USGS Water-Year Summary for Site 08088435

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	Available Parameters
	62614 Elevation, lake/res, NGVD29(Max.,Min.,Mean)

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Water year 2023: 2022-10-01 to 2023-09-30

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USGS Water-Year Summary 2023

08088435 Possum Kingdom Lake above McGinnis Point near Graford, TX

LOCATION - Lat 32°56'09", long 98°25'42" referenced to North American Datum of 1927, Palo Pinto County, TX, Hydrologic Unit 12060201, on M Anthony Loop Road, 10.5 mi west of Graford, and 3.0 mi northwest of intersection of Highways 16 and 254.

DRAINAGE AREA - 23,596 mi² of which 9,566 mi² probably is noncontributing.

SURFACE-WATER RECORDS

PERIOD OF RECORD - Oct. 2005 to current year.

GAGE - Water-stage recorder. Datum of gage is 0.00 ft above NGVD of 1929 and 0.74 ft below NAVD of 1988. To obtain elevation values in NAVD 1988, add 0.74 ft. Satellite telemeter at station.

REMARKS - The lake is formed by a reinforced concrete dam, Ambursen-type, massive buttress with flat-slab deck, a controlled spillway, two bulkhead sections, and an earthen-dike section. Total length of dam is 2,740 ft long. The dam, owned by the Brazos River Authority, was completed and storage begun Mar. 21, 1941. The spillway has nine roof-weir gates (modified bear-trap type) that are 73.66 x 13 ft each and are designed to discharge about 100,000 ft³/s at an elevation of 1,000 ft. The outlet works consist of one controlled 54-in diameter conduit. Water is used for power development, irrigation, municipal, industrial, and recreational purposes. Two generators located in the powerhouse at dam can produce 22,500 kilowatts at an elevation of 1,000 ft (Generators decommissioned). Eleven major reservoirs, with a combined capacity of 607,800 acre-ft, largely regulate the inflow. Flow is affected at times by discharge from the flood-detention pools of 12 floodwater-retarding structures with a combined detention capacity of 24,710 acre-ft. These structures control runoff from 108 mi². Conservation pool storage is 540,340 acre-ft. Data regarding the dam are given in the following table:

                                                                         Elevation (feet)
Top of dam..............................................................            1,024.0
Design flood (top of gates).............................................            1,000.0
Crest of spillway.......................................................              987.0
Invert of penstock......................................................              911.5
Lowest gated outlet (invert of 54-inch conduit).........................              874.8

EXTREMES FOR PERIOD OF RECORD - Maximum elevation, 1,000.05 ft, Mar. 18, 2020; minimum elevation, 983.71 ft, Sept. 22, 2014.