基于格尔木河流域的SWAT模型水文特征情景模拟研究

以2008—2016年格尔木河流域实测径流量数据为基础,构建SWAT分布式水文模型,采用SUFI-2算法进行参数率定、验证及不确定性分析,并设置不同的气候情景(RCP2.6、RCP4.5和RCP6.0),预测流域2022—2050年的径流变化趋势,分析了研究区未来降水、气温的变化趋势并探究了这些气候要素对格尔木河流域径流的影响。结果表明：(1)SWAT模型在格尔木河流域径流过程的模拟中具有较好的适用性,率定期R²和E_NS分别为0.84和0.73,验证期R²和E_NS分别为0.74和0.70;(2)径流预测不确定性较小;(3)未来流域降水呈现增加趋势而气温降低;(4)未来时段流域径流增加显著,且降水是控制流域径流的主要因素。     

岩溶地下河在SWAT中的概化方法——以毕节倒天河流域为例

岩溶地下河的存在严重影响了土壤和水评估工具（SWAT）在岩溶地区的普遍适用性。针对岩溶地下河在SWAT中的概化问题,提出基于数字高程模型（DEM）预处理结合SWAT流域自动识别功能的方法,将岩溶地下河暴露于地表,把岩溶区复杂的地表－地下二元结构简化为地表一元结构,并以贵州毕节地下河发育的倒天河流域为例进行应用。结果表明:① 对比未经概化地下河建立的模型,概化地下河建立的模型识别流域面积增大30.73%,子流域个数增加29.27%,水文响应单元（HRU）个数增加43.82%;② 参数取最大物理意义范围时,未经概化地下河建立的模型p因子=0.64,不满足建模条件,物理模型本身存在问题;③ 概化地下河建立的模型月步长模拟结果:校准期R2=0.96,NS=0.96,验证期R2=0.94,NS=0.93,月尺度模拟效果非常好。岩溶地下河概化方法使SWAT在流域划分方面更加合理,搭建的模型模拟更加合理。该研究拓展了SWAT模型在岩溶区的应用。      

SWAT模型在密赛流域的应用与比较研究

为对比分布式水文模型SWAT与典型集总式水文模型新安江模型的径流模拟能力,以钱塘江支流密赛流域为实验流域,以CRU气象数据集为气象输入资料,分别进行SWAT日、月径流模拟与验证,并与新安江模型模拟成果进行对比。结果显示SWAT模型在实验流域的月尺度径流模拟中更具优势,也表明SWAT模型在我国径流模拟中具有良好的适用性。     

基于SWAT模型的径流还原方法研究—以大汶河流域为例

在现有下垫面条件下还原天然径流是水资源配置的重要基础性工作。利用SWAT分布式水文模型进行径流还原计算。以大汶河流域为例,选取流域内受人类活动影响较小、能大致反映流域天然径流情况的雪野水库、黄前水库以及东周水库所控制的3个子流域,采用SUFI-2方法进行模型参数率定、验证和不确定性分析;根据就近性与相似性原则,进行全流域参数展布,并通过Arc SWAT2012分析计算大汶河流域内泰安市各分区地表水资源量。结果表明:3个典型子流域的P-factor均大于0.64,Rfactor均小于0.72,率定期和验证期的相关性系数和纳什效率系数均高于0.77,径流模拟值和实测值拟合程度高。通过SWAT模型还原天然径流是可行的。     

CMADS降水数据在温带东亚季风气候区水库控制流域适用性——以潮白河、东洋河流域为例

为探究中国气象同化驱动数据集（CMADS）降水数据在温带东亚季风气候区水库控制流域情景下水文模拟中的适用性,选择SWAT （soil and water assessment tool）模型为研究工具,分别以CMADS降水数据与年鉴实测降水数据为模型输入项,以水文站实测月径流资料对模型模拟结果进行参数率定及验证,对潮白河流域有水库、无水库控制情形下水文径流进行模拟,并对东洋河流域有水库控制情形下以CMADS降水数据作为模型输入项进行了水文径流模拟。结果表明：在潮白河流域无水库控制的支流潮河水系,CMADS降水数据和实测降水数据支撑下的模型在率定期R²（决定系数）分别为0.64、0.83,E_NS（纳什系数）分别为0.64、0.83,验证期模型R²分别为0.61、0.83,E_NS分别为0.58、0.60;在潮白河流域有水库控制的支流白河水系,CMADS降水数据和实测降水数据支撑下的模型在率定期R²分别为0.89、0.87,E_NS分别为0.87、0.86,验证期模型R²分别为0.61、0.67,E_NS分别为0.61、0.65;在东洋河有水库控制流域,CMADS降水数据支撑的模型率定期R²=0.84,E_NS=0.78,验证期R²=0.87,E_NS=0.85。说明CMADS降水数据在有水库、无水库控制流域情景下的水文模拟中均具有较好的适用性。因此CMADS降水数据可以用于温带东亚季风气候区水库控制流域水文模型的建立。     

SWAT模型在海拉尔河流域径流模拟中的应用研究

以海拉尔河上游流域作为研究区域,基于Arc GIS构建SWAT分布式水文模型对流域水文过程进行模拟,通过对流域的基础数据整合,模型采用1999~2003年实测径流数据进行参数率定,将2004~2010年实测径流数据作为模型的验证期,对模型在海拉尔河上游的适用性进行研究。通过对月和年径流模拟值和实测值的比较,率定期和验证期的Nash系数Ens和相关系数R2分别在0.861~0.873和0.877~0.899之间。基于这两个评价标准可知:SWAT模型在海拉尔河上游流域有良好的适用性,可以为该流域的水资源管理提供依据。     

基于SWAT模型的三江平原沼泽性河流的径流模拟

三江平原位于中国东北部,是国家重要的商品粮基地,水资源的变化影响区域农业经济的发展。应用SWAT(Soil and Water Assessment Tool)模型模拟挠力河上游流域径流变化特征,为研究沼泽性河流水文变化特征提供有效的方法。根据水文相似性原理和参数移植法把校准的模型应用于七星河流域,进行无资料流域的径流模拟,年径流模拟校准期和验证期的Nash-Sutcliffe效率系数、相关系数R2、相对误差PBIAS值分别为0.84、0.94、-5.70和0.91、0.93、-6.46,表明SWAT模型可以应用到七星河流域。     

气候与土地利用变化对流域水资源的影响——以美国北卡罗莱纳州Trent流域为例

分布式水文模型PRMS可为气候与土地利用变化对流域水资源影响的研究提供技术和理论支撑.对Trent流域产流过程采用PRMS模型进行模拟检验,结果表明,Nash模型确定性系数达到0.8以上.水文响应单元(HRU)划分尺度减小,可以有效地提高PRMS模拟精度达7%左右,划分尺度缩小到71个HRU时,模拟精度不再提高.流域蒸...     

滦河流域土地利用/覆被变化的水文响应

以滦河流域为研究区,利用1985和2000年土地利用数据,结合SWAT分布式水文模型定量评价了流域土地利用/覆被变化的水文效应,并分析了流域地表径流变化与主要景观类型的响应关系。结果表明:SWAT(Soil and Water Assessment Tool)模型可以较好地模拟滦河流域的月流量过程,在研究区具有较好的适用性;1985—2000年流域林地向草地和耕地的转变导致流域年均地表径流和总径流量分别增加了12.6%和5.1%;并使得流域年均地表径流变化空间差异显著,整体呈增加趋势,且主要受到林地变化的影响,而在三道河子以上集水区地表径流的变化则主要受到耕地景观的影响。合理规划土地利用格局,对于流域水资源可持续利用具有重要意义。     

滦河流域土地利用/覆被变化的水文响应

以滦河流域为研究区,利用1985和2000年土地利用数据,结合SWAT分布式水文模型定量评价了流域土地利用/覆被变化的水文效应,并分析了流域地表径流变化与主要景观类型的响应关系。结果表明:SWAT（Soil and Water Assessment Tool）模型可以较好地模拟滦河流域的月流量过程,在研究区具有较好的适用性;1985—2000年流域林地向草地和耕地的转变导致流域年均地表径流和总径流量分别增加了12.6%和5.1%;并使得流域年均地表径流变化空间差异显著,整体呈增加趋势,且主要受到林地变化的影响,而在三道河子以上集水区地表径流的变化则主要受到耕地景观的影响。合理规划土地利用格局,对于流域水资源可持续利用具有重要意义。     

Hierarchical approach to hydrological model calibration

Hydrological models have been widely used for water resources management. Successful application of hydrological models depends on careful calibration and uncertainty analysis. Spatial unit of water balance calculations may differ widely in different models from grids to hydrological response units (HRU). The Soil and Water Assessment Tool (SWAT) software uses HRU as the spatial unit. SWAT simulates hydrological processes at sub-basin level by deriving HRUs by thresholding areas of soil type, land use, and slope combinations. This may ignore some important areas, which may have great impact on hydrological processes in the watershed. In this study, a hierarchical HRU approach was developed in order to increase model performance and reduce computational complexity simultaneously. For hierarchical optimization, HRUs are first divided into two-HRU types and are optimized with respect to some relevant influence parameters. Then, each HRU is further divided into two. Each child HRU inherits the optimum parameter values of the parent HRU as its initial value. This approach decreases the total calibration time while obtaining a better result. The performance of the hierarchical methodology is demonstrated on two basins, namely Sarisu-Eylikler and Namazgah Dam Lake Basins in Turkey. In Sarisu-Eylikler, we obtained good results by a combination of curve number (CN2), soil hydraulic conductivity, and slope for generating HRUs, while in Namazgah use of only CN2 gave better results.     

GIS and ANN-based spatial prediction of DOC in river networks: a case study in Dongjiang, Southern China

This paper investigates the use of an artificial neural network (ANN) model to predict dissolved organic carbon (DOC) in a river network and evaluates the impacts of watershed characteristics on stream DOC. Samples and relevant environmental variables were obtained from field sampling at 28 hydrological response units (HRUs) and a MODIS/SRTM DEM satellite image. HRUs can provide reliable spatial interpolation for filling data gaps and incorporate potential spatial correlation among observations in each ANN neuron. The process and results of neural network modeling were assessed by deterministic and statistical methods and spatial regression kriging. The spatial prediction results show that ANN, using improved back propagation algorithms of 7-15-1 architecture, was the optimal network, by which predictions maintained most of the original spatial variation and eliminated smoothing effects of RK. The sum of the relative contributions of four sensitive variables, including soil organic carbon density, geographic longitude, surface runoff and Chl a in river water, was >75 %. A minor prediction error of ~6 % was found in HRUs of open shrublands, but HRUs of urban and croplands had an error of 24–30 %. This pattern exemplifies anthropogenic impacts in urban areas on stream DOC and agricultural activities in croplands. The usefulness of ANN modeling-based GIS in this study is demonstrated by depiction of spatial variation of stream DOC and indicates the benefits of understanding sensitive factors for watershed impact assessments.     

Assessing impact of urban impervious surface on watershed hydrology using distributed object-oriented simulation and spatial regression

In this study, we investigated the relationship between watershed characteristics and hydrology using high spatial resolution impervious surface area (ISA), hydrologic simulations and spatial regression. We selected 20 watersheds at HUC 12 level with different degrees of urbanization and performed hydrologic simulation using a distributed object-oriented rainfall and runoff simulation model. We extracted the discharge per area and ratio of runoff to base flow from simulation results and used them as indicators of hydrology pattern. We derived percentage of ISA, distance from ISA to streams, and stream density as the watershed characteristics to evaluate the relationship with hydrology pattern in watersheds using ordinary least square, spatial error and spatial lag regression models. The comparison indicates that spatial lag regression model can achieve better performance for the evaluation of relationship between ratio of runoff to base flow and watershed characteristics, and that three models provide similar performance for the evaluation of relationship between discharge per area and watershed characteristics. The results from regression analyses demonstrate that ISA plays an important role in watershed hydrology. Ignorance of spatial dependence in analyses will likely cause inaccurate evaluation for relationship between ISA and watershed hydrology. The hydrologic model, regression methods and relationships between watershed characteristics and hydrology pattern provide important tools and information for decision makers to evaluate the effect of different scenarios in land management.     

不同子流域划分对流域径流、泥沙、营养物模拟的影响——丰乐河流域个例研究

以丰乐河流域为研究对象,选用SWAT2000模型定量化研究不同子流域划分层次对模型模拟结果的影响,得到结论:①不同的子流域划分层次在阈值范围内对径流过程的影响较小,而对泥沙、营养物的影响较大;②就本流域而言,子流域划分层次对模拟结果的影响存在上限、下限两个阈值,高于上限,出现模拟失真,低于下限,尽管可通过调参获得满意结果,但难以满足流域规划与管理对空间数据的要求,阈值的确定与具体的流域特征有关;③就本流域而言,当子流域划分数量比较少时,出口泥沙响应的敏感性高于总磷、总氮;当子流域划分数量比较多时,出口泥沙响应的敏感性要低于总磷、总氮。     

Modeling watershed rainfall–runoff relations using impervious surface-area data with high spatial resolution

A distributed object-based rainfall–runoff simulation (DORS) model with incorporation of detailed impervious surface-area (ISA) data, derived from digital true-color orthophotography data with high spatial resolution, was developed. This physically based model simulates hydrologic processes of precipitation interception, infiltration, runoff, evapotranspiration, change of soil moisture, change of water-table depth, runoff routing, groundwater routing, and channel-flow routing. The modeling processes take objects based on land-cover types as fundamental spatial units in order to reduce data volume, increase computational efficiency, strengthen representation of watersheds, and utilize the data in variable scales. US Geological Survey stream-gaging data were used to validate the temporal variation of simulated discharge within two watersheds in Rhode Island State. The ratio of absolute error to the mean and the Nash coefficient in the validation period are 7.2% and 0.90 for the first watershed, and 8.0% and 0.77 for the second watershed, respectively. The results indicate that the DORS model is able to capture the relationship between rainfall and runoff in the study area, and that it is applicable in the further study of ISA impacts on the water cycle and associated pollution problems. The results also demonstrate that the performance of the hydrologic simulation is improved with ISA data with high spatial resolution.     

滁州花山水文实验流域径流与氮素耦合模拟研究

采用SWAT模型方法对滁州花山水文实验流域进行了径流与氮素耦合模拟,探讨了流域土地利用对氮素输移的影响。构建了花山水文实验流域SWAT模型,采用2008年1月~2013年12月的降雨、径流等数据对径流模型进行率定和验证,以2012年5月~2013年12月的氮浓度监测数据对氮负荷模型进行验证。利用所建立的模型对现状土地利用情形和土地利用变化情景假设下进行了径流与氮素耦合模拟,计算了现状和不同土地利用情景假设下流域的径流深和氮负荷。结果表明:汛期的氮流失量占全年氮流失的比重较大,每年的汛期是控制氮流失的关键时期;旱地的氮流失潜力较水田大,林地的增加对氮负荷具有一定的消减作用;控制氮肥的使用,加强水土保持能力,可以有效减少流域氮负荷。     

东北半干旱地区流域分布式水文模拟——以洮儿河流域为例

以东北半干旱地区典型流域-洮儿河流域为研究对象,应用SWAT模型对流域水文过程进行了模拟研究;选择流域上游子流域和中下游子流域分别进行参数敏感性分析,识别出影响模拟结果的敏感参数,研究发现部分参数敏感性存在空间变异性,分析主要原因在于气候和下垫面的空间异质性导致了流域上下游产流模式存在差异。采用1988-1997年水文气象数据进行模型率定和验证,结果表明：干流水文站月流量过程率定期Nash-Sutcliffe 效率系数平均值为0.78,验证期为0.72,相关系数都达到0.86以上,水量误差大多在20%以内,对日过程的模拟也有较高的精度;枯水年模拟结果较差,主要是因为流域降水站数量不够,难以反映降水的时空分布。对于水文、气象等资料相对缺乏的东北半干旱地区,SWAT模型的模拟结果总体令人满意,可以应用于与流域径流相关的各种模拟分析,研究成果对进一步加强洮儿河流域水资源综合管理提供了依据和手段。