and hay extending from the confluence of the South Fork at the 

 village of Riverside for a distance of 3 miles upstream,, The 

 river has an average width of 90 feet and a moderate gradient 

 below the Riverside dan. The stream bed is composed of approxi- 

 mately 30 percent large rubble, 3>0 percent medium rubble, and 

 10 percent each of small rubble and sand There are numerous 

 shallow riffles containing suitable spawning areas. Resting 

 pools are few, and almost entirely without cover c The water 

 temperature was 57«0°F. at the village of Riverside. The river 

 was turbid at the time of the survey, due to the discharge from 

 the Riverside dam. 



The Riverside dam and Warmsprings reservoir were completed 

 in the year 1919 o The reservoir has a drainage area of 1,100 

 square miles, and extends for 10^ miles up the river channel. 

 The dam is the concrete arch type, rising 91 feet above the stream 

 channel and having a crest length of 5U9 feeto At the time of 

 the survey the discharge through the two outlet gates near the 

 base of the dam was I4.O6 c.f.s e The maximum discharge through the 

 outlets is 700 c.f.s. There are no fish protective devices, and 

 the dam is a total barrier. The reservoir is of some value to 

 resident rainbow trout, and it also supports a large undesirable 

 population of rough fish. 



The stream volume above the Riverside dam is subject to great 

 seasonal variation,, Gaging station records of the U. S. Geological 

 Survey taken at the village of Drewsey, 21 miles above the dam, 

 show discharges ranging from no flow at times to a maximum of more 

 than 1,000 c.f.s. 1/ 



^'he small streams which form the Malheur in the headwaters 

 section some 6f> miles above the Riverside dam all have steep grad- 

 ients, descending rapidly from the south slope of the Blue Moun- 

 tains. The greater part of this section was not surveyed in detail 

 because it is inaccessible and of no possible value to anadromous fish. 



y 



U. S. Geological Survey, water-supply paper No. 1093, for 

 the year 19U7. 



11 



