Evaluating the SWAT Model for Hydrological Modeling in the Xixian Watershed and a Comparison with the XAJ Model

Already declining water availability in Huaihe River, the 6th largest river in China, is further stressed by climate change and intense human activities. There is a pressing need for a watershed model to better understand the interaction between land use activities and hydrologic processes and to support sustainable water use planning. In this study, we evaluated the performance of SWAT for hydrologic modeling in the Xixian River Basin, located at the headwaters of the Huaihe River, and compared its performance with the Xinanjiang (XAJ) model that has been widely used in China. Due to the lack of publicly available data, emphasis has been put on geospatial data collection and processing, especially on developing land use-land cover maps for the study area based on ground-truth information sampling. Ten-year daily runoff data (1987?C1996) from four stream stations were used to calibrate SWAT and XAJ. Daily runoff data from the same four stations were applied to validate model performance from 1997 to 2005. The results show that both SWAT and XAJ perform well in the Xixian River Basin, with percentage of bias (PBIAS) less than 15%, Nash-Sutcliffe efficiency (NSE) larger than 0.69 and coefficient of determination (R²) larger than 0.72 for both calibration and validation periods at the four stream stations. Both SWAT and XAJ can reasonably simulate surface runoff and baseflow contributions. Comparison between SWAT and XAJ shows that model performances are comparable for hydrologic modeling. For the purposes of flood forecasting and runoff simulation, XAJ requires minimum input data preparation and is preferred to SWAT. The complex, processes-based SWAT can simultaneously simulate water quantity and quality and evaluate the effects of land use change and human activities, which makes it preferable for sustainable water resource management in the Xixian watershed where agricultural activities are intensive.     

Effects of Land-Use and Climate Change on Hydrological Processes in the Upstream of Huai River, China

Land use/land cover and climate change can significantly alter water cycle at local and regional scales. Xixian Watershed, an important agricultural area in the upper reach of the Huaihe River, has undergone a dramatic change of cultivation style, and consequently substantial land use change, during the past three decades. A marked increase in temperature was also observed. A significant monotonic increasing trend of annual temperature was observed, while annual rainfall did not change significantly. To better support decision making and policy analysis relevant to land management under climate change, it is important to separate and quantify the effect of each factor on water availability. We used the Soil and Water Assessment Tool (SWAT), a physically based distributed hydrologic model, to assess the impact of Land use and climate changes separately. The SWAT model was calibrated and validated for monthly streamflow. Nash-Sutcliff efficiency (NSE), percentage bias (PBIAS), and coefficient of determination (R ²) were 0.90, 6.3 %, and 0.91 for calibration period and 0.91, 6.9 %, and 0.911 for validation period, respectively. To assess the separate effect of land use and climate change, we simulated streamflow under four scenarios with different combinations of two-period climate data and land use maps. The joint effect of land use and climate change increased surface flow, evapotranspiration, and streamflow. Climate variability increased the surface water and stream-flow and decreased actual evapotranspiration; and land use change played a counteractive role. Climate variability played a dominant role in this watershed. The differentiated impacts of land-use/climate variabilities on hydrological processes revealed that the unapparent change in stream-flow is implicitly because the effects of climate variability on hydrological processes were offset by the effects of land use change.     

利用蒸腾蒸发管理技术实现真实节水研究

依据研究区域降水量、灌溉水量、土壤含水量,分析计算单一作物的耕地蒸腾蒸发、多种作物的耕地蒸腾蒸发、耕地与非耕地的综合蒸腾蒸发;依据降水量、可利用的入境水量计算区域可利用水量,并结合水资源配置等因素分析确定目标蒸腾蒸发。利用目标蒸腾蒸发进行水权分配。采用3种节水措施,建立相应水资源配置方案,利用SWAT模型进行情景分析,通过方案比较,制定符合特定区域的、切实可行的用水规划方案。试验结果表明,采用综合节水措施后的节水效果优于单一的工程措施,综合节水措施与种植结构调整相结合节水效果更佳。     

Flow and sediment yield simulations for Bukit Merah Reservoir catchment, Malaysia: a case study

Bukit Merah Reservoir is the main potable and irrigation water source for Kerian District, Perak State, Malaysia. For the past two decades, the reservoir has experienced water stress. Land-use activities have been identified as the contributor of the sedimentation. The Soil and Water Assessment Tool (SWAT) was used to simulate and quantify the impacts of land-use change in the reservoir watershed. The SWAT was calibrated and two scenarios were constructed representing projected land use in the year 2015 and hypothetical land use to represent extensive land-use change in the catchment area. The simulation results based on 17 years of rainfall records indicate that average water quantity will not be significantly affected but the ground water storage will decrease and suspended sediment will increase. Ground water decrease and sediment yield increase will exacerbate the Bukit Merah Reservoir operation problem.     

土地利用变化和气候变化对温榆河上游流域径流变化的影响

土地利用和气候是直接影响流域水文水资源的两个主要因素,其影响分离的研究对流域的土地利用规划和水资源管理具有重要意义。以温榆河上游流域为研究对象,在统计分析1980-2014年流域气象因子、土地利用变化趋势的基础上,通过SWAT模型模拟与情景设计相结合的方法,评估了气候变化和土地利用变化对温榆河上游径流变化的影响。结果表明,SWAT模型在温榆河上游流域模拟效果良好,率定期和验证期的决定系数R2分别为0.80、0.77,纳什系数Ens分别为0.79、0.74。流域降雨量和气温呈递增趋势,林地和耕地减少,城乡及工矿和居民用地增加,草地在1995年到2005年间增加,这些变化综合影响了流域的径流变化,使得径流先增加后减少。其中气候变化的贡献率为100.46%,土地利用变化的贡献率为2.09%,气候变化的影响远远大于土地利用变化的影响。因此,如何应对气候变化在温榆河上游流域水资源管理工作中值得重视。     

潘家口水库流域土地利用变化的水文响应分析

以潘家口水库流域为研究区域,采用SWAT分布式水文模型定量评估土地利用变化对流域径流过程的影响。相对于1980年土地利用情景,2006年土地利用变化主要表现为耕地减少,林地和草地面积增大,而水域和城镇用地变化相对较小。利用3个水文站1986年1月至1999年12月的月径流实测数据进行模型的校准和验证。在不同土地利用情景下,对流域的天然径流过程进行模拟分析,模拟结果显示,与1980年土地利用情景相比,2006年土地利用情景下的多年平均径流减少11%;对于不同典型水文年份而言,土地利用变化对枯水年的影响最大,对丰水年和平水年的影响相当;土地利用变化对年径流的影响主要表现为汛期径流减少。潘家口水库流域水资源涵养能力有所增加。模拟研究土地利用变化对潘家口水库流域径流的影响对合理规划土地利用和流域水资源的综合管理具有现实意义。     

Evaluation of Using Remote Sensing Evapotranspiration Data in SWAT

This study applied a time series evapotranspiration (ET) data derived from the remote sensing to evaluate Soil and Water Assessment Tool (SWAT) model calibration, which is a unique method. The SWAT hydrologic model utilized monthly stream flow data from two US Geological Survey (USGS) stations within the Big Sunflower River Watershed (BSRW) in Northwestern, Mississippi. Surface energy balance algorithm for land (SEBAL), which utilized MODerate Resolution Imaging Spectro-radiometer (MODIS) to generate monthly ET time series data images were evaluated with the SWAT model. The SWAT hydrological model was calibrated and validated using monthly stream flow data with the default, flow only, ET only, and flow-ET modeling scenarios. The flow only and ET only modeling scenarios showed equally good model performances with the coefficient of determination (R²) and Nash Sutcliffe Efficiency (NSE) from 0.71 to 0.86 followed by flow-ET only scenario with the R² and NSE from 0.66 to 0.83, and default scenario with R² and NSE from 0.39 to 0.78 during model calibration and validation at Merigold and Sunflower gage stations within the watershed. The SWAT model over-predicted ET when compared with the Modis-based ET. The ET-based ET had the closest ET prediction (~8% over-prediction) as followed by flow-ET-based ET (~16%), default-based ET (~27%) and flow-based ET (~47%). The ET-based modeling scenario demonstrated consistently good model performance on streamflow and ET simulation in this study. The results of this study demonstrated use of Modis-based remote sensing data to evaluate the SWAT model streamflow and ET calibration and validation, which can be applied in watersheds with the lack of meteorological data.     

西南岩溶灌区水文特性及其模拟模型的构建

从岩溶水文和灌区水文两方面分析了西南岩溶灌区水文的特殊性和脆弱性。针对西南岩溶灌区水文特点,在对自然流域水文模型SWAT改进的基础上,构建岩溶灌区分布式水文模型。建立的岩溶灌区分布式水文模型主要添加了表层岩溶带水循环模块、岩溶地下河汇流过程,改进浅层岩溶水计算方法、稻田水分循环模块、渠系渗漏计算模块,增加塘堰的灌溉功能等,并介绍了模型的流域离散方法和水循环结构。岩溶灌区分布式水文模型的构建可为西南岩溶灌区水文特性及其对变化环境的响应等研究提供有效的工具和手段。     

Hydrological Simulation by SWAT Model with Fixed and Varied Parameterization Approaches Under Land Use Change

Land use and land cover (LULC) change within a watershed is recognized as an important factor affecting hydrological processes and water resources. Modeling the hydrological effects of land-use change is important not only for after-the-fact analyses, but also for understanding and predicting the potential hydrological consequences of existing land-use practices. The main aim of the study is to understand and quantify the hydrological processes in a rapid urbanization region. The SWAT model and the Qinhuai River basin, one of the most rapidly urbanizing regions in China were selected to perform the study. In the study, a varied parameterization strategy was developed by establishing regression equations with selected SWAT parameters as dependent variables and catchment impermeable area as independent variable. The performance of the newly developed varied parameterization approach was compared with the conventional fixed parameterization approach in simulating the hydrological processes under LULC changes. The results showed that the model simulation with varied parameterization approach has a large improvement over the conventional fixed parameterization approach in terms of both long-term water balance and flood events simulations. The proposed modeling approach could provide an essential reference for the study of assessing the impact of LULC changes on hydrology in other regions.     

Estimation of Groundwater Balance Using Soil-Water-Vegetation Model and GIS

This study concerns the development of a methodology using modern techniques of data generation (Modeling) and interpretation (GIS) to compute groundwater plausibly at regional scale, alternate to previously established norms. The approach is centered on quantitative estimation of two main parameters-input and output. GIS techniques along with soil vegetation model (CropSyst) have been demonstrated for the calculation of groundwater balance components. Using the developed methodology water resources of the Ludhiana district for the period between, 2000 and 2010 were estimated. The temporal changes in water balance components indicated that the major inputs to the hydrologic system are rainfall and canal water and the major out component are evapotranspiration (ET). Multi-annual (2000 to 2010) average of 719 mm rainfall, 88 mm canal water, 74 mm of groundwater inflow, with annual loss 974 mm as ET, caused 123 mm of net negative groundwater recharge in Ludhiana district. The annual computed rise/fall with the developed methodology closely matched the observed values.     

北庙水源地土地利用变化对水文要素影响的研究

选用保山市日气象观测数据和北庙水源地水库坝上径流资料,结合北庙水源地内的土地利用数据、土壤数据和DEM数据,构建其SWAT分布式水文模型,研究水源地三期不同土地利用方式变化对水文要素的影响。结果表明:在模型率定期和验证期,R2数分别为0.70和0.72,模型效率系数均大于0.55,径流模拟值与实测值相对误差在15%以内,SWAT水文模型在北庙水源地有较好的适用性。1986-2009年,北庙水源地土地利用类型以林地、耕地、草地为主;草地面积减少,耕地、未利用土地和居民用地增加是这一时期土地利用方式变化的主要特征。水源地水文要素发生相应的变化主要表现为坡面径流深、径流深和土壤侵蚀模数增加,而实际蒸散减少。     

Application of SEBAL approach and MODIS time-series to map vegetation water use patterns in the data scarce Krishna river basin of India.

Evapotranspiration (ET) from irrigated land is one of the most useful indicators to explain whether the water is used as "intended". In this study, the Surface Energy Balance Algorithm for Land (SEBAL) was used to compute actual ET from a Landsat7 image of December 29, 2000 for diverse land use in the Krishna Basin in India. SEBAL ETa varies between 0 to 4.7 mm per day over the image and was quantified for identified land use classes. Seasonal/annual comparison of ETa from different land uses requires time series images, processed by SEBAL. In this study, the Landsat-derived snapshot SEBAL ETa result was interpreted using the cropping calendar and time series analysis of MODIS imagery. The wastewater irrigated area in the basin has the highest ETa in the image, partly due to its advanced growth stage compared to groundwater-irrigated rice. Shrub and forests in the senescence phase have similar ETa to vegetable/cash crops, and ETa from grasslands is a low 0.8 mm per day after the end of the monsoon. The results indicate that wastewater irrigation of fodder and rice is sufficient to meet crop water demand but there appears to be deficit irrigation of rice using groundwater.     

北京地区夏玉米滴灌下土壤水分分布及水分利用效率的研究

在北京地区开展滴灌条件下不同灌溉水量的夏玉米田间试验,通过测定土壤含水量和夏玉米产量,研究滴灌条件下不同灌溉水量对土壤水分分布及水分利用效率的影响.研究结果表明：由于2012年是丰水年份,在相同土层各灌水处理之间的土壤水分分布差异性较小;各灌水处理耗水总量随着灌水量的减小而减小,但在丰水年份均能满足夏玉米需水的需要,各灌水处理夏玉米全生育期内土壤蓄水供水基本平衡;各灌水处理水分利用效率随着灌水量的减小而增大,30豫（ ET0-P）的灌水方式可以获得较高的水分利用效率.因此,在研究区种植夏玉米若采用30豫（ ET0-P）的滴灌灌水方式进行灌溉,耗水量为368.5 mm,灌水量仅为42.9 mm,夏玉米减产幅度较低,提高了水分利用效率,从而实现高效用水的目的.     

灌区地表水—地下水耦合模型的构建

为了定量描述灌区水平衡要素及其转化关系,构建了灌区地表水-地下水分布式模拟耦合模型。通过改进SWAT模型的稻田及旱作物水分循环、蒸发蒸腾量和渠系渗漏计算等模块,建立了灌区地表水分布式模拟模型;以SWAT模型中的水文响应单元(HRU)和MODFLOW模型中的有限差分网格(cells)作为基本交换单元,将改进SWAT模型的地下水补给量计算值加载到MODFLOW模型的地下水补给模块,实现了灌区地表水-地下水分布式模拟模型的耦合。耦合模型在柳园口灌区的应用结果表明,该模型能够准确模拟和预测灌区地表水和地下水的动态变化,为灌区水管理提供了科学依据。     

Linking a spatially explicit watershed model (SWAT) with an in‐stream fish habitat model (PHABSIM): A case study of setting minimum flows and levels in a low gradient,sub‐tropical river

As changes in landuse and the demand for water accelerate, regulators and resource managers are increasingly asked to evaluate water allocation against the need for protection of in‐stream habitat. In the United States, only a small number of river basins have the long‐term hydrograph data needed to make these assessments. This paper presents an example of how to bridge the conceptual and physical divide between GIS‐based watershed modelling of basin‐discharge and in‐stream hydraulic habitat models. Specifically, we used a Soil and Water Assessment Tool (SWAT) model for the Hillsborough River to produce data for use in a Physical HABitat SIMulation (PHABSIM) model of the same river. This coupling of models allowed us to develop long‐term discharge data in ungauged river systems based on watershed characteristics and precipitation records. However this approach is not without important limitations. Results confirm that accuracy of the SWAT‐predicted hydrograph declines significantly when either the DEM resolution becomes too coarse or if DEM data are resampled to a coarser or finer resolution. This is due to both changes in the size and shape of the river basin with the varying DEMs and subsequent shifts in the proportions of land use, soils and elevation. Results show the use of 30 m DEMs produced hydrographic patterns amenable for using in‐stream habitat protocols like PHABSIM model, especially where little or no hydrographic and land use information exists. Copyright © 2010 John Wiley & Sons, Ltd.     

土地利用变化下的水文响应及其可检测性分析

以涪江桥流域为研究区域,采用SWAT模型模拟流域水文过程,将相同水文气象条件下1985和1995年2个时期土地利用情景的SWAT模型模拟结果与土地利用空间转化图相结合,分析土地利用变化引起的水文要素变化及其可检测性问题。结果表明:1985—1995年间涪江桥流域发生较为剧烈的土地利用变化,但并未检测到足够显著的水文要素变化;不同土地利用类型水文效应的相似性、不同土地利用类型水文效应差异性以及统计中和效应和统计均化效应是导致土地利用变化引起的水文要素变化难以检测的主要原因。在此基础上,提出了水文动态响应度指标,来消除统计中和效应。该指标可以在一定程度上帮助研究者了解研究区特定水文要素变化的相对剧烈程度。研究结果可为土地利用总体规划和流域水资源保护与合理配置提供参考。     

基于SWAT 模型的区域蒸散发模拟及遥感验证

应用分布式水文模型进行灌区用水效率多尺度评价,可为灌区节水改造提供技术支持,本文运用SCE-UA算法在大兴试验站对分布式水文模型（SWAT）中的夏玉米-冬小麦轮作作物参数进行率定,对SWAT模型中蒸散发相关参数进行了敏感性分析,综合考虑农业灌溉措施和施肥措施,将模型模拟ET与遥感监测值进行对比验证.结果表明,SWAT模型模拟ET与遥感监测ET的确定性系数和Nash效率系数分别达到了0.91和0.90,模拟精度较高;不同的土地利用形式下,蒸散发变化显著,平均误差为6.9％.利用遥感监测ET数据有助于蒸散发的正确模拟,从而有效地提高水文过程的模拟精度.     

Groundwater Modeling Under Variable Operating Conditions Using SWAT,MODFLOW and MT3DMS: a Catchment Scale Approach to Water Resources Management

This paper presents an integrated modeling approach by linking soil and water application tool (SWAT), modular finite difference groundwater flow (MODFLOW) and modular 3-dimensional multi-species transport (MT3DMS) models capable of predicting a groundwater system response, in terms of flow and salt concentrations, to current and future development conditions. SWAT, a semi-distributed hydrologic model, estimates the spatio-temporal distribution of groundwater recharge rates. These rates are then input to MODFLOW using an interface module developed that maps the HRU-based spatial resolution of SWAT outflows into the cell-based spatial structure of inputs to MODFLOW and MT3DMS. The integrated SWAT-MODFLOW-MT3DMS model is used in modeling Dehloran aquifer system located in the arid western region of Iran, experiencing changes in land-use, irrigation system and pumping locations and loads. The results illustrate the significance of the developed integrated modeling tool in quantifying the impact of changes in land and surface water resources on its subsurface water system.     

黄河流域灌溉发展成就与前景

人民治黄５０年来，黄河流域（包括下游引黄灌区）灌溉事业得了迅速发展，截止１９９４年年底，全流域灌溉面积已发展到７３１万ｈｍ＾３因灌溉年净增产粮食１２０亿ｋｇ。全河灌溉技术发展迅速，在井渠结合治理盐碱地、灌区泥沙处理、节水灌溉、高气程灌溉等方面取得了突出成绩。随着灌区的开发与建设，管理水平不断提高，计划用水、水费征收、计量供水等管理措施的应用，保证了灌效益的充分发挥和灌区自身经济实力的壮大。分析认为     

山西省潇河灌区渠首枢纽工程水文监测自动化研究

山西省潇河灌区属全国大型灌区,是山西省十大灌区之一.灌区自动化建设是水利信息化建设的重要组成部分,为提高灌区用水与输配水等方面的效率,有力地促进对农业水资源的高效合理利用,在灌区渠首枢纽工程水文监测自动化方面进行了分析研究.