Impacts of Land-use Cover Changes on Flooding: a Case Study of Fen River in the Yellow River, China

The purpose of the study presented here is to further build this recent work by revealing the influence of land-use changes on floods in Fen river basin, which is the breaches of the Yellow river watershed in China. Soil and water conservation measures were adopted in the past 30 years, and hence leads to further change in land-use cover. So it becomes essential to assess the effect of change in land-use cover on floods processes of a region and of small watershed levels (sub-basin levels) in particular. Such an analysis can effectively be carried out by using watershed simulation models. A modified Xinanjiang model, which considers both Horton and Dunne runoff generation mechanisms simultaneously, was used for this purpose to simulate flood processes. The current study assesses the effect of land-use cover on flood characteristiscs of Jingle watershed, which is the upbreaches of Fen river watershed. It also assesses how the change in land-use cover in the last 30 years affected the flood processes. It can seen that the reduction in the farmland area amounts to 27.09% and 20.53% in the analyzed watershed, and the increase in the forest land and grassland amounts to 32.14% to 37.95%, and 38.89% to 39.63%, respectively. However, the changes in the flood processes for the Jingle watershed are not comparable with the changes in the land-use cover. The simulation results show that the changes in the land-use cover during 1979 1998 made the peak discharge to increase and flood volume to decrease, the changes in the land-use cover during 1999-2012 made the peak discharge to decrease and flood volume to increase. This action shall change the groundwater percolation and shall counter act the effect due to evapo-transpiration.