降雨型浅层滑坡危险性预测模型

通过分析SHALSTAB和TRIGRS等浅层滑坡物理确定性模型存在的问题,提出了基于降雨入渗动态守恒的瞬态降雨入渗模型,该模型考虑了初期降雨过程、降雨历程以及饱和非饱和入渗过程,证明了SHALSTAB模型是该模型的特殊形式,并克服了TRIGRS模型参数繁多及一维入渗路径的问题.将无限边坡模型、瞬态降雨入渗模型和GIS进行耦合,研发了可用于大范围降雨型浅层滑坡危险性预测的集成系统,根据边坡的地质条件、地形参数和降雨特征即可对降雨条件下浅层滑坡的危险性进行评估.     

山西上空水汽输送和水分循环研究

利用山西省周边共8个探空站的实测资料,计算了山西省上空1959年～1992年的水汽含量和1990年的水汽收支与水汽输送通量,包括总输送、切变输送、时间涡动输送、平均输送等分量。在此基础上建立了山西省水分循环和水量平衡模型。结果表明,山西上空水汽含量年内干湿变化大于全国平均情况,多年变化存在一定的丰枯阶段性;年水汽净输入量约690亿m3,主要从西边界和南边界输入,从东边界输出,涡动输送量是主要输入机制,平均输送是主要输出机制,受强西风环流控制;山西的自然地理条件使其对大气水资源的利用率为30%,低于全国平均利用率;山西水分内循环较全国平均情况强盛,由于水分内循环的作用,可使当地蒸发形成的降水量占全年总降水量的15%;地下水开采已对大气水分循环要素产生影响,进而可能对山西省自然环境的变化产生负效应。这些事实增进了对山西省水资源的水文和水文气候学背景的认识。     

Evaporation and energy balance estimates over a large inland lake in the Tibet-Himalaya

The process of evaporation from the lake surface is one of the main mechanisms in the energy and water budgets of the lake hydrologic cycle, and an essential component of the water balance especially for inland lakes. In this study, using routine meteorological data as input, a one-layer potential evaporation model was employed to simulate evaporation and energy fluxes over Lake Yamdrok Yumco, the largest high-elevation inland lake in the mountain area of the Tibet-Himalaya in China. Then, the calculation results were compared with the measured values from a big pan evaporator of 20 m² near the lake. The results show that the average annual input radiation flux R ^↓ is 128.2 W m⁻², the lake storage heat flux G is 19.4 W m⁻², the sensible heat flux H is 20.4 W m⁻² and the latent heat flux lE is 107.8 W m⁻². The R ^↓ and G exhibit similar seasonal variations. The lE reaches a maximum in October, lagging nearly 4 months behind the R ^↓ and the G, which indicates the large heat capacity of the lake. The simulated annual evaporation ranges from 1,113.2 to 1,429.1 mm and its mean value is 1,252.5 mm during 1961–2005. The simulated annual evaporation is in good agreement with the measured value, and the measured average lake temperature is as expected when compared with the measured lake surface temperature.     

冻结层上水的分布及工程影响研究现状与展望

作为一种多年冻土区的特殊水文地质现象,冻结层上水（或多年冻土层上水）的分布受局地因素的控制,且随活动层的季节性冻融而变化,影响地表水和地下水循环以及多年冻土环境中的水热平衡。多年冻土将冻结层上水限制在一个狭窄的空间内,在暖季冻结层上水侧向和竖向的渗流传热将加剧多年冻土的退化,也会对上覆工程构筑物的稳定运营造成极大威胁。目前关于冻结层上水的研究主要集中在分布特征、变化规律、流量计算、渗流模拟、水热耦合等方面。研究发现：在全球升温背景下,多年冻土退化速率加剧,随着冻土厚度变薄和融区出现,冻结层上水的流量及其与地下水的交换量均发生变化,除了影响局地水文特征外,还与工程病害密切相关,如坡脚积水、路基沉降以及路面裂缝等。以区域分布特征为出发点,对冻结层上水的研究现状进行了归纳和总结,并对其工程影响有关的渗流传热理论研究成果进行了梳理,对今后需要进行深入研究的方向进行了展望。这有助于全面理解冻结层上水在冻土区水文过程中的功能,为相关研究提供了进一步的理论参考。     

Adequacy of satellite derived rainfall data for stream flow modeling

Floods are the most common and widespread climate-related hazard on Earth. Flood forecasting can reduce the death toll associated with floods. Satellites offer effective and economical means for calculating areal rainfall estimates in sparsely gauged regions. However, satellite-based rainfall estimates have had limited use in flood forecasting and hydrologic stream flow modeling because the rainfall estimates were considered to be unreliable. In this study we present the calibration and validation results from a spatially distributed hydrologic model driven by daily satellite-based estimates of rainfall for sub-basins of the Nile and Mekong Rivers. The results demonstrate the usefulness of remotely sensed precipitation data for hydrologic modeling when the hydrologic model is calibrated with such data. However, the remotely sensed rainfall estimates cannot be used confidently with hydrologic models that are calibrated with rain gauge measured rainfall, unless the model is recalibrated. G. Artan, J. L. Smith and K. Asante – work performed under USGS contract 03CRCN0001.     

中国陆地-大气系统水分循环研究

建立了中国大陆尺度和区域尺度陆地-大气系统水分循环概念模型;讨论了中国大陆尺度水文循环的特点;比较了东北、华北、西北、西南、华南、长江流域、西藏高原和台湾岛水分循环的差异。对水分循环参数的计算作了改进。     

华北平原地下水形成与区域水文循环演化的关系

晚更新世以来华北平原地下水形成、演变与区域水文循环演化的周期性密切相关,区域地下水资源的形成能力取决于区域水文循环演化的进程。在多雨期,地下水可获取充足的补给;在少雨期,地下水补给较少。区域地下水资源利用潜力与水文循环陆地过程相关。人类通过调控水文循环陆地过程,可增大其利用潜力。     

Hydrologic equilibrium status of a disturbed Eastern North Carolina watershed

Evaluation of the impacts of artificial drainage systems on wetlands requires an assessment of the hydrologic equilibrium status of the surface hydrologic system. Hydrologic equilibrium is characterised by a high correlation between surplus moisture (as calculated by Thornthwaite's methodology) and stream discharge. A qualitative stability analysis shows that deterioration of artificial drainage channels is the process allowing the surface hydrologic system to adjust to the disturbances. The model is tested by examining the correlation between surplus and discharge for a small watershed altered by forestry drainage which is periodically rehabilitated. With hydrologic equilibeium arbitrarily defined as a surplus-discharge correlation coefficient 0.8, it is shown that the original, largely undisturbed watershed was in hydrologic equilibrium. Disequilibrium was induced by artificial drainage-ways, with a return to equilibrium over time. Subsequent renovations of ditches and canals were associated with a recurrence of disequilibrium. The surface hydrologic system is metastable, and cannot be expected to return to previously-existing states following a disturbance. Consistently maintained artificial drainage system appears to preclude any return to any type of hydrologic equilibrium.     

The impacts of hysteresis on variably saturated hydrologic response and slope failure

This investigation employs 3D, variably saturated subsurface flow simulation to examine hysteretic effects upon the hydrologic response used to drive unsaturated slope stability assessments at the Coos Bay 1 (CB1) experimental catchment in the Oregon Coast Range, USA. Slope stability is evaluated using the relatively simple infinite slope model for unsaturated soils driven by simulated pore-water pressures for an intense storm that triggered a slope failure at CB1 on 18 November 1996. Simulations employing both hysteretic and non-hysteretic soil–water retention curves indicate that using either the drying soil–water retention curve or an intermediate soil–water retention curve that attempts to average the wetting and drying retention curves underestimates the near-surface hydrologic response and subsequently the potential for slope failure. If hysteresis cannot be considered in the hydrologic simulation, the wetting soil–water retention curve, which is seldom measured, should be used for more physically based slope stability assessment. Without considering hysteresis or using the wetting soil–water retention curve, the potential for landsliding in unsaturated materials may be underestimated and a slope failure could occur when simulations predict stability.     

珠江流域大尺度陆面水文耦合模式的构建及应用

以珠江流域为研究对象,通过更新陆面水文模式所需的下垫面参数数据库,建立适合于珠江流域的大尺度陆面水文耦合模式系统,并利用该模式开展了1963~2006年流域水文水循环过程的数值模拟,通过与实测流量比较,系统考察了陆面水文耦合模型对珠江流域水循环各分量的模拟性能。分析结果表明,该陆面水文耦合模式对珠江流域年平均各水循环要素具有良好的模拟能力;模式对珠江流域干流主要控制水文站的月平均流量也有较高的模拟精度,模式模拟的水量平衡系数均接近1,相关系数均高于0.84,IOA相似度系数均高于0.9;相对而言,模式对流量峰值的模拟能力还有待提高。     

Dynamics and contribution of karst groundwater to surface flow during Mediterranean flood

This paper describes the role of groundwater contribution to surface flow at the Causse d’Aumelas, a karst system near Montpellier (France), which is traversed by an intermittent river, the Coulazou. A first hydrologic model integrating a digital terrain model shows the inability of a standard rainfall-runoff model to replicate recorded flood hydrographs. While the flood peaks are routed through the karstic system along the Coulazou without a phase lag, the peak magnitude is somewhat modified. These results indicate an initial karst system recharge followed by a significant contribution to surface flow. A hydrodynamic analysis of ground-water flow confirms these results: the karst system first absorbs part of the rainfall, which induces a general water table rise within the aquifer, and then contributes to surface flow in the Coulazou.     

大气水文模式耦合研究综述

首先阐明大气水文模式耦合的必要性，总结作为二者耦合的共同界面——陆面模式的发展过程。在此基础上，从耦合研究方法和目的出发，分4个类别详细论述当前国内外大气水文模式耦合研究的现状。指出了单向耦合不足和进行双向耦合所面临的几个关键问题包括：尺度问题、次网格分布非均匀性、降水模拟等。未来要求充分利用“3S”、四维变分同化等新技术和新方法，加强多学科的联合研究，深入开展大气水文模式的双向耦合试验和敏感性分析，研究大气—植被—土壤—水文系统的交互影响，从根本上提高大气和水文模式的模拟和预报水平。     

Interactive effects of hydrology and salinity on oligohaline plant species productivity: Implications of relative sea-level rise

Sea-level rise is anticipated to alter hydrologic and salinity regimes of coastal wetlands. We conducted a mesocosm experiment to determine species-level responses to 12 sea-level rise scenarios. Both hydrologic regime (−10, +5, and +20 cm flooding depth) and salinity level (fresh, 2‰, 4‰ and 6‰) were interactively manipulated. Within these various sea-level rise scenarios, we sought to determine the effects of hydrologic regime, salinity level, and the interaction of these two stresses on the productivity ofPanicum hemitomon, Sagittaria lancifolia, andSpartina patens, which are dominant macrophytes of fresh, intermediate, and brackish marsh types, respectively, in coastal Louisiana and the southeastern coastal plain. We found that altered hydrologic regimes and increased salinity levels differentially affected edaphic conditions and species-level productivity. Increases in flooding depth were most detrimental toS. patens. Salinity levels greater than 4‰ resulted in mortality ofP. hemitomon, and salinity levels of 6‰ resulted in reduced growth and eventual death, ofS. lancifolia. The effects of elevated salinity levels onP. hemitomon andS. lancifolia were exacerbated when coupled with increased flooding levels. Although soil organic matter was shown to increase in all vegetative conditions, increases were dependent upon the productivity of the species under the different hydrologic regimes and salinity levels withP. hemitomon displaying tremendous potential to increase soil organic matter under fresh conditions, especially when coupled with moderate flooding. The results of this study indicate that as plant communities are subjected to long-term changes in hydrology and salinity levels, community productivity and sustainability ulimately will be determined by species-level tolerances in conjunction with species interactions.     

城区水文循环机制与改善策略分析

在城区化过程中,由于人口快速成长且集中,随之而来的建筑物、道路等不透水面密度增加,导致地下水补给减少及破坏水文循环。为了解土地利用方式改变对长期水文量影响,建立一个适宜的城区水循环模式是非常重要的。选定台湾台北的六馆抽水站集水区进行分析,模式参数经过敏感度分析、率定与验证。采用改变不同透水铺面设置比例的方案,评估其对径流量、入渗量、蒸发散量的改变。并分析设置不同比例屋顶雨水贮集系统对地表径流量及供水量的改变。所建立的城区水循环模式是评估土地利用改变造成水文量的改变的一个有效工具,并可提供决策者做为城区土地利用决策的参考。     

A time-distribution study of doline collapse: Framework for prediction

A temporal analysis of doline collapse on the Western Highland Rim (Tennessee) indicated one approach to estimating the probability of collapse in areas where the geologic and hydrologic criteria associated with collapse have been identified. The distribution of collapse was examined for trend, autocorrelation, and goodness of fit. The distribution of doline collapse during one 12-month period conformed to a Poisson distribution with a mean occurrence rate of λ=0.346 collapses per week and with the interoccurrence times being exponentially distributed (0.01 level). Although the proposed model is spatially and temporally restricted, it may provide an initial framework for estimating the probability of doline collapse in other karst terrains of similar geologic and hydrologic settings.     

水文资料在水土保持中的应用研究

本文简要分析了我国水文资料的基本特点及其在水土保持中的应用情况,并结合水文资料在水土保持中的研究实例,探讨了加强水文资料在水土保持中应用范围与价值,在新一轮的站网调整建设中应与水土保持监测站网建设结合起来,避免重复建设,加强水文站网功能,发挥现有水文站网作用。     

Impacts of soil conservation on groundwater recharge in the semi-arid Loess Plateau, China

Soil conservation measures undertaken to address land degradation can alter the hydrologic cycle by changing partitioning of water fluxes at the land surface. While effects on runoff are well documented, impacts of soil conservation activities on fluxes to groundwater are poorly understood. The goal of this study was to examine fluxes to groundwater in a semi-arid area of China’s Loess Plateau that has been subject to extensive soil conservation activities. Unsaturated zone pore-water pressures and concentrations of chloride show that impacts on deep drainage differ between ecological and structural soil conservation approaches. High matric potentials and low chloride beneath cultivated terrace and gulley sites are consistent with deep drainage occurring at these sites. Estimated recharge rates for dryland cultivated upland sites were approximately 55??0?mm/year (11??8% of mean annual rainfall) based upon chloride mass balance. In contrast, results suggest that mature tree and shrub plantations prevent deep drainage. Stable isotope signatures of unsaturated-zone moisture and groundwater indicate that focused infiltration through gullies and other topographic lows is likely to be the primary recharge mechanism. The results of this study highlight the potential for inadvertent effects of some soil conservation approaches on regional water resources.     

热力学熵在陆地水文循环演化中的应用初探

陆地水文循环演化过程是开放的、不可逆的能量耗散过程,可以用热力学熵的概念来定量描述.初步给出了水文循环关键要素:降水、土壤入渗、蒸发蒸腾和径流的熵产率的计算方法.计算表明蒸发蒸腾作用对陆地水文循环过程的熵产率影响非常显著,并且蒸发蒸腾能够影响其他要素的熵产率.     

Influence of upwelling on the shallow water chemistry in a small wetland riparian zone (Basque Country)

Many hydrologic conceptual models in riparian areas assume that the alluvial deposits zone is hydraulically more active than the fractured bedrock below. Therefore, these models undervalue the possible contribution of deeper groundwater from the fractured bedrock system. A hydrochemical study, under various hydrological conditions, has been carried out in a small riparian zone of the Salburua wetland (Basque Country) in order to highlight the conceptual model. This wetland is included in a wide Quaternary aquifer, which has been declared a Nitrate Vulnerable Zone. The results of this study suggest that the fractured bedrock is at least as dynamic as the upper clayey deposits. The presence of more fractured zones, which act as hydraulic “windows”, allow the upwelling of deeper groundwater and, consequently, make the upper alluvial deposits and the fractured bedrock water systems to be cross-connected. Nevertheless, this upwelling is limited to some small areas in the riparian zone. As a result of this local interaction, several chemical reactions have been observed and the hydrochemical characteristics of shallow groundwater undergo seasonal variations. The study shows that a hydrologic conceptual model, which does not consider the hydraulic activity of the fractured bedrock, can be too simplistic. The presence of hydraulic windows could be considered throughout the entire Quaternary aquifer, knowledge of which could help the managers of the Vulnerable Zone and the wetland to take more effective measures for regulation and conservation.     

Analysis of flow behavior in a landfill with cover soil of low hydraulic conductivity

 This paper presents the results of field tests of hydrologic parameters in a landfill and the results of numerical simulation to find the efficiency of the pumping method to reduce leachate levels in the landfill. The field hydraulic conductivity and storativity of waste and buried cover soils in the landfill are measured by pumping and slug tests. The hydrologic condition inside the landfill is first calibrated using the drawdown-time curve obtained from the pumping test, and the flow behavior of leachate during pumping in the landfill, when various layers of waste and buried cover soil exist, is analyzed through three-dimensional numerical simulation of flow. The results of the field investigation show that the buried cover soil of low hydraulic conductivity forms an impermeable layer preventing the downward flow of leachate and upward flow of landfill gas. The hydraulic conductivities of the pumping test and slug tests were quite close on the same order of magnitude. It was also possible to match the drawdown-time data of the field tests with those of the model using input data close to the hydrologic property obtained from the field tests. The numerical flow analysis showed that pumping was possible up to 120 tons/day for a single well without a drain, while the pumping rate could be increased to 300 tons/day for the same well with the drain. From the vertical section of the flow vector with a horizontal drain, the barrier role of buried cover soil is identified, which was proposed by examining the water contents of the disposed cover soil and waste in the field. Received: 15 May 1998 · Accepted: 4 January 1999