USGS Water-Year Summary 2023

08039300 Sam Rayburn Reservoir near Jasper, TX

LOCATION - Lat 31°03'38", long 94°06'21" referenced to North American Datum of 1927, Jasper County, TX, Hydrologic Unit 12020005, in the powerhouse-intake structure of Sam Rayburn Dam on the Angelina River, 10 mi northwest of Jasper and 25.2 mi upstream from mouth.

DRAINAGE AREA - 3,449 mi².

SURFACE-WATER RECORDS

PERIOD OF RECORD - Jan. 1965 to Sept. 2000 (U.S. Army Corps of Engineers furnished contents), Oct. 2000 to Sept. 2002 (daily mean contents). Oct. 2002 to current year (daily mean elevation). PERIOD OF RECORD, Water-Quality.-- CHEMICAL DATA: Oct. 1964 to Sept. 1984, Sept. 1993 to Sept. 1999. BIOCHEMICAL DATA: Nov. 1967 to Sept. 1984, Sept. 1993 to Sept. 1999. PESTICIDE DATA: Nov. 1965 to Mar. 1968. RADIOCHEMICAL DATA: Mar. 1981.

GAGE -

Water-stage recorder. Datum of gage is NGVD of 1929 (levels by U.S. Army Corps of Engineers). Prior to Apr. 20, 1965, nonrecording gage at same site and datum. Satellite telemeter at station.

Headwater Gage: The reservoir level recorder consists of a Sutron Satlink 2 Data Collection Platform (DCP) with logger, as well as a Stevens Type AP recording transmitter set over a 30-inch-diameter steel pipe float well constructed as an integral part of the structure. It is located in a recess in the concrete wall at the left downstrean corner of the emergency generator and fan room near the ceiling at elevation 184.5. The transmitter actuates a Stevens Type PJ-C counter indicator which is integral with the instrument board in the control room of the power house. The transmitter is operated by electrical power. This gage is known as "Sam Rayburn Reservoir near Jasper, Texas."

The float well is connected to the reservoir by two 3-inch pipe intakes. The lower intake enters the gage well at elevation 120.5 and is 214 feet long. The intake at the reservoir to the lower connection to the gage well is at elevation 119.5 and is set in a recess in the face of the left upstream retaining wall. The lower intake is equipped with a 1-inch gate controlled compressed air connection and a 3-way cock between two 3- inch wedge gate valves provided for flushing the well. These controls are in the locked storage room behind the electrical shop and storage room. The upper intake enters the gage well at elevation 143.5 and is 145 feet long. (The upper intake is controlled by two 3-inch wedge gate valves with a gate controlled compressed air connection between them. Those controls can be operated from the staircase landing at elevation 143.0.) The intake to the upper gage well intake at the reservoir is at elevation 142.5 and is set in a recess in the face of the left upstrean retaining wall.

Tailwater Gage: The tailwater recorder consists of a Stevens Type AP recording transmitter set over a 20-inch diameter steel pipe well constructed as an integral part of the structure. The instrument is located in the generator room upstream from and adjoining the elevator shaft at elevation 124.0. The transmitter actuates a Stevens Type PJ-C counter indicator which is integral with the instrument board in the control room of the powerhouse. The transmitter is operated by electrical power. The tailwater gage well is connected to the tailrace by one 3-inch intake, 263 feet long, which enters the gage well at elevation y6.o. This intake is equipped with two 3-inch wedge gate valves with a compressed air connection between them. The gate valves for flushing the well can be operated from the stairway landing at elevation 75.25. The inlet is at elevation 74.0. It is equipped with a strainer and is located in the right wall of the tail-race about 7 feet from the end of the paved tailrace apron and 51 feet upstream from the control weir.

Outside tile gages: The headwater gage consists of five sections, black tile graduations and numerals on white tile background. Sections IA (elevation 105.0-153.0) and 2A (elevation 153.0-158.0) are set in concrete in the right upstream retaining wall. Sections lb (elevation 158.0-165.0), 2b (elevation 165.0-174.0), and 3b (elevation 174.0-183.7) are located on the face of the right end. wall of the power intake structure. The tailwater gage consists of two sections black tile graduations and numerals on white tile background, set in concrete on the right training wall of the tailrace. One section reads from elevation 81.0 to 117.0. The other section reads from elevation 116.0-125.7.

REMARKS - The reservoir is formed by a rolled earthfill dam 19,430 ft long, including spillway and dikes. The dam was completed and deliberate impoundment began Mar. 29, 1965. The spillway is an uncontrolled broad-crested weir 2,200 ft wide, on right bank 7,000 ft to right of outlet works and is designed to discharge 125,300 ft³/s at maximum flood design. The flood-control outlet works consists of two 10.0 x 20.0-foot rectangular concrete-lined conduits controlled by two 10.0 x 20.0-foot tractor-type service gates and one 10.0 x 20.0-foot tractor-type emergency gate. Water for turbines is admitted through four 18.0 x 26.0-foot penstocks and controlled by two wheeled-leaf-type headgates. The dam is owned by the U.S. Army Corps of Engineers. The reservoir is operated for flood control and power generation. The area-capacity tables are based on topographic maps prepared by the U.S. Army Corps of Engineers and detailed sedimentation ranges established in 1961 and dated Feb. 1965. For statement regarding regulation by Natural Resource Conservation Service flood-water-retarding structures, see station 08038000. Conservation pool storage is 2,898,500 acre-ft. Some records listed in the "Period of Record" for surface water and water quality may not be available electronically. Data regarding the dam are given in the following table:

                                                                              Elevation (feet)
Top of dam............................................................          190.0
Design flood..........................................................          183.0
Crest of spillway.....................................................          176.0
Top of flood-control pool.............................................          173.0
Top of conservation pool (power pool).................................          l64.4
Top of power head and sediment pool...................................          149.0
Lowest gated outlet (invert)..........................................          105.0