Best Management Practices Affect Water Quality in Coastal Watersheds

Abstract

Coastal ecosystems are vulnerable due to watershed sediment and nutrient loads. In this study, the hydrology and water quality of two coastal watersheds, Wolf River watershed (WRW) and Jourdan River watershed (JRW), were assessed using the Soil and Water Assessment Tool (SWAT). Model performance evaluation was performed using the coefficient of determination (R2) and the Nash–Sutcliffe Efficiency (NSE). After model calibration and validation, the effectiveness of ponds, wetlands, riparian buffers, and their combination as best management practices (BMPs) were analyzed. Total suspended solids (TSS) was reduced by 31.15% in the pond scenario and 30.37% in the wetland in WRW. In addition, mineral phosphorous (MinP) was reduced by 11.84% and 9.63% in ponds and wetlands, respectively. Similarly, in JRW, TSS was reduced by 74.89% in ponds and 74.90% in wetlands. Likewise, ponds and wetlands reduced MinP by 8.05% and 13.40%, respectively. Among four riparian buffer scenarios, the 30 m buffer prompted the estimation of higher reductions such as TSS by 28.36% and MinP by 29.77% in WRW, whereas a 13.14% TSS and 22.89% MinP reduction in JRW. In addition, combined BMP, TSS was reduced by 30.37% and MinP by 52.09% in WRW, followed by a 74.92% reduction in TSS and 27.37% in MinP in JRW. All BMP implementations were effective in reducing TSS and MinP. This study suggests that ponds and wetlands were effective in reducing TSS and riparian buffers were effective in reducing MinP. These findings could be insightful in coastal watershed management.

Evaluating Best Management Practice Efficacy Based on Seasonal Variability and Spatial Scales

“…Water quality impairment could cause the loss of aquatic life due to hypoxia, harmful algal blooms (HABs), salinity increment in benthic zones, and recreational deprivation [4,5]. Implementing conservation strategies, also known as best management practices (BMPs) has proven effective in mitigating the non-point source (NPS) pollutants that are generated from agricultural runoff [6][7][8]. The impact of BMPs can vary seasonally due to humid sub-tropical climatic conditions in the Yazoo River Watershed (YRW) and the increased precipitation experienced from November to March after harvesting the main crops [9].…”

“…Consequently, a field-scale watershed, Merigold Watershed (MW), with agriculture as a major land use type was delineated within the YRW. Numerous hydrological models including the Soil and Water Assessment Tool (SWAT) have been applied to evaluate hydrology and water quality at watershed scales [7,[19][20][21][22][23][24][25][26][27][28][29][30]. Hydrological model simulations could be beneficial in investigating seasonal variation in the efficiency of BMPs related to streamflow, sediment, nitrogen, and phosphorus [12,[31][32][33][34][35].…”

Effectiveness of stormwater control measures in protecting stream channel stability

“…Central to the USSC is the emphasis on distributed, decentralized SCMs, designed for the detention and treatment of runoff. The USSC also encourages the implementation of non‐structural SWM practices, such as cluster development (Brown et al, 1988) and riparian buffer protection (Bhattarai & Parajuli, 2023). Collectively, these practices are also known as low impact development (LID) (Prince George's County (MD), 2000).…”