基于DEM和SCS模型的四川盆地丘陵区局地径流研究

Study of Local Scale Runoff in Hilly Regions of Sichuan Basin Based on DEM and SCS Model

人类活动对产流的影响是水文科学研究的热点,如何采取有效的方法利用表面径流成为解决水资源危机的关键问题。以重庆市忠县拔山镇3个村为研究区,基于土地利用、土壤、降雨等信息,应用SCS模型对四川盆地丘陵区局地径流进行计算和分析。研究区径流空间分布与下垫面土地利用类型和土壤类型密切相关,下垫面单一的水域和裸地所形成的径流量大,而有作物的水田和旱地所形成的径流量较小;研究区径流年内分配相对集中,主要产生在4月至10月,占全年的90%以上,但整体上看,径流与降雨呈现一致性趋势;研究区年际径流量分布不均,呈现丰、枯水年交替变化的现象,年径流变差系数Cv值较小。研究结果还表明:SCS模型所需参数较少,并考虑了径流与土壤特性和土地利用情况的关系,是一种简洁且实用的径流计算方法;利用GIS软件,可使局地径流数据图像化,这使径流等水文过程更加简明和直观。因此,利用GIS等软件分析研究各个集水区径流的时空变化等规律,可为研究各个集水区内农业水资源布局等提供方法和参考,实用性和可操作性强。

It is vital to solution of water resource＇s crises to effectively utilize surface runoff. Based on data of land use,soil and rainfall,runoff in hilly regions of Sichuan basin at a local scale was calculated and analyzed as a sample of Bashan town in Zhong County. The results showed that： firstly, the spatial distribution of run- off was highly related with land use type and agro-type on the surface,and amount of runoff on water area or un-utilized land was larger than those on paddy field and dry land with crop growing. Secondly, runoff was mainly distributed in April to October, being more than 90 % of the annual total runoff,and the annual change of runoff was similar to rainfall. Thirdly, the runoff was unevenly distributed with high and low flow year by turns and its small value of Cv. The SCS model was a simple and practical runoff computation method with a few parameters, in which the relationship among soil characteristics, land use status ,and runoff was substantially considered. And the data of local runoff have been become more simple and visual by using the GIS software. Therefore, runoff space-time change on each catchment analyzed by using the GIS could provide an effective methods and adequate references for the allocation to agricultural water at a local scale.