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Comparison of SELDM simulated total-phosphorus concentrations with ecological impervious-area criteria

June 9, 2020

Ecological studies indicate that impervious cover (IC) greater than approximately 5%–20% may have adverse effects on receiving-stream ecology. It is difficult to separate the effects of runoff quality from other effects of urbanization on receiving streams. This study presents the results of a numerical experiment to assess the effects of increasing IC on water quality using the Stochastic Empirical Loading and Dilution Model (SELDM). Hydrologic and physiographic variables representative of southern New England were used to simulate receiving water quality in a basin with IC ranging from 0.1% to 30%. Simulation results mirror the results of ecological studies; event mean concentrations (EMCs) of total phosphorus (TP) increase proportionally to the logarithms of imperviousness for a given risk percentile. Simulation results indicated that commonly used stormwater treatment methods may be insufficient for mitigating the effects of imperviousness. Therefore, disconnection, rather than treatment, may be needed to protect water quality, and efforts to preserve undeveloped stream basins may be more effective than efforts to remediate conditions in highly developed basins. Results also indicate that commonly used water-quality criteria may be too restrictive for stormwater because TP EMCs frequently exceed these criteria, even in minimally developed basins.

Citation Information

Publication Year 2020
Title Comparison of SELDM simulated total-phosphorus concentrations with ecological impervious-area criteria
DOI 10.1061/(ASCE)EE.1943-7870.0001763
Authors Lillian C. Jeznach, Gregory E. Granato
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of Environmental Engineering
Series Number
Index ID 70211905
Record Source USGS Publications Warehouse
USGS Organization New England Water Science Center