嘉陵江流域下游地表径流对土地利用变化的响应

Responses of Runoff to Land Use Changes in Lower Jialing River Basin

近年来,嘉陵江流域下游发展迅速,流域内的土地利用发生了较大变化,下垫面的变化影响了流域的地表径流。在遥感和地理信息系统的支持下,通过解译1993年、2004年、2014年嘉陵江流域下游的遥感影像,获得了该流域不同时期的土地利用情况,并在此基础上,运用分布式水文模型的SCS模型模拟地表径流,分析了嘉陵江流域下游地表径流对土地利用变化的响应。结果表明:(1) 1993—2014年,嘉陵江流域下游土地利用以耕地转出为主,耕地是研究区唯一减少的土地利用类型,而且减少量较大,居民点及工矿用地和草地以转入为主,其他用地的空间转移较为复杂;(2)以汛期6月份的累年平均降水量190 mm作为嘉陵江流域下游的降水量,土地利用类型综合产流能力1993年>2004年>2014年,径流系数分别为0.699,0.671,0.668,在空间分布上南部地区>中部地区>北部地区;(3)研究区不同类型土地利用的产流情况与土地利用类型面积相关联,当土地利用—土壤组面积发生变化时,其对应的产流能力也会发生变化,进而影响地表径流。

The development of the lower reaches of the Jialing River Basin has been rapid in recent years, and the land uses in the basin have also changed dramatically, resulting in a large change of the surface runoff. In this paper, with the support of remote sensing and geographic information technology, land use data of different periods of the basin were obtained by interpreting the remote sensing images of the lower reaches of the Jialing River Basin in 1993, 2004 and 2014. The response of runoff to the land use change was analyzed based on SCS model. The results showed that:(1) in the period 1993—2014, the cultivated land which was the only decreased land use type in the study area decreased greatly, and residential, industrial area and grassland increased dramatically;other land use type transferred complicatedly;(2) In the flood season, the average annual precipitation of 190 mm in June was taken as the unified precipitation in the lower reaches of the Jialing River Basin, the integrated runoff capacity of land use type decreased in the order: 1993>2004>2014, runoff coefficients were 0.699, 0.671 and 0.668, respectively, and the rates of the runoff decreased in the oreder: southern region>the central region>the northern region;(3) the runoff was related to the land use type, when the land use-soil area changed, the corresponding runoff capacity changed, which further affected the surface runoff.