A macro-model for calculating benefit of flood control system in a basin

The present models of flood control benefit need a lot of data,and are complex in calculation.In accordance with the problems above,this paper presents the concepts of flood frequency-area coefficient and flood frequency-damage degree coefficient,and infers a macro-model for calculating benefit of flood control systems in a basin on the base of macro-hypothesis in connected with the characteristics of flood control benefit.The results of a case study prove that the model is rational and easily operated.