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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.

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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 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.

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.

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 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.

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 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.

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.