Many wind farms are under development in recent years offshore the US coast. Energy produced by the wind farms is transmitted to onshore power grid through submarine export cables. Construction of the offshore facilities and the cables involves dredging of the sea floors, causing fine sediments to be suspended into water column. Where sediments contain contaminated compounds, the dredging constructions could impact water quality in regulated waters. One key requirement in offshore windfarm construction and operation permitting at federal and state level is to investigate the impact on sediments and water quality. Because it is often cost-prohibitive to collect suspended sediment concentration and water quality data in large-scale offshore project areas, a Langrangian particle tracking approach is used to model suspended sediment concentration (SSC) and water quality over ambient condition. In this presentation, we use the USACE Particle Tracking Model (PTM) model with the input of 3-dimensional hydrodynamic forcings to simulate sediment transport and water quality from several dredging construction methods. We investigate impact parameters such as maximum SSC, sediment plume spread, deposition, and time above factor, with respect to regulated thresholds and buffer zone limits. By assuming instantaneous dissolution, we extend the discussion to water quality from contaminated sediments and compare to regulated water quality standards.
.jpg "Kathryn Teske (she/her/hers) photo")