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As populations continue to move into more mountainous terrain, a greater understanding of the processes controlling debris flows has become important for the protection of human life and property. The potential volume of an expected debris flow must be known to effectively mitigate any hazard it may pose, yet an accurate estimate of this parameter has to this point been difficult to model. To this end, a probabilistic method for the prediction of debris flow volumes using a database of 1351 yield rate measurements from 33 post-wildfire, runoff-generated debris flows in the Western USA is presented herein. A number of geomorphological, climatic, and geotechnical basin characteristics were considered for inclusion in the model, and correlation analysis was conducted to identify those with the greatest influence on debris flow yield rates. Groupings within the database were then clustered based on their similarity levels; a total of six clusters were identified with similar slope angle and burn intensity characteristics. For each of these six clusters, a probability density function detailing the distribution of yield rates within the cluster was developed. The model uses a Monte Carlo simulation to combine each of these distributions into a single probabilistic model for any basin in which a debris flow is expected to occur. This approach was validated by applying the model to ten basins that experienced debris flows of known volumes throughout the Western USA. The model predicted nine of the ten debris flow volumes to within the 95% confidence interval of the final distribution; a regression analysis for the ten volumes resulted in an R 2 of 0.816. These results compared favorably with those generated by an existing volume model. This approach provides accurate results based on easily obtainable data, encouraging widespread use in land planning and development. 相似文献
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Modelling groundwater over-extraction in the southern Jordan Valley with scarce data 总被引：1，自引：0，他引：1
To deal with the challenge of groundwater over-extraction in arid and semi-arid environments, it is necessary to establish management strategies based on the knowledge of hydrogeological conditions, which can be difficult in places where hydrogeological data are dispersed, scarce or present potential misinformation. Groundwater levels in the southern Jordan Valley (Jordan) have decreased drastically in the last three decades, caused by over-extraction of groundwater for irrigation purposes. This study presents a local, two-dimensional and transient numerical groundwater model, using MODFLOW, to characterise the groundwater system and the water balance in the southern Jordan Valley. Furthermore, scenarios are simulated regarding hydrological conditions and management options, like extension of arable land and closure of illegal wells, influencing the projection of groundwater extraction. A limited dataset, literature values, field surveys, and the ‘crop water-requirement method’ are combined to determine boundary conditions, aquifer parameters, and sources and sinks. The model results show good agreement between predicted and observed values; groundwater-level contours agree with the conceptual model and expected flow direction, and, in terms of water balance, flow volumes are in accordance with literature values. Average annual water consumption for irrigation is estimated to be 29 million m3 and simulation results show that a reduction of groundwater pumping by 40% could recover groundwater heads, reducing the water taken from storage. This study presents an example of how to develop a local numerical groundwater model to support management strategies under the condition of data scarcity. 相似文献
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Christian Ferrarin Luca Zaggia Elio Paschini Tommaso Scirocco Giuliano Lorenzetti Marco Bajo Pierluigi Penna Matteo Francavilla Raffaele D’Adamo Stefano Guerzoni 《Estuaries and Coasts》2014,37(1):79-93
A multidisciplinary approach that combines field measurements, artificial neural networks, water balance analyses and hydrodynamic modelling was developed to investigate the water budget and renewal capacity of semi-closed coastal systems. The method was applied to the Lesina Lagoon, a micro-tidal lagoon in the southern Adriatic Sea (Italy). Surface water flux between the lagoon and the sea was determined by neural network prediction and used as input in the analysis. Strong seasonal variations in the water budget equation were predicted. Fresh water inputs estimated by the water balance analysis were used as forcing by a calibrated finite element model to describe the water circulation and transport time scale of the lagoon’s surface waters. The model highlighted the spatial heterogeneity of the renewal behaviour of the system, with a strong east–west water renewal time gradient. Knowledge of spatial distribution of water renewal times is crucial for understanding the lagoon’s renewal capacity and explaining the high spatial variability of the biogeochemistry of the Lesina Lagoon. 相似文献
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实现健康的区域水平衡是中国水利工作的重要内容和挑战, 对保障国家水安全、国民经济和社会持续稳定发展具有重要意义。在总结前期水平衡理解和认识的基础上, 定义了区域水平衡的概念, 从水收支平衡、经济社会供需水平衡、经济与生态用水平衡、人水关系和谐平衡4个方面和时间、空间、系统3个维度解读其内涵。提出了区域水平衡的基本原理, 包括水量平衡原理、供需平衡原理、协同平衡原理及和谐平衡原理, 分析了以基本原理支撑实现区域水平衡需要重视的科学问题。从理论基础和基本理论2个方面论述了区域水平衡的理论体系, 其中, 理论基础包括水文学、水资源学、生态学、经济学、社会学等理论, 基本理论包括水资源收支时空均衡理论、水资源供需优化配置理论、经济与生态用水协同论、人水和谐论等, 并展望了基本理论的应用前景。研究成果可进一步拓展区域水平衡研究思路, 为今后开展区域水平衡管控与实践提供研究框架和理论基础。 相似文献
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土壤冻融过程中水流迁移特性及通量模拟 总被引：5，自引：0，他引：5
为研究季节性冻土在冻融过程中水热盐的运移规律,在野外开展了一维及二维冻土水热盐运移试验,并通过Br离子示踪法及建立冻土水盐通量计算模型对土壤冻融过程中水盐的通量变化特性进行了计算分析。基于Hangen-Poiseuille孔隙通量方程,耦合孔隙冰柱体对水力传导度的影响机理,提出了冻土水流通量模型。结果表明,冻结过程中,液态水在水势和温度梯度作用下在冻结锋处聚集,形成通量峰值,冻融过程中自地表和最大冻深位置分别向下和向上的融化过程中,一维与二维试验水流通量变化对比表明,冻融过程中水流通量受到中间层冻土和地下水顶托的影响。冻土通量模型能够有效地描述冻土中不同温度条件下水流通量特性,从微观的角度很好地解释了土壤冻结过程中冰水共存状态下土壤中水流通量变化规律。 相似文献
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In the catchment area of Scopia, Central Greece, a lumped applied approach of water balance was accomplished, by applying the Zygos model, which delineates an essential water balance forms. The model is in view of Thornthwaite model, in its modified version. It can be adjusted automatically, with the evolutionary annealing-simplex technique for nonlinear optimization, or manually and the input data are precipitation and the potential evapotranspiration. In the present study, both programmed and manual calibration occurred. Programmed calibration took place, utilizing a specimen of measured runoff values from October 2009 to March 2011. Despite the fact that the Nash–Sutcliffe coefficient (NSC) value was high (0.87), the simulated parameters of water balance had abnormal significance for Scopia catchment area. On the contrary, manual calibration uncovered that the actual evapotranspiration constitutes 64.6% (450.1 mm) of the precipitation. Runoff and percolation represent 20.6% (143.6 mm) and 14.8% (102.9 mm) of the precipitation, respectively. The NSC (0.70) and the validation criteria exhibit an ideal adjustment of simulated to measured runoff, while the hydrological parameters appeared to have a physical significance for the study site. Zygos model connects the emergence of springs with the development of the karstification in the carbonate rocks of the region and affirms the predominance of runoff versus percolation due to the hydrolithological structure of the Scopia catchment. This is related to the presence of episodic floods in the area. The yearly precipitation values were found with an error of 0.2% and are viewed as insignificant. 相似文献
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Development of a numerical model for nitrates in groundwater in the reservoir area of the Komesu subsurface dam, Okinawa, Japan 总被引：1，自引：0，他引：1
Shuhei Yoshimoto Takeo Tsuchihara Satoshi Ishida Masayuki Imaizumi 《Environmental Earth Sciences》2013,70(5):2061-2077
A numerical model consisting of simplified equations was developed to simulate nitrate concentrations in groundwater in a reservoir area of a subsurface dam in a Quaternary limestone region. The model was composed of a water balance sub-model and a nitrogen balance sub-model; the water balance sub-model was built from tank models which can express the quick dilution near caves and the effect of dam construction; and the nitrogen balance sub-model was made to represent changes in nitrogen forms and movement of nitrogen in the soil and aquifer zones. The model was calibrated and verified by observed data before and after the dam construction and then applied to a predictive simulation under a simple assumption that rainfall descends gradually. The model seemed applicable to long-term prediction of changes in NO3-N in the reservoir area. 相似文献
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Tomi P. Luoto 《Quaternary Science Reviews》2009,28(15-16):1481-1489
In the present study I utilize subfossil chironomid and chaoborid distributions in surface sediments of 68 shallow lakes. The aim is to develop a calibration model for past water-level reconstructions by applying weighted averaging-partial least squares (WA-PLS) techniques and to evaluate its potential applications and limitations. This study considers water depth at sampling sites, rather than maximum lake depth. The best of the water depth models developed uses three components and has a cross-validated coefficient of determination (r2jack) of 0.68 and root-mean-squared error of prediction (RMSEP) of 0.78 m. The model performance is tested on the sediment sequence of a previously studied lake from southern Finland that is known to have experienced past fluctuations in its water level. The water levels inferred are compared with results of chironomid-inferred air temperature reconstruction to ease separation of the effects of the variables. The reconstruction shows consistent results similar to those of previously published cladoceran planktonic:littoral ratios (P:Ls) from the same lake. However, the results indicate that factors other than depth and temperature, such as pollution, may possibly distort the inference results. The results suggest that in applying the midge-based water depth calibration model, it would be advantageous to use it together with an inference model for temperature and preferably in a multiproxy content where changes in water chemistry may be detected. The model can be useful in studies on past effective moisture variability that is closely related to climatic changes. 相似文献
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加快模型试验中水的渗流速率对库岸滑坡研究意义重大。考虑滑坡渗流特性,基于电磁驱动原理,在滑坡模型中施加相互垂直的电场、磁场,推导出孔隙水受力公式,根据电渗固结理论,推导水分迁移速率v与电压Ve、磁场强度B的关系式,进而获得时间相似比,实现了通过电磁场强度来控制滑坡模型水分迁移速率,改进模型试验,为研究库水位升降对滑坡的影响提供条件。通过试验进行验证：电磁场对水分迁移速度的影响具有显著效果,且电压大小对模型的稳定渗流场影响较小。说明在不改变模型材料参数的条件下,改变磁场强度和电压可获得任意孔隙水的渗流速度,为研究库水位波动条件下的滑坡演化机制奠定基础。 相似文献
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地下水排泄在湖泊水量及营养盐均衡中发挥着重要作用,其中地下水向湖泊排泄的量化是关键,但目前对其时间变异性的研究却十分薄弱.针对这一科学问题,以长江中游重要调蓄湖泊-洞庭湖为例,通过收集1996~2017年洞庭湖流域的水文和气象数据,基于质量平衡模型,查明地下水排泄对洞庭湖水量均衡的贡献以及地下水向洞庭湖排泄强度随时间的变化.结果显示:（1）枯水期时地下水排泄量为（0.17~1.51）亿m3/d,地下水排泄强度为38.74~207.26 mm/d,地下水排泄对湖泊水量均衡的贡献为8.70%~30.37%;（2）地下水排泄量、地下水排泄强度、地下水排泄对湖泊水量均衡的贡献在1996~2017年间均呈现出明显的先降低再升高的变化趋势,三峡水库蓄水后至三峡工程全面竣工初期的地下水排泄相较于三峡水库蓄水前和三峡工程全面运行后显著降低;（3）三峡工程运行对长江水位及地下水位的改变可能是引起湖底地下水排泄时间变异性的重要原因.为洞庭湖区域的水量均衡提供了新的认识,也为今后洞庭湖区域水资源开发利用和区域生态安全管理提供了理论支撑. 相似文献
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Chemical and water isotope ratios data for groundwaters from the Pozzo del Sale area in the Irpinia sector of the Southern Apennines are presented. The water chemistry of the aquifer system may initially be regarded as the result of easy and common, low temperature interaction between meteoric water and Late Messinian evaporites, which produce Ca-bicarbonate and Na-chloride passing through Ca-sulfate waters. However, a closer inspection reveals a more complicated geochemical setting consisting of: (1) two further Na-sulfate and Ca(Mg)-sulfate waters; (2) the existence of different meteoric recharge areas; (3) the mixing between the different groundwaters and allochthonous fluids from terrestrial mud volcanoes. The salinization mechanism and the local mineralogy were inferred by classical and novel ternary and binary diagrams. The presence of MgSO4- and Na2SO4-bearing minerals of non-marine or mixed origin other than gypsum and halite within the local evaporites suggests a mineralogical heterogeneity within the local Messinian evaporites. The paleoenvironment of this sector of the Gessoso–Solfifera Formation might have been composed of relatively small playa-lakes fed by seawater but also large amounts of continental waters of meteoric origin. 相似文献
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以平衡的GCM模型输出作为大气中CO2浓度倍增时的气候情景,采用月水量平衡模型及水资源利用综合评价模型研究我国部分流域年、月径流、蒸发的可能变化及2030年水资源供需差额变化。结果表明淮河及其以北气候变化的影响最为显着,各流域水量的增多或减少主要由汛期径流及蒸发的增减决定。在未来气候条件下,黄、淮、海三个流域水资源短缺可能进一步加剧。 相似文献
14.
诱发滑坡的地下水流系统响应历史与趋势——以甘肃黑方台灌区为例 总被引：1，自引：0，他引：1
灌溉的地下水系统响应是黑方台地区灌溉诱发地质灾害研究的基础.黑方台台塬自上而下由黄土、砂砾石和基岩3个含水岩组构成.以对斜坡稳定性影响最大的黄土含水系统为研究对象,分析了灌溉前后水均衡变化,采用数值模拟的方法恢复了引水灌溉引起的地下水流系统演化过程,对不同灌溉量下地下水流系统发展趋势进行了预测.结果表明,黑方台地区长期大量引水灌溉打破了地下水均衡,改变了地下水系统的天然状态,使地下水的分布及其水流系统发生了很大变化,中心部位地下水位44年间上升了至少20m,减少灌溉量至350× 104m3/a地下水位将呈下降趋势.研究成果可为黑方台滑坡地质灾害综合治理提供科学依据. 相似文献
15.
平顶山矿区地下热水深部温度估算——地球化学温标的应用 总被引：1，自引：0，他引：1
应用地球化学温标估算了平顶山矿区地下热水的深部温度；介绍与分析了地球化学温标的应用条件、水－岩反应平衡状态，在此基础上应用合适的温标进行了计算。其结果为该区地温场和水－岩温度关系的研究提供了资料 相似文献
16.
Many of the states in India have been facing water scarcity for more than 2 decades due to increased demand, because of the increase in population and higher living standards. Consequently, many states have almost fully utilized the available surface water resources and are exploiting groundwater to augment water supplies. Investigations were carried out in the upper Thurinjalar watershed of Ponnaiyar basin in Tamil Nadu to determine the availability of surface water and to investigate the potential for enhancing groundwater recharge to support the water demand in the watershed. Increasing the water availability would also enable the community to convert the 46% of the land area in the watershed that is currently underutilised into productive uses. The surface water potential for the upper Thurinjalar watershed was assessed by applying the USDA–NRCS model with daily time steps. This modelling exercise indicated that the annual runoff from the 323 km2 area of the watershed is 61 million m3. Groundwater recharge in the watershed was assessed by carrying out daily water balance method and indicated that about 43 million m3 of water from recharge is available on an annual basis or about 14% of annual rainfall. A simple regression model was developed to compute groundwater recharge from rainfall based on water balance computations and this was statistically verified. The modelling indicated that there is sufficient water available in the watershed to support current land uses and to increase the productivity of underutilised land in the area. The study also demonstrates that simple regression models can be used as an effective tool to compute groundwater recharge for ungauged basins with proper calibration. 相似文献
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M. B. Dyurgerov V. N. Mikhalenko M. G. Kunakhovitch S. N. Ushnurtsev Chaohai Liu Zichu Xie 《GeoJournal》1994,33(2-3):311-317
Over the period of more than 30 years the mass balance observations have been carried on the several representative glaciers of the Tien Shan. But these data are not sufficient to explain the asynchronous degradation of the glaciation in different parts of the mountains. Special field observations were undertaken to study asynchronous changes in mass balance. The programme used an imitation model of the mass balance monitoring (Dyurgerov 1988). According to the model the annual values of glacier mass balance bn and equilibrium line altitude ELAn were replaced by the current values of bt and ELAt measured during the ablation season. The imitation model was evaluated on Tuyuksu Glacier in 1987–1989. The results showed that the function bn(ELAn) can be replaced by bt(ELAt) which is nonlinear and can be approximated by the hypsographic curve of the glacier. After these tests the similar measurements were accomplished in summer of 1989 on the Tuyuksu Glacier, Sary-Tor and Glacier No. 1. It was established that the asynchronous changes in mass balance were primarily due to the increase of summer snow accumulation eastward the Tien Shan. The second reason was the difference in the altitudinal position of the glaciers. 相似文献
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Assessing climate change impacts on water balance in the Mount Makiling forest, Philippines 总被引：1，自引：0，他引：1
A statistical downscaling known for producing station-scale climate information from GCM output was preferred to evaluate the impacts of climate change within the Mount Makiling forest watershed, Philippines. The lumped hydrologic BROOK90 model was utilized for the water balance assessment of climate change impacts based on two scenarios (A1B and A2) from CGCM3 experiment. The annual precipitation change was estimated to be 0.1–9.3% increase for A1B scenario, and ?3.3 to 3.3% decrease/increase for the A2 scenario. Difference in the mean temperature between the present and the 2080s were predicted to be 0.6–2.2°C and 0.6–3.0°C under A1B and A2 scenarios, respectively. The water balance showed that 42% of precipitation is converted into evaporation, 48% into streamflow, and 10% into deep seepage loss. The impacts of climate change on water balance reflected dramatic fluctuations in hydrologic events leading to high evaporation losses, and decrease in streamflow, while groundwater flow appeared unaffected. A study on the changes in monthly water balance provided insights into the hydrologic changes within the forest watershed system which can be used in mitigating the effects of climate change. 相似文献
19.
Thomas C. Beard Christopher J. Perry Tad C. Fox Thomas G. Naymik Peter Shanahan 《Environmental Geology》1991,18(3):195-207
The regulatory requirements for characterization of the Martinsville Alternative Site (MAS) were fulfilled by applying an iterative approach to the groundwater flow modeling of the site and surrounding area. The approach consisted of field data collection and development of an initial conceptual model. The numerical model was then constructed to be consistent with the data and conceptual model. Next, the calibration results were evaluated statistically, and visually by a groundwater modeling review committee, to determine if the model accurately represented groundwater flow at the site. Initial results failed acceptance criteria because the values of numerical model input parameters had to be varied beyond observed data ranges to calibrate the results, and therefore the model was inconsistent with the initial conceptual model. This led to additional field data collection in areas where the numerical model deviated most from field-determined data. The new data provided sufficient information to revise the conceptual model and calibrate the numerical model successfully. Model calibration was followed by validation. Validation of the numerical model provided additional assurance that the model correctly simulated the observed system. No additional data were found to be necessary during validation of the MAS numerical model. The iterative approach proved to be successful for calibrating and validating this groundwater flow model and should be implemented from the onset of characterization planning in other applications. 相似文献