Hydrodynamics of Eastern Lake Ontario and the Upper St. Lawrence River
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JGLR-00386; No. of pages: 11; 4C: Journal of Great Lakes Research xxx (2011) xxx–xxx Contents lists available at SciVerse ScienceDirect Journal of Great Lakes Research journal homepage: www.elsevier.com/locate/jglr Q31 Hydrodynamics of eastern Lake Ontario and the upper St. Lawrence River Q12 Shastri Paturi a, Leon Boegman a,⁎, Yerubandi R. Rao b,1 3 a Department of Civil Engineering, Queen's University, Kingston, ON, Canada K7L 3N6 4 b National Water Research Institute, Environment Canada, Burlington, ON, Canada L7R 5 article info abstract 6 7 Article history: Eastern Lake Ontario and the upper St. Lawrence River provide drinking water for approximately 175,000 24 8 Received 10 January 2011 people. To understand the flow dynamics surrounding the eight drinking water intakes in this region, the 25 9 Accepted 27 September 2011 hydrodynamics were simulated using the Estuary and Lake Computer Model (ELCOM) for the period April– 26 10 Available online xxxx 27 11 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 28 12 Communicated by Joseph Makarewicz − 1 151314 ~5–8cms , respectively. Normalized Fourier norms ranged from 0.8 to 1.2. These errors are consistent 29 30 16 Keywords: with other applications of Reynolds-averaged models to the Great Lakes. ELCOM thus reasonably captures 17 Hydrodynamics the dynamics of the flow regimes in the nearshore region. The flow was found to be predominantly wind 31 18 Kingston Basin induced in the southwestern lacustrine portion of the domain, with observed but not modeled weak near- 32 19 St. Lawrence River inertial oscillations, and hydraulically driven in the northeastern riverine portion. Diurnal and semi-diurnal 33 20 Model calibration forcing influenced the flow throughout the domain. Flow reversal of the St. Lawrence River near Kingston 34 21 Spectral analysis occurred during strong easterly storm events. The model results were applied to delineate Intake Protections 35 22 Flow reversal Zones surrounding the municipal drinking water intakes. 36 Q423 Intake protection zones © 2011 Published by Elsevier B.V. on behalf of International Association for Great Lakes Research. 37 41 3839 40 42 Introduction by bottom topography and the circulation is affected by the presence 63 of the islands. For example, the flow around Amherst Island is 180° 64 43 There are eight municipal drinking water intakes in eastern Lake out of phase with the wind, and the currents exhibit high variability 65 44 Ontario and the upper St. Lawrence River (Fig. 1). Of the approximate due to the barotropic pressure gradients induced by the wind- 66 45 100,000 m3 day− 1 of water drawn from these intakes, 46% is for do- driven water level setup. The flow in the Kingston Basin is stratified 67 46 mestic use servicing approximately 175,000 residents. There are during summer months. The application of a finite volume model 68 47 also six wastewater treatment plant outfalls, as well as numerous (FVCOM) to Lake Ontario (Shore, 2009) revealed that the flow of 69 48 combined sewers, storm sewers, and industrial outfalls located on water from the main body of Lake Ontario into the Kingston Basin oc- 70 49 the Canadian side of this waterway. curs when the depth exceeds 20 m and that a reverse flow back into 71 50 Under the Clean Water Act (2006), it was mandated that drinking the lake can occur in shallower regions. Shore's (2009) application 72 51 water intake protection zones (IPZs) be delineated surrounding these applied monthly mean meteorological data and had relatively coarse 73 52 intakes, whereby land use will be managed within a zone extending representation of the islands in the region (e.g., Amherst, Wolfe, and 74 53 over a 2 h water travel time from each intake. To delineate IPZs, an Frontenac). Tsanis and Murthy (1990) calculated the outflow of 75 54 understanding of the hydrodynamics is required throughout the re- water from the Kingston Basin to the St. Lawrence River to be 76 55 gion, which extends from the Kingston Basin in eastern Lake Ontario 8300 m3 s− 1. The flow distribution was estimated at 55% in the chan- 77 56 to Brockville in the upper St. Lawrence River. nel south of Wolfe Island and 45% in the north Channel. 78 57 The Kingston Basin (Fig. 1) separates the main body of the lake The flow through this region of St. Lawrence is controlled by the 79 58 from the entrance toUNCORRECTED the St. Lawrence River and is characterized by Moses Saunders PROOF hydroelectric dam near Cornwall, ON. Potok and 80 59 numerous underwater ridges, channels, and islands. Observational Quinn (1979), applying a one-dimensional transient hydraulic 81 60 studies have shown the existence of complicated hydraulic and model, found the model flow to be sensitive to the Manning's n 82 61 wind-induced circulation patterns (Tsanis et al., 1991). Tsanis et al. roughness coefficient and the flow through the dam. Thompson et 83 62 (1991) found that the flow (0.8–1.8 cm s− 1) is strongly influenced al. (2008) applied a two-dimensional (depth averaged) hydrodynam- 84 ic model to the upper St. Lawrence River downstream from Lake 85 Ontario and found that uncertainties in Manning's n contributed to 86 ⁎ Corresponding author. Tel.: +1 613 533 6717. model uncertainties in water levels and velocities. A two- 87 E-mail addresses: [email protected] (S. Paturi), 88 [email protected] (L. Boegman), [email protected] (Y.R. Rao). dimensional (depth-averaged) Lagrangian model was also applied 1 Tel.: +1 905 336 4785. to simulate the transport of chemical spills in the upper St. Lawrence 89 0380-1330/$ – see front matter © 2011 Published by Elsevier B.V. on behalf of International Association for Great Lakes Research. doi:10.1016/j.jglr.2011.09.008 Please cite this article as: Paturi, S., et al., Hydrodynamics of eastern Lake Ontario and the upper St. Lawrence River, J Great Lakes Res (2011), doi:10.1016/j.jglr.2011.09.008 2 S. Paturi et al. / Journal of Great Lakes Research xxx (2011) xxx–xxx Methods 130 Model description 131 We applied the Estuary and Lake Computer Model (ELCOM; 132 Hodges et al., 2000). It is a three-dimensional, hydrodynamic, 133 z-coordinate model used for predicting the velocity, temperature, 134 and salinity distribution in natural water bodies subjected to external 135 environmental forcing such as wind stress, surface thermodynamics, 136 and inflows and outflows. It is designed to facilitate modeling studies 137 of aquatic systems over seasonal time scales, although the limit of 138 computational feasibility depends on the size of the lake, the resolu- 139 tion requirements, and available computational resources. The 140 model solves the unsteady, viscous Navier–Stokes equations for in- 141 compressible flow using the hydrostatic assumption for pressure 142 (Dallimore and Hodges, 2000). Modeled and simulated processes in- 143 clude baroclinic and barotropic responses, rotational effects, tidal 144 forcing, wind stresses, surface thermal forcing, inflows, outflows, 145 Fig. 1. Map showing the nearshore bathymetric grid with 300 m horizontal resolution and transport of salt, heat, and passive scalars. The hydrodynamic al- 146 along with locations of the eight municipal drinking water intakes (1 — Brockville, 2 — gorithms in the model are based on the Euler–Lagrange method for 147 Gananoque, 3 — Kingston Central, 4 — Kingston West, 5 — Fairfield, 6 — Bath, 7 — A.L. 148 Dafoe & 8 — Sandhurst Shores), observational moorings Stations (a — 1262, b — 1263, advection of momentum with a conjugate-gradient solution for the c — 1264, d — 1265) and the wind data for the stations along St. Lawrence River (Kings- free-surface height (Hodges, 2000). ELCOM has an eddy-viscosity/dif- 149 ton airport — e). The solid blue lines are the open boundaries. The wind rose diagram fusivity closure scheme for horizontal turbulence correlations and 150 for Station 1263 is shown in Fig. 2. (For interpretation of the references to color in employs the ULTIMATE QUICKEST advection scheme for scalars. Ver- 151 this figure legend, the reader is referred to the web version of this article.) tical mixing was computed using an explicit turbulent kinetic energy 152 budget closure scheme that was applied to each individual water col- 153 90 River (Shen et al., 1995). This model was not comprehensively vali- umn of the three-dimensional (3D) flow matrix during each model 154 91 dated against field observations. time step (Hodges et al., 2000). Turbulent kinetic energy was intro- 155 92 The objective of our study was to simulate the dynamics of both duced at the surface from surface wind stress and at the lake bed 156 93 the Kingston Basin and upper St. Lawrence River and to apply the through a bottom shear drag coefficient parameterization. The extent 157 94 model to delineate IPZs. This was the first application of a transient of mixing performed in a single model time step was limited by a 158 95 three-dimensional model to the region, which was directly forced mixing time scale, allowing for partial mixing of vertically adjacent 159 96 with observed meteorology, had detailed representation of the cells (Laval et al., 2003). Momentum was introduced into the water 160 97 islands, and was comprehensively validated against detailed field ob- column by wind stress at the surface and was distributed vertically 161 98 servations. We applied the three-dimensional, hydrostatic Estuary by the 3D mixed-layer model. 162 99 and Lake Computer Model (ELCOM; Hodges, 2000) which has been 100 shown to accurately simulate the dynamics of stratified lakes and res- Model setup 163 101 ervoirs (e.g., Laval et al., 2003).