Discussion of theory and methods for building a distributed hydrologic model

The evolution processes of the distributed hydrologic models are reviewed,and their building ways are analyzed. The physical basis is a key kernel of the distributed hydrologic models. A new and comprehensive explanation is given for the connotation of "physically-based". Two kinds of popular models,the distributed physically-based models and the distributed conceptual models,are discussed,especially about their existing problems and future. Finally,two new promising developmental directions are discussed:one is a physically-based incompact structure distributed hydrologic model that integrates the advantages of the above two kinds of popular models;the other is a deterministic-stochastic coupled distributed hydrologic model.