Hydrological Prediction in a Tropical Watershed Dominated by Oxisols Using a Distributed Hydrological Model

Hydrological models have been used in many places of the world in order to support practitioners with respect to watershed management actions. The goal of this research was to apply the Lavras Simulation of Hydrology (LASH model) to a Brazilian tropical watershed dominated by Oxisols, to estimate maximum, minimum and mean stream flows for both current land-use (“scenario 1”) and other regional trend land-use scenarios (“scenario 2”—pasture into eucalyptus; and “scenario 3”—eucalyptus into pasture). This model is a continuous, distributed and semi-conceptual model for simulation of different hydrological components on a daily basis. The model had a good performance with respect to the “scenario 1”, resulting in Nash-Sutcliffe coefficients equal to 0.81, 0.82 and 0.98 for minimum, maximum and mean discharges, respectively. When “scenario 2” was simulated, it was found that minimum, mean and maximum stream flows had their values reduced in average by 7.39 %, 13.84 % and 20.38 %, respectively. On the contrary, it was observed in “scenario 3” an increase in average by 0.23 %, 0.44 % and 1.19 % for minimum, mean and maximum stream flows, respectively. With respect to water yield, scenario 2 resulted in a mean reduction of 119 mm, whereas for scenario 3 the difference was not so pronounced in relation to the current land use. Results obtained in scenario 2 are troublesome since this watershed drains into an important regional Hydroelectric Power Plant Reservoir and this approach needs to be considered by the Minas Gerais State electric energy company for its planning strategies for the future.     

分布式水文模型EasyDHM在北江流域的应用

为了解决珠江流域咸潮上溯问题,需要在枯水期对流域水库群进行压咸调度。合理调度的前提是准确掌握流域的来水情况,以便在满足发电需要的基础上兼顾生态需要,特别是在枯水期。飞来峡水库是北江流域的重要水库,位于珠江流域下游,在流域抑咸调度中起到关键的作用。为了对飞来峡水库来水过程进行水文模拟分析,以分布式水文模型EasyDHM为基础,利用DEM、实测河网、土壤、土地利用及水文气象数据,构建了北江流域分布式水文模型。通过模型的参数率定以及验证发现,模型精度较高,可以很好的应用于流域水情形势分析;对飞来峡水库旬入库过程统计发现,枯水期来水量最小值出现在12月上中旬,这对于确定流域抑咸统一调度的最佳时期也有着重要的意义。     

分布式水文模型在大通河流域的应用研究

通过构建基于混合产流的分布式水文模型,将大通河流域内气象、水文站点观测数据与遥感数据结合起来,研究了大气、陆面、地表水和地下水的相互作用机理,确定了模型参数,并对大通河享堂水文站日均流量过程进行了模拟。结果表明:该模型能在水文、气象站点稀少,土壤及水文地质数据缺乏的条件下较好地模拟大尺度资料稀缺地区的水文过程,能较合理地揭示研究区的产汇流规律;模拟流量与实测流量高度相关,平均相对误差为-1.99%、确定性系数为0.75,模拟结果合理、可靠。     

长江中游蓄滞洪区分洪运用方案研究

蓄滞洪区是降低洪水风险的一种有效工程措施,能够充分有效地分蓄超额洪量,最大程度地降低高洪水位,从而减轻甚至消除下游的防洪压力。然而,蓄滞洪区的运用效果与洪水的类型密切相关。在水系复杂的长江中游地区,理想地运用蓄滞洪区一般比较困难,特别是在需要决策分洪运用蓄滞洪区又不知道未来的洪水过程时。以宜昌站至汉口站为研究范围,包括洞庭湖区及支流汉江,对钱粮湖、共双茶、大通湖东及洪湖东分块共计4个蓄滞洪区的分洪运用方案进行了研究。对于1998年实际洪水,利用水动力模型．研究出4个蓄滞洪区的理想运用方案。基于未来洪水的不确定性,对1998年实际洪水理想运用方案进行不同影响因素（包括水文、决策及洪水类型等因素）测试,总结出蓄滞洪区分洪运用的一般规律,并对本项目的进一步研究提出合理化建议。     

分布式水文模拟模型在流域水资源管理中的应用

旨在通过对国外比较流行的分布式流域水文模拟模型的介绍，对比分析各类模型的总体结构、特点及适应领域，结合在流域水资源管理中的应用，为流域水资源管理部门及相关研究工作人员在进行流域水文模拟模型选用时提供参考。     

Downstream Hydrological Impacts of Hydropower Development in the Upper Mekong Basin

The Mekong River Basin in Southeast Asia is experiencing extensive hydropower development. Concerns have been raised about the consequences of the development for the ecosystems, livelihoods and food security in the region. The largest planned hydropower dam cascade in the basin, the Lancang-Jiang cascade, is currently under construction and already partly built into the Upper Mekong Basin, China. In this paper we assess the impact of the Lancang-Jiang cascade on downstream hydrology by using a combination of a hydrological model and a reservoir cascade optimization model. The hydrological changes were quantified in detail at the Chiang Saen gauging station in Thailand, the first gauge station downstream from the cascade, and in lesser detail at four other downstream locations in the Mekong mainstream. We found that on average the Lancang-Jiang cascade increased the December?CMay discharge by 34?C155?% and decreased the July?CSeptember discharge by 29?C36?% at Chiang Saen. Furthermore, the Lancang-Jiang cascade reduced (increased) the range of hydrological variability during the wet season (dry season) months. The dry season hydrological changes were significant also in all downstream gauging stations, even as far as Kratie in Cambodia. Thus the Mekong??s hydrological regime has been significantly altered by the Lancang-Jiang cascade, but what the consequences are for ecosystems and livelihoods, needs further study.     

分布式水文模型构建及在黄河区间流域的应用

选择位于黄河支流洛河中游的长水—宜阳区间流域作为研究对象,基于数字高程模型,计算栅格水流方向、集水面积和栅格演算次序,为产汇流计算打下基础。把1个栅格单元作为1个小子流域,基于栅格采用新安江模型进行产流计算,采用Muskingum-Cunge算法进行河道洪水演算。结果表明,基于DEM的分布式水文模型在洪峰误差控制和过程拟合等方面表现较好,洪水模拟具有较高的精度。     

Impacts of Hydrological Changes on Annual Runoff Distribution in Seasonally Dry Basins

Runoff is expected to change due to climate and land use change. Because it constitutes a large component of the terrestrial water budget, we need to develop new policies for managing regional water resources. To do so, we must first attribute changes in the natural flow regime to either climate or land use change. In this context, the Budyko’s curve has previously been adopted to separate the impacts of climate and land use change on runoff by using long term hydrological variables. In this study, a framework based on Fu’s equation (which describes Budyko’s curve) is used to separate the impacts of climate and land use change on annual runoff distributions. Specifically, this framework is based on a recently developed method to obtain annual runoff probability density function (pdf) in seasonally dry basins—such as those in Mediterranean regions—from climate statistics and Fu’s equation parameter ω. The effect of climate change is captured through variations in the first order statistics of annual rainfall and potential evapotranspiration, while land use change is represented by changes in Fu’s equation parameter ω. The effects of these two drivers (i.e., climate and land use change) are analyzed by reconstructing the annual runoff pdfs for the current period and for likely future scenarios, based on predictions from global circulation models and urbanization trajectories. The results show that climate change can lead to a strong reduction in mean annual runoff, a shift of the runoff pdf toward lower values, and a decrease in its variance. Concurrent changes in climate and land use almost always result in a reduction in the mean annual runoff, due to the greater impact of climate change on the runoff pdf.

     

滦河流域分布式水文模型开发与验证

以WEP模型为基础,构建了基于物理机制的滦河流域分布式水文模型,采用500 m×500 m正方形网格,将流域离散为215 353个基本计算单元,采用“马赛克”法进行土地利用类型重归类,对冠层截留、地表过程、土壤过程、地下水过程以及汇流过程等水文过程进行连续30 a的模拟计算,并以桃林口水库水文站和滦县水文站的还原流量为准对模型进行了校验.结果表明:模型校验期模拟月径流与观测月径流之间的相关系数为0.85～0.94,纳什效率系数在0.72以上,模拟年径流误差控制在5％左右,表明该模型具有较高精度,可为流域水资源综合开发和管理提供支撑.     

面向分布式水文模型的汉江流域空间离散化方法

深入分析了分布式与半分布式水文模型的空间离散化方法,结合多种方法的优点对汉江流域下垫面信息进行离散化处理,既综合了子流域和地貌单元反映地形特征的优势,又引入"马赛克地块"面积分布函数,简单有效反映了不同植被覆盖影响.同时,为每个计算单元都进行了含有拓扑信息的编码,高效组织了众多空间数据,便于计算机自动处理,缩短计算时间.为构建分布式水文模型时尽可能全面反映下垫面空间异质性同时又尽可能少的引入参数打下了坚实基础.     

新安江水文模型在水文预报中的应用

以海南省万泉河流域为研究对象,在新安江水文模型的基础上,通过完善模型结构、优化参数率定等,开展了对模型的改进和实证研究,并对相关结果进行了分析.在万泉河流域1990～2000年加积站和加报站的水量平衡研究中,模拟结果比较符合实测值,证明模型对万泉河流域具有较强的适用性,在流域水资源管理中具有较好的应用前景.     

分布式水文模型软件系统MWEasyDHM 简介

本文介绍了分布式水文模型EasyDHM模型的软件系统MWEasyDHM,主要由4个部分组成：（1）面向水文分析的通用GIS软件;（2）前处理模块;（3）模拟模块;（4）后处理模块。其中面向水文分析的通用GIS软件以开源GIS软件MapWindow为基础开发,并包括了其他模块所涉及的基本GIS功能;前处理模块包括基于DEM的水文分析组件,模型参数推求模块和降水量、气象数据插值模块;模拟模块提供了实时计算功能,能实时查看模拟结果;模型后处理模块包括了模型参数自动识别、运算结果统计分析及以表格、图表等方式对模拟结果的展示。MWEasyDHM的开发解决了分布式水文模型快速建模及率定的难题,并为将来升级开发及大范围推广应用奠定了基础。     

Short-Term Predictions of Hydrological Events on an Urbanized Watershed Using Supervised Classification

Many tasks of operational watershed management at the local level require stream flow predictions delivered to decision makers in a timely manner. In highly urbanized watersheds with an impermeable surface, stormwater runoff can cause rapid increases in water levels in streams leading to flood and even flash flood events. Usually, such rapid increases in water flow characteristics are predicted by process-based models with high levels of uncertainty. In this study, the prediction of magnitudes of the stream hydrological characteristics is replaced by the forecasting of an event (i.e., flood or no-flood) using data collected by stream and rain gauges at the watershed. The proposed approach is based on a black box model developed as an ensemble of classifiers generated by independent inducers to predict the class of a future hydrological event in a small highly urbanized watershed. Eight inducers were investigated in the phase space reconstructed from observation data using time-delay embedding extended to multiple observation sites. Five inducers were selected for the ensemble, where the final decision is made by majority vote. The developed model generates 45-minute and hourly predictions of high-flow events with more than 80 % precision – a threshold used in operational flood management. Model site-specific parameterization is replaced by the training step using observation data on water levels and precipitation which are collected at 15-minute intervals and are readily available. The proposed approach to developing a prediction tool can be used by local authorities as one of the methods for flood management.     

栅格型分布式流域水文模型构建

基于地貌形成理论,充分考虑了流域内地形、植被、土壤、土壤水分等因素对流域蓄水容量空间分布的影响,提出了蓄水容量空间分布模型及建模方法,在此基础上,结合垂直混合产流机制,建立了概念性分布式流域水文模型。项目研究应用RS和GIS,是对传统水文模型改进的创新尝试,同时指出建立基于RS和GIS的耦合水文模型是未来的发展趋势。     

Assessing Options to Increase Water Productivity in Irrigated River Basins Using Remote Sensing and Modelling Tools

In regions where water is more scarce than land, the water productivity concept (e.g. crop yield per unit of water utilized) provides a useful framework to analyse crop production increase or water savings in irrigated agriculture. Generic crop and soil models were applied at field and regional scale, together with geographical and satellite data to analyse water productivity in Sirsa District (India). In this district certain parts show a serious decline in groundwater levels and water shortage, while other parts experience a serious rise of groundwater levels, causing waterlogging and salinization. The regional analysis showed a large spatial variability of water productivity, net groundwater recharge and salinization. Scenario analysis showed that improved crop husbandry, reallocation of canal water from fresh to saline groundwater areas and reduction of seepage losses in saline groundwater areas are effective measures to increase the overall water productivity and to attain sustainable irrigation in Sirsa District.     

Predictive Analysis and Simulation Uncertainty of a Distributed Hydrological Model

Distributed hydrological models should pass through a careful calibration procedure backed by sensitivity, uncertainty and predictive analysis before they are utilized as a decision making aid in watershed management and scenario studies. This paper examines whether the uncertainty of the parameters of the spatially distributed hydrologic model WetSpa causes significant uncertainty in the model predictions. The WetSpa model is applied to the Torysa river basin, a rather large catchment located in Slovakia. Parameter estimation, sensitivity and predictive analysis of the model parameters are performed using a model-independent parameter estimator, PEST. It is found that the correction factor for measured evaporation data has the highest relative sensitivity. Parameter uncertainty and predictive analysis give an insight of a proper parameter set and parameter uncertainty intervals and prove that the parameter uncertainty of the model does not result in a significant level of predictive uncertainty.     

北江下游蓄滞洪区运用对石角洪水位的影响分析

结合广东北江下游蓄滞洪区的实际情况,提出了一种考虑了蓄滞洪区和区间入流的非恒定流洪水计算模型,分析分洪效果,该模型可作为洪水调度的技术支持。     

流域水文模型分析研究

介绍了流域水文模型的分类，以及国内外现有水文模型的研究进展，分析了现有水文模型存在的问题，并提出了若干建议。对未来水文模型作了展望，指出了基于RS和GIS的耦舍水文模型是今后研究的方向。     

分布式流域水文模型研究中的几个问题

指出数值计算、GIS、雷达测雨和卫星云图等技术的进步为分布式流域水文模型的发展及实际应用提供了条件 .论述分布式流域水文模型的结构有概念性和具有物理基础之分 ,也有耦合式和非耦合式之分 .为了确定分布式流域水文模型的参数 ,对现有几种建立产汇流参数与自然地理因子之间的理论关系的途径进行了初步分析 .     

汉江流域分布式水循环模拟研究

详细描述了汉江流域分布式水文模型构建和求解的过程,验证了WEP模型模拟研究区水循环的可行性。提出了"参数分区"的新理念,为研究参数不确定性空间变异提供了高效的模型空间结构。分别采用分割样本检验法和代表样本检验法对模型模拟结果进行检验。模拟结果的评价采用年径流总量模拟的误差RE、Nash指数及模拟的降雨径流相关系数个指标。