Hydrodynamics of eastern Lake Ontario and the upper St. Lawrence River

Abstract

Eastern Lake Ontario and the upper St. Lawrence River provide drinking water for approximately 175,000 people. To understand the flow dynamics surrounding the eight drinking water intakes in this region, the hydrodynamics were simulated using the Estuary and Lake Computer Model (ELCOM) for the period April–October 2006. Model simulated water levels, temperatures, and current velocities were compared with observations. Root-mean-square errors in temperature and current simulation were ~2°C and ~5–8cms−1, respectively. Normalized Fourier norms ranged from 0.8 to 1.2. These errors are consistent with other applications of Reynolds-averaged models to the Great Lakes. ELCOM thus reasonably captures the dynamics of the flow regimes in the nearshore region. The flow was found to be predominantly wind induced in the southwestern lacustrine portion of the domain, with observed but not modeled weak near-inertial oscillations, and hydraulically driven in the northeastern riverine portion. Diurnal and semi-diurnal forcing influenced the flow throughout the domain. Flow reversal of the St. Lawrence River near Kingston occurred during strong easterly storm events. The model results were applied to delineate Intake Protections Zones surrounding the municipal drinking water intakes.