Location.--Latitude 46°49'23", Longitude
122°18'13", in SW 1/4 SE 1/4 Section 33, Township 16 North,
Range 4 East, in Thurston County, Hydrologic Unit 17110015, at
left end of gate control structure, 1.1 miles southeast of La Grande,
1.7 miles downstream of Alder Dam, and at river mile
42.5. Drainage
area is 289 mi2. Datum of
gage is 7.61 feet below NGVD of 1929, levels by City of Tacoma.