

and the morning of the 24th, and then continued northeastward across 

New York State. It was accompanied by torrential rains of such intensity over the southern tip of the drainage basin that all existing records
FLOODS OF AUGUST 1933, EAST BRANCH DELAWARE RIVER

of rainfall for Pennsylvania were broken. At York 13.28 inches were 

recorded during the 3-day period, 7 p.m. August 21 to 7 p.m. August 24, 

of which 8.48 inches fell within 24 hours.

Records of daily rainfall during the storm are available in published 

reports of the United States Weather Bureau. 14 Since records of hourly 

rainfall, however, are not so generally available, these records are included in this report as table 73.

Plate 1 is an isohyetal map, based on all available records of precipitation, showing the precipitation from August 20 to 25, 1933. There 

were three areas of outstandingly high precipitation, one in southern 

Delaware, the second at York, Pa., and the third in the Catskill Mountain region in New York. The line joining these areas generally marks 

the region of maximum rainfall, which lay east of but parallel to the 

storm track shown on figure 27.

The storm was unique in the great depths of precipitation it brought 

to large areas. Thus, according to the Miami Conservancy District, the 

rainfall in 5 days averaged 10 inches over 6,000 square miles. The area 

that received more than 5 inches probably exceeded 50,000 square miles 

and compared closely with the hurricane storm of September 17-21, 

193815 , which centered in New England.

The storm resulted in major floods in the affected area, and more notably, produced, at Marietta, Pa., the largest known nonwinter flood in 

the Susquehanna River, which drains an area of 25,990 square miles. 

The storm also produced the maximum flood during the period of record, 

1912-39, on the East Branch of the Delaware River at Fishs Eddy, N. Y. 

Hydrologic data with respect to the August 1933 floods in these two 

basins are given on pages 101-112.

FLOODS OF AUGUST 1933

EAST BRANCH OP DELAWARE RIVER AT FISHS EDDY, N. Y.

There was only one record of rainfall for the flood within the basin, 

that of the Weather Bureau at Roxbury, N. Y., and as a result the determination of mean areal rainfall may be inaccurate. The city of New 

York, through its Board of Water Supply, maintains a number of rainfall stations in the areas to the east of the basin. All available records 

are given in table 74, and plate 1 is a map of the area with isohyetal 

lines of total rainfall during the period August 20-25, 1933, based on 

these records. The mean areal precipitation was computed by Thiessen's 

method to be 6.22 inches. Table 75 lists precipitation for 6-hour periods 

at the indicated rain gages during the storm. The 6-hour rainfall amounts 

are based on the daily measurements of rainfall supplemented by dis14 Climatological data of the United States, August 1933.

«Paulsen, C. G., and others, Hurricane floods of September 1938: U. S. Geol. Survey WaterSupply Paper 867, p. 83, 1940.
102 FLOODS IN NEW YORK AND PENNSYLVANIA

Susquehanna and irecording rain precipitation, Hourlyinches, TABLE 73. in atnear gages 

20-25, River August 1933 basins, Delaware andupper 

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sss

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J53SSS

Bureau. Weather U.S

£

689S21 47 8
104 FLOODS IN NEW YORK AND PENNSYLVANIA

tribution of rainfall as indicated by the hourly records of rainfall listed 

in table 73. According to table 75 rainfall was greatest during the 12-hour 

period 6 p.m. August 23 to 6 a.m. August 24, when there was an average rainfall of 2.45 inches over the basin.

River discharge during the flood period is given in table 77 and 

graphically on figure 28. Direct runoff associated with the storm as

 4POO

BOJOOQ

44000

SQ000

topoo

iqpoo

at » «4 zs

««<iwt 1933

89 30 31 I

S«ptw*«r 1993

FIGURE 28. Hydrograph of East Branch of Delaware River at Fishs Eddy, N. Y., showing discharge, August-September, and precipitation, August 21-25, 1933.

computed in table 76 was 3.44 inches, leaving a retention of 2.78 inches. 

Ground-water runoff accounted for 0.90 inch of this retention, leaving 

1.88 inches as field-moisture accretion and evaporation-transpiration 

losses. The infiltration index as computed was 0.09 inch per hour.

The interval between centers of mass of effective rainfall and direct 

runoff was 37 hours, and the interval between center of mass of effective 

rainfall and the peak rate of discharge was 19 hours.
FLOODS OF AUGUST 1933, EAST BRANCH DELAWARE RIVER 105

TABLE 74. Daily recorded rainfall, in inches, at stations in and near East Branch 

of Delaware River at Fishs Eddy, N. Y., August 20-25, 1933_______

Station (New York)

Delhi b. ............................

Qrahamsville ...

Pine Hill «.... _ ... _ . _ .........

Altitude 

(feet)

1,006

1,460

943

1,400

1,240

1,500

1,160

1,490

1,665

20

0.01

.04

21

1.95

.87

.01

2.26

2.50

1.15

.92

.05

1.72

1.77

22

1.08

1.68

.22

.67

1.65

.38

1.95

1.15

.57

1.03

1.34

.87

August

23

0.93

,12

2.26

2.66

.07

5.88

10.08

5.30

3.16

.45

6.46

4.36

24

2.00

3.00

.32

.45

2.72

.09

1.45

1.30

.57

3.70

3.37

.33

25

0.84

.32

.05

Total 

20-25

4.85

5.13

4.75

4.69

4.45

8.61

15.98

8.90

5.22

5.28

12.89

7.33

 U. S. Weather Bureau station, observation made in morning and recorded as of same day.

b U. S. Weather Bureau station, observations made near sunset.

« New York City Board of Water Supply station, read at 8 a.m. and recorded as of the preceding day.

TABLE 75. Precipitation, in inches, for 6-hour periods, at stations in and near 

East Branch of Delaware River at Fishs Eddy, N. Y., August 20-25, 1933

Station (New York)

Delhi.............................

Pine Hill.. . .......................

Prattsville.... ...-..-.---.-.-....-.

Weight (percent)

0.6

25.8

8.3

0.4

26.0

18.4

0.5

12.4

7.6

100.0

6-hour 

period 

ending

6 a.m. 

12m. 

6p.m. 

12 p.m.

6 a.m. 

12m. 

6 p.m. 

12 p.m.

6 a.m. 

12m. 

6 p.m. 

12 p.m.

6a.m. 

12m. 

, 6 p.m. 

12 p.m.

6a.m. 

12m. 

6 p.m. 

12 p.m.

6a.m. 

12m. 

6p.m. 

12 p.m.

6 a.m. 

12m. 

6 p.m. 

12 p.m.

6 a.m. 

12m. 

6p.m. 

12 p.m.

6 a.m. 

12m. 

6 p.m. 

12 p.m.

6 a.m. 

12m. 

6 p.m. 

12 p.m.

August

20

0.00 .'0 

.00 

.00

.00 

.00 

.01 

.00

.00 

.00 

.00 

.00

.00 

.00 

.00 

.00

.00 

.00 

.00 

.00

.00 

.00 

.00 

.00

.00 

.00 

.00 

.00

.00 

.00 

.00 

.00

.00 

.00 

.00 

.00

0.00 

.00 

.00 

.00

21

0.00 

.00 

.07 

.13

.00 

.00 

.00 

.08

.00 

.00 

.13 

.23

.04 

.00 

.06 

.10

.00 

.00 

.01 

.08

.00 

.00 

.08 

.14

.00 

.00 

.06 

.11

.00 

.00 

.05 

.05

.00 

.00 

.12 

.20

0.00 

.00 

.04 

.11

22

0.88 

.91 

.02 

.00

.53 

1.05 

.02 

.00

1.59 

.22 

.00 

.00

.71 

.66 

.01 

.00

.52 

1.03 

.02 

.00

.93 

1.13 

.02 

.00

.75 

.56 

.01 

.00

.33 

.64 

.01 

.00

1.40 

1.31 

.03 

.00

0.74 

.95 

.02 

.00

23

0.60 

.05 

.79 

.67

.00 

.01 

.11 

1.31

.00 

.05 

.90 

.76

.00 

.06 

1.05 

.90

.00 

.00

.07 

1.19

.00 

.13 

2rlO 

1.79

.00 

.07 

1.25 

1.07

.00 

.03 

.42 

1.62

.00 

.15 

2.56 

2.18

0.00 

.05 

.77 

1.42

24

0.49 

.66 

.04 

.00

.95 

.69 

.05 

.00

.55 

.25 

.02 

.00

.65 

.36 

.02 

.00

.86 

.63 

.04 

.00

1.28 

1.03 

.07 

.00

.77 

.45 

.03 

.00

1.17 

.85 

.06 

.00

1.57 

2.66 

.18 

.00

1.03 

.86 

.06 

.00

25

0.14 

.00 

.00 

.00

.32 

.00 

.00 

.00

.05 

.00 

.00 

.00

.07 

.00 

.00 

.00

.00 

.00 

.00 

.00

.02 

.00 

.00 

.00

.09 

.00 

.00 

.00

.05 

.00 

.00 

.00

.53 

.00 

.00 

.00

0.17 

.00 

.00 

.00
106 FLOODS IN NEW YORK AND PENNSYLVANIA

TABLE 76. Gage height and discharge of East Branch of Delaware River at 

Fishs Eddy, N.Y., during flood of August 1933

MEAN DISCHARGE, IN SECOND-FEET, 1933

Day

16.-.--.-

17.-..--

18.......

19. ......

20-.... ..

Me 

Rui

Aug.

282 

237 

237 

388 

488

an disch 

lofl, in i

Day

21......

22......

23......

24......

25......

arge, Aug 

aches

Aug.

360 

1,480 

2,530 

31, 080 

22, 120

16 to S«

Day

26......

27......

98

29......

30......

31......

;pt. 15, in

Aug.

8,270

4,630 

3,200

2,400

1,860

1,500 

second-:

Day

2....... 

3.......

4.......

5.......

eet

Sept.

1,300 

1,160 

1,120 

5,960 

4,940

Day

6.......

7. ......

8.......

9.......

10......

Sept.

2,840 

2,240 

1,870 

1,620 

1,440

Day

11......

12......

13......

14......

15......

Sept.

1,260

1,120 

1,000 

1,160 

2,390

3,630 

5.34

GAGE HEIGHT, IN FEET, AND DISCHARGE, IN SECOND-FEET, AT INDICATED TIME, 1933

Hour

Feet Sec.-ft.

August 20

Feet Sec.-ft.

August 21

Feet Sec.-ft.

August 22

Feet Sec.-ft.

August 23

Feet Sec.-ft.

August 24

Feet Sec.-ft.

August 25

10.... 

12m. 

2....

10......

12 p.m..

3.21

3.13

3.09

3.04

3.00

2.96

2.92

2.89

2.86

2.83

2.82

2.79

600

560

540

515

495

476

457

443

430

417

413

400

2.76

2.74

2.73

2.72

2.70

2.68

2.66

2.65

2.62

2.62

2.63

2.64

388

381

377

373

365

358

351

347

336

336

340

343

2.64

2.68

2.77

2.92

3.29

3.68

3.94

5.03

5.94

6.10

6.12

6.05

343

358

392

457

644

896

1,080

2,040

3,110

3,330

3,360

3,260

5.95

5.87

5.75

5.60

5.45

5.30

5.17

5.07

4.99

4.98

5.14

6.57

3,120

3,020

2,860

2,680

2,500

2,330

2,190

2,080

2,000

1,990

2,150

4,020

7.10

8.21

10.50

12.41

14.59

17.24

19.39

20.45

20.36

19.76

18.91

18.06

4,920

7,160

12,800

18,600

25,900

36,600

47,000

52,500

52,000

48,800

44,600

40,300

17.00

15.96

15.00

14.20

13.53

12.96

12.38

11.88

11.40

10.97

10.55

10.16

35, 500

31,300

27, 500

24,600

22, 200

20,200

18, 500

17,000

15,600

14,300

13,000

11,900

Hour

10... 

12m.

2...

4...

6...

10..... 

12 p.m.

Feet Sec.-ft.

August 26

9.84

9.52

9.23

8.97

8.76

8.56

8.37

8.19

8.00

7.81

7.63

7.48

11,100

10, 300

9,580

8,940

8,440

7,980

7,570

7,190

6,800

6,420

6,080

5,800

Feet Sec.-ft.

August 27

7.31

7.17

7.05

6.93

6.84

6.75

6.65

6.55

6.45

6.35

6.24

6.15

5,510

5,270

5,070

4,880

4,730

4,600

4,440

4,300

4,150

4,010

3,860

3,740

Feet Sec.-ft.

August 28

6.05

5.96

5.89

5.82

5.76

5.70

6.65

5.59

5.52

5.46

5.40

5.33

3,620

3,500

3,410

3,320

3,250

3,180

3,120

3,050

2,960

2,890

2,820

2,740

Feet Sec.-ft.

August 29

5.27

5.20

5.15

5.10

5.05

5.01

4.97

4.92

4.88

4.84

4.78

4,72

2,680

2,600

2,540

2,490

2,440

2,390

2,350

2,290

2,250

2,200

2,140

2,080

Feet See.-ft.

August 30

4.69

4.64

4.60

4.56

4.52

4.49

4.46

4.43

4.40

4.37

4.34

4.31

2,050

2,000

1,960

1,920

1,880

1,850

1,820

1,790

1,760

1,730

1,710

1,680

 Peak discharge: August 24, 5 p.m., 53,300 sec.-ft.

LOCATION. Water-stage recorder, lat. 41°58'00", long. 75°10'50", at railroad bridge in Fishs 

Eddy, Delaware County, 4% miles below mouth of Beaver Kill. Zero of gage is 950.84 feet 

above mean sea level.

DRAINAGE AREA. 783 square miles.

REMARKS. Records supersede those given in Geol. Survey Water-Supply Paper 741.
FLOODS OF AUGUST 1933, SUSQUEHANNA RIVER 107

TABLE 77. Computation of volume of direct runoff associated with precipitation 

Period August 21-25, 1933, East Branch of Delaware River at Fishs Eddy, N. Y.

Day

Aug. 21

22

23

24

25

26

27

28

29

30

31

Sept. 1

2

Total

Sec.-ft.-^days.....

Sec. -ft. -days.......

12-hour 

period 

ending

12m.

12 p.m.

12m.

12 p.m.

12m.

12 p.m.

12m.

12 p.m.

12m.

12 p.m.

12m.

12 p.m.

12m.

12 p.m.

12m.

12 p.m.

12m.

12 p.m.

12m.

12 p.m.

12m.

12 p.m.

12m.

12 p.m.

12m.

Daily mean 

discharge 

(second-feet)

385

343

465

2,500

2,835

2,230

14,860

47,300

28,500

15,720

9,720

6,820

5,100

4,155

3,430

2,970

2,550

2,245

1,965

1,760

1,600

1,500

1,390

1,310

1,220

1 <o 0*70 lO6,O/6

81,436

Estimated

recession from 

preceding storm 

and base runoff

(second-feet)

385

343

320

285

305

335

365

430

500

560

620

680

740

800

860

910

950

990

1,040

1,070

1,100

1,130

1,160

1,190

1,220

ID OCR lo,^oo 

9144 , lf*r

Direct runoff 

(second-feet)

0

0

145

2,215

2,530

1,895

14,495

46,870

28,000

15,160

9,100

6,140

4,360

3,355

2,570

2,060

1,600

1,255

925

690

500

370

230

120

0

144,585

72,292 ( =

3.44 inches)

SUSQUEHANNA RIVER AT MARIETTA, PA.

Precipitation between August 20-25, 1933, was computed to average 

4.13 inches over the basin using records listed in table 78. Rainfall listed 

in this table for August 21-25, inclusive, is for the calendar day and was 

prepared on the basis of daily readings, made in the morning or in the 

afternoon, supplemented by records of hourly precipitation at gages 

listed in table 73. According to the isohyetal lines of total storm precipitation which are shown on plate 1, precipitation was greater in the 

eastern part of the basin, and the maximum of 13.82 inches fell in the 

lower basin at York, Pa.

The discharge at Marietta, Pa., during the storm period is given in 

table 79, and graphically on figure 29. Direct runoff associated with the 

storm as computed in table 80 totaled 1.39 inches, leaving a retention of 

2.74 inches, of which about 0.36 inch appeared as ground-water runoff. 

Field-moisture accretion and evaporation-transpiration losses therefore 

totaled 2.38 inches. The average infiltration index over the basin was 

0.15 inch per hour.

The interval between centers of effective rainfall and direct runoff 

was computed as 81 hours, which may be less than for uniform rain over
TABLE 78. Precipitation, in inches, at rain gages in and near Susquehanna River 

[In this table "T" indicates a trace]

Station

New York: 

Alfred.. ...................

Delhi................... 

Haskinville. ...............

Pennsylvania:

Pleasant Mount _ .......

Altitude

(feet)

1,840

1,420

1,006

858

1,200

1,129

1,460

863

1,620

872

1,325

1,015

1,112

1,037

400

1,615

1,442

1,060

1,050

520

467

800

580

1,120

2,000

1,325

553

535

337

650

1,637

469

255

1,000

1,680

1,750

1,045

420

540

1,820

Weight

(percent)

1.24

.02

1.51

3.06

2.61

2.21

.32

2.71

2.11

1.21

1.34

1.50

1.40

1.38

.06

1.92

1.71

2.34

1.69

2.90

2.58

2.34

1.42

3.57

.68

2.72

1.06

.02

1.87

3.75

2.48

1.40

.09

2.30

2.40

2.19

3.28

2.88

1.60

1,35

21

0.36

T

.31

.42

.40

.35

.15

.04

.10

.23

.90

.05

1.28

.90

.18

1.20

.80

22

0.19

1.35

2.29

.64

.30

1.68

.90

.20

.70

1.30

.88

.95

.68

.76

.26

.55

.50

.31

.73

1.30

.65

1.02

.20

.30

.86

1.13

2.47

1.25

.36

.17

2.90

2.30

.71

1.90

.64

.50

.48

a 14

2.34

23

1.18

.71

1.60

1.17

.67

.79

1.12

2.52

1.20

.90

1.15

.74

.83

1.00

.63

1.80

1.33

1.20

3.39

4.09

3.27

2.15

2 91

.90

1.75

1.20

1.99

2.10

4.66

3.00

1.33

3.82

2.75

1.05

1.10

1.25

2.72

4.25

3.37

3.80

24

1.90

1.05

1.26

.78

1.26

1.01

2.21

.05

1.25

.82

1.07

1.31

1.47

.88

84

.47

.47

.20

.53

.58

.77

.40

.69

.23

.47

.92

.30

1.76

.62

.50

.52

.20

1.53

.70

1.40

1.21

1.50

.74

.50

25

0.28

.02

.03

1.48

.11

.01

.09

.03

.18

.04

Total 21-25

3.27

1.76

4 81

4.26

2 Q1

3.58

«; 19

3.47

2.65

3.61

3.35

3.68

3.09

2.27

2.53

2.35

4.23

5.55

5.38

3.20

4.72

1.33

2.52

2.98

3.65

7.23

6.58

3.86

2.02

8.00

6.15

3.29

3.70

3.29

4.61

6.23

7.45

7.44
Benova.. _______ ....

Scranton __ ________

Smethport.. ___ __

State College....... __ ...

Sunbury. _ __

Towanda. ___ . __ . _ ..

Weikert __ .

Wellsboro ......

Wilkes-Barre... __ ....

Williamsport...... ____ .

York.............. . ....

672

7dfi

1,217

520

754

750

540

521

400

3 14

1 96

1.67

2.15

2 41

2.88

1 ^7

9 QX,

2.68

2.11

on

.14

.36

.70

1.29

0.17

1.51

T

.21

.80

QQ

.82

.77

.94

.36

4.54

O QQ

2 24

2.46

1 9*

a

OA

3 04

1.13

i ^a

1 44

3.66

6.41

9 1 Q

qe

OQ

.69

1.06

1 1R

1.10

1.57

.70

1.74

1.58

0.85 O f\A

1.64

5

t)A

3.66

3 79

5.76

13.82

4.13

NOTE. Entries for August 26-31 .inclusive, have not been adjusted on a midnight to midnight basis.
19202122232429262728293031 I K 17 

FIGURE 29. Hydrograph of Susquehanna River at Marietta, Pa., showing discharge, August
FLOODS OF AUGUST 1933, SUSQUBHANNA RIVER 111

the basin, because the storm rainfall was greater in the lower than in 

the upper basin. The interval between center of effective rainfall and the 

peak discharge at Marietta was 46 hours.

TABLE 79. Gage height and discharge of Susquehanna River at Marietta, Pa., 

during flood of August 1933

MEAN DISCHARGE, IN SECOND-FEET, 1933

Day

1 

2.. _ 

3..... 

4..... 

5..... 

6 

Aug.

6,720 

5,680 

6,060 

18,300 

9,540 

6,760

Mean 

Runofl

Sept.

31, 500 

25, 900 

22, 600 

27,900 

54, 000 

75, 600

month] 

, ininc

Day

7.... 

8.... 

9 . 

10... 

11... 

12. ..

y disch 

hes

Aug.

6,160 

5,880 

6,370 

6,990 

14, 100 

21, 600

arge, ii

Sept.

58,400 

44, 600 

34, 500 

27, 700 

?3,400 

21, 000

i secon

Day

13... 

14... 

15... 

16...

17... 

18...

d-feet

Aug.

14, 700 

13, 500 

12, 600 

12, 200 

11, 600 

9,740

Sept.

20,200 

18, 800 

20, 200 

38, 500 

82, 700 

107, 000

Day

19 

20 

21 

22 

23 

24...

Aug.

9,080 

9,860 

8,720 

12,400 

22,900 

159, 000

Sept.

75.600 

59, 700 

48, 200 

37, 700 

31,500 

27,700

Day

25... 

26 

27... 

28... 

29... 

30 

31...

Aug.

287,000 

190,000 

121,000 

80,400 

58,400 

45, 800 

37, 700

39,700 

1.76

Sept.

25,000 

23,400 

21, 800 

20, 200 

19, 500 

18, 100

38, 100 

1.63

GAGE HEIGHT, IN FEET, AND DISCHARGE, IN SECOND-FEET, AT INDICATED TIME, 1933

Hour

6 ......

12m.... 

6..... 

12 p.m. .

6... ....

12m.. 

6_ 

12p.m. .

Hour

8-..-. 

12m.._. 

6 .

12p.m. .

Feet Sec.-ft.

August 21

33.55 

33.16 

33.70 

33.48

8,750 

6,840 

9,490 

8,510

August 26

46.54 

45.38 

44.47 

43.80

217, 600 

190, 300 

168, 700 

152, 600

Feet

Feet Sec.-ft.

August 22

33.43 

34.02 

34.85 

35.03

8,280 

11, 070 

16, 280 

17, 300

August 27

43.25 

42.74 

42.14 

41.51

Sec.-ft.

August 31

37.52 

37.34 

37.13 

36.99

39, 770 

37. 390 

35, 100 

34, 000

139, 100 

128, 100 

115, 500 

103, 400

Feet

Feet Sec.-ft.

August 23

34.77 

34.63 

35.70 

39.42

15,620 

14,960 

22,340 

66, 470

August 28

40.97 

40.51 

40.09 

39.72

93, 850 

84, 760 

77, 840 

71, 240

Sec.-ft.

September 1

36.82 

36.69 

36.46 

36.30

31, 890 

30,880 

28,950 

27, 140

Feet Sec.-ft.

August 24

42.27 

44.52 

46.00 

47.26

119, 700 

168, 700 

205, 100 

238, 300

August 29

39.38 

39.07 

38.79 

38.53

66, 470 

61,790 

57,260 

52, 910

Feet Sec.-ft.

September 2

36. 17 26, 280 

36. 02 24, 650 

35. 96 24, 650 

35. 88 23, 870

Feet Sec.-ft.

August 25 

48.93 

49.43

48.84 

47.77

281,600 

295, 700 

278, 800 

251, 500

August 30

38.31 

38.08 

37.88 

37.70

Feet

50, 110 

47, 390 

44, 770 

42, 230

Sec.-ft.

September 3

35.78 

35.66 

35.*61 

35.70

23,100 

22,340 

21, 590 

22,340

 Peak discharge: August 25, 11:30 a.m., 296,000 second-feet.

LOCATION. Water-stage recorder, lat. 40°03'1S", long. 76°31'50", 420 feet above mouth of 

Chickies Creek and 1 mile downstream from Marietta, Lancaster County. Zero of gage is 

200.00 feet above mean sea level.

DRAINAGE AREA. 25,990 square miles.

REMARKS. Records of daily mean discharge published in Geol. Survey Water-Supply Paper 741.
112 FLOODS IN NEW YORK AND PENNSYLVANIA

TABLE 80. Computation of -volume of direct runoff associated with precipitation 

period August 21-25, 1933, Susquehanna River at Marietta, Pa,

Day

Aug. 

21...................

22....................

23........... ........

24....................

25...................

26....................

27....................

28....................

29...................

30....................

31.....................

Sept. 

1. ...................

2...................

3....................

4. ...................

5...................

6................. ...

Total

Daily mean 

discharge 

(second-feet)

8,530 

11,800 

22,900 

161,000 

274,000 

194,000 

127,300 

84,760 

60,260 

46,070 

37,390

30,880 

25,450 

b22,000 

b !8,000 

b !6,SOO 

b !4,500

1,155,340

Estimated 

recession from 

preceding storm 

and base runoff 

(second-feet)

8,530 

8,500 

8,500 

8,600 

9,000 

9,400 

9,800 

10,200 

10,600 

11,000 

11,500

12,000

12,400 

12,800 

13,200 

13,600 

14,000

183,630

Direct runoff 

(second-feet)

0 

3,300 

14,400 

152,400 

265,000 

184,600 

117,500 

74,560 

49,660 

35,070 

25,890

18,880 

13,050 

9,200 

4,800 

2,900 

500

971,710 ( = 

1.39 inches)

 Based on records published in Water-Supply Paper 741. 

b Estimated recession under subsequent rise.

FLOOD OF MAY 1894, SUSQUEHANNA RIVER 

AT HARRISBURG, PA.

The storm of May 17-23, 1894, which produced the greatest nonwinter flood of record at Harrisburg, Pa., had its origin in a low-pressure 

area that appeared over the Great Lakes region on May 17. The low 

pressure followed a southeastward path over West Virginia and Virginia, where it stagnated and merged with a similar area that had come 

up from the Gulf region. It finally moved out to sea on May 21. Figure 

30 shows the position of the low-pressure area on May 20, 1894, when 

heavy rainfall was general over the Susquehanna River Basin. Rainfall 

began early on May 17 and was nearly continuous until May 26. Daily 

recorded rainfall as given in table 81 indicates that the heaviest portion 

occurred on May 19-21. The maximum 24-hour rainfall of 5.94 inches 

was measured at Quakertown, Pa., on May 21. The flood which crested 

at Harrisburg on May 22 was apparently produced by the rains during 

May 17-23. The rainfall that followed on May 24-26 was assumed to 

have produced a second and smaller rise that began on May 25 at Harrisburg, reaching its crest at about 12 p.m. of May 26, and was therefore 

not directly considered in this study.

Plate 2 is an isohyetal map showing total storm rainfall in the Susquehanna River Basin, May 17 23, 1894. The average over the basin was 

4.96 inches. Precipitation was general over the entire basin but was
100* SO" 

FIGURE 30. Map of United States showing position of storm, 8 a.
114 FLOODS IN NEW YORK AND PENNSYLVANIA

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GEOLOGICAL St

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116 FLOODS IN NEW YORK AND PENNSYLVANIA

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FLOOD OF MAY 1894, SUSQUEHANNA RIVER 117

pany, which gives times of beginning and ending of rainfall on a 

number of days, May 17-26, 1894.

&

17...................

18...................

19...................

19...................

20...................

21...................

22...................

24...................

25...................

26 ...................

[ay Rainfall (inches)

n <;?

.12

.48

.96

2.88

2.88

.72

1.72

.18

.18

TABLE 83. Gage height and discharge of Susquehanna River at Harrisburg, Pa.,

during flood of May 1894

MEAN DISCHARGE, IN SECOND-FEET, 1894

Day

1_ _ 

2 

3__.__ 

4 _. 

5-.... 

6...-.

May

46,100 

44,900 

39, 900 

35, 000 

30, 400 

28,100

Mean 

Runofl

June

139,000 

138, 000 

126. 000 

118,000 

114,000 

104,000

monthly 

, in inct

Day

7 

8.... 

9.... 

10 

11 

12,..

discha 

IBS

May

27,100 

28, 100 

30, 400 

30, 400 

30, 400 

24, 900

rge, in

June

82, 500 

69,000 

60, 600 

52,600 

47, 400 

37, 400

seconc

Day

13... 

14... 

15 

16... 

17... 

18 

mr 

-feet

May

23, 000 

21,000 

18, 400 

18, 400 

16, 700 

16, 700

June

33, 900 

32, 700 

32, 700 

31, 500 

29,300 

26, 100

Day

19 

20 

21... 

22... 

23... 

24...

May

19, 900 

94, 400 

385, 000 

575,000 

423, 000 

251,000

June

24,000 

30, 400 

29,300 

24,900 

21, 900 

18, 400

Day

25... 

26... 

27... 

28 

29 

30... 

31...

May

185,000 

180,000 

175,000 

129,000 

99, 700 

88, 500 

105,000

104,000 

4.97

June'

18, 400 

20, 100 

19, 200 

20, 100 

17,600 

21, 000

51,300 

2.38

GAGE HEIGHT, IN FEET, AND DISCHARGE, IN SECOND-FEET, AT INDICATED TIME, 1894

Hour

6........

12m....

6........

12p.m. .

6..... _

12m.... 

6.... ....

12p.m..

Hour

6... .....

12m-... 

6........

12p.m..

Feet Sec.-ft.

May 18

2.3 

2.3 

2.3 

2.3

16,000 

16, 000 

16, 000 

16, 000

May 23

21.8 

20.1 

18.5 

16.9

475, 400 

420, 200 

371,000 

324, 100

Feet

Feet Sec.-ft.

May 19

2.3 

2.5 

2.9 

3.7

16,000 

18,000 

22,400 

32,800

May 24

15.6 

14.5 

13.5 

12.7

Sec.-ft.

May 28

9.7 

9.2 

8.7 

8.4

140, 300 

129,800 

119,600 

113, 600

287, 100 

256, 900 

230, 300 

209,800

Feet

Feet Sec.-ft.

May 20

4.9 

6.2 

7.8 

9.6

50,600 

72, 200 

101, 800 

138, 200

May 25

12.0 

11.5 

11.2 

11.1

192,400 

180, 500 

173,600 

171, 300

Sec.-ft.

May 29

8.0

7.7 

7.4 

7.2

105,600 

99,900 

94, 200 

90, 400

Feet Sec.-ft.

May 21

12.8 

20.9 

22.9 

24.4

212, 300 

445, 800 

512, 600 

565,400

May 26 -

11.2 

11.6 

11.8 

11.9

173, 600 

182,800 

187,600 

190,000

Feet Sec.-ft.

May 30

7.0 86,600 

7. 0 86, 600 

7. 1 88, 500 

7. 2 90, 400

Feet Sec.-ft.

May 22 »

25.5 

25.5 

24.6 

23.3

605, 500 

605, 500 

572, 600 

526,500

May 27

11.8 

11.5 

11.0 

10.4

Feet

187, 600 

180, 500 

169,000 

155, 600

Sec.-ft.

May 31

7.4 

7.8 

8.2 

8.6

94,200 

101, 800 

109, 600 

117, 600

 Peak discharge: May 22, 6:30 to 9:30 a.m., 613,000 sec. -ft. 

LOCATION. Staff gage, lat. 40°15'35", long. 76°S3'05", at Harrisburg water supply pumping

station, Harrisburg, Dauphin County. 

DRAINAGE AREA. 24,100 square miles. 

REMARKS. Discharge based on once daily readings on staff gage.
118 FLOODS IN NEW YORK AND PENNSYLVANIA

The observer at Smethport, Pa., reported that 1.90 inches of rain and 

hail fell between 7 p.m. and 8:15 p.m. on May 17, and the observer at 

Addison, N. V., reported 1,27 inches between 1 p.m. and 2 p.m. on 

May 18.

The discharge at Harrisburg during the flood is given in table 83 and 

shown as a hydrograph in figure 31. Direct runoff associated with the 

storm of May 17-23 as computed in table 84 was 3.44 inches.

The difference between average rainfall and direct runoff is 1.52 

inches, of which 0.75 inch appeared as ground-water runoff, leaving 0.77 

inch for field-moisture accretion and evaporation-transpiration losses.

The interval between center of mass of effective rainfall and direct 

runoff was 99 hours. This lag interval is greater than that found for 

the Susquehanna River at Marietta during the August 1933 storm. The 

latter storm centered in the lower basin, which would shorten the lag 

interval, whereas that of May 1894 was heavier in the upper reaches 

of the basin, probably accounting for some of the difference.

TABLE 84. Computation of volume of direct runoff associated with storm period 

May 17-23, 1894, Susquehanna River at Harrisburg, Pa.

Date

May 

18. ..................

19...................

20 ...................

21...................

22...................

23...................

24....................

25...................

26...................

27...................

28...................

29...................

30. ..................

31...................

June 

1... ................

2...................

3...................

4. ...................

5....... ............

Total

Daily mean 

discharge 

(second-feet)

16,700

19,900

94,400

385,000

575,000

423,000

251,000

 180,000

 145,000

 114,000

 90,000

 75,000

 61,000

 51,000

 43 000

 36,000

 31,000

 27,000

aoc nnn

2,643,000

Estimated 

recession from 

preceding storm 

and 

base runoff 

(second-feet)

16,700

17,300

17,900

18,500

19,100

19,700

20,300

>>n Qnn

21,500

99 inn

22,700

23,300 ">\ onn

24,500

OC (\f\f\

25,000

25,000

25,000

25,000

413 400

Direct runoff 

(second-feet)

0

2,600

76,500

366,500

555,900

403,300

230,700

159,100

123,500

91,900

67,300

51,700

37,100

26,500

18,000

11,000

6,000

2,000

0

2,229,600 ( 

3.44 inches)

* Estimated recession under subsequent rise.

FLOOD OF APRIL-MAY 1909, WEST BRANCH OF 

SUSEQUEHANNA RIVER AT WILLIAMSPORT, PA.

The storm, which brought an average rainfall of 3.66 inches in 5 

days to the basin of the West Branch of the Susquehanna River above 

Williamsport, Pa., was associated with an extratropical cyclone that had
FIGURE 32. Map of United States showing position of storm, 8 a
120 FLOODS IN NEW YORK AND PENNSYLVANIA

its origin in the Rocky Mountain region near Salt Lake City. As shown 

on figure 32, the low-pressure area reached the Great Lakes on April 30. 

Active rainfall over the West Branch of the Susquehanna River Basin 

from April 29 to May 1 resulted in the flood peak of May 1. Additional 

rainfall after May 1 and until May 5, although not of the same amount 

or intensity and not adding to the flood height, contributed materially

T8»00' T7»00'

79* 00" TT'OO1

FIGURE 33. Map of basin of West Branch of Susquehanna River above Williamsport, Pa., 

showing lines of equal precipitation, April 27-May 1, 1909.
FLOOD OF APRIL-MAY 1909, WEST BRANCH SUSQUEHANNA RIVER

to the volume of stream flow while the flood was receding and has therefore been included in this compilation. Total rainfall over the basin in 

8 days from April 27 to May 4 was 4.08 inches. The storm followed a 

30-day period in which precipitation was about 25 percent above normal.

Figure 33 shows lines of equal precipitation, April 27 to May 1, based 

on the available records of the United States Weather Bureau. There 

were broad areas without rainfall measurements and the actual amounts 

may differ considerably from that shown, particularly in the regions of 

high precipitation.

Daily rainfall at rain gages in and near the basin during the flood 

period are listed in table 85. Rainfall in this table is that for the 24-hour 

period ending at 7 p.m. of the indicated day. All rain gages were read 

at 7 p.m., and the table lists the daily precipitation as measured except 

for the Renovo gage, which was read in the morning and for which 

the measurements were adjusted to conform with the others. Rainfall 

was greatest on April 29 and 30, when there was 2.72 inches of rain 

over the basin.

Precipitation fell mainly as rain but temperatures on some days, as 

shown in table 86, dropped below the freezing point and there were 

reports of local snowfall. At State College, Pa., the report of the Weather 

Bureau observer that the ground was frozen on April 24 and 25, suggests that soil conditions were not uniformly favorable for the retention 

of rainfall.

The records of gage height and discharge at the gaging station at 

Williamsport, Pa., during the flood period is given in table 87 and a 

discharge hydrograph is shown on figure 34. The direct runoff as computed in table 88 was 2.84 inches, indicating a retention of 1.24 inches, 

of which it was computed that ground-water runoff accounted for 1.10 

inches. The remaining 0.14 inch seems too low to represent field-moisture 

accretion and evaporation-transpiration losses. However, the rate of 

ground-water discharge at the beginning of the flood was about 10,000 

second-feet or 1.75 second-feet per square mile. This is the highest rate 

observed for any of the nonwinter floods studied in this report and discloses moisture conditions before the flood not favorable for the retention of rainfall.

Lack of automatic rainfall recorders in or near the storm area prohibits the computation of infiltration capacity.

The interval between centers of effective rainfall and direct runoff as 

computed in table 89 was 56 hours, which is about 6 hours longer than 

during the March 1936 flood as reported in table 1. As the March 1936 

storm was generally uniform over the area, the differences in lag interval 

probably is partly a result of the April-May 1909 storm centering in the 

upper basin.
122 FLOODS IN NEW YORK AND PENNSYLVANIA
TABLE 85. Daily precipitation, ain inches, at stations in an

Susquehanna River basin above Williamsport, Pa., Apri

[In this table "M" indicates a record missi

Station 

(Pennsylvania)

Clear-field ...... _ ... _ ...................

Emporium

Altitude 

(ft.)

1,181

826

1,107

1,050

1,400

560

1,191

1,327

530

Weight 

(percent)

6.83

7.64

21.21

14.82

.83

9.36

16.89

3.96

11.63

6.83

100.0

27

0.44

.15

.30

.27

.10

.03

.04

0.17

AE

28

0.40

.23

.08

.10

.22

.27

.40

0.22

ril

29

0.71

.80

1.33

2.56

2.06

.73

1.05

1.23

2.30

1.00

1.42

30

0.60

2.12

1.71

.44

.54

1.01

1.78

1.61

.62

1.87

1.30

May

1

0.16

.56

b.60

.96

.66

.53

1?

.69

.59

.67

0.55

Total 

Apr. 27- 

May 1

1.91

3.63

4.34

4.46

3.34

2.37

3.32

3.56

3.78

3.98

3.66

0

0

 7 p.m. to 7 p.m. 

b Estimated.
124 FLOODS IN NEW YORK AND PENNSYLVANIA

TABLE 86. Daily mean areal precipitation and temperature, West Branch of 

Susquehanna River at Williamsport, Pa., April 27 to May 4, 1909

Day

27.

28.

29.

30.

1.

2.

3.

4.

April

May

Total or average.

Mean areal 

precipitation a

(inches)

0.17

.22

1.42

1.30

.55

.03

.30

.09

4.08

Maximum

(°F.)

60

53

49

64

57

47

49

54

54

Minimum

<°F.)

33

31

30

37

40

34

32

38

34

Meanb

(°F.)

47

42

40

50

48

40

40

46

44

a 7 p.m. to 7 p.m.

b Average of maximum and minimum.

TABLE 87. Gage height and discharge at indicated time, West Branch of Susquehanna River at Williamsport, Pa., April-May 1909

MEAN DISCHARGE, IN SECOND-FEET, 1909

Day

1 . 

2.... 

3 

4 

5.... 

6....

April

10, 400 

9,690 

9,360 

9,030 

8,710 

8,090

Mean 

Eunol

May

141, 000 

124, 000 

70, 000 

47, 400 

37, 400 

30, 200

monthl 

I, in inc

Day

7 

8 

9 

10.. 

11- 

12..

7 disc 

hes

April

10, 000 

18, 100 

19, 900 

16, 700 

14, 000 

11,900

urge, ir

May

24,400 

19, 900 

16, 200 

14, 000 

13, 600 

13, 200

i second

Day

13_. 

14.. 

15- 

16.. 

17- 18-

feet

April

10, 400 

17, 200 

54, 600 

44, 100 

30, 200 

22, 400

May

11, 500 

10, 000 

9,030 

8,710 

7,780 

7,170

Day

19.. 

20- 

21_. 

22.. 

23.. 

24..

April

17, 600 

15, 400 

13, 600 

14, 000 

19, 900 

21,400

May

6,580 

5,750 

5,490 

5,230 

4,970 

4,720

Day

25- 

26- 

27- 

28_. 

29- 

30- 

31

April

18, 100 

16, 200 

14, 000 

12, 800 

12, 800 

36, 800

17,900 

3.54

May

4,470 

4,220 

3,980 

5,230 

6,580 

6,580 

6,020

21, 800 

4.46

GAGE HEIGHT, IN FEET, AND DISCHARGE, IN SECOND-FEET, AT INDICATED TIME, 1909

Hour

6........

12m.. 

6........

13p.m..

8.-..-. 

12m-... 

6.......

12 p.m..

Hour

6........

12m.... 

6-.._ 

12 p.m..

Feet Sec.-ft.

April 27

8.20 

5.10 

5.00 

4.90

14,600 

14, 100 

13, 700 

13,300

May 2

19.70 

18.40 

16.90 

15.60

Feet

127,000 

113,000 

97, 000 

83,900

Feet Sec.-ft.

April 28

4.80 

4.75 

4.65 

4.60

12, 800 

12,800 

12, 000 

12,000

May3

14.50 

13.60 

12.75 

12.05

Sec.-ft.

May 7

7. 40 25, 100 

7. 15 24, 100 

6. 90 22. 600 

6. 65 21, 200

73, 400 

65,300 

58, 600 

52, 300

Feet

Feet Sec.-ft.

April 29

4.70 

5.15 

5.95 

7.10'

12, 400 

14, 600 

18,300 

23, 600

May 4

11.45 

10.95 

10.55 

10.20

47, 900 

45, 200 

42, 700 

40, 300

Sec.-ft.

May8

6.45 

6.25 

6.05

5.15

20, 200 

19,300 

18, 300 

17, 300

Feet Sec.-ft.

April 30

8.80 

11.85 

17.90 

20.45

32, 400 

50, 800 

107, 000 

135,000

May 5

9.85 

9.50 

9.15 

8.85

38, 000 

36,300 

34,600 

32, 400

Feet Sec.-ft.

May 9

5. 65 16, 400 

5. 50 15, 900 

5.35 15,400 

5. 25 14, 600

Feet Sec.-ft.

May 1»

20.95 

20.95 

20.75 

20.40

142, 000 

142, 000 

140, 000 

135,000

May 6

8.50 

8.20 

7.95 

7.70

Feet

30, 800 

29, 200 

28, 200 

26. 600

Sec.-ft.

May 10

5.15 

5.10 

5.05 

5.00

14, 600 

14, 100 

13, 700 

13, 700

Peak discharge: May 1, 8 a.m.. 142,000 second-feet, gage height 21.0 feet. 

LOCATION. Chain gage, lat. 41°14'15", long. 76°59'55", at highway bridge at Williamsport,

Lycoming County. Zero of gage is 494.55 feet above mean sea level. 

DRAINAGE AREA. 5,682 square miles. 

REMARKS. Records of daily mean discharge published in Geol. Survey Water-Supply Paper 261.
FLOOD OF MAY 1916, GENESEE RIVER 125

TABLE 88. Computation of volume of direct runoff associated with precipitation 

period April 27 to May 4, 1909, West Branch of Susquehanna River at

Williams port, Pa.

Day

Apr. 

28....................

29....................

30...................

May

3

4...................

5. ..................

6...................

7...................

8...................

9...................

Total

Daily mean 

. discharge 

(second-feet)

12,430

15,425

68,600

140,000

112,000

66,200

45,880

36,275

90 94D

24,115

19,260

15,900

585,325

Estimated 

recession from 

preceding storm 

and base runoff 

(second-feet)

12,430

11,320

10,210

9,100

10,100

11,200

12,200

13,300

14,300

15,400

16,500

15,900

151,960

Direct runoff 

(second-feet)

0

4,105

58,390

130,900

101,900

55,000

33,680

22,975

14,940

8,715

2,760

0

433,365 ( =

2.84 inches)

TABLE 89. Computation of time of center of mass of net supply, and lag intervals, 

West Branch of Susquehanna River at Williamsport, Pa., April 27 to May 4, 1909

Day

Apr. 

27.................

28.................

29.................

30.................

May 

1...... ..........

2.................

3..................

4..................

Mean areal 

precipitation 

(inches)

0.17

.22

1 4?

1.30

.55

.03

.30

.09

4.08

Estimated 

net supply 

(inches)

0

.09

1.10

1.00

.39

.01

.22

.04

2.84

Time 

from 

origin 

(days)

0

1

2

3

4

5

6

7

Product 

(inch-days)

0

.09

2.20

3.00

1.56

.05

1.32

.28

8.50

a 7 p.m. to 7 p.m.

8 50 Center of mass of net supply occurred -y - = 3.00 days after 7 a.m. April 27 = April 30.29.

Time of center of mass of direct runoff was at April 32.62 or 2.33 days (56 hours) after 

center of graph of net supply.

Peak discharge occurred at 8 a.m. May 1 or 1.05 days (25 hours) after center of graph of 

net supply.

FLOOD OF MAY 1916, GENESEE RIVER AT ST. HELENA, N. Y.

The flood of May 1916 in the Genesee River Basin was the result of 

heavy 3-day precipitation, centering on May 16 and following a 30-day 

period in. which the precipitation was 20 percent above normal. The 

precipitation was associated with an extra-tropical cyclone whose position 

on May 16 is shown on figure 35.
126 FLOODS IN NEW YORK AND PENNSYLVANIA
FLOOD OF MAY 1916, GENESEE RIVER 127

FIGURE 36. Map of Genesee River basin above St. Helena, N. Y., showing lines of equal 

precipitation, May 14-20, 1916.
128 FLOODS IN NEW YORK AND PENNSYLVANIA

Precipitation at the several rain gages in and near the basin for each 

calendar day during the storm period is listed in table 90. Of the average 

storm rainfall of 3.67 inches over the basin, 2.64 inches fell on May 16. 

The recording rain gage at Rochester, N. Y., listed in table 91, indicates 

that although it rained nearly all day, most of the precipitation fell during 

the latter half. Figure 36 shows an isohyetal map of the total storm precipitation based on published Weather Bureau records of rainfall. The 

precipitation progressively increased from 2 inches in the upper basin 

to 5 inches in the lower basin.

The discharge at bi-hourly intervals during the storm is published in 

table 92 and is shown as a hydrograph on figure 37. Direct runoff assoSOjOOO

40jOOO

1 30(900

'& 20,000

10,000

19 20 21 22 23 24 23 26 27 28 29 30

May 1916

FIGURE 37. Hydrograph of Genesee River at St. Helena, N. Y., showing discharge, 

May, and precipitation, May 12-21, 1916.

ciated with the storm as computed in table 94 was 1.96 inches, leaving 

a retention of 1.71 inches. Ground-water runoff as computed was 0,68 

inch, leaving 1.03 inches for field-moisture accretion and evaporationtranspiration losses.

The infiltration capacity as computed averaged 0.07 inch per hour, the 

lowest of any of the nonwinter storms studied.
FLOOD OF MAY 1916, GENESEE RIVER 129

Table 93 shows the computation of the lag intervals between rainfall 

and runoff. The time of the center of mass of effective rainfall is based 

on mean areal 12-hourly rainfall reduced to net supply by methods previously explained. The time interval between center of rainfall and runoff 

was computed as 29 hours and that between the center of rainfall and 

the peak discharge at St. Helena was 21 hours.

TABLE 90. Daily precipitation, in inches, at rain gages in and near Genesee River 

at St. Helena, N. Y., May 13-19, 1916

Station

New York: 

Alfred . -- .._._ __ .

Hunt ___ 

Pennsylvania: 

W. Bingham. ___ . ___ ..

Altitude 

(feet)

1,840

1,420

1,800

1,150

1,260

1,171

Weight

(per-* 

cent)

12.7

33.1

8.0

11.4

16.8

18.0

100.0

13

0.04

.00

.05

.01

.03

.00

0.02

14

0.14

.02

.15

.06

.08

.00

0.06

15

0.67

1.15

.28

1.65

.53

.21

0.80

M

16

3.07

2.87

2.20

2.25

3.37

1.66

2.64

ay

17

0.11

.07

.20

.03

.11

.10

0.09

18

0.00

.00

.00

.00

.00

.00

0.00

19

0.08

.03

.10

.20

.05

.00

0.06

Total 

13-19

4.11

4.14

2.98

4.20

4.17

1 97

3.67
TABLE 91. Hourly precipitation, in inches, at recording Weather Bureau gages 

[In this table "T" indicates a trace]

Station

Buffalo, N. Y... ..............

Ithaca, N. Y. .................

Rochester, N. Y. ..............

Day 

13

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24

13

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24

13

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24

a.m.

1

.....

0.01

a

.17 

.01

.01

.02

2

T 

T

0.01

.01

.03

3

0.07 

.02

.03

.01

.05

.03

4

0.16 

T

.03

T

.22

.13

5

0.22 

.01

T

T

07

.12

~

6

0.09 

T

.01

.Is

(

7

0.03 

.03

.10

,01

8

0.01 

.01

T

.86

07

.01

T

9

T

T

0.26

10

0.01 

.01

T

*

T 

.06

T

11

0.04

.12

T 

T

.011

12

T

0.06

.01

.02

1

T

T

0.15

T

.03

T

0.0

.0

.0

..

.1
Harrisburg, Pa. -_____________ 

14

15

16

17

18

1Q

20

91

22

23

24

13

14

15

16

17

18

19

20

21

22

23

24

T

i<>

,01

.04

Ofi

19

,01

.03

.Ofi

11

.02T

01T

09

03

.07T

.01

.09

nnT

.03

.01

.01

.01

,07T

.03

.07

.17

noTT

.01

.04

Ofi TTTTT

T

.05

.01TTT

Ofi TT

.03

.02TTT

.02

01

01TT

TTTTT

'Included in following measurement.
132 FLOODS IN NEW YORK AND PENNSYLVANIA

TABLE 92. Gage height and discharge of Genesee River at St. Helena, N. Y., 

during flood of May 1916

MEAN DISCHARGE, IN SECOND-FEET, MAY 1916

Day

1. ......

2.......

3.......

4.......

5.......

Me

Ru

Sec.-ft.

2,000 

1,640 

1,480 

2,000 

1,580

jan mon 

nofl, in

Day

6. _--

7 . 

8 ....

9 --..

10 

thly discb 

inches

Sec.-ft.

1,300 

1,150 

1,020 

970 

870

arge, in

Day

11-- ..-

12 

13.._...

14 

15 

second-fee

Sec.-ft.

779 

676 

602 

562 

662

t

Day

16 

17---.

18... 

19-..-.

20 

Sec.-ft.

11,600 

31, 300 

7,600 

4,160 

3,040

Day

21--.--

22 .-.

23 

24 

25 

Sec.-ft.

2,250 

1,810 

5,730 

3,110 

2,080

Day

26. 

27 

28......

29 

30 

31 

Sec.-ft.

1,930 

1,560 

1,790 

1,570 

1,280 

1,170

3,202 

3.63

GAGE HEIGHT, IN FEET, AND DISCHARGE, IN SECOND-FEET, AT INDICATED TIME, 1916

Hour

10.... 

12m. 

2....

10 

12p.m..

Feet Sec.-ft.

May 14

3.31

3.28

3.30

3.30

3.30

3.29

3.31

3.27

3.29

3.30

3.32

3.32

566

550

560

560

560

555

566

545

555

560

572

572

Feet Sec.-ft.

May 15

3.31

3.28

3.32

3.34

3.45

3.41

3.41

3.42

3.46

3.57

3.77

3.96

566

550

572

584

655

627

627

634

662

746

930

1,130

Feet Sec.-ft.

May 16

5.64

6.42

7.57

8.00

8.11

7.93

7.91

7.94

8.01

8.62

9.77

11.13

3,830

5,860

9,880

11,700

12, 200

11,400

11,300

11, 400

11, 700

14,600

21,000

29,900

Feet Sec.-ft.

May 17

11.88

12.36

12.73

12.81

12.63

12.13

11.44

10.68

9.73

8.90

8.41

8.01

35, 900

40, 200

43. 600

44. 400

42, 700

38,100

32, 300

26,800

20,800

16,100

13, 600

11,700

Feet Sec.-ft.

May 18

7.75

7.55

7.35

7.22

7.00

6.85

6.71

6.56

6.45

6.33

6.26

6.16

10,600

9,800

9,020

8,530

7,750

7,230

6,760

6,290

5,950

5,600

5,400

5,120

Feet Sec.-ft.

May 19

6.07

6.01

5.93

5.87

5.81

5.77

5.71

5.65

5.61

5.54

5.49

5.45

4,730

4,520

4,380

4,230

4,140

3,990

3,860

3,760

3,610

3,500

3,420

Hour

Feet Sec.-ft.

May 20

Feet Sec.-ft.

May 21

Feet Sec.-ft.

May 22

Feet Sec.-ft.

May 23

Feet Sec.-ft.

May 24

10... 

12m. 

2...

10. 

12p.m.

5.41

5.35

5.31

5.29

5.26

5.26

5.25

5.25

5.21

5.16

5.12

5.07

3,330

3,210

3,130

3,090

3,030

3,030

3,020

3,020

2,940

2,850

2,780

2,690

5.01

4.96

4.92

4.87

4.83

4.80

4.76

4.73

4.69

4.66

4.63

4.59

2,580

2,490

2,420

2,340

2,280

2,230

2,170

2,120

2,060

2,020

1,980

1,920

4.55

4.54

4.51

4.49

4.47

4.43

4.44

4.44

4.45

4.52

4.64

4.82

1,860

1,850

1,800

1,780

1,750

1,690

1,710

1,710

1,720

1,820

1,990

2,260

5.57

6.42

6.84

6.93

6.90

6.75

6.57

6.38

6.23

6.10

5.97

5.84

3,670

5,860

7,200

7,500

7,400

6,900

6,320

5,740

5,310

4,960

4,620

4,310

5.72 

5.62 

5.50 

5". 41 

5.32 

5.23 

5.18 

5.11 

5.04 

4.97 

4.93 

4.88

4,020

3,790

3,630

3,330

3,150

2,980

2,150

2,760

2,630

2,610

2,440

2,360

LOCATION. Water-stage recorder, lat. 42°37'20", long. 77° 59'20", at highway in St. Helena,

Wyoming County, 1% miles downstream from Wolf Creek. 

DRAINAGE AREA. 1,017 square miles. 

REMARKS. Records supersede those published in Geol. Survey Water-Supply Paper 434.
FLOOD OF MAY 1916, GENESEE RIVER 133

TABLE 93. Computation of time of center of mass of net supply, and lag intervals, 

Genesee River at St. Helena, N. Y., May 13-19, 1916

May

13... ..............

14... ..............

IS....... ..........

16........... .....

17.................

18......... ........

19......... ........

12-hour 

period 

ending

12m.

12 p.m. 

12m.

12 p.m. 

12m.

12 p.m. 

12m.

12 p.m.

12m. 

12 p.m. 

12m.

12 p.m.

Mean areal 

precipitation 

(inches)

0.02

.03

.03 

.55

.25 

.76

1.88 

n?

.07 

.00

.00 

t\ft

.00

3.67

Estimated 

net supply 

(inches)

0.00

.00

.00 

oe

.09

1.15 

.00

.02 

.00

.00 

.02

.00

1.96

Time 

from 

origin 

(days)

0.0

.5

1.0 

1.5

2.0

2 "5

3.0 

3.5

4.0 

4.5

5.0 

5.5

6.0

Product 

(inch-days)

0.00

.00

.00 

.38

.18 

1.07

3.45 

.00

.08 

.00

.00 

.11

.00

5.27

Center of mass of net supply occurred 5.27

1.96 r= 2.69 days after 6 p.m. of May = May 16.44.

Time of center of mass of direct runoff was at May 17.66 or 1.22 days (29 hours) after center 

of mass of net supply.

Peak discharge occurred at 8 a.m. May 17 or 0.89 day (21 hours) after center of mass of 

net supply.

TABLE 94. Computation of volume of direct runoff associated with precipitation 

of May 13-19, 1916, Genesee River at St. Helena, N. Y.

May

14..................

15..................

16..................

17..................

18..................

19..................

20..................

21..................

22

23

OX

Total 

Sec -ft -% days

12-hour 

period 

ending

12 p.m. 

12m. 

12 p.m. 

12m. 

12 p.m. 

12m. 

12 p.m. 

12m. 

12 p.m.

12m. 

12 p.m.

12m. 

12 p.m. 

12m. 

12 p.m.

12m. 

12 p.m. 

12m. 

12 p.m. 

12m.

Daily mean 

discharge 

(second-feet)

560 

585 

740 

8,220 

15,040 

40,250 

22,350 

9,180 

6,015 

4,560 

3,750 

3,160 

2,910 

2,440 

2,070 

 1,800 

 1,600 

 1,475 

 1,400 

 1,350

129,455 

64,728

Estimated 

recession from 

preceding storm 

and base runoff 

(second-feet)

560 

555 

600 

670 

800 

900 

1,000 

1,100 

1,200 

1,300 

1,400 

1,400 

1,350 

1,350 

1,350 

1,300 

1,300 

1,300 

1,300 

1,300

22,035 

11,018

Direct runoff 

(second-feet)

0

30 

140 

7,550 

14,240 

39,350 

21,350 

8,080 

4,815 

3,260 

2,350 

1,760 

1,560 

1,090 

720 

500 

300 

175 

100 

50

107,420 

53,710 ( = 

1.96 inches)

a Estimated recession under subsequent rise.
134 FLOODS IN NEW YORK AND PENNSYLVANIA

RATES OF FLOOD DISCHARGE

The rates of flood discharge are generally the most important flood 

characteristic. The maximum rate of discharge determines the height to 

which a given river will rise and the velocities that will occur. The flood 

crest discharge is a function of many factors among which three are 

significant: (1) the volume of supply as it may be influenced by the 

quantity of rainfall or snow melt and by the absorptive qualities of the 

ground, (2) the time distribution of the supply, and ultimately (3) the 

storage capacities and other hydraulic characteristics of the ground and 

river-channel system. The first two mentioned are variables and are 

different for each storm. They have been described insofar as permitted 

by available data for each flood. The last factor on the other hand is 

relatively fixed, and its effect may be measured in most respects by the 

basin lag interval as described by Langbein. 16 This section of the report 

is directed toward a discussion of the influence of the volume of supply 

and its time distribution on the discharges during the major winter and 

nonwinter floods studied.

 The ratio between the total volume of rainfall and snow melt and the 

maximum rate of rainfall, plus total snow melt, tends to be an inverse 

measure of the concentration of the supply. Likewise the ratio between 

the total volume of direct runoff and the peak rate of discharge tends to 

be an inverse measure of the concentration of the runoff. If the total 

volumes were expressed in inches and the maximum rates in inches per 

hour, these two ratios would have the dimensions of hours, and when 

compared, might serve as a measure of the degree of smoothing produced by the various basin and channel factors in the transition from 

precipitation supply to stream flow.

For convenience the two ratios are termed, respectively, equivalent 

duration of supply and equivalent duration of direct runoff, inasmuch 

as instead of the actual time distributions of supply or direct runoff, 

they define the widths of single rectangular bar graphs of heights equal 

to the maximum rates of supply and of direct runoff and of areas corresponding to the respective volumes in inches. Algebraically these ratios 

can be expressed as follows:

Volume - of supply £lf-^- = equivalent . , duration , of supply , (1) /1N

Volume of direct runoff . , , , ,. ,,. /0 .

 = equivalent duration of direct runoff (Z)

where p is the maximum rate of mean areal rainfall (plus snow melt) 

in inches per hour, and q is the maximum rate of discharge from direct 

runoff in inches per hour. As not all of the supply produces direct 

runoff, ratio 1 preferably should be evaluated in terms of the net supply. 

To accomplish this, separate coefficients of runoff are applied to the

la Langbein, W. B., Channel storage and unit hydrograph characteristics: Am. Geophys. Union 

Trans., 1940, pp. 620-628.
RATES OF FLOOD DISCHARGE 135

numerator and denominator of this ratio, or in other words the volume 

of supply is placed equal to the total volume of direct runoff, and an 

estimate is made of the amount that the peak rate of supply was reduced 

by infiltration or absorption by the ground. Generally the peak rate of 

supply is reduced by a smaller percentage than is the total volume.

Instantaneous crest-discharge data are available for many drainage 

basins, but this is not true with respect to short-period rainfall data. 

Therefore in order to place the rainfall and runoff data on a comparable 

basis, p in equation 1, and q in equation 2, were evaluated as the mean 

rates, in inches per hour, over a selected period that was less than half 

the lag interval for the particular basin depending on the limitations of 

the available rainfall data.

Table 95 lists the values of the factors in equations 1 and 2 and the 

computed values of the equivalent duration of net supply and direct 

runoff. In this table the maximum rate of effective supply, column 6, 

is the mean areal rate of rainfall (plus snow melt) reduced by an amount 

sufficient to account for the infiltration. The maximum rate of direct 

runoff in column 9 is equal to the maximum average rate over a period 

equal to that listed in column 7.

3.0

0.4

0.5 0.6 0.7 0.80.9 1.0 2.0

Volume of direct runoff

4-.0 5.0

q x Lag

FIGURE 38. Concentration of direct runoff in relation to concentration of net supply.
136 FLOODS IN NEW YORK AND PENNSYLVANIA

Figure 38 shows the result of plotting the computed equivalent duration of net supply against the computed equivalent duration of direct 

runoff in terms of runoff when both are expressed in ratio to the lag.

TM, c. u 4.u * 4.1. j * r -/volume of direct runoff\ The figure shows that the duration of runoff I : I

\ q X lag /

increases with the duration of the supply and that for the long storms 

the graph tends to approach the line of equal concentration of supply 

and runoff.

The positions of the plotted points shown are dependent among other 

things on the quality of the rainfall data. If more short-period rainfall 

data were available, it might be expected that greater variations in intensity would be disclosed with the result that points would tend to plot 

below those shown on figure 38.

The average rate of flood discharge, as reported in table 95 for the 

seven greatest nonwinter floods (omitting Susquehanna River at Marietta, Pa.), is 0.051 inch per hour, and the average rate of flood discharge 

for the greatest winter floods at the same seven stations is 0.056 inch 

per hour or 1.10 times as great. There are three factors given in table 95 

that are of influence in these rates, namely (1) lag interval, (2) volume 

of direct runoff, and (3) equivalent duration of net supply.

The lag intervals are respectively 54 and 50 hours, nearly equal, indicating that the channel and related hydraulic basin factors were sensibly 

constant in their effects during the nonwinter and winter floods studied. 

The volumes of direct runoff, however, averaged, respectively, 2.44 

inches for the nonwinter floods and 4.24 inches for the winter floods, the 

latter being 1.74 times as great. Other conditions being the same, flood 

discharge rates are directly proportional to the volume of runoff. But 

according to the data in table 95, the equivalent duration of net supply 

for the group of nonwinter floods averaged 41 hours and that for the 

winter floods 64 hours, indicating that the volumes of net supply during 

the winter season are spread over a longer interval and so are less concentrated with respect to time. The decreased concentration during winter 

tends to compensate for the larger volume of direct runoff during that 

season.

The decrease in concentration of supply cannot be directly converted 

into differences in discharges. However, table 95 also lists the equivalent 

durations of direct runoff for each flood, which are inverse measures of 

the concentration of the direct runoff and as such are inversely proportional to the flood discharges, other factors such as volume and lag 

interval being the same. Thus the average equivalent duration of direct 

runoff during the nonwinter season is 55 hours and that during the 

winter season 82 hours for the same seven basins. Other factors being

constant, flood discharges in the winter would be = 0.67 times non82
TABLE 95. Concentration of rainfall and runoff during majo

Drainage basin

Nonwinter floods:

East Branch of Delaware River at Fishs Eddy, N. Y. .

West Branch of Susquehanna River at Williamsport, Pa.

Average b -~ - . - ...... ..

Winter floods:

East Branch of Delaware River at Fishs Eddy, N. Y. . 

East Branch of Delaware River at Fishs Eddy, N. Y. .

West Branch of Susquehanna River at Williamsport, Pa. 

West Branch of Susquehanna River at Williamsport, Pa. 

Qenesee River at St. Helena, N. Y. .. ___ ........

Storm period

July 8-12, 1921 

Aug. 21-25, 1933 

July 7-10, 1935 

July 7-10, 1935 

May 17-23, 1894 

Aug. 21-25, 1933 

Apr. 27 to 

May 4, 1909 

May 14-20, 1916

Mar. 8-14, 1936 

Mar. 15-22, 1936 

Mar. 9-15, 1936 

Mar. 15-21, 1936 

Mar. 9-14, 1936 

Mar. 15-21, 1936 

Mar. 9-15, 1936 

Mar. 16-21, 1936 

Mar. 9-14, 1936 

Mar. 16-21, 1936 

Mar. 9-15, 1936 

Mar. 16-21, 1936 

Mar. 10-14, 1920

Drainage 

area 

(sq. mi.)

491 

783 

2,530 

9,960 

24,100 

25,990

5,682 

1,017

491 

491 

783 

783 

2,530 

2,530 

9,960 

9,960 

24,100 

24,100 

5,682 

5.682 

1,017

Lag 

interval 

(hours)

38 

37 

45

77 

99 

81

56 

29

54

52 

45 

34 

36 

33 

30 

67 

70 

86 

83 

49 

50 

32

50

Volu

of 

dire

runo

(inch

 Rate of net supply based on all available data is less than rate of discharge; not used in preparation of f

b Omitting Susquehanna River at Marietta.

« Using floods associated with maximum crests only.
138 FLOODS IN NEW YORK AND PENNSYLVANIA

winter discharges. The net result of increased volume and decreased 

concentration on flood discharges during the winter floods with respect 

to the nonwinter floods is therefore 1.74 X 0.67 1.16. The net effect 

on the average in the basins studied, therefore, appears to be nearly but 

not entirely compensating.

It is of interest to note that in two of the smaller basins studied the 

nonwinter flood-crest discharges exceeded those in winter even though 

the volumes of direct runoff for all basins were greater during the maximum winter floods than during the maximum nonwinter floods of record. 

As a generalization it might be ventured that basins of the size studied, 

being less influenced by short-period concentrations of rainfall, usually 

attain their greatest flood heights in the winter season, when snow and 

unfavorable ground and vegetal conditions result in large volumes of 

runoff. In basins smaller than those studied, there is the possibility that 

the increased concentration of precipitation into short periods of time 

may produce discharge rates exceeding those produced by the larger but 

less concentrated net supply in winter.
INDEX

Page 

Acknowledgments for aid ................ 4

denning River at Chemung, N. Y. 39-48, 94-97

Discharge, computation of ...... 6-9, 134-138

See also discussion under 

particular areas.

East Branch Delaware River at Fishs

Eddy, N. Y. .... 23, 27-39, 101-107, pi. 1

Fishs Eddy, N. Y., East Branch Delaware

River at ....... 23, 27-39, 101-107, pi. 1

Floods, April-May 1909 ............ 118-125

August 1933 ............. 100-112, pi. 1

data on, methods of analysis of .... 4-13

utility of ...................... 1-2

July 1921 ....................... 87-89

July 1935 ....................... 91-99

March 1920 ..................... 70-80

March 1936 ..................... 13-70

May 1894- ............... 112-118, pi. 2

May 1916 ..................... 125-133

nonwinter ...................... 85-133

relation of meteorologic conditions to 13-14 

winter ........................... 13-85

Genesee River at St. Helena,

N. Y. .................. 70-80, 125-133

Ground water, recharge of, computation of 7-9

Harrisburg, Pa., Susquehanna

River at .......... 55-62, 112-118, pi. 2

Hope, N. Y., Sacandaga River

near .......... 7-9, 14-23, 24-26, 87-90

Infiltration index, computation of...... 11-13

Lag interval, computation of ........... 9-11

definition of ........................ 9

Marietta, Pa., Susquehanna River

at ...................... 107-112, pi. 1

Meteorologic conditions, general,

relation of floods to .............. 13-14

See also discussion under 

Particular storms.

Page 

Precipitation, computation of ............ 4-5

summary of data on,

for nonwinter floods ......... 85-87

for winter floods ................ 14

See also discussion under particular 

areas and storms.

Rainfall. See Precipitation.

Recharge, computation of ............... 7-9

Runoff, computation of .......... 6-9, 81-85

summary of data on,

for nonwinter floods .......... 85-87

for winter floods ................ 14

See also discussion under 

particular areas.

Sacandaga River near

Hope, N. Y. .... 7-9, 14-23, 24-26, 87-90

St. Helena, N. Y., Genesee

River at ................ 70-80, 125-133

Scope of the report .................... 2-4

Snow cover, relation of, to runoff.. 5-6, 81-85 

Storms, April-May 1909............ 118-125

August 1933 ............. 100-101, pi. 1

July 1921 ....................... 87-88

July 1935 ....................... 91-94

March 1920 ..................... 70-78

March 1936 ..................... 13-70

May 1894 ................ 112-118, pi. 2

May 1916 ..................... 125-129

Susquehanna River,

at Harrisburg, Pa... 55-62, 112-118, pi. 2 

at Marietta, Pa. .......... 107-112, pi. 1

at Wilkes-Barre, Pa. ...... 48-55, 97-99

Temperature, relation of, to floods..... 13, 14 

Thiessen method, computation of

precipitation by .................... 4-5

Wanakena, N. Y., hydrologic data

observed at ..................... 20, 22

West Branch Susquehanna River

at Williamsport, Pa....... 63-70, 118-125

Wilkes-Barre, Pa., Susquehanna

River at .................. 48-55, 97-99

Williamsport, Pa., West Branch

Susquehanna River at .... 63-70, 118-125

U. S. GOVERNMENT PRINTING OFFICE: 1946-689521

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