Simulation of Hydrological Response to Land Cover Changes in the Suomo Basin
流域土地覆被变化水文效应的模拟——以长江上游源头区梭磨河为例

In order to study the effects of land cover changes on hydrology, t he TOPMODEL was tested for the Suomo basin on the upper reaches of the Yangtze River. A modified version of the model was used to adapt to the basin condition and data availability. The model was calibrat ed with five year measured daily discharge record (1980-1984) and the parameters were estimated. With this model and the maps of land cover of the 1970s, the 1980s and the 1990s, daily discharge from 1960 to 1999 was simulated. Comparing simulated discharge with the measured records from 1 960 to 1999 in percentage efficiency, the model gave a sound result. After that, simulation was conducted under four land cover scenarios w ith the tested model. The main results were as follows: With the increase in lan d cover and interception capability, the basin interception evaporation i ncreased, transpiration and soil evaporation decreased, and overall evap oration increased. Soil moisture increased and saturation zone storage and basin water storage decreased with the increase in land cover and maximum int erception capability. Surface runoff and stream discharge decreased and subsurface runoff increased with the increase in land cover at the b eginning while decreased with further land cover increase. The degree of hydrological effects of land cover increase depends on the differen ce value between actual evapotranspiration and potential evaporation.The bigger difference, the higher effects of land cover changes on basin hydrology a re.