Abstract: The construction of hydraulic projects directly affects the hydrological response of a river basin, increasing the difficulty and uncertainty of flood forecasting. Through a case study of the Xinlicheng wetlands, this paper first chooses several characteristic indexes to identify the arid or humid state of wetlands, and groups the relevant historical flood events into two sets－the arid wetlands and humid wetlands. Then, we analyze the hydrological characteristics of the corresponding two types of flood events. On this basis, we develop a new method to consider the impact of the wetlands on reservoir inflows by adopting the Xin’anjiang model and modifying its sensitive parameters. The results show that the two-type wetlands can be reasonably divided using the antecedent precipitation and the occurrence times of previous flood events, and the simulation results of flood events are satisfactory for each type. Our new method simulates effectively the reservoir inflows affected by the upper wetlands, useful and applicable to other similar basins.

Key words: flood forecasting, upper wetland, Xin’anjiang model, flood event classification, Xinlicheng Reservoir