Prediction of surface water turnover time in coastal waters using digital bathymetric information

Abstract

AbstractThis paper presents a new type of geographical information system (GIS) for scientific planning of coastal waters. One hypothesis in the work is that the morphometry of the coast plays a significant role for how the water system functions as a receiving water system, for example, as a receiver of industrial and urban pollution and in response to various forms of aquaculture. A digital technique for transferring information from standard charts into morphometric parameters expressing various characteristics of the coast has been developed. Empirical data on surface water turnover times, which are costly and demanding to determine with traditional hydrodynamic methods, has been obtained from the literature for 20 defined Swedish coastal areas. Two models for simple predictions of the median surface water turnover time, based on morphometric parameters, have been developed to exemplify the use of “morphometrical models” in expressing a coast ecological key parameter. In these models, more than 90 per cent of the variation in empirical values of surface water turnover times can be statistically explained by the topographic openness. The topographic openness describes the exposure of the coastal area towards the open sea or adjacent coastal area. The models are valid for the temperature stratified period (May–October) in areas non‐affected by tides, strong coastal currents and river inflow. The areas should also be in the size range 0.15–150 km2.