Feasibility of Retrofitting Drainage Facilities to Improve Water Quality

Project Description

Urban runoff poses challenges to the Texas Department of Transportation (TxDOT) in determining the best storm water structure for use in urbanized areas. Storm water treatment structures (also called best management practices [BMPs]) are capable of removing a wide range of pollutants from storm water. However, no single structure is capable of satisfying all water quality parameters. The primary pollutants found in urban and highway runoff are sediments like sand silt, clay minerals, and other granular materials; metals; nutrients, primarily nitrogen and phosphorous; bacteria; organic compounds; hydrocarbons; floatables; and other chemical compounds. The processes that remove these pollutants include: sedimentation, adsorption, flotation, filtration, infiltration, biological uptake, biological conversion, and degradation. This project identified technologies available for retrofit, like the Austin sand filter. Researchers collected water quality performance data for the available technologies so that TxDOT would have access to current BMP and performance data for future retrofit projects. Researchers also developed a selection guidance process and a pilot prioritization scoring system that address the numerous aspects of a retrofit project. In order to anticipate and adequately consider all the influencing factors involved in a storm water quality retrofit project, TTI researchers recommend early, active planning and prioritizing. This would involve identification and evaluation of water quality performance goals, budget resources available, land resources, and terrain. This project identified and developed tools directed toward jointly attaining water quality goals, cost, and land considerations.

Project Publications

Retrofitting TxDOT Drainage Structures to Improve Stormwater Quality 0-4173-2

Retrofitting Existing Drainage Systems for Water Quality 0-4173-S

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