SCS模型在贵州省毕节市石桥小流域坡面产流模拟中的应用

[目的]研究喀斯特地区径流形成规律,得到适合研究区的SCS(space cooperation system)模型参数取值。[方法]利用野外径流小区观测获得的径流数据与降雨资料,对研究区的降雨进行雨型分类,并利用SCS模型进行坡面产流模拟。[结果](1)根据降雨随历时的分配可将研究区的降雨雨型分为4类,即前期型(Ⅰ类)、中期型(Ⅱ类)、后期型(Ⅲ类)以及均匀型(Ⅳ类)。(2)基于SCS模型对研究区坡面径流进行模拟时,初损系数λ取值多为0.01,0.05,远小于λ=0.2的取值。(3)随着坡长的增加,前期型降雨、中间型降雨和后期型降雨的CN(curve number)值变幅较小,均匀型降雨的CN值呈现增加的趋势。随着坡度的增加,前期型降雨和中期型降雨的CN值呈现减少的趋势,后期型降雨和均匀型降雨的CN值增幅不大。[结论]基于SCS模型得到的模拟径流量与实测径流量之间的相关系数和模型效率系数都较高,具有较好的模拟效果。

Application of SCS Model to Simulate Runoff in Slope Field at Shiqiao Small Watershed in Bijie City of Guizhou Province

[Objective] The rule of runoff formation in karst area was studied to get the parameters of space cooperation system(SCS) model and to test whether it is applicable in the study area.[Methods] Based on field observations of runoff and rainfall characteristics,rainfall events in the study area were classified.Runoff generated on the slopes was simulated by using the SCS model.[Results] (1) Rainfall events in the study area can be divided into four types according to event-based rainfall concentration,namely the pre-type(type Ⅰ),medium-type(type Ⅱ),back-type(typeⅢ) and even-type(typeⅣ).(2) The value of the initial loss coefficient(λ) was 0.01 or 0.05,much less than 0.2,when simulating runoff on the slopes in the study area by using the SCS model.(3) The curve number(CN) values of type Ⅰ,type lⅡ and typeⅢ rainfall showed small changes as slop length increased,while the CN value of typeⅣrainfall tended to increase.The CN values of type Ⅰ and type Ⅱ rainfalls tended to reduce with the increase of slope gradient,the CN values of type Ⅲ and typeⅣ rainfall did not increased obviously with the increase in slope gradient.[Conclusion] Based on SCS model,the correlation coefficient and model efficiency coefficient of simulated runoff and observed runoff are both high,which indicates the model performed well.