基于SWAT模型的阜平流域土地利用/覆被变化的径流响应

The response of runoff to land use and coverage change in Fuping watershed based on SWAT model

以阜平流域为研究区,基于1980、2005、2010年3期土地利用数据,采用土地利用转移矩阵分析阜平流域土地利用的时空变化情况,并构建适用于阜平流域的SWAT分布式水文模型,定量分析土地利用变化对径流的影响。结果表明:1980-2010年林地和草地是阜平流域的主要土地利用类型,共占流域面积90%以上,1980-2005年各土地利用类型面积变化不明显,2005-2010年土地利用类型变化主要表现为草地转换为林地,转换面积为1 007.55 km^2;通过敏感性分析,确定了10个敏感参数,在参数率定和模型验证期,R^2和Ens均大于0.80,说明SWAT模型能够较好地对阜平流域径流进行模拟;与2005年土地利用情景相比,2010年土地利用变化引起年均径流量减少0.44亿m^3/s,变化主要集中在7-9月,子流域1、11变化较大,主要位于流域东北部以及南部地区。

Taking the Fuping watershed as a research area, a land use transfer matrix was used to analyze the spatialtemporal changes of land use in the Fuping watershed based on the land use data of three periods in 1980, 2005, and 2010, and a SWAT hydrological distribution model was established to quantitatively analyze the impact of land use change on runoff of Fuping watershed. The results showed that forest and grassland were the main land use types in the Fuping watershed from 1980 to 2010, accounting for more than 90% of the watershed area. The area of each land use type did not change significantly from 1980 to 2005. Changes in land use types from 2005 to 2010 were mainly realized as grassland conversion to forest land, with a conversion area of 1007.55 km^2. Through parameter sensitivity analysis, 10 sensitive parameters were determined. During the parameter calibration and model verification period, R^2 and Ens were greater than 0.80, indicating that the SWAT model can well simulate runoff in Fuping watershed. Compared with the land use scenario in 2005, the annual average streamflow decreased by 44 million m^3/s. The changes were mainly concentrated on period between July and September. The annual streamflow changed largely in sub-watershed 1 and 11, locating in the northeast and southern parts of the watershed.