MIXED-LAYER HYDROTHERMAL RESERVOIR MODEL

This paper describes a new epilimnetic mixing formulation for two-dimensional reservoir models. This formulation incorporates a wind-mixing algorithm based on a mixed-layer theory developed previously for the upper Ocean. Given an input of relevant meteorological parameters, the algorithm computes a heat-flux source term and a mixed-layer thickness using a mechanical energy balance approach. The computed heat-flux profile is used as a source term to the two-dimensional longitudinal-vertical) transport equation for temperature. This transport equation is coupled with a corresponding laterally averaged hydrodynamic model developed previously. The combined formulation is solved using a semi-implicit, central-differencing scheme. Overall, this modeling approach requires minimal parameterization of wind-mixing processes. The combined model was adapted to an elongated (10.6-km-long, 0.8-km-wide) reservoir system, the Wanaque Reservoir, New Jersey. Wanaque Reservoir data were collected semimonthly during a calibration period (August 1983 through November 1983) and a year-long verification period (November 1985 through November 1986). The model adaptation successfully reproduced salient features of the vertical structure, including a warm, well-mixed epilimnion, a relatively thin and abrupt metalimnion, and a cold, nearly isothermal hypolimnion.