USGS Water-Year Summary 2024
12122000 SAMMAMISH LAKE NEAR REDMOND, WA
LOCATION - Lat 47°34'36", long 122°06'36" referenced to North American Datum of 1927, in SE 1/4 SW 1/4 sec.12, T.24 N., R.5 E., King County, WA, Hydrologic Unit 17110012, on west shore 5.6 mi above lake outlet, and 6.5 mi south of Redmond. Prior to Sept. 21, 2009, at site 0.2 mi north.
DRAINAGE AREA - 99.6 mi². includes 1.9 mi² of Cedar River drainage from upper Rock Creek, which normally is diverted into Issaquah Creek.
REVISIONS HISTORY - WSP 1446: Drainage area.
SURFACE-WATER RECORDS
PERIOD OF RECORD - January 1939 to current year.
GAGE - Water-stage recorder. Datum of gage is NGVD of 1929 and is 3.278 ft above NAVD of 1988. Prior to June 22, 1942, nonrecording gage at different site at datum 25.04 ft higher. June 22, 1942, to Aug. 22, 1951, nonrecording gage at different site at datum 25.04 ft higher and Aug. 23, 1951, to Sept. 30, 1996, at datum 24.04 ft higher, April 29, 1965, to Sept. 21, 2009, recording gage at site 0.2 mi. north.
EXTREMES OUTSIDE PERIOD OF RECORD - An elevation of 34.87 ft, present datum, was observed on Dec. 22, 1933, from information provided by Corps of Engineers.
EXTREMES FOR PERIOD OF RECORD - Maximum elevation observed, 33.44 ft, present datum, Feb. 12, 1951; minimum observed, 25.13 ft, Aug. 25-27, 1951.