Integrated Surface Water-Groundwater Modelling

Abstract

Two Integrated Surface water - Groundwater flow Models (ISGMs) have been developed
 at the National Technical University of Athens (NTUA), Greece and Cardiff University
 (CU), UK to investigate surface water-groundwater interactions. The models are based on
 physical processes and are capable of describing more accurately the recharge and
 discharge flow paths between surface and ground waters.
 The NTUA ISGM consists of a 3-D surface water flow sub-model (FLOW-3DL) and a 3-D
 saturated groundwater flow sub-model. The CU ISGM is based on the 2-D surface water
 model DIVAST, which has been extended to include 2-D saturated groundwater flow.
 Both models use the finite difference method and orthogonal grids. The momentum and
 mass conservation equations are the governing equations for both surface and
 groundwater flows.
 The ISGMs have been applied to two simple cases and their results have been compared
 to computations using only surface water models (FLOW-3DL and DIVAST) to
 demonstrate the need to use ISGMs for accurate and satisfactory calculations.
 Furthermore, the results of the two ISGMs are compared for a channel, which fully
 penetrates an aquifer. The two ISGMs show a similar behaviour; the NTUA ISGM exhibits
 a slightly slower response of the aquifer water levels to the water level changes in the
 channel than the CU ISGM.