Events Page Header


The Environmental Sciences Department regularly works on small or short term (less than 5 years) water quality, pollution investigations or scientific studies. When studies are completed, a report may be created, published or put on the Antonio River Authority (River Authority) web site. Often these projects are funded by tax dollars or grants, but they may also be funded through private sources.

Streams within the San Antonio River (SAR) watershed are influenced by non-point sources during storm events. The San Antonio River Authority (River Authority) is challenged with the task of defining stream water quality within the SAR watershed during storm events. To accomplish this, the River Authority is incorporating the latest innovative procedures to collect water quality data by implementing permanent long-term automated sampling stations designed to collect water samples under storm water conditions. Automated sampling procedures can collect water quality samples throughout the duration of a storm event, making the collection effort more economically feasible and safer without endangering field personnel during hazardous storm conditions.

Select a Category

Olmos Dam was originally constructed in 1925-1927 as part of the City of San Antonio’s early efforts to effectuate a flood control plan for San Antonio at a cost of $1.5 million.

In 1973-1974 the city hired Hensley-Schmidt, Inc., Consulting Engineers, to investigate the structural integrity, stability and carrying capacity of the dam. The findings indicated th at the reservoir would contain a 200-year frequency flood but had stability and erosion problems if tested under certain storm conditions. Modifications to the structure were therefore recommended.

Completed in 1998, this project stabilized and rebuilt the river channel section from Houston Street to Commerce where the channel slope drops dramatically from the shallow upstream Hugman section to the broader and deeper concrete River Bend “cutoff” channel.  Sidewalks, hardscape, and landscaping in this reach had to be replaced in the historic style of the River Walk.  

The San Pedro Creek flood diversion tunnel is approximately 6,000 feet long with a finished inside diameter of 24 feet, 4 inches lined with precast concrete segments. It commences near the Interstate 35-Interstate 10 interchange, between N. Santa Rosa Street on the west and Camaron Street on the east, where an intake approach channel is constructed (See Figure 2 for route). The tunnel inlet shaft is constructed downstream of the approach channel and is 24 feet by 4 inches in diameter dropping approximately 119 feet to the tunnel invert.

The San Antonio River Betterments III Project—Durango Boulevard to Nueva Street was designed and administered by the Authority as part of a six phase project which included the structural modifications to the Arsenal Street Bridge. The betterments III project ties into the Nueva Marina and Dam complex. In addition to the improved flood carrying capacity of a “U” framed channel constructed by the U. S. Army Corps of Engineers, a number of amenities were realized as a result of the betterments III project.

The labyrinth weir dam project was designed to replace an existing failing double gated structure built in 1973. The 2,000 foot-long labyrinth weir design was conceived in order to accommodate the floodwater in an area only 350 feet wide.

The San Antonio River flood diversion tunnel is approximately 16,200 feet long with precast concrete segmented liners of 24 feet by 4 inches inside diameter. The tunnel starts near Josephine Street where the tunnel inlet shaft is constructed adjacent to the existing channel (See Figure 2 for the tunnel’s route). The inlet shaft is 24 feet by 4 inches in diameter dropping approximately 118 feet to the tunnel invert. The tunnel outlet shaft near Lone Star Boulevard is 35 feet in diameter and contains embedded piping for dewatering facilities. 

Constructed as part of the federal San Antonio Channel Improvements Project (SACIP), the Espada Dam was designed and built to maintain a base flow to the Spanish Colonial Dam on the west bank while also permitting flood flows to overtop the dam and flow directing down the improved flood channel. The impoundment behind the dam was named Davis Lake.

The San Antonio River was the focal point and life line of the early Spanish missionaries and colonists. The missions were in fact located in close proximity to the San Antonio River because it was the last source of water before moving into the great Chihuahua desert to the south. Mission San Juan Capistrano was one of the five colonial missions established along the San Antonio River. The Spaniards and the Native Americans built a dam and acequia to divert fresh water to the mission and to irrigate mission fields.

This project, completed in September 1987, consisted of an underground boat repair and storage marina, a leaf gated flood control dam across the San Antonio River, and reconstruction of the Nueva Street Bridge. An elevated control tower on the west bank of the river is now being fitted to serve as the headquarters of the San Antonio River Tunnel control system.

The San Antonio River has a new, modern flood control system in downtown San Antonio. The new system will be much more convenient for all city personnel involved with the operation and maintenance of the flood control gates.