| Popis: |
A series of three major dams and reservoirs located along the Lower Susquehanna River have historically acted as a system of sediment and nutrient pollution traps. However, episodic pulses of these pollution loads are released following short-term extreme storm events, affecting subaquatic vegetation, benthic organisms, and the overall water quality in the Upper Chesapeake Bay. In addition, all three reservoirs have reached a state of near maximum storage capacity termed as dynamic equilibrium. Based on prior research, this study seeks to reduce the sediment buildup behind the dams through a sediment removal and processing operation, and thereby reduce the ecological impact of major storms. A set of scour performance curves derived from a regression analysis, and a stochastic lifecycle cost model were used to evaluate the sediment scouring reduction and economic feasibility of three processing alternatives: Plasma Vitrification, Cement-Lock, and Quarry/Landfill, and three removal amount cases: Nominal, Moderate, and Maximum. Since the scour performance curves treat the dams as static, a fluid system dynamics model was used to determine if the dynamic interaction between the capacitance of the dams during major scouring events is negligible or considerable. A utility vs. cost analysis factoring in time, performance, and suitability of the alternatives indicates that a Cement-Lock processing plant at moderate dredging for the Safe Harbor and Conowingo Dams is the most cost-performance effective solution. |
