概念性土壤侵蚀模型的建立及在紫色土小流域的应用

Establishment of conceptual soil erosion model and application in purple soil watershed

概念性土壤侵蚀模型在描述流域基本过程的同时对参数要求较低,现有概念性模型中计算产沙所需参数主要靠律定或借鉴经验值。该文介绍了1个无需流域出口产沙量长序列观测资料来律定且能适用于研究流域的概念性土壤侵蚀模型。模型中引入了分布式水文模型WetSpa Extension作为水文模块,结合流域内试验小区上建立的流量—产沙量经验关系计算侵蚀量,再结合泥沙输移比构建起产沙模块。通过在紫色土地区小流域的应用表明,模型能够得到较合理的流域出口产流量、产沙量以及侵蚀率的空间分布等模拟结果,在没有试验小区的邻近流域地区也具有推广性,且能作为评价水保措施效益的有力工具。该概念性模型对于流域出口泥沙资料稀少的地区具有很高的应用价值和协助流域管理的潜力。

Conceptual soil erosion model can depict basic watershed processes yet does not require intensive data. Erosion-related parameters in the current conceptual erosion models are determined either by calibration based on long series of sediment data at watershed outlets or by referring to the related empirical parameter values.This paper presented a conceptual soil erosion model which did not need long series of sediment records at watershed outlets to calibrate parameters.The model incorporated a conceptual soil erosion module,which was based on the empirical relationship between the discharge and sediment yield observed from experimental plots,into a physically-based distributed hydrology model,WetSpa Extension.The model had been tested in three watersheds in the purple soil region in China.The results of simulated discharge and sediment at outlets as well as spatial distribution of erosion rates were satisfactory.The model was also proved to be applicable in similar watersheds nearby and useful in assessing the effect of soil and water conservation practices.This conceptual model provides a new option for areas with sparse sediment data series at watershed outlets,and it has a great potential in assisting watershed management.