Submitted to: Journal of Environmental Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/21/2012
Publication Date: 6/1/2013
Citation: Jeong, J., Kannan, N., Arnold, J.G., Glick, R., Gosselink, L., Srinivasan, R., Barrett, M.E. 2013. Modeling sedimentation-filtration basins for urban watersheds using Soil and Water Assessment Tool. Journal of Environmental Engineering. 139(6):838-848. Interpretive Summary: Holistic watershed planning requires understanding of management and climate impacts on all land uses within a watershed including urban areas. A common management practice used to mitigate water quality in urban streams are sedimentation-filtration basins. A new physically based model of water flow and sediment and organic deposition in sedimentation-filtration basins was developed and integrated into the Soil and Water Assessment Tool (SWAT). The model was validated with measured data from the City of Austin. The new model provides a tool to determine the impact of a common urban best management practice (sedimentation-filtration basins) on water quality within a complex watershed.
Technical Abstract: Sedimentation-filtration (SedFil) basins are one of the storm-water best management practices (BMPs) that are intended to mitigate water quality problems in urban creeks and rivers. A new physically based model of variably saturated flows was developed for simulating flow and sediment in SedFils within the Soil and Water Assessment Tool (SWAT). The integrated SWAT-SedFil model allows for simulation of unsaturated flow in the filtration basin during small storms and fully saturated flow. Unsaturated flow was modeled using a modified Green and Ampt equation, and saturated flow was simulated with Darcy’s Law. Unsaturated flow comprises only a small fraction of large storm events; however, many regular storms are small and may not generate sufficient runoff to create a saturated flow in the filtration basin. Therefore, the combined unsaturated/saturated flow approach for modeling SedFils improved the accuracy of the model, especially in long-term evaluations. The model performs well with respect to estimating storm-water and sediment at the inlet and outlet of a SedFil.