沂河上游土地利用变化的设计洪水响应研究

Study on Design Flood Response of LUCC in the Upper Reaches of Yihe River

土地利用变化会显著影响流域产汇流过程,进而改变流域洪水响应.为了探讨沂河上游不同重现期下设计洪水对土地利用变化的响应,分析了沂河上游1985年和2015年土地利用变化状况,构建沂河上游(HEC-HMS)模型对1985年和2015年土地利用状况下的设计洪水进行模拟研究,通过洪峰变化率和CN变化值的关系趋势对沂河上游进行空间响应分区.结果表明,沂河上游30年间林地耕地占比分别减少了3.23%、4.33%,草地建设用地占比分别增加了1.13%、6.67%,土地利用的变化导致了沂河上游不同重现期的洪峰与径流深均出现增加,峰现时间出现提前,重现期越低变化越明显,东部地区土地利用变化的设计洪水响应最强,特别是石桥镇区域,西部地区次之,南部地区则响应最弱.

LUCC will significantly affect the process of runoff yield and concentration,and then change the response of basin flood.In order to study the response of design flood to LUCC under different return periods in the upper reaches of Yihe River,the LUCC in 1985 and 2015 was analyzed,and HEC-HMS model was constructed to simulate the design flood under the land use conditions in 1985 and 2015.The spatial response zoning of the upper reaches of Yihe River was carried out through the relationship between peak change rate and CN change value.The results showed that the proportion of forest land and cultivated land decreased by 3.23%and 4.33%respectively,and the proportion of grassland and construction land increased by 1.13%and 6.67%respectively in the upper reaches of Yihe River in 30 years.The LUCC led to the increase of flood peak and runoff depth in different return periods in the upper reaches of Yihe River.The peak time appeared earlier,and the lower the return period was,the more obvious the change was.LUCC has the greatest impact on the design flood in the eastern area,especially in Shiqiao Town,followed by the western area,and the southern area.