MODFLOW’s River Package: Part 1: A Critique

Abstract

Most widely used integrated hydrologic models were conceived and their development started some 50-60 years ago.  These models have undertaken many major improvements since. However they still describe the flow interaction between streams and aquifers using the primitive early concepts. Most users seem unaware of the limitations of these concepts, which use parameters that are empirical and can only be obtained by calibration.  In this Part1 the shortcomings of the methodology are shown in great details. In the article reference is made specifically to the code MODFLOW.  Most of the other integrated hydrologic models used for large-scale regional studies apply essentially the same methodology to estimate seepage. In a second Part means are presented by which improvements can be introduced in the procedures.