SOME CHARACTERISTICS OF RUN-OFF IN. THE ROCKY 

. MOUNTAIN REGION. 

By RoBERT FoLLANSBEE. 

BASIS OF REPORT. 

For the last nine years the United States Geological Survey has 

made a special study of the run-off of mountain streams, particularly 

in Colorado and Wyoming. The gradual installation of water-stage 

recorders on the larger streams has made available sufficient data to 

permit a study of the characteristics of these streams. During this 

period 40 or more stations, located in the mountains and above 

practically all diversions, have been maintained for periods ranging 

from two to eight years or more, and the records thus obtained, 

together with studies of the topography of the drainage basins, form 

the basis of this report. 

COMMON CHARACTERISTICS OF RUN-OFF.· 

All streams that rise in the Rocky Mountains have the same 

characteristics of flow. In the spring of the year they have a highwater period,· due to the melting of the mountain snows, and after 

the snow disappears the discharge decreases rapidly until it reaches 

a stage where the chief source of supply is the ground water. From 

that time on the decrease is more gradual, the flow diminishing with 

the decrease in the discharge of ground water. This decrease continues gradually throughout the fall and winter and usually reaches 

a minimum late in the winter, JUSt before the melting snow again 

causes the streams to rise. Figure 8 is a typical hydrograph of a 

mountain stream in this region-that for the Roaring Fork at 

Glenwood Springs, Colo., for the year ending September 30, 1918. 

The discharge gradually decreased during the fall and winter, and 

there was no marked variation in discharge until March, when the 

melting of the snow at the lower altitudes first caused an increase in 

discharge. With increasing temperature in April the discharge 

increased noticeably, and the variations in flow were due to corresponding variations· in temperature. The more abundant snow at 

the higher altitudes began to melt in May, and the melting increased 

until the peak was reached by the middle of June. After that time 

the decrease was very rapid for several weeks and then became 

more gradual. The rise in September was due to rainfall, which is 

generally not sufficient during the summer to affect the flow of 

the mountain streams. 

55 
OCT. NOV. DEC. JAN. F'EB. MAR . APR. MAY JUNE JU'LY AUG. SEPT. 

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IFJGURE 8.-Typical h ydrograph of a Rocky Mountain stream (Roaring Fork at Glenwood Springs, Colo., for the year ending September 30, 1918). 
RUN-OFF IN THE ROCKY MOUNTAIN REGION. 57 

RELATION BETWEEN TEMPERATURE AND DISCHARGE. 

General relation.-As already stated, high water is caused by the 

melting of the mountain snow, and the amount of rise varies directly 

with the temperature. In figure 8 the maximum temperatures 

given above the hydrograph show that a decrease in the maximum, 

which retards the melting of the snow, caused a con-esponding 

decrease in discharge. Similarly, an increase in the daily maximum 

temperature rapidly increased the discharge until the snow had so 

far melted that it was no longer able to supply water as rapidly, and 

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May, 31 19_14 J une, l914 

FIGURE 9.- High-water hydrograph for Arkansas River a t SaUlla, Colo., showing relation between tem-

• perature and daily discharge. -

in consequence the discharge then decreased. Beyond the time 

when the melting of snow with an increase in temperature causes an 

increase in discharge there is no relation between temperature and 

discharge, except during the winter. Figures 9 and 10 show strikingly the relation between temperature and discharge as brought 

out by hydrographs of two Colorado streams. As both hydrographs 

are for the same year (1914), they show the same variations in temperature and discharge. The sudden decrease in discharge between 

June 2 and June 10 was due to a drop in temperature. This drop 

occurred while a considerable amount of snow remained, and con-
58 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1921. 

sequently the subsequent increase in temperature caused an immediate increase in discharge. Had the drop in temperature occurred 

after the snow had melted, there would have been no subsequent 

increase in discharge. 

Relation between total snowfall and maximum run-off- As the discharge of the mountain streams is mainly dependent upon the 

mountain snow, the water equivalent of the snow that accumulates 

in the drainage basin determines the total run-off of the following 

year. If the snow falls early in the winter, it becomes compact and 

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F IGURE 10.-High-watcr hydrograph for Uncompahgre River below Ouray, Colo., showing relation 

betwee!' temperature and daily discharge. 

melts slowly in the spring, causing the high-water period to be prolonged, but the water does not reach so high a maximum stage. On 

the other hand, if the snow falls late in the season it is loose and melts 

more readily, producing a short high-water period with a high maximum discharge. The maximum discharge depends not only upon 

the amount of mountain snow but also upon the rapidity with which 

the temperature rises in the spring. Figures 11 and 12 show the 

high-water hydrographs for two Colorado mountain streams for 1917 

and 1918, together with the maximum daily temperatures for the 
RUN-O:FF IN THE ROCKY MOUNTAIN REGION. 59 

two years. In 1918 the temperature was high during the} later part 

of May and increased rapidly during the first half of June. This 

caused the streams to rise rapidly to a high maximum and then 

recede rapidly, as the snow was soon melted. In contrast to this, 

in 1917 the temperature was low during the later part of May and 

increased but slowly during June; moreover, there were sudden 

drops in temper~ture during that period. As a result the discharge 

MAY J UNE. JULY 

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l<'JGURE 11.-High-water hydrographs for Uncompahgre River below Ouray, Colo., showing relation 

between temperature and maximum discharge. 

increased more slowly and receded :!llore slowly, giving a longer highwater period but one that reached a lower maximum. 

Diurnal fluctuations.-At the high altitudes of the Rocky Mountains, which range from 8,000 to 14,000 feet, the temperature during 

the 24-hour period fluctuates 20° to 30° or more, and during the 

spring this fluctuation causes the snow to melt during the warmer 

• part of the day but-to remain frozen the remainder of the time. This 

in turn causes a diurnal variation in the amount of water entering 
60 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1921. 

the streams. Figures 13, 14, and 15 show the change in discharge 

during each 24-hour period for a week or more during high water 

for three typical streams. The discharge was determined from continuous gage-height graphs obtained by means of water-stage 

recorders. It will be seen that the hours of maximum and minimum 

discharge are not the same for each stream, as they depend upon the 

distance the melted snow has to travel before reaching the gage. For 

the Roaring Fork at Glenwood Springs (fig. 13) the maximum and 

minimum daily temperatures are given. It should be noted that the 

period covered by this graph includes the maximum discharge and 

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FIGURE 12.-High-watcr h ydrographs for Colorad9 River at Hot Sulphur Springs, Colo., showing relation 

between temperature and maximum discharge. 

tha t after June 14 the discharge decreased, although the temperatures 

continued high, a relation which shows that th~ snow had nearly 

disappeared. 

The diurnal fluctuations are directly dependent upon the daily 

range of temperature up to the period of maximum discharge and also 

upon the increase in both maximum and minimum temperatures. 

Figure 16 shows the continuous discharge of Roaring Fork at Glenwood Springs from May 18 to June 10, 1919, together with the curve 

of maximum and minimum temperatures. From May 18 to 29 the 

extremes of temperature and their relation to each other remained 
RUN-OFF IN THE ROCKY MOUNTAIN REGION. 

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61 

FIGURE 13.-Discharge graph of Roaring Fork at Glenwood Springs, Colo., showing diurnal fluctuations. 

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}' JGURE H.- Discharge graph or Uncompahgre River below Ouray, Colo., showing diurnal fluctuation&. 

31219°-22-5 
6~ CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1921. 

fairly constant, and as a result the diurnal fluctuations were somewhat 

uniform, although the mean discharge.gradually increased. On May 

30 the temperature suddenly dropped, and this resulted in an immediate decrease in the mean daily discharge and an almost complete 

elimination of diurnal fluctuations. Subsequently an increase in 

both mean and extreme temperatures caused a gradual increase in 

the mean daily discharge and a reappearance of the diurnal fluctuations, which increased in range as the temperature increased. 

The range of fluctuation in percentage of mean discharge decreases 

as the distance of the point of measurement from the source increases, 

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June, 1918 ' 

FIGURE 15.-Discharge graph of Tensleep Creek near Tcnsleep, Wyo., showing diurnal fluctuations. 

or, to express it in another way, as the drainage area abov:e the point 

of measurement increases. This is. due to the fact that water from 

melting snow in different portions of the drainage basin reaches the 

stream at different hours, thus tendmg to reduce the fluctuations. 

The larger the drainage basin the greater a:re the number of tributaries 

that bring their maximum discharges to the main streams at different 

hours and the greater the consequent equalizing effect. The accompanying table (p. 64) shows the percentage of variations in daily discharge of streams draining different-sized areas for simultaneous 

periods in 1918 and 1919. 
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May, 19.19 June,l919 

FIGURE 16.-Discharge graph of Roaring Fork at Glenwood Springs, .COLo., showiqg !lltioA be~w~!J. temperature and mean and hourl y discharge. 
Station. 

Percentage of variation in daily discharge for strea7n8 draining different-sized areas. 

1918. 

1une9. 1une10. 1une 11. 1une 12. 1une 13. 1une 14. 1une15. 

u-~ruverbelowOurW,Colo.......... 76 1,4M 12& '12 1,630 143 '12 1,730 1as '12 .1,500 145 '12 t,MO 141 67 1,8l0 u1 73 1,00 uo 

Tens!eeJ:I'Ciooknear Tensleep,. yo.............. 228 ......••....•... 1,750 118 73 131, 600 850 124 67 1,600 131 69 1,600 116 78 1,550 134 63 1,4M 117 Boarini:f~k.atGienwood Spnngs, Colo ......... 1;450 9,~ 109 92 11,400 111 94 , 114 87 14,200 lU 92 14,000 114 88 15,200 116 88 14,200 l,l3 

Coloradq.RiveratGienwoodSprlngs,Colo ........ 4,~ 19,500 103 95 21,700 104 90 24,300 106 92 27,300 103 96 28,600 102 95 29,400 102 96 29,400 102 

Ul19. 

~ Jlay25. llay26. :May27. :May28. :May29. 

"' 

73 

70 

87 

99 

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a! i ! 0 .... 

=~ )!~ =~ .. <=~ ~ .. g . ~ Q ~ ::;t8 ~ ::;t8 ~~ " ,~ ::.!<> ::.!<> ~ ::.!<> 

Unoom~e River at Ouray, Colo. 0 •••••• 44 335 tal 81 399 137 80 488 127 81 509 122 79 537 120 80 Unoom~ River below Ouray, Coli) .... 76 503 lJ6 82 590 147 78 771 124 84 725 121 81 811 121 84 CasUe near A~n, Colo .............. 72 320 112 83 34() 110 87 340 120 85 358 103 85 348 115 86 ~Creek at homasville, Colo ..... 175 1,260 110 84 1,350 103 85 1,390 118 85 1,390 114 88 1,410 119 85 R~ Fork at Glenwood S~rings, Colo. 0. 1,4M 5,700 no· 90 6,340 112 90 6,440 110 90 6,640 110 91 6,840 111 89 Colora o River. at Glenwood prings, Colo .. 4,520 ll,:JJO 102 98 11,400 103 96 11,8)0 103 97 11,600 102 99 12,000 102 97 
R't.TN-OFF IN THE ROCKY MOUNTAIN REGION. 65 

The drainage areas above the measuring points on the streams 

shown for the seven days inJ918 range from 76 to 4,520 square miles. 

The average maximum discharge ranged from 139 per cent of the mean 

for the smallest area to 103 per cent for the largest, and the average 

minimum discharge from 72 to 95 per cent. The drainage areas considered in the comparison for the five days in 1919 range from 44 to 

4,520 square miles. The average maximum discharge ranged from 

127 to 102 per cent of the mean for the smallest and largest areas, 

respectively, and the average minimum discharge ranged from 80 to 

97 per cent. The range of percentages was smaller in 1919 on account 

of the smaller total discharge and the colder spring. The tabulation 

also shows the possible errors that may be made by basing computations of daily discharge upon one gage reading. The mean of two 

daily readings taken nearly 12 hours apart will be very much nearer 

the true mean for the day, as will be seen by inspecting figures 13 to 16. 

UNIT RUN·OFF. 

Stations in the same basi'n.-.As snowfall, which is the chief source 

of run-off in the mountain streams, increases with altitude, it is 

evident that in general the upper portions of a drainage basin have 

a greater run-off per unit of area drained than the lower portions. • 

It is not possible to show directly the varying run-off from different 

altitudes, but a comparison of the records for different stations on 

the same stream shows that the smallest unit run-off occurs at the 

lowest altitude. The table on page 66 shows three comparisons between stations in the same basin for practically the same years, 

together with an analysis of each drainage area, showing percentages 

above different altitudes. The figures represent the natural run-off, 

as allowances have been made for the few diversions that affect the 

run-off. 

Laramie River at Glendevey, Colo., with 13 per cent of its 'drainage 

area above an· altitude of 11,000 feet, has a mean annual run-off of 

880 acre-feet to the square mile. At the station near Woods, Wyo., 

only 3 per cent of the drainage area is above 11,000 feet, and the 

remaining 97 per cent, of which 38 per cent is below 9,000 feet, contributes so small a run-off. that the unit run-off for the entire drainage 

area is reduced to 474 acre-feet. Similarly Deep Creek, a tributary 

of Rock Creek, with its entire drainage area between 10,000 and 11,000 

feet, has a run-off of 1,340 acre-feet to the square mile, but Rock 

Creek itself, which has only 43 per cent of its drainage area above 

10,000 feet, has a run-off of only 804 acre-feet to the square mile. 

South Boulder Creek near Rollinsville, with 94 per cent of its drainage area above 9,000 feet and 13 per cent above 11,000 feet, has a 

mean annual run-off of 1,180 acre-feet to the·square mile. At Eldo-
SiS CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 192L 

rado Springs,· where only 56 per cent 'of the drainage area is above 

9,000 feet and 9 per cent above 11,000 feet, the lower areas contribute 

so small a run-off that the unit run-off for the entire drainage area is 

reduced to 496 acre-feet. 

Comparison ofunit run-off for station~ in the same drainage basim. 

Drainage area. Average annual run-off (acre- feet). 

Station. Years covered 

Per Per Per Per by records. 

Total. cent cent cent cent Per 

(square above above above above Total. square miles). 9,000 10,000 11,000 12,000 mile. 

feet. feet. feet. feet. 

--------------

Lm-amie River ba8in. 

Laramie River at Glendevey, 102 74 24 13 1 89,700 880 1911-1918. 

Colo. 

Laramie River near Jelm, 293 48 10 4 .3 173,000 590 1905, 1911-

Wyo. 1918. 

Laralnie River near Woods, 409 35 7 3 .2 194,000 474 1912-1918. 

Wyo. 

Rock Creel: ba8in. 

D~ Creek near Arlington, 3. 7 '100 100 0 0 4,970 1,340 1915,1917. 

yo. Rock Creek near Arlington, 70 85 43 0 0 56,200 804 1915, 1917. 

Wyo. 

80tlt1J Belllder Creek btuln. 

South Boulder Creek near 39 1M 62 13 2 *II, 400 1,180 1911-1917. 

Rollinsville, Colo. . South Boulder Creek at El- W.i 56 28 9 1 57,'200 496 1911-1917. 

dorado Springs, Colo. 

Stations in dtfferent basins.-The unit run-off of mountain streams 

varies not only with the altitude, as shown in the preceding paragraphs, but also with the presence or absence of higher mountain 

masses near by yet outside the drainage basin itself. 

The following table, compiled from records of mountain streams 

at stations above diversions, or where known diversions have been 

accounted for, shows an analysis of altitudes for eaeh drainage area, 

the total run-off, and the mean annual run-off per square mile for 

each stream. The analysis of altitudes is based on measurements 

made on topographic maps. . 

In this table the stations are arranged geographically, beginning at 

the northwest corner of Wyoming and following south along the west 

side of the main mountain masses, then taking the stations in the 

interior mountain ranges, and finally those on the eastern slope of 

the front range, facing the great plains. This arrangement brings 

out the fact that in general the streams which drain the western 

ranges have a much higher unit run-off than those which drain the 

interior and .eastern ranges. 
Unit run-off of mountain streama. 

Drainage area. Mean Bllnual run- off (sere-feet). 

Station. Percent Percent Per cent Percent Percent Y' ears covered 

Total above above above above above Per by records. 

~uare ~~ 10,000 11,000 12,000 13,000 Total .. square es). feet. feet. feet. feet. rilile. 

---

=~~El!r!iir!:.ii:::-:::::::::::::::::::::::::::::::::::::::::: 820 4 1 0 0 0 1,260,000 1,540 1904--1918 128 56 42 12 3 0.5 160,000 1,2!i0 1916--191.8 

26 78 15 0 0 0 28,000 1,080 1917-1918 ,gncompabgre River at Ouray. Colo .............................•......... 44 9! 88 66 28 2 59,700 1 360 1911-1918 ncompahgre River below Otiray, Colo .................................... 76 95 88 66 32 4 127,000 1:670 1913-1918 Canyon Creek at Oilray1 Colo .....•................•..........•............ 26 95 !!6 69 35 7 46 200 }·;: 1911-1915 Rio Grande at Thirtyriille Bridge, Colo ............•.. : .................... 163 100 95 77 39 2 118:000 1914--1918 Lake Fork near Lake Citb(, Colo ..•...•.. __ ........ _ ..........•......... _ ... 102 99 92 70 41 6 74,000 '-725 1918 Crystal River at Marble, lo ......••......................... :·; ........... 77 95 78 52 26 3 180,000 2,340 1911-1915,1917 

=~::r1*~~~~~~:::::::::::::::::::::::::::::::::::::::::::: 42 95 79 43 21 2 64,200 1,530 1911--,1916 62 98 82 57 18 1.5 7fl, 700 ~~~~ 1913-1918 109 95 80 46 18 3 HO,OOO 1912-1918 l''rvi.ngpan Creek at Thomasville1 Colo ..................................... 175 93 70 39 11 2 190,000 t;090 1914--1917 Dmwoody Creek n~ Lenor~ Wyo ........................................ 114 .................. 51 31 13 1. 5 128,000 1,120 11100,-1918 · D~ Creek near Arlington, yo ....•....................................• 3. 7 100 0 0 0 4,970 1,340 1915,1917 

R CreeknearArlington, ww················-·--·······-·····--······· 70 85 43 0 0 0 56,200 804 1915,1917 

Donglas Creek near ~tone, yo ........................................ 26 100 9 0 0 0 22,000 846 1916 Eagle River at Redc · , Colo ................•............ c •••••••••••••••• 74 76 3! 6 0 55,000 744 1911-1918 Hoinestake Creek at Redcliffi Colo ......................................... 64 98 63 47 12 1 77,500 1,:!z 1911-1912,1914--1918 Turkey Creek at Reddiff, Co o ........•................•................... rT 95 38 8 0 0 25,500 1914--1918. Tennessee Fork near Leadville, Colo ...•..........•........................ 45 100 64 23 9 0 28,100 623 1913-1918 East Fork of Arkansas River near Leadville, Colo ......................... 52 100 95 65 23 3 30,900 595 1913-19111 

~~~~;=~··~~~···········~·····~·············· 26 100 92 -58 .27 4.5 22,800 877 1911-1912, 1914 48 ·······w· 99 74 30 4 36 800 767 1914--1918 92 81 48 17 1 121 800 792 1911-1912,1914--1918 113 98 64 41 6 0 m;ooo 985 1911-1918 141 80 54 23 3.5 0 129_,000 914 1911-19).6 28 100 90 ....... ia· 21 0 37,700 1,400 1914--1918 Laramie R!ver at Glendev;, Colo .................................. ' ...... 102 74 24 1 0 ~700 880 1911-1918 

·.=:ru~:~=~s W'y.;,:::::::::::::::::::::::::::::::::::::::::: 293 48 10 4 0.3 0 1 ,000 590 1905, 1911-191"8 409 35 7 .... 3 0.2 0 194,000 474 1912-1918 Geneva Creek at Granti Colo ..................................... -......... 74 99 87 56 28 3 53,200 718 1912-1917 North Fork of Sonth Patte River at Grant, Colo ................•......... 51 92 69 34 8 0 23,800 470 1912-1917 Soltth Boiilder Creek at Rollinsville, Colo .................................. 39 ~ 62 13 2 0 45,400 1,180 1911-1917 Tensi~CreeknearTensleep, Wyo ....................................... 228 38 16 5 1 {) 134,000 587 1911-1912,19!5-1918 

-~==~~hf~~~wl;,::::::::::::::::::::::::::::::::::::::::::::: 256 35 6 1 0 0 115,000 450 1914--1gl8 120 46 19. 8 1 0 59,000 491 1918 Boelm!er Creek near Pikes eak, Colo .................................... --~ 7.2 ....... 99. 100 47 11 4,~ 667 1901H917 Lion Creek near Halfway, Colo ............................................ 2.0 70 54 22 1 398. "1Q--1917. 

Cabin Creek near Halfway, Colo ........................................... 2.4 99 40 22 17 1 1,010 420 1907,.-1917 South R~ton Creek near .Halfway, Colo .......................... , ......•• 4.0 99 6o 13 4- t)· 1,550 387" 1907-1917 - . -- .·~- .. .. _, ____ 

-
68 CONTRIBU'l'IONS TO HYDROLOGY OF UNITED STATES, 1921. 

The :most striking comparison shown in the table is that between 

the station on Snake River near Moran, Wyo., and those on the eastern slope of Pikes Peak, in Colorado. At the Moran station the 

drainage area is practically all below 10,000 feet and the annual runoff is 1,540 acre-feet to the square mile; on Boehmer Creek near 

Pikes Peak, Colo., whose drainage area lies between 11,000 and 14,000 

feet, the mean run-off is 667 acre-feet to the square mile, and the 

other streams in that vicinity, with the greater part of their drainage 

areas between 10,000 and 14,000 feet, have a run-off of approximately 

400 acre-feet to the square mile. The Snake River basin above the 

upper end of the Teton Range has no large mountain masses of high 

altitude to the west, but Pikes Peak, .although detached from the 

main mountain mass, has the entire Rocky Mountain system to the 

west but faces the plains on the east. ' 

The difference in run-off on different sides of a large mountain 

mass is shown by the comparison between the Uncompahgre, the 

Rio Grande, and Lake Fork, which drain one of the largest mountain 

masses in the Rockies. The Uncompahgre drains the northwestern 

slope, the Rio Grande the eastern slope, and Lake Fork the northeastern slope. The altitude of these drainage areas is ~ar, from ~ 

32 to 41 per cent lying above 12,000 feet and from 2 to 6 per cent 

above 13,000 feet, yet the run-off decreases from 1,670 acre-feet to 

the square mile on the northwestern slope to 1,090 acre-feet on the 

eastern slope and to 725 acre-feet on the northeastern slope. ~ 

figure for the northeastern slope, being based on records for only one 

year (1918), is somewhat uncertain, although in the Uncompahgre 

drainage basin the run-off for that year is 95 per cent of the mean for 

six years. The highest run-off given in the table is. 2,340 acre-feet 

for Crystal River at Marble, Colo., whose drainage area is not at an 

excessively high altitude, being surpassed by those of several other 

streams on which the run-off is co'nsiderably.lower. An explanation 

of this phenomenon is found in the fact that west of the mountain 

range whose eastern slope is drained by Crystal River there are no 

other mountain masses higher than the flat-topped mesas of western 

Colorado. 

The comparatively high run-off of Deep Creek near Arlington 

(1,340 acre-feet) is due to altitude and position, of which position is 

relatively more important. The drainage area lies on the flat top of the 

Medicine Bow Mountains. To the east is the main bulk of the range, 

one small area of which reaches an altitude of 11,000 feet, but to the 

.west the nearest rang.e approaching 10,000 feet in altitude is the 

Wasatch Range, in eastern Utah, and to the northwest the nearest 

range is the Wind River Mountains. 

A noticeable effect of altitude upon run-off is shown by the comparison between Eagle River and Homestake Creek. Eagle River, 

with 6 per cent of its drainage area above 12,'000 feet and 34 per cent 
RUN -OFF IN THE ROCKY MOUNTAIN REGION. 69 · 

above 11,000 feet, has a run-off of 744 acre-feet to the square mile; 

Homestake Creek, which drains an area joining that of the Eagle on 

the west and which has 12 per cent of its area above 12,000 feet 

and 47 per cent above 11,000 feet, shows a run-off of 1,210 acre-feet. 

South Boulder Creek at Rollinsville, Colo., presents an apparent 

exception to the generally low run-off of streams draining the eastern 

ranges. Its drainage area, 2 per cent of which is above 12)000 feet, 

lies on the east side of the Continental Divide, and its run-off is 1,180 

acre-feet. This may be explained by the fact that west of this 

part of the divide lies the comparatively open region of Middle Park, 

and west of that no mountain masses as hig as the divide itself. 

The foregoing comparisons show that in th Rocky Mountain region 

unit run-off varies not· only with altitude b t also with the location 

of the drainage basin in reference to mounta masses near by on 'the 

west, as the storms coming from the west apparently carry more 

moisture and preeipitate the greater part f their moisture on the 

:first ranges they strike, the amount preci itated becoming less as 

each succeeding range is reached. 

WINTER RUN-OF • 

Below timber line.-The winter run-off of ountain streams, being 

_wholly dependent upon groundwater, gradu ly decreases and reaches 

a minimum just before the melting of the ow i:n the spring. The 

higher the altitude drained the less is the likelihood of temporary 

rises of temperature being sufficient to affec the discharge. Sudden 

drops in temperature at the beginning of t e winter have a decided 

temporary effect on the run-off, but the eff ct of similar drops later 

in the winter is much less. Figure ·17 sh ws four hydrographs of 

streams ranging in drainage area from 8,080 to 48 square miles for 

the winter of 1918-19. The hydrograph for Colorado River at Glenwood Springs, Colo. (drainage area 4,520 square miles), shows that 

the .flow dropped suddenly during the later part of November as a 

result of the low temperature, then rose with the temperature, and 

again fell more gradually, registering a minimum on December 25 

as a result of the low temperature at that time. After rising again 

the run-off gradually decreased for the remainder of the winter until 

early in March, when the rising temperatures caused the snow at the 

lower altitudes to melt and increase the run-off. The daily fluctuations were due to the operation of the Shoshone power pla~t, 7 miles 

upstream from the station. The hydrograph for Big Horn River at 

Thermopolis, Wyo. (drainage area 8,080 square miles), has the same 

general characteristics and shows the decided effect of sudden drops 

and rises in temperature at the beginning of the winter but the very 

slight effect of similar changes later in the winter until March, when 

the temperature rose sufficiently to melt the snow at the lower altitudes. The hydrograph for Terisleep Creek near Tensleep, Wyo. 
40 

30 

20 

10 

.....__ 

0- Chalk Creek (upper station) near St. Elmo. Col<. '\._ ~ LA ) ....... r--1--- /' ~ '-' 

Qj 

Q) ..,_ 100 ..:, 

c 

8 

Q) 

cJl 50 c 

t""-" ~ I ---v v-- -v- v 

""' 

Tensleep Creek near Tensleep, Wyo. 

""' dJ 

~ ll) 

tji,OOO 

cJl 

i5 

500 

f""'-r\ Vv ..;-\ Big Horn River a Therm opol is, Wyo. / ,...../ 

v i'--r h fv I'-v 

""' !--' "-- ~ 

1,500 

1,000 

500 

r I 

r\ ~ ~ h r- Colorad o River atGlen wood Sp_:i ngs, Colo. 

1\r [,..-' I~ lr II ~ ~ ft'v r--- f) v N" 1'- .A 

~ IV M fJ h !_./ 

I"-" 

li 20 25 310 5 10 15 20 25 30 5 10 15 20 25 30 s 10 15 .zo 25 5 10 15 20 25 so 5 10 15 20 25 31 Nov. Dec.l918 Jan. l919 Feb. txl.sr. Apr. 

FIGVRE 17.-Winter hydrographs for streams. or dillerent-sized drainage areas. 
RUN-OFF IN THE ROCKY MOUNT.AI:N REGION. 71 

(drainage area 228 square miles), shows that the only effect of temperature on this stream was at the beginning of the winter, as for the 

greater part of the season the flow was almost constant, with a slow 

decrease. The upper station on Chalk Creek near St. Elmo, Colo. 

(drainage area 48 square miles), is at so high an altitude that changes 

in temperature during the winter had little effect on the run-off, being · 

insufficient to cause the snow to melt. 

AbO'IJe timber line.-In this region the altitude of timber line (the 

upper limit at ·which timber grows) increases from 10,000 feet in 

northern Wyoming to 12,000 feet in central Colorado. Above this 

line the ground is covered with short grass and the soil is generally 

thin and at the higher altitudes gives way entirely to the bare rocks 

of the mountain peaks. Although the snowfall is very heavy in 

these areas, the scantiness of the soil does not afford any considerable 

reservoir for storing ground water. Observations made by the United 

States Forest Service show that at the Wagonwheel Gap experiment 

station, where the timber line is at 12,000 feet, the mean soil temperature at depths of 1 foot and 4 feet is 33° F. At a depth of 1 foot the 

soil is frozen on an ttverage seven and one-half months of the year, 

and at a depth of 4 feet it is frozen five months of the year~ Similar 

observations on Pikes Peak, where the timber line is likewise at 

12,000 feet, show that the soil there at a depth of 1 foot remains 

frozen six months each year. As the temperature decreases with an 

increase in altitude, it is evident that above the lowest altitude 

reached by timber line the soil remains frozen for a longer period 

and the frost reaches a greater depth. The ground water is the only 

source of supply for streams in these areas during the winter, and the 

. small amount of water in the soil remains mostly in the form of ice, 

little if any of it reaching the streams. 

Records of winter run-off for stations at or above timber line in 

this region are very meager, but such as are available show the run-off 

to be practically zero. During the winter of 1914-15 Mr. S.C. Hulse, 

consulting engineer, maintained three gaging stations, of which one 

had its entire drainage area above timber line and the other two half 

their areas above timber line. These stations were visited weekly 

from November to March by a hydrographer, who found 1 that at 

the upper station on Spruce Creek near Breckenridge, with an area of 

1. 7 square miles wholly above timber line, the flow ceased entirely 

at the end of November and did not begin again until spring. The 

lower Spruce Creek station, with a drainage area of 3.4 square miles, 

had a winter flow decreasing from 0.25 second-foot in December to 

0.15 second-foot in March, or from 0.07 .to 0.03 foot to the square 

mile. Similarly Crystal Creek near Breckenridge, with a drainage 

area of 2 square miles, had a winter flow decreasing from 0.10 to 

0.05 second-foot to the square mile. 

I U.S. Geol. Survey Water-Supply Paper 409, pp. 77-79, 1918. 

. \ 

INDEX. 

Page. 

Aclalowledgments for ald.................... 2,33 

Arkanllas River at Salida, Colo., relation of 

tempei'ature to dJSch8rge of...... 57-.58 

:Arnett, Okla., well of county COill'thoo8e at.. 43 

wells northwest of .......... • ............ 46-47 

Beaver, Okla., preoipltsti~mat.. ............ 40 

Chambers, Alfred A., analysfa by............ 50 

Coeur d'Alene Lake, Idaho, contiO'fersy OOilo 

cemlng ............................... 1-2 

description of............................ 3-:4 

drainage district on, proposed. • • . . • .. .. • 8 

inflow and outflow of .................... 12-13 

influence of storage on level of ........... 16-l!f 

lowering the outlet of, feasibility of... • • • 25 

interference with navigation by...... 25 

purposes to be served by ............ 21-23 

overflow lands near, value of............. 7-s 

transportation on.............. . .. .. .. .. 7 

use of, for storage water.................. 1 

.parties In interest in ................. •21 

value of, for development of water power, 8-9 

water level of............................ 6-7 

Coeur d'Alene Lake -region, Idaho, dlklng of 

lands in, commercial aspect of . • • 28 

diking lands in, effects of. .. .. .. .. .. .. .. • 26-27 

public Interest In .................... 29-30 

field work ln............................. 2 

lead deposited on lands ln............... 8 

reconciling of Interests ln...... . .. .. .. . .. • 30-31 

settlement of............................ 9-10 

water-logging of lands ln .............. 1&-20, 28 

dlklng and draining necessary to relieve ............................. 26,28 

Coear d'Alene River, Idaho, deposition of soU 

by............................... 3 

Colorado River, high-water fluctuations of ... 60, M 

Davenport, R. W., Coear d'Alene Lake, 

Idaho, and the overflow lands... 1-31 

Fargo, Okla., well at........................ 42 

Follansbee, Robert, Some characteristics of 

run-oft In the Rocky Mountain 

region ........................... 56-71 

Foster, Margaret D., analysfa by............. 50 

Gage, Okla., flowing well near ......... 44-46,50,51 

flowing well near, plates showing........ 44 

public water supply of ................ 42,50,51 

wel13 mlles south of, quality of water ln. 50,51 

Gage, Okla., and vicinity, artesian conditions 

in the "Red Beds" ln........... 48 

cllmate of ................................ 40-41 

feasibility of irrigation ln .......... 33-M, 51-53 

geography of ............................. 34-37 

Page. 

Gage, Okla., ad vlciDlty, geology of. ....... 37-39 

ground-water Investigation ln............ 33 

quality of waters in ................... 38, li0-51 

"Red Beds" In, features of .............. 37-39 

springs ln. ............................. ~. 44 

T~ and Quaternary deposits ln..... 39 

water from alluvium ln .................. 41-42 

water from Permian "Red.Beda" ln ..... ~ 

water from Tertiary deposits ln .......... 42-44 

Gate, Okla., Well near....................... 47 

Guarantee Development Co., well of, near 

Gage, Okla ................ «-46,50,51 

Herrfck, Fred, acknowledgment to.......... 2 

Holmes, C. H., acknowledgment to.......... 33 

Home Producers OU & Gas Co., acknoWI· 

edgmentto...................... 33 

well drilled by ........................... 47,48 

Idaho, northern, cllmate of.................. 6-6 

Jessup, L. T., acknowledgment to........... 2 

Kidwell, c. H., a.ualysfa by.................. 50 

Land, vaiues of, for agriculture and for water· 

power storage compared... . • • • • • 28-30 

Lipecomb, Okla., well near.................. 47 

May, Okla., well southwest of............... 47 

Minton, C,J.,acknowledgmentto........... 33 

Mullan, Capt. :John, cited ................... H, 21 

Mutual, Okla., precipltationat.............. 40 

Noble, T. A., estimate of, on enlarging the 

channel of Spokane River........ 22 

Nye, Capt. John A., acknowledgment to..... 2 

Parker, M. B., acknowledgment to........... "2 

Post Falls,Idaho, building of dams at. • .. .. • • 10, 13 

elevations of dams v-t, diagram showing.. 10 

operationofdamsat.. ................... 13-14 

Power, hydroelectric, development of, on 

Spokane River.. .• .. .. .. • .. .. .. . 8-9 

Roaring Fork, Colo., diurnal discharge, fluctuations ol ................ 60, 61, 63, M 

Run-oft, diurnal fluctuations of. ............. ~ 

maximum, relation between rate of melting of snow and .................. 58-511 

relations of temperature and discharge 

shownln ........................ 57-65 

unit, C!llculation of ....................... 66-68 

Run-oft of Rocky Mountain streams, com· 

mon characteristics of .... , . . • • • • • 55 

Bt. :Joe River, Idaho, deposition of soU by... 3 

description ofvelley ol.................. H 

drainage district on, proposed...... • • • .. . 8 

73 
74 INDEX. 

Page. 

St. Maries, Idaho, temperature and precipitation recorded at...... • • • • • • • • • • • • 6-6 

Schultz, C. D., weUs1on farm of. •••••••.••••• 441-47 

Sowers, R. M., acknowledgment to.......... 33 

Spokane River, Idaho and Wash., desorl.ption of ••.••••.•••.•...•••••••• ,.. II! 

discharge of, at Spokane, Wash.......... - 1 

elevation of dams on, diagram shoWing 10 

flow records of........................... 6 

measurements and materials of bed of... 23 

minor Improvements feasible ln......... . 211-26 

profile and cross sections of. . • • • • • • • • • • • • 24 

proposed improvement of, benefits to be 

expected from ..••••••••••• , • •• • • 24 

damages possible from.. • • • • • . . • • • • • • 25 

excavation neoessary for. • • • . . . • • • • • • 23-24 

Spokane River.basln, Idaho and Wash., map 

of................................ 4 

Tensleep Creek, Wyo., diurnal discbarge, 

fiuotuatioDS of. • •. • • . • • •• • • • • • • • • • 62, M 

0 

•, 

Page. 

Thompson, David G.,Ground water forlrrl· 

gation near Gage, Okla .•.....•.. 33-63 

UncomPahgre River, Colo., blgh-water and 

discharge ftuctuatlons of .•. 58,59,61,8& 

Washington Water Power Co., acknowledgment to.......................... 2 

acquirement of water rights by .... 10-12,27-28 

enlargement of the channel of Spokane • 

River proposed by............... 22 

use of Coeur d'Alene Lake by............ 1 

Waters, clallsiftcatlon of.... • . . . . . . • . . . . . . . . • . 48-50 

Winter run-otf of mountain streams, ftuctuation of. .•. ~ .••• , •. ,. • . . . . . . . • . • • • • 69-71 

Wolf Creek, Okla., irrigation weDs ln VBlleY 

of •••••••. : .........•..••..•.•.•.. 34,42 

quality of water of... • . • . • • • • . . . . . . • • . . . . 50, 51 

Woodward, Okla., precipitation at.......... 40 

temperatu.rea.t •..••.•.•.••. ;............. 41 

well southwest of.·... • ..• . • . . • . . . . . . . • . . • . . · 47 

Zahn, L., well of, near Gage, Okla........... 43