摘要
梯田改变了流域下垫面,对降雨径流过程势必产生影响,径流曲线模型(Soil Conservation Service Curve Number,SCS-CN)在中国黄土区,特别是梯田分布广泛流域的适用性仍存争议。为此,该研究以位于甘肃天水的罗玉沟流域为研究对象,利用梯田修建前后2个时段(1985—1990年、2000—2010年)的降雨径流实测资料,分析梯田修建对降雨-径流过程的影响,验证SCS-CN模型的适用性,进一步考虑梯田修建的影响,针对不同降雨类型分别提出了基于降雨量和平均雨强的模型改进方法。结果表明:1)梯田修建对流域径流过程的影响与降雨强度关系密切。当雨强较小时,梯田显著削减流域洪峰和径流总量,削减幅度均在55%以上;而当降雨量和雨强较大时,梯田削减洪峰和径流总量效果并不显著。总体上,梯田修建后流域平均降雨径流系数显著减小至0.06,减小幅度约54%。2)基于最小二乘法优化与考虑前期土壤含水率修正的SCS-CN模型并不适用于梯田分布广泛流域的径流预报。引入降雨量和平均雨强改进后的模型模拟效果显著提高,此时流域暴雨量级以下和以上降雨事件的初损率分别为0.29和0.02。该研究基于降雨因子改进的模型在梯田分布广泛流域具有一定的适用性,可为流域产流计算及水土保持规划提供参考依据。
Bench terraces have been playing an important role in the control of soil and water loss in the loess plateau of China.However,it is still lacking on the effect of terrace construction on the rainfall-runoff processes in a watershed.Meanwhile,the Soil Conservation Service Curve Number(SCS-CN)model also remains rarely used to predict the hydrological evolution in the watershed that is distributed with the wide terrain modification including bench terraces.Since 1995,large-scale bench terraces have been constructed in the Luoyugou watershed of Gansu Province(34°35′21.7″-34°39′22″N,105°30′33.8″-105°44′2.5″E)in China,particularly in the loess hilly and gully region.Taking the Luoyugou watershed as the research object,this study aims to clarify the influence of the terrace on the rainfall-runoff,further calibrating and improving the SCS-CN model.The rainfall-runoff process data was firstly collected in the study area.The 88 rainfall-runoff events were then selected,where 34 events occurred in 1985-1990(before the terrace construction)and 54 events in 2000-2010(after terrace construction).The results showed that the performance of the terrace in controlling runoff processes depended mainly on the rainfall events.The terrace significantly decreased in the peak discharge and the total runoff volume by more than 55%under the relatively small rainfall events,while only a very limited role was played in the peak discharge and runoff under the high rainfall events.The ratio of runoff to rainfall in the watershed significantly decreased from 0.13 in 1985-1990 to 0.06 in 2000-2010.All rainfall events were divided into small and moderate-heavy precipitation intensity events,according to the relationship between the rainfall and runoff.The least square method was first used to determine the parameters of the standard SCS-CN and two revised models by using the antecedent soil moisture.Then,an improved SCS-CN model was established,considering the rainfall amount and intensity.A correlation analysis was also mad
作者
马勇星
张栋
潘成忠
降亚楠
Ma Yongxing;Zhang Dong;Pan Chengzhong;Jiang Yanan(College of Water Science,Beijing Normal University,Beijng 100875,China;Upper and Middle Yellow River Administration,Yellow River Conservancy Commission,Xi’an 710021,China;College of Water Resources and Architectural Engineering,Northwest A&F University,Yangling 712100,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2022年第12期85-91,共7页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金项目(31471413)。
关键词
降雨
径流
模型
梯田
SCS
罗玉沟流域
水文过程
precipitation
runoff
models
bench terrace
SCS
Luoyugou watershed
hydrological process
