基于SWAT模型的抚河流域土壤侵蚀模拟

为模拟流域土壤侵蚀状况,分析土地利用方式对土壤侵蚀的影响,构建抚河流域SWAT模型.应用SWAT模型对研究区的径流、产沙状况进行了校准和验证,在此基础上分析了抚河流域土壤侵蚀强度特征,探讨了不同土地利用方式对产沙的影响.结果表明:4个测站月径流、月输沙量的校准期和验证期的决定系数(R2)均在0.7～0.93之间,Nash-Sutteliffe效率系数(NSE)在0.64～0.92之间,径流、泥沙模拟结果达到满意精度,模型在本区域具有良好的适用性;土壤侵蚀以微度侵蚀和轻度侵蚀为主,城乡及工矿用地的土壤侵蚀模数最大,而林地的产沙量绝对量最大.研究成果可为研究区水土保持提供参考.     

三峡库区大宁河流域径流泥沙的AnnAGNPS定量评价

选择位于三峡库区的大宁河流域为研究区,利用著名的农业非点源污染模型-AnnAGNPS对该流域的径流与泥沙进行了定量评价.首先基于流域土地利用、土壤、地形及气象数据等资料对模型参数化,在数字滤波法切割水文站总径流中的基流后,利用偏差、相关系数r~2和Nash-Sutcliffe模拟系数(NS)等多个指标评价了模型对径流和泥沙量预测性能,校正期(1998-1999年)预测与实测的直接径流深偏差为3.71%,相关系数r~2为0.94,斜率k为1.04,NS系数0.94;验证期(2003-2005年)预测与实测直接径流深偏差-6.37%,相关系数r~2为0.93,斜率k为0.93,NS系数0.94;预测与实测的多年平均输沙量偏差为-16.5%.最佳管理措施(BMPs)评价显示退耕还林方案削减了总输沙量和侵蚀量的24.5%,是一种水土流失较好的治理措施.研究证实了AnnAGNPS模型在该流域的适用性,显示了模型在流域径流与泥沙负荷估算及其评价中的应用潜力.     

贵州省猫跳河流域土壤侵蚀动态变化分析

通过实际观测,获得蒋家沟流域近2a的径流资料,总结出2008—2009年间径流的年内特征。通过收集蒋家沟流域土壤、土地利用和气象数据,用SWAT模型模拟了蒋家沟流域的基流月径流模拟和日径流变化。基流月模拟中旱季的模拟效果比较好,汛期由于泥石流暴发时无法观测流量,导致实测资料不完整,模拟结果比较差。日径流模拟分为旱季和汛期模拟,模拟结果的Nash效率系数和相关系数都在0.7以上,表明SWAT模型可以应用于泥石流流域蒋家沟地区的降雨—产流机制研究。     

浑南区尖山小流域SCS-CN方法初损率研究

土壤侵蚀受降雨径流作用影响显著,科学准确的对降雨径流进行分析是开展水土流失治理和综合效益评估的重要内容。SCS-CN模型因具备高效、简单等优点被广泛应用于降雨径流模拟分析中,初损率是决定SCS-CN法地表径流预测的重要参数,是影响模拟精度的关键因素。以浑南区尖山小流域为研究对象,将径流模拟结果与该流域8场降雨数据资料进行对比分析,通过对初损率的取值研究探讨了SCS-CN方法的适用性和可靠性。研究表明:模型理论初损率λ为0. 2时的径流预测效果良好,而对于尖山小流域初损率λ为0. 3时的模型效率系数明显增大,径流预测精度得到显著提高,模型预测结果与实测值保持较高的一致性,可适用于相似流域的径流预测研究。     

基于SWAT模型的湟水流域径流模拟与评价

以青海省湟水流域民和水文站以上流域为研究区,在GIS技术支持下,运用分布式水文模型SWAT（Soil and Water Assessment Tool）进行了湟水流域天然径流的产流模拟,通过选用湟水流域1980～1997年相应的水文气象资料作为SWAT模型的输入数据,选用1980～1987年湟水流域出口民和站的年、月平均天然流量进行模型的参数率定,1989～1997年民和站的年、月平均天然流量进行模型的验证,采用了相对误差（RE）、相关系数（R2）以及Nash-Suttclife模拟系数（Ens）作为模型适用性的评价系数,结果表明SWAT模型对湟水流域长期天然径流变化过程模拟结果良好,较好地反映了湟水流域水资源的变化过程,为研究湟水流域的水资源提供了模型支持。     

基于SWAT东北黑土区乌裕尔河流域径流模型模拟

黑土区是我国的粮食主产区之一,在该区研究径流特征,对东北水资源调控、侵蚀产沙治理和粮食安全,都有非常重要的意义。以乌裕尔河流域为研究对象,利用SWAT模型对乌裕尔河流域水文过程进行模拟,通过SWATCUP程序的SUFI-2算法进行模型参数敏感性和不确定性分析,结合手动参数调整,得到了较为理想的模拟结果。结果表明:年径流及月径流在校准期和验证期的相关系数R2均达到0.8,Nash Suttcliff效率系数大于0.75,相对误差小于15%。SWAT模型可较准确地模拟流域径流过程,该模型在东北地区的水文模拟具有一定的适用性。研究发现,模型对某些降雨突增月份径流模拟较差,并且对春汛和夏汛双峰型径流模拟效果也不尽人意,春季径流量模拟普遍偏低,夏季径流量普遍偏高。因此,尽管东北地区产流结构较为复杂,一些地方如模型土壤属性数据库建设、融雪过程还需要深入研究。就目前研究来看,SWAT模型对于该地区的径流模拟总体效果可以接受,这可为该地及类似地区径流乃至侵蚀产沙模拟,为水资源的开发利用与流域的综合管理提供科学依据。     

基于3个站点校准与验证的晋江流域径流模拟

 应用分布式水文模型SWAT,对东南沿海晋江流域内3个水文站点的年、月径流和基流分别进行模拟。选取1972—1975年作为模型校准期,以效率系数、平均误差、相对误差和决定系数为评价指标,率定出6个模型敏感参数,并用1976—1979年的资料进行模型验证。结果表明:利用3个站点模拟的方法可以从流域尺度上更客观地率定模型参数,改善模型的模拟效果;模型在东南沿海流域的模拟效果较好,精度较高;模拟期内降水量的差异以及水库年径流调节均会对水量模拟结果造成影响。     

东辽河流域吉林省境内的径流模拟研究

以东辽河吉林省境内河段为研究对象,采用SWAT分布式水文模型对东辽河泉太水文站进行径流模拟,模型采用2006—2008年实测的逐月径流资料进行参数的率定,并以2009—2010年为模型的验证期,分析对水文过程影响较大的因素、模型的模拟精度及对研究区的适用性。结果表明:泉太水文站率定期与验证期径流的模拟值与实测值总体上拟合较好,率定期与验证期径流模拟的相关系数（R²）均大于0.6,Nash-Suttclife效率系数（E_ns）均大于0.75,相对误差（R）均小于30%。验证期的月径流模拟相对误差较率定期小,且相关系数R²、效率系数均大于0.9,降雨是径流的重要影响因素,月径流模拟值与年内的降雨过程存在较好的正相关性,且率定期相关性较验证期相关性大。应用率定后的参数在SWAT模型中进行径流模拟的结果较好,精度较高。将SWAT模型应用于东辽河吉林省段的径流过程模拟,具有较强的适用性。     

湟水流域SWAT模型构建及参数不确定性分析

敏感性分析和不确定性分析是分布式水文模型参数校准和模型构建的先决条件.以位于青藏高原与黄土高原过渡地带的青海湟水流域为例,基于SWAT模型的拉丁超立方和单次单因子(LH-OAT)采样方法和SWAT-CUP程序的拉丁超立方采样方法进行模型参数敏感性分析,同时以SWAT-CUP的P因子和R因子进行模型不确定性分析,最终结合手动调参和自动率定算法,构建湟水流域分布式水文模型.结果表明:湟水流域日尺度模拟中,率定期模型平均确定系数为0.7,平均效率系数为0.68;验证期平均确定系数为0.65,平均效率系数为0.53,可以满足应用要求;PSO算法在水文模型率定中总体表现良好;基于SWAT模型和SWAT-CUP程序的单次率定用时分别为3.5 min和2.2 min,SWAT-CUP程序明显快于SWAT;分析结果还表明:模型不确定性和模型率定结果精度并不一致,但模型不确定性决定着模型验证期的结果精度,为确保验证期精度,必须降低模型不确定性;模型自动率定中,相同迭代次数下,SWAT模型对于流量较大的子流域率定效果较好.     

HBV水文预报模型在白龙江流域的应用研究

[目的]在白龙江流域武都站以上区域构建HBV水文模型,通过对区域日径流模拟研究,来评估模型在该区域的适用性。[方法]在参数敏感性分析的基础上,对模型参数进行率定和验证,并分析径流和降水量的年际变化特征。[结果](1)在率定期Nash—Sutcliffe效率系数Ens=0.65,确定性系数R2=0.74,验证期Ens=0.60,R2=0.70,HBV模型在该流域模拟精度较高,具有较好的适用性;(2)降水量与模拟径流变化趋势对应,HBV模型较好地模拟出了洪水对降水的响应过程。[结论]HBV模型可进一步用于研究气候变化对白龙江流域水资源的影响。     

Estimating the annual runoff frequency distribution based on climatic conditions and catchment characteristics: A case study across China

Estimation of the annual runoff frequency distribution is an essential basis for water resource management. This study proposes a framework for estimating the annual runoff frequency distribution across 252 catchments in China based on climatic conditions and catchment characteristics from 1956 to 2000. The Budyko land-specific parameter n, which intergrates influences other than the mean climate conditions, is firstly estimated based on easily ascertainable catchment characteristics without the requirements of having long-term runoff observations. Second, the annual runoff statistical parameters, namely, the mean value and standard deviation (STD), are derived based on the Budyko rainfall-runoff model with the central moment method. Finally, the annual runoff on any recurrence interval is obtained by the Pearson-III frequency function. Results show that the parameter n can be estimated from the catchment average slope, longitude, and climatic seasonality index. The estimated statistical parameters of annual runoff have acceptable agreement with observed values (mean value: R² ∼0.94, STD: R² ∼0.91, and both relative errors <10%). In addition, estimated annual runoff at each catchment for typical wet and dry years (25% and 75% ranked percentiles) coincides well with observed values, with R² of 0.92–0.93 and relative errors less than 10%. This result indicates the robustness of this framework for estimating the annual runoff frequency distribution, which provides a simple and effective tool for ungauged or poorly gauged catchments.     

SWAT径流模拟及其对流域内地形参数变化的响应研究

SWAT(soil and water assessment tool)模型是一个集成遥感(RS)、地理信息系统(GIS)和数字高程模型(DEM)技术的基于水文过程的、具有较强物理机制的先进的分布式流域水文模型。为了进一步研究流域尺度内水文过程的时空变化规律,深入了解流域水文时空过程与气象、地—气界面条件及流域地貌特征间的关系,选取汉江上游马道流域,运用AVSWAT2000版模型进行1981—1985年间的年、月径流模拟,以月径流模拟的N—S模型效率系数为主要指标,率定出月模拟效果最佳时的各参数值。在此基础上从马道出水站点沿主河道往上游再选取6个控制点,运用River Tools软件提取出各个控制点控制流域和地形参数,分析参数变化情况,并在此基础上用前面率定好的参数来模拟各个控制点处的出口流量,分析径流对地形参数变化的响应关系,并提出了归一化径流—河道总长比指数。该指数受到河源密度的影响,在流域内的变化趋于常数1。     

大通江、平洛河水保措施减水减沙分析

嘉陵江流域水土流失严重,“长治”工程首批治理的四大片区中,嘉陵江上游的陕南陇南地区和中下游土石山区两大片区名列其中。自20世纪80年代末开始实施水土保持治理以来,对控制流域内水土流失现象起到了较为明显的积极作用。选择了分别位于两大片区的大通江和平洛河两条典型河流,以实测水沙资料为依据,采用水文学方法,着重分析研究两个典型流域水保措施实施以来的水沙变化。     

嘉陵江流域非点源溶解态氮污染负荷模拟研究

嘉陵江流域是乏峡水库最大的支流,为研究嘉陵江流域非点源溶解态氮污染负荷的年际变化规律及其来源的空间分布情况,以流域土地利用类型为研究单元,通过引入具有物理机制的半分布式水文模型——sLuRP水文模型,并推导溶解态氮的流域输移损失系数,建立了流域非点源溶解态氮污染年负荷模型。借助GIS技术,应用所建模型,对嘉陵江流域各土地利用类型L的年地表径流量和溶解态氮污染负荷进行了模拟。模拟结果表明,以旱地和水田为主的涪江流域的溶解态氮流失情况最为严重,其次是渠江下游流域和西汉水流域,1990---2005年嘉陵江流域各土地利用类型上产生的非点源溶解态氮年均负荷为35726t·a^-1,约占流域出口总氮负荷的32％。     

基于能量转换的地貌单位线计算方法及应用

该研究基于能量转换原理构建汇流模型,针对中小河流汇流参数确定困难、汇流计算准确度低的问题,分析流域内水质点能量的空间分布,采用将重力势能转化为动能的方式估计地表水流速度,计算空间流速场并提取地貌单位线。采用分辨率30 m×30 m的数字高程模型（Digital Elevation Model,DEM）数据,将湖南省竹溪坡流域划分为57个计算单元,分别采用能量转换法和坡度雨强法提取了地貌单位线。构建了研究区的分布式模型,其中产流计算采用新安江模型,坡面汇流采用地貌单位线模型,河网汇流采用马斯京根法,对竹溪坡流域36场降雨径流过程进行模拟。采用统计方法分析汇流参数,对参数的取值范围进行了评估。结果表明,与坡度雨强法相比,基于能量转换方式的洪水模拟结果中,峰现时间误差不超过1 h的场次比例由30.5%提高到83.3%,确定性系数不低于0.9的场次由9场提升至17场,平均确定性系数达到0.89,显著提高了模拟精度。通过对断面流速进行统计分析,评估竹溪坡流域汇流参数取值范围为[0.008, 0.014],当参数在此区间浮动时,确定性系数不低于0.9的场次比例为44%～50%,与率定得到的结果接近。该方法物理意义明确,参数可以通过率定或者测量方式确定,为无资料地区汇流规律研究提供了一种可靠思路。     

Reliability of an expert-based runoff and erosion model: Application of STREAM to different environments

During the last decades, the European loess belt has been confronted with a significant increase in environmental problems due to erosion on agricultural land. Spatially distributed runoff and erosion models operating at the catchment scale are therefore needed to evaluate the impact of potential mitigation measures. Expert-based models offer an alternative solution to process-based and empirical models, but their decision rules are only valid for the local conditions for which they have been derived. The STREAM model, which was developed in Normandy (France), has been applied in two Belgian catchments having a similar soil texture, as well as in a catchment of southern France differing by soil, land use and climate characteristics. The performance of hydrological models can be assessed for instance by calculating the Nash–Sutcliffe efficiency criterion (E_NS). When applied to Belgium, the model results are satisfactory to good after an adaptation of the decision rules (0.90 < E_NS < 0.93 for runoff predictions and 0.85 < E_NS < 0.89 for erosion predictions). Given the important environmental differences between Normandy and southern France, the model rules were also adapted for application in the latter environment. Unfortunately, the quality of runoff predictions was insufficient to simulate erosion in southern France. In conclusion, STREAM is a reliable model providing satisfactory runoff and erosion predictions in the regions where hortonian overland flow dominates. Nevertheless, an adaptation of decision rules based on local multi-scale (plot, field, catchment) data is needed, before running the model. STREAM can then serve as a decision support tool to design for instance flood control measures.     

Using Cs measurements to validate the application of the AGNPS and ANSWERS erosion and sediment yield models in two small Devon catchments

Distributed erosion and sediment yield models are being increasingly used for predicting soil erosion and sediment yields in agricultural catchments. In most applications, validation of such models has commonly been restricted to comparison of the predicted and measured sediment output from a catchment, because spatially distributed information on rates and patterns of soil redistribution within the catchment has been lacking. However, such spatially distributed data are needed for rigorous model testing, in order to validate the internal functioning of a model and its applicability at different spatial scales. The study reported in this paper uses two approaches to test the performance of the agricultural non-point source pollution (AGNPS) and areal non-point source watershed environmental response simulation (ANSWERS) erosion and sediment yield models in two small catchments in Devon, UK. These involve, firstly, comparison of observed and predicted runoff and sediment output data for individual storm events monitored at the basin outlets and, secondly, information on the spatial pattern of soil redistribution within the catchments derived from ¹³⁷Cs measurements. The results obtained indicate that catchment outputs simulated by both models are reasonably consistent with the recorded values, although the AGNPS model appears to provide closer agreement between observed and predicted values. However, the spatial patterns of soil redistribution and the sediment delivery ratios predicted for the two catchments by the AGNPS and ANSWERS models differ significantly. Comparison of the catchment sediment delivery ratios and the pattern of soil redistribution in individual fields predicted by the models with equivalent information derived from ¹³⁷Cs measurements indicates that the AGNPS model provides more meaningful predictions of erosion and sediment yield under UK conditions than the ANSWERS model and emphasises the importance of using information on both catchment output and sediment redistribution within the catchment for model validation.     

Simulation of Nitrogen and Phosphorus Losses in Loess Landforms of Northern Iran

Population growth, urban expansion and intensive agriculture and thus increased use of fertilizers aimed at increasing the production capacity cause extensive loss of nutrients such as nitrogen and phosphorus and lead to reduced quality of soil and water. Therefore, identification of nutrients in the soil and their potential are essential. The aim of this study was to evaluate the capability of the SWAT model in simulating runoff, sediment, and nitrogen and phosphorus losses in Tamer catchment. Runoff and sediment measured at Tamar gauging station were used to calibrate and validate the model. Simulated values were generally consistent with the data observed during calibration and validation period (0.6 < R² and 0.5 < NS). In the case of nitrogen loss, the model performed an almost good simulation (0.6 < R² and 0.47 < NS), but phosphorus simulation yielded better results (0.76 < R² and 0.66 < NS). The results showed that cultivated lands had higher loss of nitrogen and phosphorus than other types of land use. Among the various forms of nitrogen and phosphorus, the loss of organic nitrogen and nitrate and soluble phosphorus and mineral phosphorus attached to the sediments showed the greatest sensitivity to the type of land use. Results also showed that the average nutrient loss caused by erosion in this catchment, was 6.99 kg/ha for nitrogen, 0.35 kg/ha for nitrate, 1.3 kg/ha for organic phosphorus, 0.015 kg/ha for soluble phosphorus, and 0.45 kg/ha for mineral phosphorus.     

基于SWAT模型的TRMM降水数据径流模拟适宜性评价

以辉发河流域为研究区,采用SWAT分布式水文模型,以实测降水数据和TRMM降水产品作为模型输入,在月尺度和日尺度上构建了四种径流模拟情景,并利用SUFI_2算法分析了不同降水输入和时间尺度下模型的参数敏感性、参数不确定性和径流模拟结果。结果表明:(1)TRMM降水产品的误差会改变参数的敏感性排序,尤其是在日尺度上;(2)4种模拟情景P因子的范围为0.58~0.9,R因子的范围为0.47~1.58,模型拟合精度较好。月尺度上TRMM数据的估算误差较小,其更高的空间分辨率可使径流模拟不确定性得到明显改进,而随着时间尺度的变化,TRMM数据在日尺度上的误差增大会导致日径流模拟结果不确定性的增加;(3)在月尺度和日尺度上,采用TRMM数据降水输入模拟径流,其NS和R2系数均达到较好水平,实测降水模拟结果略优于TRMM数据。研究表明,在辉发河流域,TRMM降水产品在径流模拟方面表现出较好的适宜性,是一种较为可靠的降水数据源。     

Evaluation of Sediment Deposition in a Mediterranean Reservoir: Comparison of Long Term Bathymetric Measurements and SWAT Estimations

This study aims to demonstrate that the SWAT model can be used to predict discharge and sediment yield values in reservoir contributing catchments helping also to define the main factors that determine sedimentation rates in semi‐arid Mediterranean environments. This aim was achieved by comparing SWAT simulation results with water flows (over 29 years) and sediment deposition (over 47 years) volumes collected (by a campaign of bathymetric surveys) in a Sicilian reservoir. The mean monthly runoff coefficient calculated for the period 1980–2008 was 0·17. The mean sedimentation volume in the reservoir during the period 1963–2009 was 51,000 m³ year⁻¹. Field surveys and collection of spatially distributed databases of soil, topography and climate were carried out in order to characterize the contributing catchment. The SWAT model was applied to simulate sediment volumes cumulated over group of years as well as water flow volumes reaching annual and monthly the reservoir. The performance of the hydrological and erosion components of the model was evaluated by a combination of both summary and difference statistical measures after a sensitivity analysis and a calibration/validation process. The model was able to simulate observed runoff volumes at both annual and monthly scale. The mean sedimentation volume simulated by SWAT during the whole period was 8·1% lower than the value obtained by the bathymetric measurements (equal to 72·10³ Mg) with very good values of the efficiency coefficient (equal to 0·91). Copyright © 2016 John Wiley & Sons, Ltd.