Olmos Dam

Olmos Dam is a detention dam located in San Antonio, Texas.[1][2] It was built in the 1920s, following the disastrous September 1921 San Antonio floods.[3] Work began on the dam on January 19, 1925,[4] completed in 1926,[2][5][6][7] and in 1929 a cut-off channel, to allow excess water to bypass the Great Bend in downtown,[8] was completed. Projects, which together have been providing flood control.[9]

In the 1970s, improvements were made by the City of San Antonio and the San Antonio River Authority.[10][11] In March 1979, an improvement was made to strengthen and anchor the dam, as well as modifying gate operations, in order to provide an emergency spillway.[5]

There are six gates within the dam, two of which are open at all times to a height of 2 ft (0.61 m). They are rotated once a week. Each gate is controlled via an actuator that is situated inside the dam's gatehouse.

San Antonio Express-News history columnist Paula Allen has referred to the dam as "the jewel in the crown of San Antonio’s system of flood control."[4]

It has become a "staple structure north of downtown San Antonio."[3]

Excavations in the area around Olmos Dam, both prior to the dam's construction in the 1920s and in subsequent excavations such as in 1979, have yielded a good number of Native American artifacts.[12][2]