consisting entirely of slopes with 

 steep gradients has a rapid and high 

 percentage of runoff with the re- 

 sultant soil erosion. During this 

 period, the solvent power of the 

 water has little time to put into 

 solution any of the soluble minerals, 

 A flat terrain absorbs a large pro- 

 portion of the rainfall, giving the 

 water time to dissolve soluble 

 mineral matter. The amount and rate 

 of surface runoff is also lessened. 



Stream Flow Characteristics 



The Wenatchee River is an unre- 

 gulated, rapid, snow-fed stream, 

 with an average discharge of 2,900 

 cubic feet per second, having the 

 maximum runoff usually during the 

 month of May or June , and the minimum 

 during the month of September (fig, 

 3), The river has a fall of 1,230 

 feet from Lake Wenatchee to its con- 

 fluence with the Columbia River. 



The Chiwawa River is also a 

 snow-fed stream, with the maximum 

 'and minimum flows occurring during 

 the same months as the Wenatchee 

 River, with an average discharge of 

 443 c.f.s. (fig. 4). 



J»igure 2. — ^Wenatchee River Basin (nap) 



A major percentage of the 

 stream flow in the Wenatchee River 



o 

 5 



- = : _i^ 1 1 



I 1 



M 



M 



M J JASON 



Tigure 3. — Hydrograph. Wenatchee River at 

 Peshastin, Washington. Average 

 for period 1929-1953. Drainage 

 area 1,000 sq. mi. 



Figure 4. — Hydrograph. Chiwawa River near 

 Plain, Washington. Average for 

 period 1936-1950. Drainage surea 

 170 sq. mi. 



