68 research outputs found
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Comparison of Austin-Area Stream Sediments to Sediment Quality Guidelines
This report contains a comparison of sediment content between many Austin creeks.Existing sediment data collected by local, state, and federal agencies from the stream beds and spring pools of the Austin area were compared to human-exposure and environmental toxicity criteria in order to identify the source and location of potential threats to human and ecosystem health. Polycyclic aromatic hydrocarbons (PAH) parameters were found to be in excess of sediment quality guidelines more frequently, and also were more spatially widespread than any other parameter type assessed. The majority (96%) of parameters evaluated for human health toxicity were below Protective Concentration Limits (PCLs), although data for PAHs, metals, and pesticides were found in Austin-area sediments at levels indicating potential ecosystem toxicity. Applicability of the PCL levels to Austin-area streams is questionable, since a complete exposure pathway may not exist, thus making the use of the PCL criteria an extremely conservative measure of potential adverse human health effects from stream sediments.Waller Creek Working Grou
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Waller Creek Tunnel LA-Qual (v 9.05) Dissolved Oxygen Model for Recirculation Operations
This short report details the function and expected results of a Waller Creek tunnel designed to move sediment and regulate dissolved oxygen within the system.The City of Austin is constructing a stormwater bypass tunnel in lower Waller Creek. Water must be recirculated from Lady Bird Lake through the tunnel during non-storm conditions to prevent water in the tunnel from becoming anoxic. LA-Qual (version 9.05) steady-state models were used to identify optimum tunnel recirculation flow rates under three seasonal conditions and during summer months immediately following storm events in order to maintain dissolved oxygen in the tunnel near 4 mg/L. Model predictions were applied to measured Waller Creek flow data from 1994 to 2009 to estimate the total recirculation withdrawal from Lady Bird Lake for comparison to the maximum allowed under a Firm Water Contract with the Lower Colorado River Authority. Predicted Lady Bird Lake withdrawal for recirculation varies from 1 to 4 ft3 /s during non-storm conditions depending on season, with 4th Street and 8th Street side inlet tunnel flows less than 0.5 ft3 /s. Post-storm recirculation rates are predicted to optimally be 35 ft3 /s, although the actual maximum pump capacity is 28 ft3 /s. Operating the Waller Creek immediately following storm events at 28 ft3/s will not maintain DO in the tunnel above 4 mg/L, but should be sufficient with cascade aeration prior to discharge to Waller Creek to maintain aquatic life use standards. Operation of the Waller Creek Tunnel under these recirculation flow conditions are not anticipated to exceed the annual maximum withdrawal from Lady Bird Lake allowed by the Lower Colorado River Authority.Waller Creek Working Grou
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Summary of 303(d)/305(b) Listed Segments from the Draft 2010 Integrated Report in the Austin area, Texas
This report provides brief descriptions of primary recreation impairments of several Waller Creek locations. The report also mentions that the Waller Creek tunnel will change its hydrology and water quality.The Texas Commission on Environmental Quality (TCEQ) is required by the federal Clean Water Act sections 303(d) and 305(b) to biennially report on the quality of water bodies in Texas with available data. A review of water bodies identified as impaired or of concern in Austin was conducted. Twelve segments in Austin were identified as impaired in 2010. All but one of the twelve impairments were previously identified in 2008. The most frequent impairment was elevated bacteria levels. Two impairments previously identified in 2008 were de-listed in 2010. There are 27 assessment units in the Austin area identified as being of concern. Not all City of Austin water quality monitoring is submitted to TCEQ for assessment, and Austin’s Environmental Integrity Index is a broader and more consistent comparison of relative water quality citywide. Despite the large number of impaired or of concern water bodies, Austin maintains stream segments with excellent water quality.Waller Creek Working Grou
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Action Plan Items Related to EII Site Scores - Fiscal Year 2006
The Environmental Integrity Index (EII) was used to identify creek reaches with at least a 13% decrease in environmental health in using data collected in 2006 compared to initial conditions sampled in 1996 (phase I watersheds). City of Austin teams with the potential to reverse the recent degradation in five problem areas (aquatic life, habitat, nutrients plus bacteria, nutrients alone, and litter) through structural and non-structural BMPs were identified. Primary and secondary problem reach lists are provided for the teams.Waller Creek Working Grou
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Linking BMPs to Receiving Water Impact Mitigation in Austin, TX
This report mentions how the water quality of upstream Waller Creek can affect downstream sites.Changes to receiving water bodies following Best Management Practices project (BMP) implementation were evaluated using the Environmental Integrity Index (EII). Data from five wet ponds and one channel restoration project were used. Changes in the six EII sub-indices (water quality, sediment quality, contact recreation, non-contact recreation, habitat quality and aquatic life support) were generally positive except for habitat quality, which declined initially but tended to recover. Water quality through wet pond sites improved by an average of 7%, and the channel erosion site improved water by 18%. Additional data collection is needed to strengthen conclusions.Waller Creek Working Grou
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Diel dissolved oxygen patterns and aquatic life use assessment
This report mentions Waller Creek as one of three streams "listed as "of concern" for DO impairments".Diel dissolved oxygen (DO) data from 318 deployments at 38 stream sites were evaluated for spatial and temporal patterns and compared using TCEQ aquatic life use assessment DO criteria versus benthic macroinvertebrate aquatic life use categories. Diel DO data suggest that Austin streams generally maintain high or excellent aquatic life use potential. TCEQ assessment methods may not be appropriate for identifying aquatic life use impairments in some high quality Austin streams, and may yield impairments based on DO that are not observed in benthic macroinvertebrate data. Additional investigation of low DO in Bull Creek preserve lands is needed.Waller Creek Working Grou
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Action Plan Items Related to EII Site Scores - Fiscal Year 2005
The Environmental Integrity Index (EII) was used to identify sites with at least a 13% decrease in environmental health in recent years. City of Austin teams with the potential to reverse the recent degradation in five problem areas, aquatic life, habitat, nutrients plus bacteria, nutrients alone, and litter, through structural and non-structural BMPs were identified. Program areas or teams addressing these areas are the surface water evaluation team, masterplan committee, community education, Austin Clean Water Program, and Keep Austin Beautiful programs. Primary and secondary site lists are provided for each of the teams.Waller Creek Working Grou
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Action Plan Items Related to EII Site Scores - Fiscal Year 2009
The Environmental Integrity Index (EII) was used to identify creek reaches with at least a 13% decrease in environmental health in using data collected in 2009 compared to initial conditions sampled from 1996-1999. City of Austin programs with the potential to reverse the recent degradation in five problem areas (aquatic life, habitat, nutrients plus bacteria, nutrients alone, and litter) through structural and non-structural BMPs were identified. Primary and secondary problem reach lists are provided for these programs. There was a sharp increase in the number of sites with litter problems. No watershed yielded a significant decline in overall EII score, and three watersheds yielded a significant improvement.Waller Creek Working Grou
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Supplemental Monitoring of Selected Water Bodies with Contact Recreation Impairments
This report contains data regarding E.coli, ammonia and nitrate levels in a variety of Waller Creek locations There are pictures of monitoring sites where the data was collectedNutrient and indicator bacteria data were collected at seven sites in five Austin creeks that are on the draft 2010 Clean Water Act section 303(d) list of impaired water bodies proposed by the TCEQ. The supplemental data was collected to verify the TCEQ assessment that the creeks are not supporting designated uses of primary contact recreation in the Texas Surface Water Quality Standards due to elevated bacteria levels (30 TAC 307.7(b)(1)(A)(i)). These streams may also be “of concern” under Clean Water Act section 305(b) due to nutrient enrichment. Flow monitoring indicated that Eanes Creek below the Barton Springs Edwards Aquifer recharge zone is ephemeral; therefore, the bacteria impairment for this site is not appropriate according to TCEQ assessment methodology. Bacteria levels are low enough at the Westlake-Davenport Tributary site to fully support primary contact recreation uses. Primary contact recreation is not supported at the Waller Creek, Taylor Slough South or Spicewood Tributary to Shoal Creek sites. Elevated nutrients at Waller Creek appear to be from and indeterminate source of sewage contamination and those at Westlake-Davenport are most likely from nearby residential fertilizer application.Waller Creek Working Grou
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The Town Lake Report, Volumes I and II
This report makes brief references to sediment and other trends seen in Waller Creek.EXECUTIVE SUMMARY: Town Lake’s importance as a natural resource is growing in tandem with Austin’s rapid population. The lake is a source of drinking water for the City, and its greenbelt and open waters are widely used for recreation and as a focal-point for public events. In 1992, under the Clean Lakes program, a comprehensive report entitled the “Town Lake Study” (COA 1992a; COA 1992b; COA 1992c) was prepared. It examined the condition of the lake (Volume I), water quality control alternatives (Volume II) and a feasibility study (Volume III). This report updates the diagnostic study, Volume I (COA 1992a), including the current status of water quality with data analyzed through the year 2000. It also includes a summary of measures taken to reduce pollution from urban runoff since 1990.Waller Creek Working Grou
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