Evaluating the effectiveness of management practices on hydrology and water quality at watershed scale with a rainfall-runoff model

• Published in: The Science of the total environment Vol. 511; pp. 298 - 308
• Main Authors: Liu, Yaoze, Bralts, Vincent F., Engel, Bernard A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-04-2015
• Subjects: Best management practices; Conservation of Natural Resources - methods; Cost engineering; Cost-effective; Hydrology; L-THIA; Low impact development practices; Modeling; Models, Theoretical; Nitrogen - analysis; Phosphorus - analysis; Pollutants; Rain; Reduction; Runoff; Scale (ratio); Water Pollutants, Chemical - analysis; Water Pollution; Water quality; Water Quality - standards; Water Supply - statistics & numerical data; Watersheds; Wetlands; Runoff; Best management practices; Low impact development practices; Water quality; L-THIA; Modeling; Cost-effective
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2014.12.077

The adverse influence of urban development on hydrology and water quality can be reduced by applying best management practices (BMPs) and low impact development (LID) practices. This study applied green roof, rain barrel/cistern, bioretention system, porous pavement, permeable patio, grass strip, grassed swale, wetland channel, retention pond, detention basin, and wetland basin, on Crooked Creek watershed. The model was calibrated and validated for annual runoff volume. A framework for simulating BMPs and LID practices at watershed scales was created, and the impacts of BMPs and LID practices on water quantity and water quality were evaluated with the Long-Term Hydrologic Impact Assessment-Low Impact Development 2.1 (L-THIA-LID 2.1) model for 16 scenarios. The various levels and combinations of BMPs/LID practices reduced runoff volume by 0 to 26.47%, Total Nitrogen (TN) by 0.30 to 34.20%, Total Phosphorus (TP) by 0.27 to 47.41%, Total Suspended Solids (TSS) by 0.33 to 53.59%, Lead (Pb) by 0.30 to 60.98%, Biochemical Oxygen Demand (BOD) by 0 to 26.70%, and Chemical Oxygen Demand (COD) by 0 to 27.52%. The implementation of grass strips in 25% of the watershed where this practice could be applied was the most cost-efficient scenario, with cost per unit reduction of $1m3/yr for runoff, while cost for reductions of two pollutants of concern was $445kg/yr for Total Nitrogen (TN) and $4871kg/yr for Total Phosphorous (TP). The scenario with very high levels of BMP and LID practice adoption (scenario 15) reduced runoff volume and pollutant loads from 26.47% to 60.98%, and provided the greatest reduction in runoff volume and pollutant loads among all scenarios. However, this scenario was not as cost-efficient as most other scenarios. The L-THIA-LID 2.1 model is a valid tool that can be applied to various locations to help identify cost effective BMP/LID practice plans at watershed scales.
•The L-THIA-LID 2.1 model was developed for simulating BMP and LID practice impacts.•Grass strips were the most cost-efficient practice to reduce runoff and pollutants.•The L-THIA-LID 2.1 model is valid to help users identify cost effective plans.