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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.

In an effort to restore and sustain the native life in this section of the river, Bexar County, the City of San Antonio, the River Authority, and the US Corps of Engineers (USACE) are conducting the River Road Aquatic Ecosystem Restoration Feasibility Study in order to identify potential projects, as well as scientifically evaluate these projects for their impact and cost-effectiveness.

With its lush vegetation, effortless accessibility and modern recreation amenities, Escondido Creek Parkway will be the favorite outdoor hub in the City of Kenedy, a gathering place for the community to relish their time in nature and with each other. This inviting linear park will transform the way people connect with their community and the environment by providing unparalleled opportunities to safely recreate in a native landscape.

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.

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.

Combining purpose with beauty, San Pedro Creek Culture Park weaves public art and architectural design into historic preservation, flood control, water quality and ecosystem restoration.

The San Pedro Creek Culture Park will encompass a total of four phases, with three segments in Phase 1. With Segment 1 complete, the second segment is currently under construction.

To keep up with the project and learn more about the art and upcoming events, visit:

This project was funded by the City of San Antonio and Bexar County. The project primary purpose was to protect and enhance the conveyance in San Pedro Creek from the historic San Pedro Springs Park downstream to IH-10. Along with the channel work, street and drainage replacement was done on North Flores, Fredericksburg Rd.

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 Westside Creeks Project is a community-based creek restoration effort started in 2008 by the San Antonio River Authority. Its mission is: 1) to develop and advance planning concepts for restoring the environmental condition of the Alazán, Apache, Martínez, and San Pedro Creeks, 2) to enhance or maintain the current flood control components of these creeks, and 3) to provide increased opportunities for community enjoyment.

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.

Completed in 2003, this $13M project was jointly funded by the City of San Antonio and Bexar County. Project design and construction was overseen by SARA to stabilize and repair both the river channel walls and the high bank retaining walls, many dating back to the 1940’s era Hugman era River Walk. Additionally, historic sidewalks, stairs, and hardscape were repaired or replaced. New sidewalks were added on the west bank and the east bank was made fully ADA accessible including a new access point and a pocket park at Convent and Augusta Street.

The SARA Floodplain Viewer engages users in an interactive floodplain map, displaying the Federal Emergency Management Agency’s (FEMA) National Flood Hazard Layer (NFHL) data.

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. 

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.  

Through more accurate flood maps, risk assessment tools, and outreach support, FEMA's Risk Mapping Assessment, and Planning (Risk MAP) strengthens local ability to make informed decisions about reducing flood risk. Risk MAP uses a watershed-based study approach which improves engineering credibility and allows for the understanding of risks in a more comprehensive way. 

Native plant communities, and particularly grassland systems can benefit from periodic, low-intensity fires and other natural processes that reduce competition from taller plants and trees. Land managers use fire ecology for restoration purposes through a process called prescribed burning. Prescribed burning is a controlled, planned, and scientific management tool widely used to manage vegetation under very specific and safe conditions.

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.

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.

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.

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.

Specified reaches of the Upper San Antonio (segment 1911) and Salado Creek (segment 1910) have been identified on the TCEQ 303 (d) list as not meeting state stream standards due to elevated levels of coliform bacteria. The TCEQ Total Maximum Daily Load (TMDL) effort has determined the bacterial load reductions that will be required in order to meet compliance with state surface water quality standards. The Environmental Protection Agency requires that an Implementation Plan (IP) be developed to address the water quality impairments identified in the TMDL.

The Texas Department of Health has issued a fish consumption advisory stating that the consumption of fish from Leon Creek may pose a threat to human health due to polychlorinated biphenyls (PCBs). This advisory extends from Old U.S. Highway 90 Bridge downstream to the Loop 410 bridge in South Bexar County. Previous

The draft 2008 TCEQ 303(d) List (March 19, 2008) identified several assessment units in the Lower Leon Creek as being impaired based on the state's contact recreation (bacteria) and high aquatic life (dissolved oxygen) use criterion. In response to these conditions, the TCEQ Total Maximum Daily Load Program in partnership with the San Antonio River Authority (SARA)initiated a project to verify depressed dissolved oxygen and develop information necessary to support a bacterial (E. coli) Total Maximum Daily Load (TMDL) in the Lower Leon Creek, Segment 1906.

This project assessed the abundance of Guadalupe Bass Micropterus treculi in the San Antonio River (SAR) watershed and collect, tag and reintroduce the species to a restored reach of the SAR where the species had been extirpated. An assessment of Guadalupe bass in the SAR watershed was completed to gather genetic and baseline abundance information.

Citizens in the lower portion of the San Antonio River Watershed have expressed concerns about bacteria levels in the San Antonio River and asked that the San Antonio River Authority address their concerns. Many felt that the City of San Antonio was the principle source of the bacterial concerns on the lower San Antonio River (Segment 1901).

The objective of the Lower Leon Creek Use-Attainability Analysis is to conduct monitoring in support of Texas Commission on Environmental Quality efforts to assign the appropriate aquatic life use and dissolved oxygen criterion in Lower Leon Creek; additional dissolved oxygen data on Menger and Picosa creeks was also collected.

Under contract to the National Park Service, biologists of the San Antonio River Authority Environmental Services Department conducted a series of fish collections at representative sites along watercourses in or adjacent to the San Antonio Missions National Historical Park properties in Bexar and Wilson counties, Texas . Fishes were collected from October 2003 to September 2004 at five sites along the San Antonio River and at three tributary sites utilizing electro-fishing and seining techniques. Fish community composition, habitat and water quality were evaluated.

The adopted environmental flow standards developed by the Guadalupe, San Antonio, Mission, and Aransas Rivers and Mission, Copano, Aransas, and San Antonio Bays Basin and Bay Stakeholder Committee (BBASC) relied on limited data about the location, reproduction and recruitment of Rangia clams for the spring months. This study developed maps of Rangia clam beds in Mission Lake, Guadalupe Bay and parts of Hynes and San Antonio Bay. Rangia clam growth rings were examined to establish correlations between growth and recruitment with environmental flow conditions.

Three freshwater mussel species under review for federal listing as threatened or endangered have historically been found in the San Antonio River Basin. One species, Golden Orb, has been recently found in numerous locations in the San Antonio River.

From 2002 through 2009, faculty and students from the Department of Wildlife and Fisheries Sciences at Texas A&M University conducted field, laboratory, and modeling studies to investigate the diet, behavior, and habitat of the whooping crane (Grus americana) at Aransas National Wildlife Refuge (ANWR), Texas. During this period the research team also conducted complementary studies of environmental conditions in San Antonio Bay.

The goal of this project was to develop methodologies to validate environmental flows adopted by the State. This was accomplished by first conducting a workshop with an expert panel to develop several theories on how certain chemical and physical parameters as well as biological indicators will respond to the various tiered flow recommendations. These indicators were identified by the expert panel. Then the selected indicators were studied at several sites and under several flow regimes to validate the theories and the associated flow recommendations.

In recent history, use of groundwater to sustain rapid development in the basin has resulted in increasing base flows in the San Antonio River resulting from discharged groundwater-based return flows. This trend in increasing flows may continue if population growth in the basin is supported by additional groundwater usage or surface water transfers from outside the basin; however, lower river base flows may also result should water management strategies such as reuse, both direct and indirect, be increased.

The Texas Instream Flow Program (TIFP), jointly administered by Texas Commission on Environmental Quality, Texas Parks and Wildlife Department, and Texas Water Development Board, has initiated a study of instream flows necessary to support a sound ecological environment in the Lower San Antonio River. The TIFP seeks to incorporate stakeholder input, insight, and concerns while conducting this study. With the assistance of the San Antonio River Authority, initial stakeholder meetings were held in February 2005.

A portion of the Upper San Antonio River, Segment 1911, has been identified by the Texas Commission on Environmental Quality (TCEQ) as impaired due to bacteria levels that exceed the state criteria for contact recreation. Also identified as impaired due to bacteria are Salado Creek, Segment 1910, a tributary of the Upper San Antonio River, and Walzem Creek, Segment 1910A, a tributary of Salado Creek. The urban environment surrounding the Upper San Antonio River has many potential sources of bacteria.

The Westside Creeks are a cluster of tributaries to the San Antonio River that flow through some of San Antonio’s oldest Westside neighborhoods – a community with a rich historical and cultural background. A feasibility study was developed by the U.S. Army Corps of Engineers and San Antonio River Authority, for the ecological restoration of the Westside Creeks. However, the current

The San Antonio River Authority (River Authority) is collaborating with the City of San Antonio for the 2017-2022 Bond project Panther Springs Creek Restoration. The creek restoration efforts will focus on improving the water and sediment conveyance of the existing natural channel.