There were two permanent dams and thirteen irrigation 

 diversions on the main stream at the time of the survey. The first 

 permanent dam is located about U miles above the mouth. It is 

 about 2 feet high, and was installed by a former County Game Com- 

 mission to prevent the migration of suckers from the Snake River 

 into Asotin Creek# This dam does not prevent the migration of 

 steelhead during high water, but during periods of extreme low 

 water during the summer months it is doubtful if salmon and trout 

 are able to pass above this obstruction The other permanent dam 

 is that of the Washington Water Power Company, located approximately 

 72 miles above the mouth. This dam is 6 feet high, and is used 

 for irrigation and as a source of domestic water supply for the 

 towns of Clarkston and Asotin. No water has been diverted for power 

 for many years. The amount of water diverted here for present uses 

 ranges from a minimum of 10 c,f,s, to a possible maximum carrying 

 capacity of U0 c,f,s. On March 8, 1935, it was estimated by the 

 difference in flow measurements above and below the point of diver- 

 sion that 2U c.f.s. was being withdrawn. The intakes to the diver- 

 sion pipe line are adequately screened with 1/u and 1/8 inch mesh 

 screens to prevent the loss of downstream migrants. In periods of 

 extremely low water this dam diverts the entire stream flow t 

 leaving the stream bed dry except for the deep pools along the 

 course. During the month of August, 19 3U, the State of Washington 

 found it necessary to perform considerable fish salvage work in the 

 area below the dam. Three miles of ditches were dug in this dry 

 area connecting the various pools. Fish seining methods were also 

 used, and in this manner it was estimated that 2^0,000 steelhead 

 fingerlings and 25 adult Chinook salmon spawners were saved from 

 destruction. A fish ladder has been installed at the dam under the 

 direction of the Washington State Department of Game, Most of the 

 steelhead trout ascending at high water jump directly over the dam, 

 and rarely use the ladder. It is doubtful if chinook salmon are 

 always able to ascend the stream and pass above the dam because at 

 the time of their appearance, later in the summer, most of the water is 

 being diverted. The efficiency of the ladder depends on the amount of 

 water discharged through it. Normally it provides little attraction 

 to upstream migrants. The twelve other irrigation diversions on the 

 main stream were not in use at the time of observation, and the 

 amount of water withdrawn by them during the irrigation season was not 

 determined. Most of them are small open ditches, but several use 

 temporary wing diversion dams. None of them was provided with screens 

 to prevent the loss of downstream migrants, 



Asotin Creek formerly supported excellent runs of chinook sal- 

 mon and steelhead trout. At present it has a good spring run of 

 steelhead trout and a very samll summer run of chinook salmon. Most 

 of the steelheads ascend the north fork, although a few enter the 

 smaller tributaries and some spawn in the main stream. In 1936 at 

 the peak of the steelhead run 56 steelhead were counted jumping over 

 the old power dam in an elapsed time of 5 minutes. The stream is of 



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