The Nueces River Project is located on the coastal plain of South Texas midway between the cities of San Antonio and Corpus Christi. Choke Canyon Dam is on the Frio River about 4 miles west of the town of Three Rivers, named for the confluence of the Frio, Nueces, and Atascosa Rivers. Low-lying hills force the three rivers into a constricted channel, thus the name Choke Canyon. Live Oak and Post Oak trees are generally found near the rivers while Mesquite, Huisache, Blackbrush, and grasses cover most of the rest of the area. The area has long and hot summers, mild winters, and erratic precipitation.
Occasional hurricanes produce major storms and flooding.
Plan Choke Canyon Dam and Reservoir Choke Canyon dam is a rolled earthfill structure about 115 feet high and approximately 3 miles long. Almost 6 million cubic yards of earthfill were used in construction of the dam. The dam has a cutoff trench along its entire length excavated to sound rock and backfilled with select impervious material and was completed in 1982. A concrete spillway, located on the left abutment of the dam, consists of an inlet structure, a chute, a stilling basin, and a gate structure with seven radial gates designed to pass the probable maximum flood without endangering the safety of the structure. The radial gates are 50 by 24 feet with a a release capacity of about 250,000 cubic feet per second.