A geohydrological study of the Richards Bay area
Numerical methods such as groundwater models can play a vital rplein understanding the dynamics of an aquifer provided that the input data is accurate and sufficient to represent the environmental system adequately. The groundwater flow mode! used in this project requires specific information about geological features, hydraulic properties as well as recharge and evapotranspiration. All the available information has been collected and interpreted to use.in the model. There is a need to develop conceptual models of the region for theicnplementation of the numerical methods. The regional geology is well described in the literature, but observations on a local scale do not always conform to the?regional stratigraphy. Consequently, many assumptions have been made in the construction of three conceptual models, namely a single layer model, a multi-layer model with homogeneous hydrological properties and a heterogeneous multi-layer model. MODFLOW (McDonald and Harbaugh, 1983), a quasi three dimensional, finite difference, groundwater flow model, was used to determine the regional groundwater flow patterns in the Richards Bay area. A summary of the theory and parameterization process used in the model is presented. Considerable detail is offered for the conceptual modelling of specific processes not incorporated in the finite difference scheme of the numerical model. These include recharge and evapotranspiration. The model domain and parameters that were used in the model as-well as the calibrations are described. For Hie general flow pattern for the region, the groundwater divides for each catchment were determined and are presented in relation to the diverse land use sectors. The project identified the different land use sectors within the principle catchment areas of the main water resources of the region. In particular, it provided a demarcation of which parts of the Richards Bay Industrial sectors could influence the water quality of the various water bodies of the region.
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