鄱阳湖流域分布式水文模型的多目标参数率定

以鄱阳湖流域为研究区,构建其分布式水文模型WATLAC。以鄱阳湖流域6个水文站点2000～2005年河道径流量及地下水基流指数为多目标函数来优化耦合模型,采用PEST进行WATLAC模型参数自动率定。结果表明：6个水文站点拟合的纳希效率系数变化范围为071～084,确定性系数介于070～088,取得较好的模拟效果。基于遥感反演的实际蒸散发结果进一步验证模型,模拟值和遥感反演值在时间和空间上的变化趋势呈现较好一致性。基于地下水位及流场特征模拟效果的定性评价,表明地下水位模拟空间趋势性较好,水位与地面高程的空间变化一致,地下水主要以下游平原区和河道为主要排泄区,符合大尺度流域地下水流运动基本规律和评估结果。所提出的多目标率定方法及率定技术应用于大尺度鄱阳湖流域,也为其它水文模型在相似区域的连续模拟及参数率定方面提供借鉴。〖HJ1〗〖HJ〗     

Application of artificial intelligence in groundwater ecosystem protection: a case study of Semnan/Sorkheh plain,Iran

Groundwater ecosystems have unparalleled environmental value. Accurate modeling of groundwater level (GWL) fluctuations is a vital requirement for the protection of the groundwater ecosystems. The GWL modeling is a challenge due to complexities of the underground geological structure. Among the various modeling methods, artificial intelligence (AI)-based approaches serve as desirable alternatives due to their distinctive and potent properties. One of the most practical AI-based approaches is an artificial neural network (ANN) model. The purpose of the current study was to apply time delay neural networks (TDNN) with different network structures and input delays to model the GWL fluctuations. The variables used in the construction and validation of the models were average weekly GWL from January 2002 to January 2013 in two monitoring sites in Semnan/Sorkheh plain, Iran. The study area is an arid region, where overutilization of groundwater threatens the water security in this area. The computational results of the current research demonstrated that the TDNN model is a practical tool in modeling time-series GWL compared to the other state-of-the-art AI-based approaches. Future studies are recommended to explore application of proposed model for more sustainable and effective Groundwater Resources Management (GWRM).

     

地下水资源危机及其对策

水资源危机在我国已显端倪。本文主要讨论水资源分布特征,随着人口急增以及水资源超采不合理使用,已产生了一系列的环境地质问题,如地下水位持续下降、地面沉降、海水入侵、地面塌陷和地裂缝、水质恶化等。为此,提出了地下水资源开发利用的建议。     

上海城区地面沉降及其对地下水采灌量的响应

上海城区地面沉降主要是由超采地下水、松散沉积地层压实等因素共同作用导致的,并引发多种次生灾害。F4分层标监测数据指示的地面沉降情况,显示上海城区地面沉降表现为总体具有非线性变化的规律,特别是1980年代以来,表现出垂向逐渐增大的特点,在空间上也不断扩展,直至2001年才始有缓和的趋势。在不同时段,随地下水开采量及开采层次的变化,上海城区地面沉降表现出不同的特征。结合1990~2009年20年内第四含水层地下水采灌量数据,得出地面沉降对地下水采灌量的响应关系为:地下水开采量增加,地层沉降量增大;地下水开采量减少,地层沉降量减小,但地面沉降相对于地下水开采具有滞后性;随着逐年的回灌,地层沉降量减小,且地下水回灌效果与回灌层位有直接关系。     

高潜水位煤矿区土地利用景观格局分析与模拟预测研究——以沛北煤矿区为例

我国东部高潜水位煤矿区因煤粮复合、煤水复合、煤村复合成为我国土地复垦难度最大的典型地区之一；研究高潜水位煤矿区土地利用景观格局的时空演变规律，可为制订有效的土地复垦策略提供重要的科学依据。本研究选择位于江苏省徐州市的沛北煤矿区为例，选用1995年TM、2005年ETM+和2015年OLI遥感影像作为数据源，运用土地利用转移轨迹、景观格局指数等分析其景观格局变化特征，并采用CA-Markov模型预测了2025年研究区的土地利用景观格局。结果表明：(1) 研究区景观变化轨迹趋势明显，耕地主要流向建设用地、塌陷积水区、水域和湿地；园林地转变为建设用地和耕地；塌陷积水面积的增加主要来源于建设用地和耕地，贡献比例分别为47.68%、19.20%；(2) CA-Markov模型情景模拟结果表明：2015～2025年，耕地、水域和湿地面积减小；建设用地和塌陷积水面积明显增加；(3) 景观格局指数分析结果表明：在类型水平上，耕地、水域和湿地是主导优势地类，但耕地、塌陷积水、水域和湿地破碎化程度较高；景观水平上，景观格局总体边缘形状趋向简单。综上表明，研究区土地利用景观变化源于区域城镇化进程加快、因采矿活动导致的地表沉陷积水情况加重；建议提前编制预计塌陷区的防治及已塌陷区的规划治理方案。 关键词： 景观格局演变；煤矿区；高潜水位；土地景观格局；CA-Markov模型     

How to amend land subsidence treatment policies to solve coastal subsidence problems in Taiwan

Coastal land subsidence is a serious problem in Taiwan. Starting in 1995, the goal of the “Land Subsidence Prevention and Treatment Implementation Program” is to restructure the aquaculture industry to reduce groundwater consumption and reduce coastal land subsidence problems. However, this goal has not been met. This study aims to determine the reasons for its failure through a literature review and an analysis of questionnaires of stakeholders taken over a 5-year period, and design a new program to resolve these problems. The study was conducted in 2005–2009. According to the literature, over-pumping of groundwater around densely concentrated coastal fish ponds is the primary cause of coastal land subsidence. However, the key measure of the program was to establish aquaculture districts primarily in subsiding coastal areas, which failed to reduce land subsidence. In addition, the program did not consider reductions in agricultural and industrial groundwater use. Results of the questionnaire survey were in accord with the literature review results. This paper proposes to establish a “Fish Farming Abandonment Program” offering compensation payments and job training to fish farmers who leave the aquaculture business, thus reducing the amount of coastal land devoted to fish farming, decreasing groundwater consumption, and halting further coastal subsidence. In addition, the proposal also suggests adjustments to the structure of the agriculture industry. The results of this study can serve as a reference for governments of Taiwan and other countries.     

Assessment of groundwater potential in Tirukalukundram block of southern Chennai Metropolitan Area

Groundwater is an important resource in all major urban centres. Continuous extraction leads to degradation and depletion in the water quality which can be protected by selecting proper groundwater recharging techniques. The present study aims to determine the groundwater potential by integrating the remote sensing and geographic information system which helps to identify the locations which are in critical stage and immediate steps can be taken to recharge the groundwater. Thirukalukundram block of Kanchipuram district in Tami Nadu, India, has been chosen as study area. To demarcate the groundwater potential zone, surface attributes such as geomorphology, land use/land cover, contour map, drainage density and sub-surface attributes such as lineaments and soil maps are created using satellite imageries, toposheet, soil and geomorphology data of the study area. The thematic maps prepared using geographic information system and weights have been assigned to the attributes by considering the influence on the storage capacity of groundwater. Four categories of groundwater potential zones such as below low, low, moderate and high have been classified. From the analysis, 5% along the coastal plain area covers high groundwater potential zone, 20% of the area towards north-west and south-west hold moderate groundwater potential. 60% of the total area hold low groundwater potential zone which are located towards south-west direction. 15% of the study area contains below low groundwater potential zone in parts of south-west direction. This study helps to identify the suitable locations for extraction and recharge of groundwater.     

Climate change and modeling of an unconfined aquifer: the Triffa plain,Morocco

The Triffa plain covering about 307 km² is located in the semiarid region of northeastern Morocco. The cover consists of Quaternary and Mio-Pliocene formations, including alluvial material, silt, sandstone, limestone, clay, and marl, underlain by a sequence of Jurassic carbonates and clastics. Two principal aquifers occur in this region: (1) An unconfined aquifer hosted by the Quaternary formations, which opens up on the coastal plain of Saïdia, giving rise to the Aïn Chebbak and Aïn Zebda springs; and (2) a confined aquifer hosted by the underlying Liassic (Jurassic) formations, composed of limestone and dolostone. In this paper, we present a conceptual hydrogeological model for the Triffa aquifer, which opens laterally into the Saïdia aquifer, based on borehole data, bedrock geology, hydrodynamic parameters, piezometric maps, and time series groundwater level and precipitation data, obtained from several meteorological stations and pumping wells. These comprehensive data were incorporated in the Geographic Information System platform and processed using groundwater modeling software, with the development of the numerical model and its limitations discussed in detail in the present work. Subsequently, we evaluated the impact of climate change on the Triffa aquifer, assuming three different climate scenarios developed by the Intergovernmental Panel on Climate Change. These were the B1—low, A1B—mean, and A1F1—extreme scenarios, which we modeled by simulating a decrease in the recharge in all of the study area up to year 2099 that would correspond to 9, 19, and 47%, respectively. The calibration of the model in steady and transient states produced a good agreement between the observed and simulated heads. The simulation of the impact of climate change on groundwater by a decrease in the recharge highlights the groundwater drawdown occurring in this region. This work can significantly help the authorities in the sustainable management and exploitation of local groundwater.     

江西省地面塌陷的形成及其防治对策

论证了江西省地面塌陷的环境背景条件及其形成,特征,危害,控制因素以及防治对策,结果表明,非岩溶地面塌陷的发生和分布,除了与岩石性质和地质构造有关外,主要受人类工程活动的控制;而岩溶地面塌陷的发生和分布规律,除了与岩石性质和结构,地质构造,地形地貌,上覆第四系土层的性质和厚度等因素有关外,主要还受岩溶发育程度和地下水的动力条件控制。     

荆州市地下水动态特征及影响因素分析

利用2008~2011年4年荆州地区36个水位观测孔、30个水质监测孔的连续监测资料，结合地下水补径排条件，分析了该区上部孔隙承压水水位和水质的时空变化特征及其影响驱动因子。结果显示:(1)荆州地下水位动态类型分为自然动态型和人为动态型两种，不同类型地下水水位动态规律在时空分布上有明显差异，呈现出周期性、同步性、特殊性等特点。4167%~50%的监测孔地下水位处于稳定状态，2222%~3611%的监测孔地下水位下降幅度大于02 m，1944%~3611%的监测孔地下水位上升幅度大于02 m，地下水位动态主要受气候条件与人工开采条件影响。(2)荆州地区地下水质不容乐观，整体较差。连续四年均超标的指标有总硬度、亚硝酸盐、氨氮、砷、铁、锰、溶解性固体含量，同时在部分监测点存在超标异常情况，铁、锰、砷的超标与江汉平原区域特有的原生地质环境条件密切相关，而其它组分的超标在很大程度上受到人类活动的影响     

三峡工程对武湖地区生态环境影响及其对策

以实地考察和水文资料分析结果为依据，阐述了三峡工程对武湖地区防洪，春旱时灌溉和航运带来的有利影响，及枯季１～５月排水所产生的不利影响。建议加强湖区水利建设，提高电排能力；将地面高程１８Ｍ以下耕地退田还湖，以提高湖泊调蓄功能。     

Development of a land-use forecast tool for future water resources assessment: case study for the Mekong River 3S Sub-basins

Land-use change is one of the major factors that alter local and regional hydrology. For areas experiencing fast expansion of urban and agriculture areas, land-use changes often adversely affect stream flow and water resources at the local and watershed scale. The Sekong, Sesan, and Srepok (3S) Sub-basins are a part of the Lower Mekong River Basin and include land in Cambodia, Lao People’s Democratic Republic (Laos), and Viet Nam. The region is experiencing a dynamic land-use transition because of rapid changes in its economy, society, and environment. Major land-use changes include deforestation of native rain forest, expansion of agricultural and urban areas, and expansion of commercial plantation such as rubber trees. These land-use alterations have affected local and regional hydrologic processes, resulting in stream flow shortages during the dry season and flash flooding due to deforestation. In this research, deforestation in the 3S Sub-basins over the period 1993–1997 was analyzed using multi-logistic regression. The regression analysis indicated that density of agricultural cells within a 5-km radius from each forest cell and slope strongly affected the deforestation process. A land-use forecast model to simulate deforestation and urbanization sites was developed in GIS based on local land-use change trends. The model was applied to 2003 land use to forecast 2033 land use and future water demand, which was further compared with present stream flow measurements during the dry season at various places in the region. The entire approach from the land-use forecast to its impact assessment on stream flow could help local stakeholders understand watershed-wide future water resources risks and develop future water resources plans. With the 3S Sub-basins being used as a case study area, this article presents a land-use forecast tool; simulated 2033 land-use and water demand; and the estimation of the impact of the forecasted future water demand on the local stream flow.     

江汉平原涝渍地域分异规律研究

通过五年研究，澄清了江汉平原涝渍灾害形成的原因。根据微地貌特点和涝渍状况将江汉平原涝渍地域土地分为7种类型：洲滩平地季节性洪涝地域，淤高平地季节性暗渍地域，中间平地季节性渍害地域，低湿平地渍害地域，滨湖平地涝渍地域，湖泊水面调蓄地域，碟形洼地涝渍圈。江汉平原涝渍微地域分异和演变规律主要表现在6个方面：(1)在平面上与河流呈水平带状分布；(2)在空间上呈梯度分布；(3)碟形洼地涝渍特征呈同心圆分布；(4)涝渍微地域随时间推移发生有序地演变；(5)人类活动越来越成为江汉平原涝渍地域分异的主导因素；(6)江汉平原涝渍微地域与涝渍灾害呈显著的相关性。根据江汉平原涝渍微地域涝渍发生特征，提出了因地制宜、分区开发的指导思想，并选点进行了实证开发示范，取得了显著成效。     

后寨河流域岩溶含水层脆弱性及其对土地利用方式的响应

由于强烈的溶蚀作用,岩溶地区溶蚀裂隙、管道等高度发育,并相互贯通,形成岩溶区特有的地下、地表“双层空间”结构体系,地下空间成为地下水存储和运移的重要场所。岩溶地区由于土层浅薄或缺失,并且溶蚀裂隙、管道、落水洞、竖井等高度发育,使含水层更易受地表状况的影响,土地利用/覆被变化在很大程度上影响着地下水的水质、水量,岩溶水质的变化能集中反映人类活动胁迫下岩溶含水层脆弱性程度的增加。以典型岩溶单元--贵州普定后寨河流域为例,分析了流域水文地质背景下的岩溶含水层本质脆弱性,结合流域地下河水近20年的水化学资料,分析了含水层脆弱性对土地利用变化的响应。结果显示：土地利用/覆被变化、农业活动、城镇建设及居民活动都对地下水质变化有明显影响。因此,调整土地利用结构,恢复岩溶植被,改善生态环境是保护和改善岩溶水资源的重要途径。     

Influence of global warming on coastal infrastructural instability

The increasing infrastructure instability is an important issue in relation to the influences of global climate change in urban areas. A serious issue pertaining to this is the dual nature of damage triggered by events combined with climate change and natural hazards. For example, catastrophic damage could result from the combination of global warming with a great earthquake, which is a worst-case scenario. Although this worst-case scenario has rarely occurred and presents a low probability of occurrence, countermeasures must be prepared in advance based on an appropriate response and adaptation strategies. After an overview of possible infrastructural instabilities caused by global warming, methodologies are proposed placing emphasis on the increasing probability of infrastructural instability triggered by natural hazards resulting from groundwater-level (GWL) variations. These effects are expected to be particularly serious in coastal regions because of the influence of the rising sea level resulting from global warming. The influence of sea-level rises (SLR) will become apparent along with land subsidence because groundwater abstraction will become severe in coastal regions. Additionally, the probability of earthquake liquefaction increases if GWL rises in accompaniment with SLR. Using case histories, we examined the possible occurrence of these natural hazards as a result of global warming. Finally, possible countermeasures and adaptation strategies for reducing and mitigating infrastructure damage accelerated by global warming are described for each case in specific regions. In particular, special attention should be paid to adaptation strategies in coastal lowlands, which particularly suffer from the effects of land subsidence.     

Determination of the optimal land use allocation pattern in Nowshahr County,Northern Iran

Regional models of land use change are evaluated as a way of identifying land use pattern based on recent quantitative and probabilistic approaches. Differentiation between models in this area is the result of the approach to the concept of land use and type of indicators used in the modeling process. Since the determination of the optima land use pattern, due to the different uses of land based on the availability of regional capabilities and spatial difference in land use, depends on an integrated model, there must be a model that can assess the existing conditions of the region and present reasonable models of land use according to regional capacities and potentials. In this research, we developed a model to present the Optimal Land Use Allocation Pattern (OLUAP) for maximizing the advantages of change and determining the methods of influencing land use change priorities. This model uses spatial models and analysis, moderates the cost-benefit function, and calculates the allocation priorities of various areas based on regional conditions. The model results show that a wide scope of Nowshahr area is allocated to natural and agricultural uses. At the same time, a limited area has been assigned to urban and industrial uses. In addition, it shows that northern strip of the region due to higher accessibility of services and infrastructures is more suited than other regions to urban and industrial areas, and these two uses have first and second priority, respectively. Besides, according to the man-made environment and the special environmental conditions, the model allocates the central lowlands and southern parts sporadically to agricultural and natural areas as first and second priorities. Since the model is spatial optimization, the suggestions of the model show the OLUAP. Therefore, one can see the optimal condition for each plot and compare it with the existing land use.     

Economic water management decisions: trade-offs between conflicting objectives in the sub-middle region of the São Francisco watershed

Hydro-economic models can measure the economic effects of different reservoir operating rules, environmental restrictions, maintenance of ecosystems, technical constraints, institutional constraints, land use change, and climate change. To determine the optimal economic water allocation, for its main uses in the sub-middle of the São Francisco River Basin, a hydro-economic optimization model was developed and applied. Demand curves were used rather than fixed requirements for water resources. The results show that operation rules of reservoirs and institutional constraints, such as priorities for human consumption, have high impacts on costs and benefits of the principal economic uses in the study area. Especially, costs of environmental demands, like minimum ecological river flow, have high impacts on the water resource management. Scarcity costs of irrigation users associated with maintaining ecosystems and environmental constraints are particularly significant. The results from this study provide a better understanding of the water trade-offs for future policymaking and efficient water management. Policymaking for the water resources should consider the food-water-energy-environment nexus at a regional scale to minimize environmental and economic cost under water scarcity and land use change.     

Using radon-222 as indicator for the evaluation of the efficiency of groundwater remediation by in situ air sparging

A common approach for remediation of groundwater contamination with volatile organic compounds (VOCs) is contaminant stripping by means of in situ air sparging (IAS). For VOC stripping, pressurized air is injected into the contaminated groundwater volume, followed by the extraction of the contaminant-loaded exhaust gas from the vadose soil zone and its immediate on-site treatment. Progress assessment of such remediation measure necessitates information (i) on the spatial range of the IAS influence and (ii) on temporal variations of the IAS efficiency. In the present study it was shown that the naturally occurring noble gas radon can be used as suitable environmental tracer for achieving the related spatial and temporal information. Due to the distinct water/air partitioning behaviour of radon and due to its straightforward on-site detectability, the radon distribution pattern in the groundwater can be used as appropriate measure for assessing the progression of an IAS measure as a function of space and time. The presented paper discusses both the theoretical background of the approach and the results of an IAS treatment accomplished at a VOC contaminated site lasting six months, during which radon was applied as efficiency indicator.     

Water Environmental Degradation of the Source Area of the Yellow River on Northeast Qinghai-Tibet Plateau

1 INTRODUCTION Environmental changes caused by mankind's exploitation and regional climate changes have long been a severe problem in the world, especially in the arid and semiarid areas because of their ecosystems' vulnerability (Chen & Qu, 1992; Wang & Cheng, 1999; Liu et al., 1999). During the last half-century, especially the last 30 years, drastic environmental changes have occurred owing to exploitation and development, which have invoked society's concerns. In the Qinghai-Tibet …     

Deltas at risk

The long-term sustainability of populated deltas is often more affected by large-scale engineering projects than sea-level rise associated with global warming and the global ocean volume increase. On deltas, the rate of relative eustatic sea-level rise is often smaller than the rate for isostatic-controlled subsidence and of the same order of magnitude as natural sediment compaction. Accelerated compaction associated with petroleum and groundwater mining can exceed natural subsidence rates by an order of magnitude. The reduction in sediment delivery to deltas due to trapping behind dams, along with the human control of routing river discharge across delta plains, contributes to the sinking of world deltas. Consequences include shoreline erosion, threatened mangroves swamps and wetlands, increased salinization of cultivated land, and hundreds of millions of humans put at risk.