THE EFFECTS OF URBANIZATION ON CATCHMENT STORAGE CAPACITY-A CONCEPTUAL MODEL IN PLAIN CATCHMENT IN YANGTZ RIVER DELTA

摘要

Drainage networks and underlying surface in Yangtze river delta area have been significantly changed due to the rapid urbanization and adversely affects the hydrological processes. In this study we took the Qinhuai River Basin in Yangtz River delta as study area, analyzed the total catchment storage capacity and its temporal variation from 1980s to 2010s, based on a conceptual model involving four modules: river network, lakes/reservoir, wetland and forest. The data source is TM images from 1980s and 2010s, thematic maps, digital elevation model, and hydrological data from gauge stations. The main findings of this study is, 1) the current storage capacity of Qinhuai river catchment decreased by 13.45%, from 207.39*106 m3 to 179.49*106 m3 during the study period; 2) the lake/reservoir storage is the most sensitive module to the urbanization, while the river network module serves as the biggest contributor to the total catchment storage capacity. More efforts should be made in the protection and restoration of the low-level rivers, forest and wetlands to optimize the catchment storage capacity. The results of the study would provide support in policy formulating and intervention strategies, and at the same time, opening new challenges for the evaluation of the hydrological process in high urbanized area.