Maintaining numerical stability of flood plain calculations by time increment splitting

Abstract

An algorithm for simulating flood plain water levels during flood propagation in embanked river systems is presented. The algorithm uses volume conservation to simulate flood plain conditions. It differs from other storage pond algorithms in that it automatically adjusts the time increment used to maintain numerical stability. The time increment adjustment is carried out locally on the flood plain, permitting the main channel solution to proceed, using a time increment suitable for efficient implicit flood routeing calculations. Test results using hypothetical river data are presented