Quasi‐Two‐Dimensional Reservoir Simulation Model

Abstract

A quasi‐two‐dimensional model for the simulation of temperature, salinity, and density in a reservoir is described. The model is based upon the one‐dimensional reservoir simulation model DYRESM, and is extended into two dimensions using a Lagrangian formulation of self‐contained parcels within the layer structure of the one‐dimensional model. These parcels resolve the horizontal motions and gradients by moving vertically or horizontally and splitting and combining to simulate the various physical processes in the reservoir occurring in response to the prevailing climatological conditions. The model is not a full two‐dimensional model, because not all horizontal processes are included. Algorithms to simulate inflow, selective withdrawal, and adjustment of horizontal density gradients are included, however, and the model is therefore quite useful for examining some simple scenarios in which these processes are dominant. The results of simulations of Canning Reservoir in Western Australia showing several inflow and intrusion events at different times of the year, and the return of the reservoir temperature field to a one‐dimensional structure after the cessation of inflow, are presented. These results are compared with measurements taken in the field, with good agreement. The usefulness of the model in its present form for following the path and estimating the detention time of various parcels of water is discussed.