PROGRESS IN BIOLOGICAL INQUIRIES, 1937 27 



this area a total of 117 dams of all types were found, of which 32 

 are permanent structures, and 85 temporary. Three of the per- 

 manent dams are obstructions at all times, and 21 are barriers at 

 low water onl}-. The number of dams used for irrigation totals 107, 

 of which 23 are permanent and 81 are temporary in nature. Two 

 dams are used for power, 1 for irrigation and power, and 7 for other 

 purposes. There are 143 diversions, of which 133 are for irrigation, 

 4 for power, 1 for power and irrigation, and 5 for other purposes. 

 In the 34 streams examined in this area, which are part of the 4 

 major river systems, it was estimated that 35 percent of the river 

 bottom Avas suitable for spawning purposes, with approximately 

 four-sevenths of this total available to fishes at all times, and three- 

 sevenths unavailable at low water. 



In the south central area, the Yakima River system is the only- 

 large stream that has been surveyed to date, although 69 minor 

 streams have been examined. In this survey a total of 163 dams 

 were recorded, of which 40 are permanent and 123 are temporary. 

 One hundred and fifty-nine of these are used for diverting water for 

 irrigation purposes and of this number 38 are permanent and 12L 

 are temporary. Five of the permanent dams are complete barrierSj, 

 26 are barriers at low water only, and the remainder are passable to^ 

 fish at all stages of water level. The number of diversions in this 

 region total 280, of whicli 270 are used for irrigation, 5 for power, 1 

 for power and irrigation, and 4 for other purposes. In the 34 

 streams in the south central area that have been examined, it was 

 estimated that 59 percent of the bottom was suitable for spawnings 

 with three-fifths of this total available to spawning fish at all times 

 and tAvo-fifths unavailable at low water. 



The survey of the southeastern area of tlie State of Washington has 

 been completed. This included the following river systems: the 

 Tucannon, Asotin, and Walla Walla Rivers, and 29 minor streams. 

 There were 112 diversion dams in this area, 32 of which were per- 

 manent structures and 80 temporary. A total of 172 diversions were 

 found, of which 160 were used for irrigation, 2 for power, 6 for 

 power and irrigation, and 4 for other purposes. In the 17 streams 

 examined it was estimated that 71 percent of the bottom was suitable 

 for spawning, but of this total only one-third was available to fisb 

 at all times, two-thirds of the area being unavailable at low water. 



The survey of the southwestern area of the State of AVashington 

 has not been completed to date. Thus far, a total of 22 dams have 

 been recorded. They are used for the following purposes : 1 for 

 irrigation, 6 for power, and 15 for other uses. 



In the State of Oregon stream surveys were conducted on the 

 middle fork of the Willamette River from the proposed flood con- 

 trol dam site at Lookout Point to Tumblebug Creek; on the McKenzie 

 River from the proposed dam site at Quartz Creek to Tamolitsh 

 Falls: on the North Santiam River from the proposed dam site 

 near Detroit to Big Meadows Camp ; and on the South Santiam from, 

 the proposed dam site at Sweet Home to House Rock Camp at Sheep 

 Creek. During the survey of these streams 4 permanent dams were 

 found, of which three formed partial barriers and one a complete 

 barrier to migratory fishes. 



A total of approximately 2,300 miles of stream have been sur- 

 veyed in tlie Columbia River drainage up to the present time.. Data 



