The San Antonio River Authority is charged by the state of Texas to preserve, protect and manage the resources and environment of the San Antonio River and its tributaries. The San Antonio River Authority was established as the San Antonio River Canal and Conservancy District by the 45th Texas Legislature in 1937. At that time the district's boundaries were limited to Bexar County, but it had the authority to acquire easements outside the county. The agency's original purpose was to seek development of a barge canal from the Gulf Coast to the city of San Antonio, but its functions were expanded in 1939 to include the promotion of flood control. Early studies addressed both the canal project and flood control concerns, but after floods in September 1946 cost San Antonio six lives and $2.1 million in property damage, the district discontinued its navigation studies in favor of flood control efforts.

The U.S. Army Corps of Engineers completed its study of the San Antonio River Basin in 1951, recommending the channelization of 2.1 miles of Escondido Creek in the city of Kenedy and thirty-one miles of improvements along the San Antonio River and its tributaries in San Antonio. Both the San Antonio Channel Improvement Project and the Escondido Creek Channelization Project were approved by Congress with the passage of the Flood Control Act of September 3, 1954. The San Antonio River Authority (as the San Antonio River Canal and Conservancy District was renamed in 1953) acted as the local sponsor of the projects and was responsible for obtaining partial funding and all necessary rights-of-way, as well as for relocating all utilities and constructing all required bridges and in-channel dams. The river authority was initially funded through the proceeds of a state flood-control tax, but this source of money was eliminated by a 1948 constitutional amendment. In 1951 Bexar County instituted a thirty-cent ad valorem tax, fifteen cents of which was to be used by the district to finance the nonfederal cost of its flood-control projects. In 1955 Bexar County authorized the sale of $12 million in bonds, to be repaid over thirty years through the flood-control tax.

In 1961 the legislature enlarged the authority's jurisdiction, adding Wilson, Karnes, and Goliad counties to make the water authority's district conform roughly with the San Antonio River Basin. The legislature also expanded the duties of the agency to include the conservation and use of ground water in the district, irrigation, sewage treatment, pollution prevention, development of parks and recreational facilities, reforestation, and preservation of fish species. The governing board of the authority was expanded from nine appointed to twelve elected members: six from Bexar and two each from Wilson, Karnes, and Goliad counties. Members were elected on a nonpartisan basis to serve six-year, staggered terms. Board policies were implemented under the direction of a board-appointed manager.

Through the efforts of Congressman Henry B. Gonzales, the authority obtained funding in 1963 to renew feasibility studies for the barge canal project; however, after several years the project was set aside indefinitely because of the inadequate ratio of cost to potential benefits. The authority turned its efforts instead toward pollution prevention and sewage treatment facilities, as well as continuing its work on flood control through the river channel improvement project. Delays and cost increases associated with the channel improvements had raised the local obligation to $21 million. Efforts to raise revenue through increased county taxes failed, meaning that additional funds to finish the projects would have to come from the city of San Antonio and from state and federal sources. In 1976 the authority's flood control contract with the county was restructured so that $30 million would be available for modifications to Olmos Dam, reconstruction of San Juan Dam, and channel improvements along Six Mile and San Pedro creeks.

In 1982 the San Antonio River Authority and the Corps of Engineers began to consider the feasibility of a bypass system to divert flood water through two tunnels to be built under downtown San Antonio, instead of risking uncontrolled flooding along the Paseo del Río. The authority obtained the necessary rights-of-way, and construction of the tunnel began in 1988. In 1990 an amendment to the 1976 contract provided for an additional $40 million in local revenue. In 1992 the San Pedro Creek tunnel, which was 24 feet 4 inches in diameter and 6,000 feet in length, had been built beneath the city and was operational; the San Antonio River Tunnel, which was the same diameter but was three miles in length, was scheduled for completion in 1995. In the 1980s the authority conveyed several tracts of land near Mission San Juan to the San Antonio Missions National Historic Park. By 2006 the river authority operated 42 flood control structures, three sewage treatment plants, 173 water-sampling stations, and three fee-supported public recreational areas (Braunig Park, Calaveras Park, and Jackson Nature Park).

(Sources include: Handbook of Texas Online article, San Antonio River Authority (http://www.tshaonline.org/handbook/online/articles/mws02); and the San Antonio River Authority website (http://www.sara-tx.org/); both accessed May 2, 2012.)