SCS-CN模型在小流域产流计算中的应用

山洪灾害的发生与流域产流特性密切相关,科学准确预测流域径流对山洪预警具有重要意义。SCS-CN模型因其计算过程简单、所需参数较少而广泛应用于小流域径流估算,径流曲线数CN和初损率λ是SCS-CN模型中的两个主要参数。选取沂源县为研究区,运用ArcGIS软件计算沂源县24个小流域的CN值,并根据实测降雨径流资料优化初损率λ,确定适用于高村河小流域的初损率λ为0.13,其模型效率系数E为0.789 7,研究得出的径流曲线数和初损率取值可用于沂源县小流域的地表径流预测。     

黄土区SCS-CN模型径流曲线数计算方法研究

美国农业部开发的SCS-CN模型是较为常用的一种径流计算方法。模型中的CN值是模型中反映土地利用、土壤类型和土壤前期含水量的一个综合参数,其值的选择对于准确计算地表径流具有重要意义。利用黄土高原地区杨青川流域、燕沟流域和西川流域不同土地利用类型42场模拟降雨的径流资料,应用平均值法、中值法、算术平均值法、S对数频率分布法和渐近线法5种方法计算CN值,并利用CN值反推径流深。采用均值比较、模型评价指标的方法比较了5种方法计算的径流深与实测值的差异,根据相对隶属度最大最优原则确定最优计算方法。结果表明:在杨青川流域,最优的计算方法是平均值法,燕沟流域和西川流域的最优计算方法则是中值法,不同流域同一计算方法确定的同一土地利用类型CN值差异较大;单独进行草地和裸地的评价分析时,草地的最优计算方法是平均值法,裸地的最优计算方法是算术平均值法,不同土地利用类型CN值的最优计算方法不同。     

SCS-CN模型的改进及其空间尺度效应

SCS-CN (Soil Conservation Service Curve Number)模型是广泛应用经验性水文模型,其模型参数的确定与空间尺度效应对径流模拟结果有着重要的影响。选取淮河上游为研究区,分析SCS-CN模型参数的敏感性并对模型进行改进,探讨了9种栅格尺度(100～2 000m)下径流模拟结果的空间尺度效应。研究结果表明:SCS-CN模型输入参数中,系数b的敏感性高于初损系数(λ),将参数b值作为模型需要修正的参数;随着空间尺度增加,下垫面各要素的尺度变化使得参数b呈指数递减趋势;模型模拟精度的最佳空间尺度范围是250～500m尺度。     

SCS产流模型在渭河流域的修订研究

SCS模型简单实用且不依赖于实测水文资料,可用于解决无资料地区的水文模拟与预报问题,但若直接采用模型推荐的综合参数,模拟或预报精度往往不高.为提高SCS模型在渭河流域的适用性,选择渭河流域资料较为充分的咸阳、秦渡镇和武山3个典型子流域,通过改变前期土壤湿度的估算方法和增加径流曲线数CN的分级,重新确定潜在蓄水能力与径流...     

兰州新区SCS径流模型改进与应用研究

近年来全国气候异常,由强降雨引发的洪涝灾害已成为城市经济快速发展面临的严峻水问题之一.因此,以无水文资料地区——兰州新区为研究区,开展降雨径流过程模拟研究是十分必要的.首先根据黄河干支流区综合概化时程分配雨型表、《甘肃省暴雨洪水图集》,利用地方经验公式计算得到研究区不同频率的产流量;其次借鉴相关研究成果,考虑地形地貌特...     

径流曲线数模型在湖南省山区小流域的优化与应用

径流曲线数模型(Soil Conservation Service Curve Number Model,简称SCS-CN模型)可以利用降雨资料估算径流,对水资源合理配置和山洪灾害预警具有重要意义,因为其方便计算、参数简单,而被广泛应用。目前标准SCS-CN模型在山区小流域的适用性欠佳,因此需要对模型参数进行优化以提高预测精度。本文以湖南省螺岭桥流域为例,根据实测降雨径流资料优化径流曲线数CN (Curve Number)查算表,并利用步长优化参数算法研究初损率对模型精度的影响,将优化模型的方法应用于湖南省凤凰小流域,验证该优化方法的可靠性。结果分析表明：与标准SCS-CN模型相比,优化后的SCS-CN模型效率系数NSE从0.576提升至0.813,决定系数R²为0.858。将模型优化方法验证于气候地形条件相似的凤凰流域,模型NSE值提高117%。通过预测径流深与实测径流深比较,优化模型模拟精度较为理想,对湖南省山区小流域场次降雨产流预报有一定的参考意义。     

重庆市典型下垫面SCS-CN模型基于坡度修正的径流曲线数优化

以重庆市渝北区和巴南区的典型下垫面为研究对象,基于SCS-CN模型原理和坡度修正公式,通过开展人工模拟降雨实验,优化了不同植被覆盖程度的紫色土和黄壤下垫面在不同坡度(5°、10°、15°和20°)下的CN值,同时采用模型评价参数对优化前后的模型预测精度进行对比.结果表明:地形坡度变化对径流深有显著影响,地表径流深随坡度...     

无资料地区水文系列移用简化算法

在无资料地区推求年径流系列,目前常用的方法是均值修正法,此法的基本假定是变差系数Cv值相等或接近。在水利水电工程设计实际工作中参证站与设计站的变差系数Cv值往往差距较大,直接影响设计精度,故笔者紧密结合实际工作现状探讨了同时修正均值和变差系数Cv的简化算法。采用该法可以直接求得设计站的水文系列,不仅可以提高设计精度,还可以节省多次试算变差系数Cv的工作量。     

吉林省中小流域经验模型的应用探讨

由于中小河流水文站点多数都属于无资料站,所以用传统的经验相关或者流域水文模型有一定难度。吉林省水文水资源局水情预报中心的工作者根据多年预报经验总结提出吉林省中小流域经验模型。该方法主要依据流域特征以及降雨和洪峰流量的关系,推算流域产流;再根据时段降雨按照产流过程叠加处理,概化流量过程,进行洪水预报。属于产汇流一体的流量过程计算模型。     

基于地形坡度的SCS模型优化 ——以长峪城小流域为例

由于SCS模型结构简单、计算参数少且易于获取,被广泛应用于水文资料缺少地区的产流估算.SCS模型中的径流曲线数CN作为主要参数对产流模拟结果有重要影响,但现有水文土壤分类标准提供的CN值不能很好地适用于地形复杂的流域中.通过坡度和土地利用类型对CN值进行优化,使用田寺、汤河口等径流试验场数据对模型优化进行精度验证分析,...     

重庆市典型下垫面 ＳＣＳ-ＣＮ模型基于坡度修正的径流曲线数优化

以重庆市渝北区和巴南区的典型下垫面为研究对象,基于ＳＣＳ-ＣＮ模型原理和坡度修正公式,通过开展人工模拟降雨实验,优化了不同植被覆盖程度的紫色土和黄壤下垫面在不同坡度（5°、10°、15°和20°）下的ＣＮ值,同时采用模型评价参数对优化前后的模型预测精度进行对比。结果表明:地形坡度变化对径流深有显著影响,地表径流深随坡度的增大大体呈现增加的趋势。同一类型下垫面的ＣＮ值随坡度的增大而增大,同一坡度下的ＣＮ值存在黄壤＞紫色土,自然草地（稀疏）＞自然草地（浓稠）。从模型评价参数来看,由Ｈｕａｎｇ坡度修正公式修正后的模型效率系数最高且平均相对误差最小。因此,在山地城市应用ＳＣＳ-ＣＮ模型时,建议使用Ｈｕａｎｇ坡度修正公式对ＣＮ值进行优化,以便更精准地预测径流。     

SCS-CN模型改进及其径流预测

黄土高原的土壤侵蚀与水土流失程度都很严重,对其进行水土流失的预报有着重要的生态意义和经济意义。利用SCS-CN(soil conservation service curve number)模型进行地表产流预测。针对黄土高原特定的气候及下垫面条件,以陕西省榆林市绥德韭园沟典型小流域为研究区域,借助韭园沟流域次降雨径流资料,优化影响降水产流关系的相应参数(初损率和降雨强度)。结果表明:①使用反算法来优化初损率,确定初损率为0.075,模型效率系数为0.208;②使用MATLAB结合粒子群算法来进一步优化初损率,确定初损率为0.13,模型效率系数为0.504,相比于反算法提高了142%,模型预报精度得到了很大提高;③在黄土丘陵沟壑区引入雨强因子修正降雨量函数,改进后模型效率系数为0.652,确定性系数为0.753,利用雨强修正函数后的SCS模型相比于标准SCS模型,确定性系数和模型效率系数分别提高了101%和534%。通过预测流域径流深与实测流域径流深的比较,模型模拟精度较为理想,可用于黄土高原不同小流域场次降雨的产流预报。     

Application of GIS-based SCS-CN method in West Bank catchments,Palestine

Among the most basic challenges of hydrology are the prediction and quantification of catchment surface runoff.The runoff curve number(CN)is a key factor in determining runoff in the SCS(Soil Conservation Service)based hydrologic modeling method.The traditional SCS-CN method for calculating the composite curve number is very tedious and consumes a major portion of the hydrologic modeling time.Therefore,geographic information systems(GIS)are now being used in combination with the SCS-CN method.This paper assesses the modeling of flow in West Bank catchments using the GIS-based SCS-CN method.The West Bank,Palestine,is characterized as an arid to semi-arid region with annual rainfall depths ranging between 100 mm in the vicinity of the Jordan River to 700 mm in the mountains extending across the central parts of the region.The estimated composite curve number for the entire West Bank is about 50 assuming dry conditions.This paper clearly demonstrates that the integration of GIS with the SCS-CN method provides a powerful tool for estimating runoff volumes in West Bank catchments,representing arid to semi-arid catchments of Palestine.     

An Improved I a S Relation Incorporating Antecedent Moisture in SCS-CN Methodology

Employing a large dataset of 84 small watersheds (area = 0.17 to 71.99 ha) of U.S.A., this paper investigates a number of initial abstraction (I _a )-potential maximum retention (S) relations incorporating antecedent moisture (M) as a function of antecedent precipitation (P ₅), and finally suggests an improved relation for use in the popular Soil Conservation Service Curve Number (SCS-CN) methodology for determination of direct runoff from given rainfall. The improved performance of the incorporated M = α and I _a = λ S ²/(S + M) relations, where λ is the initial abstraction coefficient, in the SCS-CN methodology exhibits the dependence of I _a on M, which is close to reality; the larger the M, the lesser will be I _a , and vice versa. Such incorporation obviates sudden jumps in the curve number variation with antecedent moisture condition, an unreasonable and undesirable feature of the existing SCS-CN model.     

Comparison of AMC-dependent CN-conversion Formulae

The available antecedent moisture condition (AMC)-dependent runoff curve number (CN) (SCS, National Engineering Handbook, Supplement A, Section 4, Chapter 10, Soil Conservation Service, USDA, Washington, DC, 1956) conversion formulae due to Sobhani (M.S. Thesis, Utah State University, Logan, UT, 1975), Hawkins et al. (J Irrig Drain Eng, ASCE 111:330–340, 1985), Chow et al. (McGraw-Hill, New York, 1988), and Neitsch et al. (Texas Water Resources Institute, College Station, TX, TWRI Report TR-191, 2002) were compared utilizing the NEH-4 CN-values (SCS, National Engineering Handbook, Supplement A, Section 4, Chapter 10, Soil Conservation Service, USDA, Washington, DC, 1972) as target values. The Sobhani formula was found to perform the best in CN_I-conversion, and the Hawkins formula in CN_III-conversion. When evaluated on a large set of Agriculture Research Service (United States) data, a newly proposed formula performed the best of all, and the Neitsch formula the poorest, and therefore, the former was recommended for field use. The poorest performance of the latter is largely attributed to the occurrence of unreasonable negative CN_I-values at low CN_II-values.     

SCS-CN模型在济南市南部山区径流估算中的优化应用

济南市南部山区崮山流域地处我国北方土石山地丘陵区,以水力侵蚀为主的土壤侵蚀现象严重且生态环境脆弱,径流预测是水土保持监测和预报的重要基础,精度较高的的径流计算模型可以为济南市南部山区更好地开展水土保持工作提供技术支撑与数据基础。根据径流曲线模型(SCS-CN)原理和崮山流域内5个雨量站、1个水文站近10年的实测降雨、径流资料,借助ArcGIS平台利用优度拟合统计分析法及Nash-Sutcliffe效率系数验证法对模型参数初损率(λ)和径流曲线数(CN)进行了优化检验,结果表明：参数优化后的模型精确度较高(实测值与计算值分析结果为回归直线斜率K=0.905 8、确定系数R²=0.812 7、纳什效率系数E_NS=0.796 9)可以更好地适用于崮山流域径流测算;对2019年崮山流域29次侵蚀性降雨进行降雨产流估算,并累加计算得流域年径流量为0.53亿m³,年径流深处于34.15～371.52 mm,年均径流深为134.52 mm,汛期降雨产生的径流量占年径流量的90.27%。     

Estimation of Parameters of a Conceptual Water Balance Model for Ungauged Catchments

The problem of parameter estimation constitutes the largest obstacle to successful application of conceptual catchment models in ungauged catchments. This paper investigates the usefulness of a conceptual water balance model for simulating river flow from catchments covering a wide variety of climatic and physiographic areas. The model is a 6-parameter water balance model which was applied to 26 seasonally snow covered catchments in central Sweden. The model was calibrated on a group of catchments and the calibrated parameter values related to physical catchment indices. The relationships were tested by comparing observed and simulated runoff records from 4 catchments that were not contained in the regression analysis. The results show that the model can be satisfactorily applied to ungauged basins in the study region. In order to test the physical relevance of the model to a wider set of conditions, the model was modified by excluding the snow routine part. The resulting model and the same technique were tested on 24 catchments taken from northern Belgium. The verification results were found to be satisfactory.     

Temporal and spatial dynamics of surface run‐off from Lake Basaka catchment (Ethiopia) using SCS‐CN model coupled with remote sensing and GIS

The Lake Basaka catchment (Ethiopia) has undergone a significant land use–land cover (LULC) change and lake level rise over the past five decades. Significant quantities of water and sediment flow annually into the lake through erosion processes. An appropriate method of estimating the surface run‐off from such ungauged and dynamic catchment is extremely important for delineating sensitive areas (based on run‐off responses) to be protected and for development of suitable measures to reduce run‐off and associated soil loss. Reliable prediction of run‐off, however, is very difficult and time‐consuming for catchments such as that of Lake Basaka. The present study estimated the dynamics of surface (direct) run‐off using the NRCS‐CN model in ArcGIS, assisted by remote sensing and ancillary data. The results indicated the Lake Basaka catchment experienced significant temporal and spatial variability in its run‐off responses, depending on the rainfall (amount and distribution) pattern and LULC changes. A significant run‐off increase occurred after 1973, consistent with significant LULC changes and lake level increments occurring after that period. A reduced vegetation cover also resulted in increased run‐off coefficient of the lake catchment from 0.11 in the 1970s to 0.23 in the 2000s, indicating the important need to consider possible future LULC evolution when forecasting the lake catchment run‐off behaviour.     

利用EXCEL工具率定典型流量数学模型方法探讨

介绍EXCEL【规划求解】功能拟合流量数学模型的操作方法和步骤,并与EXCEL内置图形函数拟合的流量数学模型进行对比分析,说明该功能拟合流量数学模型的优越性。分别以天然河道、水库堰闸、水电站实测流量系列资料为实例,应用该功能拟合不同类型的流量数学模型,结果表明【规划求解】功能拟合流量数学模型均能满足水文资料整编规范要求。