Geometric representation of rivers and lakes in hydrologic models: a review

An accurate representation of river and lake geometry is crucial for hydrologic modeling, influencing simulations of water storage/discharge, flood routing, and inundation extent. However, for spatially distributed hydrologic modeling, it is challenging to obtain high-resolution data on the shape, depth, and width of river channels and lake basins. Therefore, simplifying assumptions, such as representing river reaches as rectangular or trapezoidal channels or lakes as idealized geometries, are often used. In this paper, we review some of the existing methods and challenges for representing river and lake geometry in hydrologic models and discuss their implications and limitations for model accuracy. We also propose some guidance and improved approaches that can account for more realistic geometry while maintaining parsimony in model input and runtime.