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Water-Year Summary for Site 08179500

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  • Water-Year Summary reports summarize a year of hydrologic data in a printer-friendly format.
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Available Parameters
00053 Surface area(Mean)  
00054 Reservoir storage(Max.,Min.,Mean,Obs.,Obs.)  
62614 Elevation, lake/res, NGVD29(Max.,Min.,Mean,Obs.,Obs.)  

Water year 2021: 2020-10-01 to 2021-09-30

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USGS Water-Year Summary 2021
08179500 Medina Lake near San Antonio, TX
LOCATION - Lat 29°32'24", long 98°56'01" referenced to North American Datum of 1927, Medina County, TX, Hydrologic Unit 12100302, at gate-operating platform, 576 ft from the left end of Medina Dam on Medina River, 4.2 mi upstream from Medina diversion dam, 13 mi north of Castroville, 28 mi west of San Antonio, and 70.4 mi from mouth.
DRAINAGE AREA - 634 mi².
REVISIONS HISTORY - WSP 1923: 1953(M), Drainage area.
PERIOD OF RECORD - May 1913 to Sept. 1994, Aug. 1997 to current year. Prior to Oct. 1965, end of month contents only from records provided by Bexar-Medina-Atascosa Counties Water Control and Improvement District No. 1. PERIOD OF RECORD, Water-Quality.-- CHEMICAL DATA: Oct. 1969 to Sept. 1984.
GAGE - Water-stage recorder. Datum of the gage is NGVD of 1929. Prior to Oct. 1999, datum of gage was 7.81 ft higher. Satellite telemetry at station.
REMARKS - Some records listed in the "Period of Record" for surface water and water quality may not be available electronically. The lake is formed by a gravity-type concrete dam, 1,580 ft long. The dam was completed and storage began May 7, 1913. The uncontrolled spillway is a cut through natural rock 880 ft long, with a 3-foot wide cutoff wall, located near right end of dam. The dam and lake are owned and operated by Bexar-Medina-Atascosa Counties Water Control and Improvement District No. 1. Water is released downstream to Medina Diversion Lake where it is diverted into Medina Canal by the Water District. Capacity table based on survey made by the Texas Water Development Board, July 1995. Conservation pool storage is 254,843 acre-ft. Data regarding the dam are given in the following table:

                                       Elevation (feet)
Top of dam                               1,076.2
Crest of spillways                       1,064.2           
Water-supply outlet pipe (invert)          958.7             
Lowest gated outlet (invert)               912.2
EXTREMES FOR PERIOD OF RECORD - Maximum contents, 322,700 acre-ft July 5, 2002, elevation, 1074.65 ft; minimum contents, 780 acre-ft, Apr. 11, 1948, elevation, 936.2 ft (present datum).