MODCYCLE-An object oriented modularized hydrological model II. Application

The distributed hydrology model-MODCYCLE was used to simulate the water cycle in Tianjin, It includes the analyzsis on water transfer relationship and basin water balance influenced by human activities in the period from 1997 to 2004. The model has been verified on five aspects, and the results show that the whole annual average recharge amount of Tianjin is this period is 7.409 billion m3, the whole annual average ET amount is 7.126 billion m3, the whole annual average discharge amount is 0.870 billion m3, and the whole annual average change amount is -0.582 billion m3. The ratio of precipitation to the whole recharge is 74.2%. Among the composition of total ET, the amount of land ET is the largest, amounting 76.8%. Most discharge, amounting 97.3%, flows into the Bohai Bay. The soil water resource, surface water resource, and the shallow groundwater resource all keep balance, but the deep groundwater resource needs pumping because of water recharge shortage. According to this study, it is suggested that the MODCYCLE model has supplied a method and tool to describe the characteristics of the artificial-natural dual water cycle on regions.