FOREST COVER IN PROTECTING RESERVOIRS 
31 
Table 1. — Flow and turbidity of typical streams of different sections of the 
United States 
Area 
basin 
Sus- 
pended 
matter 
Aver- 
age 
annual 
precip- 
itation 
on 
basin 2 
Maximum 
rainfall for 
region 2 
Flow: Second- 
feet per square 
mile of drain- 
age areas 
Relation 
minimum 
to maxi- 
Per 
day 
Per 
month 
Maxi- 
mum 
Mini- 
mum 
mum flow 
Northeast and Lakes regions: Con- 
Square 
miles 
3,100 
24,100 
7,294 
34, 200 
24,600 
58, 600 
257 
237, 000 
26, 200 
71, 000 
Parts 
per 
million l 
""a" 
142 
351 
~~2~ 032" 
81 
5 40 
720 
5,000 
Inches 
42 
45 
62 
32.5 
24 
25 
i 78 
45 
26 
16 
Inches 
8.31 
8.37 
22.22 
23.98 
"16.33" 
9.68 
7.66 
Inches 
17.55 
15.82 
35.49 
25.87 
6.90 
18.67 
71.54 
20.14 
18.5 
29.0 
42.5 
7.0 
2.2 
3.1 
62.0 
5.0 
4.6 
8 2. 8 
30.09 
.09 
.19 
.0003 
.09 
.0011 
.43 
M8 
.02 
8.00 
1 to 205 
Middle Atlantic: Susquehanna 
Southeast : Savannah 
Texas Plateau: Colorado (of Texas) - 
Rocky Mountain, east slope: Mis- 
souri above Fort Benton . _ _ __ 
1 to 322 
1 to 233 
1 to 18,000 
1 to 24 
Plains: Kansas at Lecompton 
California: Sacramento 
1 to 2,820 
1 to 145 
1 to 28 
Interior Basin: Colorado: 
Colorado (Grand) 6 . 
1 to 230 
Gila at Yuma 
Connecticut, above Orford, N. H. (1904-1923): Maximum, March, 1913; minimum, September 28, 1908. 
Susquehanna, above Harrisburg, Pa. (1889-1920): Maximum, June 2, 1889; minimum, September 28-29, 
1900. 
Savannah, above Augusta, Ga. (1884-1891): Maximum, 1888; minimum, October 16, 1904. 10 
Colorado, above Austin, Tex. (1898-1923): Maximum, April, 1900; minimum, August, 1918. 11 
Kansas, above Lecompton, Kans. (1899-1906): Maximum, May 31, 1903; minimum, March 6, 1902. 12 
Although the conditions of the Kansas at Lecompton are so unfavorable, on the headwaters of the Mis- 
souri River at Fort Benton, drainage area 24,600 square miles, the conditions are as follows: Maximum 
flow, 2.2 second-feet; minimum flow, 0.09 second-foot; relation, 1 to 24. 13 
Sacramento, above Castella, Calif. (1910-1920): Maximum, January 2, 1914; minimum, August 5 to 
September 21, 1920. 14 This is the fork of the Sacramento River which heads in the mountains. 
Columbia, above The Dalles, Oreg. (1879-1919): Maximum, 1894; minimum, January, 1890. 15 
1 U. S. Geological Survey. 
2 U. S. Weather Bureau. 
3 This low minimum evidently the result of artificial storage on preceding day. 
4 The rainfall given is that at Helen mine, the heaviest in the basin. The average rainfall for the basin 
is 23 inches. 
5 The material comes largely from the Idaho plains, which are treeless. 
6 For Grand, Green, and Gunnison above junction, since only scant figures are available for any one 
stream . 
' 1925. 
8 June 22, 1916. This was chiefly from the Salt River, but no records on that stream. 
9 Dry for one or more months each year. 
w Newell, F. H. results of stream measurements. U. S. Geol. Survey Ann. Rpt. (1892-93) 14 
(2) : 148. 1894. 
11 Grover, N. C, Gray, G. A., and Ellsworth, C. E. surface water supply of the united states, 
1918. part vm. western gulf of Mexico basins. U. S. Geol. Survey Water-Supply Paper 478: 29. 
1922. 
12 Kansas Water Commission, surface waters of Kansas, 1895-1919. 463 p., illus. Topeka. 
1921. 
13 Grover, N. C, Lamb, W. A., and Follansbee, R. surface water supply of the united states, 
1918. part vi. Missouri river basin. U. S. Geol. Survey Water-Supply Paper 476: 17. 1921. 
14 Grover, N. C, McGlashan, H. D., and Henshaw, F. F. surface water supply of the united 
states, 1919 and 1920. part xi. pacific slope basins in California. TJ. S. Geol. Survey Water-Supply 
Paper 511, 456 p., illus. 1923. 
15 Parker, G. L., and Lee, L. summary of hydrometric data in Washington, 1878-1919. TJ. S. 
Geol. Survey Water-Supply Paper 492, 363 p., illus. 1923. 
If the average quantities of suspended matter in the water and 
the wide ratios between maximum and minimum flow are used as 
a guide, the streams of the Plains region and those of Texas and 
the Southwest are more urgently in need of protection than those 
of any other group. The very conditions, however, wdiich determine 
the wide fluctuations between maximum and minimum flow — that 
is, the extremely irregular rainfall and the long periods of drought 
broken by short periods of most concentrated precipitation (prac- 
tically 24 inches having fallen in a single day in Texas, which is 
three-fourths of the precipitation for an average year) — make it 
