Use of geographic information systems for assessing groundwater pollution potential by pesticides in Central Thailand

This study employed geographic information systems (GIS) technology to evaluate the vulnerability of groundwater to pesticide pollution in Thailand. The study area included three provinces, Kanchana Buri, Ratcha Buri, and Suphan Buri, located in west-central Thailand. Factors used for the vulnerability assessment included soil texture, slope, land use, well depth, and rainfall. These vulnerability factors were reclassified to a common scale, and a weighted average was computed to yield a vulnerability score. Vulnerability factors and weights were assigned considering pesticide concentrations in 90 wells throughout the study area. Well depth was the most significant vulnerability factor. Groundwater vulnerability maps were generated for several pesticides. The eastern, agricultural part of the study area has relatively deep wells and fine soils. Shallow wells are present in the mountainous west; however, fewer pesticides are applied in that region. Consequently, much of the study area had a medium groundwater vulnerability rating, although there were pockets of high vulnerability, for example, in agricultural areas with shallow wells. The groundwater vulnerability maps are effective for identifying locations warranting more detailed groundwater pollution and vulnerability investigations.     

A study on mountain front recharge by using integrated techniques in the hard rock aquifers of southern India

Mountain front recharge (MFR) is the contribution of mountains to recharge the aquifers in the adjacent basins. The estimation of MFR is essential to obtain a detailed investigation of recharge of the groundwater at the mountain front. This study summarises the current understanding of recharge processes by comparing daily groundwater fluctuation to daily rainfall and identifies the recharge rates. The recharge rates vary with time due to difference in water table depth and travel time. Thus to understand the MFR along the foothills of Courtallam, a total of 14 surface water, rainwater and groundwater samples were collected and measured for stable isotopes. The isotopic data were used to investigate the recharge process and to identify the elevations to recharge. The study findings also suggest that predominantly rainfall along the foothills contributes recharge to the riparian zone (basin block region), whereas foothill regions receive recharge from rainfall over mountain block.     

基于生态和社会经济约束的区域土地整治潜力评价研究

准确评价区域耕地整治、农村居民点整治、废弃地复垦和未利用地开发4种类型的土地整治潜力是实现区域统筹规划和保障粮食安全的重要前提。通过选取能反映区域四种土地整治类型内在和外在潜力的指标因素,引入生态安全和社会经济双重制约条件,结合层次分析法和约束条件评价模型对研究区域生态安全和经济社会约束下的土地整治综合潜力开展定量评价,并采用K-Means聚类方法进行潜力分区。研究结果表明:高生态安全和经济发展水平条件能提高区域土地整治潜力水平,反之则制约土地整治潜力水平,同时根据约束条件的土地整治潜力评价结果将研究区域划分为土地整治高潜力区、较高潜力区、一般潜力区和低潜力区,与无约束条件下的土地整治潜力评价结果相比,该分区结果更加符合当地实际情况。该研究一方面可为生态文明建设背景下的土地整治潜力评价提供新方法,另一方面可为新一轮土地整治统筹规划提供有效的依据和参考。     

九江市地下水易污性评价——基于DPASTIC指标的模糊综合评价模型

从污染物入渗土壤-包气带-含水层的过程出发，以地质、地貌、水文地质条件为主控因素，选取地下水埋深〖WTBX〗(D)、降雨入渗补给量(P)、含水层岩性(A)、土壤类型(S)、地形坡度(T)、非饱和带介质(I)及含水层渗透系数(C)〖WTBZ〗7个指标，建立了九江市地下水易污性评价DPASTIC指标体系。结合模糊数学理论和方法，建立了基于DPASTIC指标的模糊综合评价模型。该模型克服了指标参数级别划分定额差异和指标值不连续性变化的缺陷，寻求出最优的级别定额划分状态和指标值的连续性变化情况；在指标级别定额划分上，引用了指标标准特征值的概念，根据实测参数数据资料，建立了10个级别的指标标准特征值矩阵，确定指标参数的最优相对隶属度。结合MAPGIS软件得出最后的地下水易污性分区，评价结果与规划区的实测及预测的水环境质量相吻合。     

Economic implications of groundwater exploitation in hard rock areas of southern peninsular India

The present paper analyses the consequences of groundwater exploitation by using field-level data collected from two distinct well irrigated areas of Karnataka. The study results show that the consequences arising out of groundwater overexploitation are severe in high well interference area compared to low well interference area. The burden of well failure is more or less equally shared by all categories of farmers but small farmers are the worst victims of resource scarcity. As a result, overexploitation of groundwater has different impacts on different categories of farmers in terms of access to groundwater, cost and returns to groundwater irrigation and its negative externality cost. The study suggests maintaining inter-well distance to prevent resource mining and calls for supply and demand side interventions. The institutional reform is necessary to restore surface water bodies to facilitate aquifer recharge.     

九江市地下水易污性评价——基于DPASTIC指标的模糊综合评价模型

从污染物入渗土壤-包气带-含水层的过程出发,以地质、地貌、水文地质条件为主控因素,选取地下水埋深(D)、降雨入渗补给量(P)、含水层岩性(A)、土壤类型(S)、地形坡度(T)、非饱和带介质(I)及含水层渗透系数(C)7个指标,建立了九江市地下水易污性评价DPASTIC指标体系.结合模糊数学理论和方法,建立了基于DPASTIC指标的模糊综合评价模型.该模型克服了指标参数级别划分定额差异和指标值不连续性变化的缺陷,寻求出最优的级别定额划分状态和指标值的连续性变化情况;在指标级别定额划分上,引用了指标标准特征值的概念,根据实测参数数据资料,建立了10个级别的指标标准特征值矩阵,确定指标参数的最优相对隶属度.结合MAPGIS软件得出最后的地下水易污性分区,评价结果与规划区的实测及预测的水环境质量相吻合.     

Modelling land use change across elevation gradients in district Swat, Pakistan

District Swat is part of the high mountain Hindu-Kush Himalayan region of Pakistan. Documentation and analysis of land use change in this region is challenging due to very disparate accounts of the state of forest resources and limited accessible data. Such analysis is, however, important due to concerns over the degradation of forest land leading to deterioration of the protection of water catchments and exposure of highly erodible soils. Furthermore, the area is identified as hotspot for biodiversity loss. The aim of this paper is to identify geophysical and geographical factors related to land use change and model how these relationships vary across the district. For three selected zones across the elevation gradient of the district, we analyse land use change by studying land use maps for the years 1968, 1990 and 2007. In the high-altitude zone, the forest area decreased by 30.5 %, a third of which was caused by agricultural expansion. In the mid-elevation zone, agriculture expanded by 70.3 % and forests decreased by 49.7 %. In the lower altitudes, agriculture expansion was 129.9 % consuming 31.7 % of the forest area over the forty-year time period. Annual deforestation rates observed were 0.80, 1.28 and 1.86 % in high, mid and low altitudes, respectively. In the high-altitude ecosystems, accessibility (distance to nearest road and city) had no significant role in agriculture expansion; rather land use change appears significantly related to geophysical factors such as slope, aspect and altitude. In the low-elevation zone, accessibility was the factor showing the closest association with agriculture expansion and abandonment. The analysis illustrates that land use change processes vary quite considerably between different altitudinal and vegetation cover zones of the same district and that environmental constraints and stage of economic development provide important contextual information.     

1980~2010年江苏沿海城市土地利用变化及其与环境因子关系分析——以东台市为例

2009年江苏省沿海开发规划上升为国家战略,了解江苏沿海城市过去土地利用变化轨迹以及驱动因子是未来江苏省沿海城市土地利用规划的重要基础性工作。基于5期TM30 m×30 m RS遥感影像和GIS技术,分析东台市1980~2010年土地利用结构与变化轨迹,并通过典型对应分析(CCA)分析其与环境因子之间的关系。结果表明,东台市1980~2010年主要土地利用类型为耕地(2029.02 km²)、建设用地(155.31 km²)、草地(60.41 km²)和水域(56.56 km²)。近30年土地利用变化量占总面积的16.98%,其中耕地、草地和建设用地变化量最大。土地利用变化最主要轨迹为耕地转建设用地,主要位于市区及周边地区,其次为草地转耕地,主要位于海岸带地区。东台市土地利用变化热点区域分别为市中心和海岸带,二者相距较远,相对独立。CCA分析显示城镇、交通和斑块形状复杂程度等是影响沿海城市土地利用变化的重要因子,海岸线作为沿海城市主要特征,随着海岸滩涂围垦开发,到海岸距离也是沿海城市土地利用变化的重要影响因子。因此,在沿海城市土地利用规划中需要重点考虑城镇布局、交通等基础设施分布、斑块的形状等因子,通过海岸带土地利用方式转变来加强市区与海岸带之间联系,促进社会经济转变,进一步保护海岸生态环境,提高海岸开发综合效益,引导土地利用走向可持续发展道路。     

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.     

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。     

江淮生态经济区土地利用格局及生态系统服务价值变化

基于2005~2015年土地利用变更调查数据，结合土地利用变化模型和生态系统服务价值理论，分析了江苏省江淮生态经济区县域单元土地利用结构演化规律及生态系统服务价值变化。结果表明：研究期间建设用地、水域面积增加的最多；土地利用程度指数呈现北高南低的空间格局；生态系统服务价值略有上升，空间上总体为南高北低的格局，呈现市区较低，周边县（市）较高的现象；研究期内水域对于江淮生态经济区生态系统服务价值的贡献和生态环境的调控作用十分显著；结合区域建设开发现状，利用生态系统服务价值敏感性指数，在县域尺度上将研究区划分为以下五种类型：优先保护区、优先开发区、保护均衡区、开发权衡区、开发调整区，并提出建设开发策略，以期为江淮生态经济区开发建设、环境保护提供科学指引。     

Potential for the desalination of a brackish groundwater aquifer under a background of rising sea level via salt intrusion prevention river gates in the coastal area of the Red River Delta,Vietnam

Additional freshwater sources are required in many parts of the world, including the coastal areas of the Red River Delta (RRD), where the groundwater (GW) is generally brackish. Determining a feasible method for desalinating brackish aquifers would help provide additional freshwater sources. However, substantial desalination of brackish aquifers cannot be achieved under the natural conditions of GW flow and precipitation recharge. Although rainfall recharge to the shallow Holocene aquifer has occurred for hundreds of years, the aquifer still remains brackish since the natural hydraulic conditions do not allow a complete mixing between the fresh recharged water and aquifer salinized water or the discharging of the aquifer salinized water. The planned salt intrusion prevention gates in the Red River, Tra Ly River and Hoa River in the RRD coastal area, combined with increased GW abstraction and associated aquifer recharge with fresh river water, could result in the gradual desalination of the shallow Holocene aquifer. These effects would help improve the area’s resilience to freshwater shortages and sea level rises and would allow for the creation of a long-term sustainable water resource development plan to manage the salinization of water resources caused by sea level rises. Finite element (FE) modeling of GW flow, solute transport via GW flow and dynamic programming (DP) have been used to study the potential desalination of brackish aquifers, the magnitude of GW abstraction quantities and the spatial and temporal aspects of desalination. FE modeling of GW flow coupled with DP was utilized to identify the magnitude of sustainable abstraction quantities and the GW flow field, which is required in salt transport models. Multiple sizes of elements and time steps were used to adapt to the unsteady state of GW flow and hydraulic head variables between the elements in the FE meshes in order to ensure reasonable accuracy of numerical modeling. The GW flow and salt transport modeling and DP allowed determining quasi-steady-state GW abstraction rates and aquifer salinity levels for conditions that did and did not include the shallow Holocene unconfined aquifer recharge from rainfall. The aquifer modeled domain which is supposed to serve the pumping well field is 1.5 km². The results showed that the Holocene aquifer may provide a stable abstraction rate of 100 m³/day starting in the 6th year (for the worst-case scenario with zero aquifer recharge from rainfall) to 130 m³/day starting in the 3rd year (for the scenario with aquifer recharge equal to 3% of the rainfall levels). During the first years of GW abstraction, the desalination of the brackish upper Holocene aquifer will mainly occur in the area close to the river, and at the 18th year of abstraction, almost the entire area between the river and line of pumping wells would be desalinized. From the 10th year of abstraction, the abstracted water has a total dissolved solids content lower than 0.5 g/l for the worst-case scenario with zero aquifer recharge from rainfall and lower than 0.42 g/l for the scenario with aquifer recharge equal to 3% of the rainfall. The modeling results indicate the simulated process by which abstraction of groundwater adjacent to the Tra Ly River could desalinize the brackish aquifer via freshwater recharge from the river.     

不同地貌类型区城镇扩展对土地利用景观格局的影响

基于RS和GIS的支持，以名山县为研究案例，分析与探讨西部经济以农业为主地区城镇扩展的时空特征和不同地貌类型下土地利用景观格局，以期为城镇规划及区域城镇可持续发展提供决策支持。结果显示：1975 ~ 1999 年土地利用类型在不同地貌区的分布格局变化显著。林地面积大幅减少，分布区域向海拔较高地区收缩。居民及建设用地在低丘区增长较快，城镇用地大幅增加，成为影响研究区景观格局的重要要素。农业生产活动向地势较高的区域扩展，中丘区成为农业生产的主要场所，水田和旱地成其主要土地利用方式。高丘区旱地分布面积占首位；园地在低山区分布面积有所增加。1999~2005 年基本维持1999年景观格局，居民及建设用地继续增长，尤其在低丘区表现明显；低丘和中丘区斑块总数减少，各景观要素平均斑块面积增加，形状指数和分维数降低；高丘、低山区水田、旱地减少，园地面积增加.     

Spatio-temporal modelling of electric vehicle charging demand and impacts on peak household electrical load

This paper presents a composite methodology for obtaining spatial and temporal projections of charging demand and peak-shaving potential from plug-in electric vehicles (EVs), and the associated spatio-temporal impacts on peak household electrical load. The methodology comprises a suite of models of future EV uptake, travel by households, household electricity demand and recharge/discharge of EVs at their home locations. The analysis is disaggregated to hourly time-steps over a full year, and spatially to mesh blocks comprising around 250 houses per block. The modelling suite is applied to an analysis of peak household load impacts across the state of Victoria, Australia, under nine different combinations of EV uptake and charging/discharging behaviour. The projected increase in peak household electrical loads under expected penetration rates and charging demands is less than 10 % on most high-demand days, but can be up to 15 % on a handful of days and geographic locations. Peak-load impacts under off-peak charging are mostly less than 5 %. With judicious EV discharging strategies, there is potential to shave peak loads on the highest demand days by up to 5 %.     

江汉平原土地资源数据库的建立与功能

根据所收集的江汉平原土地资源数据及相关图件（包括１９８３年版１：５万地形图,１：５万各县市土壤图,利用多时相卫片编制的１：２５万专题图）,以ＰＣ－５８６微机为主机,以ＰＣ ＡＲＣ／ＩＮＦＯ地理信息系统工具软件为支持,建立了江汉平原土地资源数据库,其内容包括行政区划空间数据库（各县市行政区划图１：５万）,水系空间数据库（各县市河流,沟渠及水面图,１：５万）,土壤空间数据库（各县市１：５万土壤图）,土     

Modeling groundwater flow and its associated environmental problem in a lowland coastal plain: a first step towards a sustainable development plan

Groundwater is an important resource in the alluvial coastal lowland plains. In the Shiroishi lowland plain, southwestern Kyushu Island of Japan, land subsidence due to groundwater development has long been recognized as an environmental issue. Land subsidence can have several negative economic and social implications. In this study, an integrated numerical groundwater and land subsidence model, which combines a three-dimensional numerical groundwater flow model and a one-dimensional soil consolidation model, was used to simulate the dynamic groundwater flow and ground subsidence due to pumping. On the other hand, a groundwater optimization model was also formulated to search for an optimal safe yield of groundwater pumping without violating physical, environmental, social-economic constraints. The model results reveal that groundwater levels in the aquifers greatly vary from season to season in response to varying climatic and pumping conditions. Consequently, land subsidence has rapidly occurred throughout the area with the central prone in Shiroishi plain. The study also proposes a countermeasure against subsiding process in the area by means of numerical models. The optimization model result suggests that pumping can be increased in the northern part of the study area without leading to significant land subsidence.     

基于GMS的山区三维地质模型及应用研究

本文基于GMS平台,在综合分析重庆某山区地质平面图、地质剖面图、钻孔资料等数据基础上构建了三维可视化地质模型。模拟结果表明:研究区砂泥岩倾斜互层的沉积顺序和不同岩性的空间分布情况与该区已有资料相一致;模型剖面与实际地质剖面面积之比约为1.15,主要岩性面积百分比相对误差绝对值均在15%以内。运用该模型概化为三维水文地质模型,模拟得出研究区地下水流场空间分布,体现了三维地质模型在地下水数值模拟方面的运用价值。该模型的构建为山区区域地质结构研究提供了参考,也为今后该地区开展地下水相关工作打下了基础。     

巢湖水陆交错带生态服务价值梯度分析

基于巢湖水陆交错带1995、2000、2007和2013年4期遥感影像提取土地利用信息,参考前人的相关研究成果,测算研究区的生态服务价值。在综合研究区实际情况和相关研究基础上采用等距离缓冲带法,对研究区生态服务价值的梯度变化进行研究。结果表明:(1)各土地利用类型的梯度变化在不同时期有较为一致的变化趋势,在不同的缓冲带内都有1~2个贡献率较大的土地利用类型;(2)在研究期内各缓冲带生态服务价值处于基本平稳的状态,其中缓冲带1到缓冲带2的变化幅度较大;(3)从生态服务价值的空间分布来看,缓冲带1的生态服务价值始终最高,外层的缓冲带5和缓冲带6由低等级到中等级平稳过度,缓冲带3和缓冲带4则始终处在低水平;(4)林地和水域对生态服务价值的贡献率与距巢湖水陆边界的距离有显著的相关性,表明林地和水域对研究区生态服务价值的影响大。     

基于集约评价的城市开发区规模计量研究——以南京市省级以上开发区为例

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