Construction Site Sediment Control: Laboratory and Field Assessment of Best Management Practices for Nutrient and Sediment Removal

Abstract

Construction sites significantly contribute to sediment and nutrient pollution due to soil disturbance and vegetation removal. This poses risks to surface water quality by increasing turbidity, promoting eutrophication through enhancing nitrogen and phosphorus transport, with runoff acting as the primary mechanism for nutrient and sediment delivery. This thesis evaluates the sediment and nutrient control performance of three temporary best management practices (BMPs) consisting of compost filter sock (CFS), silt fence (SF), and triangular silt dike (TSD). A multi-method approach was used to compare and validate data across multiple experiments including a two-year paired catchment field study and controlled hydraulic flume testing.The TSD demonstrated the most effective sediment control with an average sediment retention rate of 86% in laboratory trials and 89% in field conditions. SF exhibited moderate sediment retention with 76% in laboratory and 78% in field while CFS showed 65% in the field but underperformed in the lab at 29%. An increase in nutrients in the CFS and TSD effluent in both the lab and field studies suggest nutrients present to the organic media in the CFS and the urethane foam media of the TSD. SF had little nutrient interaction, but some effluent increases in the field can be attributed and bring attention to SF installment methods. However, it is crucial to note that this behavior was likely influenced by the smaller stormwater volume used, which captured the initial nutrient release with limited dilution, resulting in elevated effluent concentrations. These findings underscore the need for BMPs that target both sediment and nutrient retention with emphasis that each BMP may provide differing solutions given site conditions and objectives. This thesis supports the need for a flexible and adaptive approach to erosion and nutrient control, in which BMP selection is guided by sediment removal efficiency, nutrient interaction behavior, and compatibility with site characteristics and performance goals.