内河洪水对龙赛湖蓄滞洪区蓄洪容积影响特点的计算分析

蓄滞洪区的有效蓄洪容积是蓄滞洪区在分洪运用时实际能够蓄纳洪水的容积，是制定蓄滞洪区调度预案、实时优化调度方案的重要依据，内河洪水的调度将会占用蓄滞洪区内湖泊、圩垸及洼地的蓄洪容积，从而使有效蓄洪容积减少。选取汉北河龙赛湖蓄滞洪区，计算分析了不同频率内河洪水调度占用湖泊、圩垸及洼地蓄洪容积的变化特点，调蓄内河洪水后蓄滞洪区有效蓄洪容积的变化规律及影响，结果表明：(1)对于同时包括湖泊、圩垸和洼地的蓄滞洪区，调蓄内河洪水占用湖泊蓄洪容积显著大于占用圩垸及洼地蓄洪容积，内河洪水越大，占用湖泊与圩垸及洼地蓄洪容积的差别就越大。龙赛湖蓄滞洪区内河发生5年至50年一遇洪水时，在被占用蓄洪容积总量中，占用湖泊容积的比例达到97.9%～98.1%。(2)调蓄内河洪水减小蓄滞洪区有效容积随内河洪水频率的不同而改变，内河洪水越大，蓄滞洪区有效蓄洪的减小就越显著，龙赛湖蓄滞洪区内河发生50年一遇洪水时，有效蓄洪容积减小了约13.5%，而在发生5年一遇洪水时，有效蓄洪容积仅减小了7.81%。(3)当内河发生洪水并可能遭遇干流洪水时，蓄滞洪区有效蓄洪容积的减小将对干流防洪调度产生较为明显影响，应根据来水情况实时...     

淀北蓄滞洪区洪水模型及局部冲刷特性的研究

以天津市淀北蓄滞洪区为例,采用有限体积法剖分网格、建立泛区洪水演进数学模型,模拟塔基工程建设前后泛区的洪水演进进程。通过数值模拟分析工程建设对蓄洪过程的影响;构建工程局部加密网格模型,计算工程建设前后水力条件的变化量,分析电塔基础桩柱对局部行洪的影响,并采用局部冲刷公式估算局部加密模型冲刷深度。结果显示塔基工程建设后,不会明显影响淀北蓄滞洪区的总体洪水演进过程,对局部行洪影响也较小,所以在此蓄滞洪区建立塔基工程是可行的。     

基于ArcGIS的潮白河地下水库三维地质建模及动态模拟

三维地质建模是实现地质信息可视化的一种重要手段。通过收集、分析北京市潮白河冲洪积扇地质及水文地质资料,开发运用ArcGIS软件的三维可视化应用程序ArcScene,对钻孔数据进行样条插值,采用基于面的建模方法建立了潮白河地下水库三维地质结构模型。同时,在此基础上,利用ArcScene中的Animation工具条,通过控制潜水面的升降模拟地下水库补给与消耗的动态变化,建立地下水库动态模拟展示模型。模型形象地展示、模拟了研究区地下水库地质结构特征及地下水库补给与消耗的动态变化特征,为地下水库的分析与建立提供技术支持,且为以后利用ArcScene进行三维地质建模提供依据。     

基于GIS的澧南垸分洪洪水三维可视化淹没模拟

研究适用于中小型蓄洪垸分洪洪水淹没模拟的可视化技术.利用Arcgis Engine 9.3在Visual Studi0 2008平台下,运用C#语言来建立澧南垸分洪洪水淹没程序.考虑到蓄洪垸分洪洪水的特殊性,选用给定水位的编程思路,近似地模拟了分洪洪水的蓄洪过程,并与相关成果的数值计算结果做比较.结果表明,该程序能较好地反映澧南垸分洪洪水的淹没过程,可以动态演示澧南垸分洪洪水的蓄洪过程,自定义查询淹没时的水位、范围和容积等洪水要素特征.该编程思路在类似于澧南垸的中小型蓄洪垸有更好的适应性,可以为澧南垸的防洪调度及防洪规划提供参考和依据.     

基于OpenGL的三维边坡稳定分新可视化软件研究

基于0penGL开发了针对三维边坡稳定分析的可视化软件。软件框架由3个部分组成：前处理模块、计算模块和后处理模块。由于三维边坡建模的复杂性，前处理采用面向对象的编程语言，在VisualC＋＋平台下使用0pen-GL图形库进行图形应用开发来完成前处理建模。0penGL是用于开发简捷的交互式二维和三维图形应用程序的最佳环境，有使用简便，效率高的优点。软件利用openGL提供的多种成熟的库函数进行点、线、多边形等基本图元的绘制，然后对基本图元进行相应的组合以得到复杂的边坡三维模型，能比较直观地显示滑坡体的三维特征。软件具有开放性，便于以后的扩展、升级及维护。计算模块采用刚体极限平衡法。结合工程实例验证了软件的适用性。     

蓄滞洪区洪水演进过程数值模拟及洪灾损失分析

以二维非恒定流基本控制方程为理论基础,采用有限体积法建立洪水演进数学模型。根据蓄滞洪区内不同地形条件及洪水调度方案,以相应的水动力学方法,对模型区域的通量、蓄水量和洪水实时淹没水位进行计算,并考虑了公路建设中路基体积、涵洞尺度、取土方量对蓄滞洪区洪水演进的影响。采用小清河蓄滞洪区的历史洪水淹没资料进行模型验证,模拟了自然滞洪和分区滞洪两种情况下的洪水淹没过程,模拟结果与历史统计淹没范围基本吻合,为蓄滞洪区中的工程建设和防洪影响评价提供了研究思路和方法。     

中望三维软件环境下SWL丝杆升降机的结构设计及运动仿真

中望三维软件在对机构进行建模的同时,能模拟机构运行的过程,同时还可以演示机构的运动过程,并做成动画文件,用于演示和存档。以SWL丝杆升降机为例,介绍了三维实体建模过程和方法,并进行升降机的三维装配和升降机的动画演示。     

新安江模型与GIS集成框架和方法研究

采用模块化思想,结合Python编程语言构建水文模拟模块,将新安江模型以Add In方式集成到ArcGIS桌面系统。研究详细介绍了地形预处理、水雨情监测、水文模拟模块的处理流程,并以汝河流域为研究区进行水文模拟案例研究,结果表明集成系统在数据管理、过程可视化及结果模拟方面都有很好的效果,为水文过程模型与GIS的集成提供了新的方法。     

MIKE系列模型在蓄滞洪区洪水模拟中的应用研究

基于MIKE系列模型的原理和方法,以杨庄蓄滞洪区为例,结合其调度运用预案,构建小洪河河道退洪一维MIKE11模型、杨庄蓄滞洪区洪水演进二维MIKE21模型和一二维动态耦合MIKE FLOOD模型。采用2000年"6.26"和"7.13"实测洪水验证了模型参数。模拟计算了杨庄蓄滞洪区3种运用方案,从区内洪水淹没演进情况、退洪过程、与原设计调度方案比较等3个方面进行分析,成果较为准确合理。基于MIKE构建的蓄滞洪区洪水模拟模型,能够较好地模拟蓄滞洪区的运行和区内洪水的演进过程,可为蓄滞洪区相关应用研究提供借鉴。     

基于OpenGL的三维边坡稳定分析可

基于OpenGL开发了针对三维边坡稳定分析的可视化软件。软件框架由三个部分组成：前处理模块、计算模块和后处理模块。由于三维边坡建模的复杂性,前处理采用面向对象的编程语言,在Visual C++平台下使用OpenGL图形库进行图形应用开发来完成前处理建模。OpenGL是用于开发简捷的交互式二维和三维图形应用程序的最佳环境,有使用简便,效率高的优点。软件利用OpenGL提供的多种成熟的库函数进行点、线、多边形等基本图元的绘制,然后对基本图元进行相应的组合以得到复杂的边坡三维模型,能比较直观的显示滑坡体的三维特征。软件具有开放性,能便于以后的扩展,升级及维护。计算模块采用刚体极限平衡法,结合工程实例验证了软件的适用性。     

辽河流域防洪系统综合评价指标体系研究

随着我国许多流域防洪体系建设的逐渐完善和水利部门防洪思路的逐渐改变，对流域防洪系统进行综合评价显得很有必要，而要进行防洪系统综合评价首先要建立评价指标体系。阐述了社会系统、经济系统和防洪系统之间的既相互制约又相互促进的关系，说明三者处于一种动态的协调平衡中；结合三者之间的关系，从辽河流域实际情况出发，考虑资料收集的可行性，以全面而精练为准则，分别建立了社会系统、经济系统和防洪系统指标体系，以期对辽河流域防洪系统进行全面、客观的科学评价。该指标体系结合实际作适当修改可以应用于其他流域的防洪系统评价中。     

基于水文水动力模型的浦阳江流域洪水情景模拟

浦阳江流域地形复杂,包括山丘、盆地和平原。中游诸暨盆地是人口主要聚集地,受上游山区洪水和下游钱塘江潮位顶托影响,洪涝灾害形势严峻。为解决上述问题,本文对流域上游山区采用新安江水文模型模拟降雨径流过程,对下游盆地区采用IFMS一、二维水动力模型模拟水流运动,并以水文模型的计算结果作为水动力模型的边界条件进行水文水动力模型耦合。结果表明水文水动力模型适用于浦阳江全流域洪水模拟,能够弥补新安江模型中马斯京根汇流无法考虑潮水顶托影响以及水动力模型难以响应降雨变化的不足。根据地区防洪特点设置致灾因子变化和水利工程建设两类情景进行洪水模拟,得到不同条件下浦阳江流域的洪水淹没水深分布,通过结果分析,总结得出浦阳江流域洪涝问题的解决对策和建议。     

Evaluation of the flood mitigation effect of a Paddy Field Dam project

To mitigate flood damage due to a recent increase in the frequency and magnitude of heavy rainfall events, the Kamihayashi district in Niigata prefecture, Japan, has undertaken flood mitigation measures using paddy fields by installing runoff control devices in drainage boxes of paddy field plots. The purpose of this study is to evaluate the flood mitigation performance of the Paddy Field Dam project in terms of a decrease in discharge volume, drop in channel water level and reduction of inundation damage using combined hydrologic analyses and flood routing. The model constructed for runoff analysis is composed of three modules: a hilly/residential area module in which the overland flow is estimated using the kinematic wave method, a paddy field module in which runoff from paddy fields is calculated using water balance analysis, and a channel network module in which flood routing is performed using a one-dimensional unsteady flow model. The outputs of the first two modules are the input of the third module. The result of the simulation shows the main channel discharge decreased by 26% and the water level dropped by 0.17 m in the case of the largest observed rainfall event. The simulated effect was larger for larger rainfall events. In terms of flood water volume, the runoff control devices have the effect of reducing the flood damage due to the 50-year return period rainfall event to almost that due to the 10-year return period rainfall event.     

考虑资料缺失的小型水库影响的洪水预报方法研究

流域中修建的大量小型水库会改变洪水的自然特性,而小型水库资料往往缺失或信息不全,使得在洪水预报中难以考虑其调蓄作用,给洪水预报带来困难。利用遥感RS、地理信息系统GIS和支持向量回归机SVR算法,构建地形地貌参数-水库库容关系模型,推算水库资料缺失地区的小型水库库容信息;在定量概化小型水库对洪水拦蓄影响的基础上,建立了新安江-水库模型。以淮河上游北庙集流域为对象进行应用研究,结果表明:(1)小型水库总库容与地形地貌特征有较强的相关关系,建立的地形地貌参数-水库库容模型具有较高精度,可用于资料缺失的小型水库的库容推算;(2)加入水库拦蓄模块后,新安江模型的洪水预报精度得到一定提高。研究成果可供受小型水利工程影响地区的实时洪水预报参考。     

Assessment of irrigation and environmental quality at the hydrological basin level: I. Irrigation quality

Irrigated agriculture notably increases crop productivity, but consumes high volumes of water and may induce off-site pollution of receiving water bodies. The objectives of this paper were to diagnose the quality of irrigation and to prescribe recommendations aimed at improving irrigation management and reducing the off-site pollution from a 15,500 ha irrigation district located in the Ebro River Basin (Spain). Three hydrological basins were selected within the district where the main inputs (irrigation, precipitation, and groundwater inflows) and outputs (actual crop's evapotranspiration, surface drainage outflows, and groundwater outflows) of water were measured or estimated during a hydrological year. The highest volume of water (I = 1400 mm/year) was applied in the basin with highly permeable, low water retention, flood irrigated soils where 81% of the total surface was planted with alfalfa and corn. This basin had the lowest consumptive water use efficiency (CWUE = 45%), the highest water deficit (WD = 5%) and the highest drainage fraction (DF = 57%). In contrast, the lowest I (950 mm/year), the highest CWUE (62%), and the lowest WD (2%) and DF (37%) were obtained in the basin with 60% of the surface covered with deep, high water retention, alluvial valley soils, where 39% of the cultivated surface is sprinkler irrigated and with only 48% of the surface planted with alfalfa and corn. We concluded that the three most important variables determining the quality of irrigation and the volume of irrigation return flows in the studied basins were (i) soil characteristics, (ii) irrigation management and irrigation system, and (iii) crop water requirements. Therefore, the critical recommendations for improving the quality of irrigation are to (i) increase the efficiency of flood-irrigation, (ii) change to pressurized systems in the shallow and highly permeable soils, and (iii) reuse of drainage water for irrigation within the district. These management strategies will conserve water of high quality in the main reservoir and will decrease the crop water deficits and the volume of irrigation return flows, therefore, minimizing the off-site pollution from this irrigation district.     

Micro-catchment water harvesting potential of an arid environment

Micro-catchment water harvesting (MCWH) requires development of small structures across mild land slopes, which capture overland flow and store it in soil profile for subsequent plant uses. Water availability to plants depends on the micro-catchment runoff yield and water storage capacity of both the plant basin and the soil profile in the plant root zone. This study assessed the MCWH potential of a Mediterranean arid environment by using runoff micro-catchment and soil water balance approaches. Average annual rainfall and evapotranspiration of the studied environment were estimated as 111 and 1671 mm, respectively. This environment hardly supports vegetation without supplementary water. During the study period, the annual rain was 158 mm in year 2004/2005, 45 mm in year 2005/2006 and 127 mm in year 2006/2007. About 5000 MCWH basins were developed for shrub raising on a land slope between 2 and 5% by using three different techniques. Runoff at the outlets of 26 micro-catchments with catchment areas between 13 and 50 m² was measured. Also the runoff was indirectly assessed for another 40 micro-catchments by using soil water balance in the micro-catchments and the plant basins. Results show that runoff yield varied between 5 and 187 m³ ha⁻¹ for various rainfall events. It was between 5 and 85% of the incidental rainfall with an average value of 30%. The rainfall threshold for runoff generation was estimated about 4 mm. Overall; the soil water balance approach predicted 38-57% less water than micro-catchment runoff approach. This difference was due to the reason that the micro-catchment runoff approach accounted for entire event runoff in the tanks; thus showed a maximum water harvesting potential of the micro-catchments. Soil water balance approach estimated water storage in soil profile and did not incorporate water losses through spillage from plant basins and deep percolation. Therefore, this method depicted water storage capacity of the plant basins and the root zone soil profile. The different between maximum water harvesting potential and soil-water storage capacity is surplus runoff that can be better utilized through appropriate MCWH planning.     

Simulation of putting-green soil water dynamics: Implications for turfgrass water use

Results from a field experiment examining soil water fate within U.S. Golf Association (USGA) putting greens were used to examine the validity of a water flow simulation model. The experiment used six different sandy root zones each with depths of 300 mm overlying a 100 mm thick gravel layer. Data collected over two growing seasons consisted of measured rainfall, irrigation, drainage volume, and soil water contents; and calculated turfgrass evapotranspiration (ET). Turfgrass rooting was measured at the end of each growing season, and water retention curve and saturated hydraulic conductivity measurements were conducted at the end of the study. For each root zone treatment, HYDRUS-2D (H2D) was calibrated using a subset of the experimental data and then validated by comparing observed and predicted water contents at 76, 152 and 229 mm depth and over both growing seasons. Model efficiency (E) ranged from 0.33 to 0.78; Mean Absolute Error (MAE) ranged from 0.012 to 0.024 m³ m⁻³; and Root Mean Square Error (RMSE) ranged from 0.015 to 0.028 m³ m⁻³, for the six treatments and both years. Also, RMSE values were at best slightly larger than and at worst twice as large as the mean standard deviation values of replicate measurements. Thus, H2D simulation performed reasonably well in describing the water content results of the field study. The calibration results provide evidence of hysteresis in water retention where water retention properties from the field appear to follow the sorption or wetting curve as compared with the laboratory measurements following the desorption or drying curve. This suggests that standard laboratory measurements of water release would not precisely predict water retention behavior in the field and over estimate water storage of these capillary barrier soils. The validation results provide evidence for turfgrass use of perched water held within these profiles, even though turfgrass rooting is shallow and water storage principally occurs deep within the root zone. Thus, the perched water of USGA putting greens should serve reasonably well as a water reservoir for subsequent turfgrass use, allowing for water conserving irrigation practices that makes use of this stored water.     

A mathematical model for simulating water balances in cropped sandy soil with conventional flood irrigation applied

In this paper, a model that integrates various complex model components for the purposes of water balance modeling throughout crop development in arid inland region under the conventional flood irrigation practiced is presented. These components are modules for calculating dynamic soil water content based Richard's equation, potential and actual evapotranspiration, and crop root water uptake. Soil water content in the active root zone and soil evaporation simulation obtained from the model were test using field data in 2003. The low values of MARE and high values of R² and PE in the active root zone of soil profile as well as daily soil evaporation indicated that the soil water balance simulation model presented in the paper can be used with reliable accuracy to simulate the components of water balance in cropped sandy soil under the conventional flood irrigation condition in arid inland regions. The model simulation on components of water balance using observed field data in 2004 indicated that large quantities – about 43% of irrigation water (amounting to 840 mm) – were consumed by deep percolation, only small (less than 41%) proportions of irrigation water used by the plants for transpiration. The current irrigation scheme is characterized by the unreasonable agricultural water management with the waste of water in the irrigational system in this region. The impact of irrigation scheduling on water balance presented in this paper showed that the reasonable irrigation scheme with more frequent irrigation and less amounts is more suitable for the irrigation of spring wheat in Heihe River basin, northwest China. Therefore, to establish a decision-making system for agricultural irrigation scheme and to utilize the limited water resources in this region have become an urgent problem that needs to be solved.     

Assessment of irrigation and environmental quality at the hydrological basin level: II. Salt and nitrate loads in irrigation return flows

Irrigation return flows may induce salt and nitrate pollution of receiving water bodies. The objectives of this study were to perform a salt and nitrogen mass balance at the hydrological basin level and to quantify the salt and nitrate loads exported in the drainage waters of three basins located in a 15,500 ha irrigation district of the Ebro River Basin (Spain). The main salt and nitrogen inputs and outputs were measured or estimated in these basins along the 2001 hydrological year. Groundwater inflows in the three basins and groundwater outflow in one basin were significant components of the measured mass balances. Thus, the off-site impact ascribed solely to irrigation in these basins was estimated in the soil drainage water. Salt concentrations in soil drainage were low (TDS of around 400–700 mg/l, depending on basins) due to the low TDS of irrigation water and the low presence of salts in the geologic materials, and were inversely related to the drainage fractions (DF = 37–57%). However, due to these high DF, salt loads in soil drainage were relatively high (between 3.4 and 4.7 Mg/ha), although moderate compared to other areas with more saline geological materials. Nitrate concentrations and nitrogen loads in soil drainage were highest (77 mg NO₃⁻/l and 195 kg N/ha) in basin III, heavily fertilized (357 kg N/ha), with the highest percentage of corn and with shallow, low water retention flood-irrigated soils. In contrast, the lowest nitrate concentrations and nitrogen loads (21 mg NO₃⁻/l and 23 kg N/ha) were found in basin II, fertilized with 203 kg N/ha and preponderant in deep, alluvial valley soils, crops with low N requirements (alfalfa and pasture), the highest non-cropped area (26% of total) and with fertigation practices in the sprinkler-irrigated fields (36% of the irrigated area). Thus, 56% of the N applied by fertilization was lost in soil drainage in basin III, as compared to only 16% in basin II. In summary, a low irrigation efficiency coupled to an inadequate management of nitrogen fertilization are responsible for the low-salt, high-nitrate concentrations in soil and surface drainage outflows from the studied basins. In consequence, higher irrigation efficiencies, optimized nitrogen fertilization and the reuse for irrigation of the low-salt, high-nitrate drainage waters are key management strategies for a better control of the off-site pollution from the studied irrigation district.     

Assessing grain crop water productivity of China using a hydro-model-coupled-statistics approach. Part II: Application in breadbasket basins of China

We assessed the basin-scale crop water productivity (CWP) on staple grain crops, i.e. rice, wheat, maize, soybean, at major breadbasket basins of China over time periods of 1997-2004. The multiple-year average CWP was 1.06 kg m⁻³ for the selected basins (equivalents of 946 m³ water consumption in producing 1 metric ton of crop economic yield), varying from 0.97 kg m⁻³ to 1.18 kg m⁻³. Of all the water consumed in crop production, irrigation water contributes 28-41%, while soil-stored precipitation contributes 59-72%, confirming the crucial yet hitherto under-estimated role played by green water in total crop yield formation. The blue water depletion rate ranges from 0.48 to 0.87, with most of the basins exceeding 0.50, while the green water depletion rate from 0.39 to 0.85, with the majority of basins being beyond 0.60. We conclude that both blue and green water shortage will contribute to water scarcity in grain crop production. The mission of ensuring China's food security will entail multiple trade-offs among water security, ecosystem conservation, environment protection, and human development with increasing challenges in the years to come. However, increasing water productivity through research innovation and technological upgrades at river basin scale is a key to mitigating water stress that may be caused by increasing food production in the coming decades.