徐州市土地利用变化对径流的影响

Effects of Land Use Change on Runoff in Xuzhou City

[目的]研究1983—2013年徐州市土地利用变化对径流的影响,为该市水资源利用与保护和土地利用结构调整服务。[方法]基于Landsat TM/ETM＋影像提取徐州市土地利用变化信息,采用验证后的SCS（soil conservation service）水文模型模拟了不同降水条件和下垫面状态下径流量的时空特征。[结果]（1）丰、平、枯降水条件下,年均径流深分别增加46,42和38mm;（2）径流深变化范围为299~800mm;（3）林地与建设用地之间转换导致径流系数的变化超过0.3,其余在0.1~0.3之间;（4）不同土壤湿润程度条件下,径流增幅大小表现为：AMCⅠ〉AMCⅡ〉AMCⅢ。[结论]建设用地的增加是近期径流增大的主要因素;2003年建设用地比超过20%,为土地利用变化影响径流突变的一个阈值;径流深的高值区为水体、建设用地、耕地以及煤矿区,低值区为林、草地;林地转为建设用地导致最大的径流增加值。

[Objective] To study the influence of land use change on the runoff in Xuzhou City from 1983 to 2013, and provide reference for water resources utilization and protection and land use structure adjustment in the city. [Methods] Using the data of land use change derived from Landsat TM/ETM＋ , the spatiotem- poral characteristics of runoff were simulated using soil conservation service hydrological model（SCS）. [Results] （1） In the years with abundant, normal and scarce rainfalls, the annual runoff depth was found increased by 46, 42, and 38 mm, respectively; （2） The runoff depth ranged from 299 mm to 800 mm. （3） The runoff coefficient was found with the most significant variation as high as 0.3, when forest was transformed to construction lands, other transformation ranged from 0.1 to 0.3; （4） The averaged increases of runoff on different soil moisture conditions ranked as. AMC Ⅰ 〉AMC Ⅱ 〉AMCⅢ. [Conclusion] The increase of con- struction land was the major factor that resulted in the increase of the runoff in recent years. The percentage of construction land reached the threshold value of 20 % in 2003, which corresponded to the runoff inflection point. Water-covered land, construction land, farmland, and coal mining land were the types with high depth value of runoff, whereas, forest and grass land has the low runoff depth. The transformation from forest to construction land caused the most significant increase of runoff coefficient.