The Survey 



2. Main Waieer River .— (August 16-29, 1941; Frey and Bryanto ) 

 The main Weiser River is approximately 82 miles long. Gaging-station 

 records for the wat«r-year 1940-41 (U.S.G.S,, 1942), taken at a sta- 

 tion about 15 miles above the mouth, shov discharges rarigiiig from a 

 maximim of 600C o.f.s. in December to a minimum of 51 o.f.s. in July. 

 The streajn bed in the lower part of the river is covered with a layer 

 of silt resulting from the turbid discharge of several reservoirs lo- 

 cated on tributary streams. The upper part is more often clear, and 

 contains a large amount of good spawning area. 



There are 13 irrigation diversions on the main Weiser. Six 

 of these have water rights ranging from 9 to 240 o.f.s. 



The Mill Ditch irrigation diversion dajn is located about 11 

 miles above the mouth. This is a low structure, passable at high 

 water, and not equipped with a fishway. The ditch has a water right 

 of 9 c.f.s. 



A short distance above the Mill Ditch there is located the 

 Galloway diversion dam of the Weiser Irrigation Project. This is a 

 concrete structure 4 feet high, with flashboards increasing the height 

 to 5 feet. Along the base of the dam there is a concrete apron extend- 

 ing 12 feet downstreson. A poorly designed fishway parallels the face 

 of the dam and disoharges onto the apron. It was reported that when 

 there is sufficient spill over the dam, wi-iich usxially occvire only 

 during the spring run-off, steelhead jump directly over this obstacle* 

 As the discharge decreases it becomes increasingly difficult for fish 

 to pass over the long, shallow downstream apron and enter the fish 

 ladder. There is usually little or no spill over the dam during 

 August and September, and during these months the stream bed below ic 

 practically dry. A large part of the Chinook run has sometimes been 

 blocked at this dan, and the fish caught in large numbers. It was 

 reported that this occurred in 1939. The Galloway ditch has a cari^'ing 

 capacity of 240 c.f.s., and has a right to all the water in the river 

 at the diversion point except for the 9 o.f.s which must bo supplied 

 *• the Mill ditch. 



Other major irrigation diversions and their carrying oapaci- 

 ties are the Middle Valley ditch, 60 o.f.s; the Robertson-Levey 

 ditch, 30 o.f.s. but adjudicated for 16 o.f.s; the Sunnyside ditoh, 

 30 o.f.s, and the Alii son- Jewell ditoh, about 9 o.f.s. 



2A. Mann Creek .— (August 17-28, 1941; Frey and Bryant.) Mann 

 Creek enters the Weiser River approximately Sg- miles above the mouth. 

 The stream is about 33 miles long, of whioh the lower 29 miles wore 

 surveyed. It is of small size and has a fairly steep gradient above 



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