A GIS-based DRASTIC Model for Assessing Aquifer Vulnerability in Kherran Plain, Khuzestan, Iran

The Kherran plain is located in the northeast of Ahwaz in Khuzestan Province, Iran. The state of groundwater pollution is a critical issue with increasing population and agricultural development in Iran. For this reason, vulnerability assessment is an important factor in any policy making decision in any part of country. Focusing on this issue, the article attempts to presents a groundwater vulnerability map for the Kherran plain. The map designed to show areas of highest potential for groundwater pollution based on hydro-geological condition and human impacts. Seven major hydro-geological factors (Depth to water table, net Recharge, Aquifer media, Soil media, Topography, Impact of vadose zone and hydraulic Conductivity) were incorporated into DRASTIC model and geographical information system (GIS) was used to create a groundwater vulnerability map by overlaying the available hydro-geological data. The output map shows that the west and southwest of the aquifer are under medium vulnerability while small areas on northwest and east of the study area have no risk to pollution. Other parts of aquifer have low vulnerability. For testing of the vulnerability assessment, 27 groundwater samples were collected from the different vulnerability zones of the study area. The chemical analysis results show that the southwest and west parts of aquifer (moderate vulnerability zones) have higher nitrate concentration relative to the rest of aquifer, that are located in low vulnerability zone.     

A New Approach for Trend Assessment of Annual Streamflows: a Case Study of Hydropower Plants in Serbia

The authors propose a new approach for trend assessment that takes into account long-term periodicity of annual flows. In particular, analysis is performed of annual flows recorded at the locations of 30 operating and designed hydropower plants (HPPs) in Serbia, in order to assess the current and future water availability for hydropower generation. The composite annual trend is determined by sliding a fixed time window of 30 years along the observed time series with a one-year time step. Such a linear moving window (LMW) approach enables the identification of the flow trend as a median of all values for each time step. Significant trend harmonics are determined using discrete spectral analysis. The results show an alternation of upward and downward trend phases of different durations, namely: 67–87, 33–43 and 21–29 years. On the other hand, the results of the Mann-Kendall test indicate a monotonic downward trend at the studied sites in the Drina River Basin, while statistically insignificant trends are noted at other river basins. The Mann-Kendall test with the Theil-Sen estimator also implies a downward and statistically insignificant flow trend after the observed period, whereas the LMW approach indicates a probable trend increase at all the examined sites. The proposed approach can be used to predict annual flows in order to establish long-term water management plans at hydropower plants.     

Intrinsic Vulnerability Assessment for the Alluvial Aquifer in the Northern Part of Jordan Valley

The Northern Jordan Valley (NJV) is an important and significant water basin in Jordan where most of Jordan’s agricultural crops are produced. Knowing that the aquifer system is mainly composed of alluvial deposits, it is important to assess the potential of ground water for pollution. For this purpose intrinsic vulnerability was assessed using SINTACS model with the aid of geographic information system (GIS) techniques. The final results show that about 40% of the investigated area has been classified as high to very high vulnerable to groundwater pollution. These results were correlated with measured concentration of nitrate (NO₃^-1)_{3}^{-1}) at different locations. A high correlation was found between areas of high nitrate concentrations and those of high vulnerability category. To validate the model results, a sensitivity analysis has been carried out to assess the influence of each of SINTACS parameters on the obtained vulnerability values. It was found that the soil overburden attenuation capacity parameter (T) and the depth to the groundwater parameter (S) are the most sensitive parameters to SINTACS vulnerability model. The effective-weights analysis was also performed in this study to revise the weights in the computed vulnerability index. It was noticed that the effective weights for each parameter were sometimes varies from the theoretical weights assigned by the SINTACS method.     

Assessment of Agricultural Drought Vulnerability in the Guanzhong Plain,China

The Guanzhong Plain, as an important traditional agricultural area, is suffering from high frequency droughts and a trend towards more serious drought. In this paper, eight factors, precipitation, evapotranspiration, surface water availability, depth to groundwater, well yield capacity, slope, potential water storage of soil, and GDP from agriculture, are integrated into an index to represent drought vulnerability based on the overlay and index method. In this approach, according to the internal connections between factors, precipitation and evapotranspiration are integrated into the moisture index, and depth to groundwater and well yield capacity are integrated into groundwater availability. To improve the rationality and accuracy, normalization is employed to assign rating values, and the analytic hierarchy process is introduced into the weighting scheme. Two local drought monitoring datasets endorses the results of the model. The map removal sensitivity analysis indicates the vulnerability index has low sensitivity in removing each layer. The single-parameter sensitivity analysis indicates the major contribution to the vulnerability index is meteorology followed by groundwater availability and surface water availability. The vulnerability map shows the low vulnerability coincides roughly with irrigation districts on the terraces and floodplains. The northwest tableland generally has moderate vulnerability, due largely to inefficient groundwater withdrawal. The high vulnerability is concentrated at the peripheries of the plain, where agriculture is generally rain-fed without irrigation and groundwater support, and land is rugged with high slopes.     

A Dynamic Model for Vulnerability Assessment of Regional Water Resources in Arid Areas: A Case Study of Bayingolin, China

Water scarcity is a common problem in many countries, especially those located in arid zones. The vulnerability of water resources due to climate change is an imperative research focus in the field of water resources management. In this study, a System Dynamics (SD) model was developed to simulate the water supply-and-demand process in Bayingolin, a prefecture in China, and to evaluate water resources vulnerability currently as well as in the future. The model was calibrated and validated using historical data. Three alternative scenarios were designed by changing parameters to test the vulnerability of water resources: i) increase the Wastewater Treatment Rate by 50 %; ii) decrease the Irrigation Water Demand per Hectare by 20 %; iii) increase Total Water Supply by 5 %. Results show that the baseline vulnerability of study region is high. The agricultural irrigation is the largest water use, and the water demand structure will change in future. Decreasing the irrigation water demand is the most suitable intervention to relatively reduce the vulnerability. Results also demonstrated that SD is a suitable method to explore management options for a complex water supply and demand system.     

Simulation-Optimization Modeling for Sustainable Groundwater Development: A Moroccan Coastal Aquifer Case Study

A transient simulation model characterizing groundwater flow in the coastal aquifer of Rhis-Nekor was constructed and calibrated. The flow model was then used in conjunction with a genetic algorithm based optimization model to explore the optimal pumping schemes that meet current and future water demands while minimizing the risks for several adverse environmental impacts, such as saltwater intrusion prevention, avoiding excessive drawdown, as well as controlling waterlogging and salinity problems. Modeling results demonstrate the importance of this combined simulation-optimization methodology for solving groundwater management problems associated with the Rhis-Nekor plain.     

Integrated Index for Assessment of Vulnerability to Drought,Case Study: Zayandehrood River Basin,Iran

Drought is an extended period of deficient precipitation that causes damage to crops and reducing their performance, causes temporary scarcity of water for human/livestock consumption. Over the years, various indices have been proposed to identify onset, characterize and quantify the attributes of meteorological, hydrological and agricultural drought by various researchers. Because of the spatial and temporal variability and multiple impacts of drought, it is necessary to develop an integrated index for assessment of vulnerability of this natural phenomenon. The aim of this paper is presenting an integrated index for assessment of vulnerability to drought using multiple factors which includes hydrological, meteorological, land use and other factors. Spatial information of various factors was categorized in to various sub-classes and maps were prepared in spatial domain using Geographic Information System (GIS). This study has been carried out in the Zayandehrood River basin located in west-central Iran with semi-arid region. Due to continue droughts at recent decade, this area has been chosen as a case study. The long-term climate data (1991–2011) used for assessment. The results show that Zayandehrood River basin has experienced 11 dry years, 4 normal years, and 6 wet years in the 21 years. The results have been validated with intensive field surveys.     

Analysis and Assessment of Hydrochemical Characteristics of Maragheh-Bonab Plain Aquifer,Northwest of Iran

The present study aims at assessing the hydrochemistry of the groundwater system of the Maragheh-Bonab Plain located in the East Azarbaijan Province, northwest of Iran. The groundwater is used mainly for drinking, agriculture and industry. The study also discusses the issue of the industrial untreated wastewater discharge to the Plain aquifer that is a high Ca-Cl water type with TDS value of about 150 g/L. The hydrogeochemical study is conducted by collecting and analyzing the groundwater samples from July and September of 2013. The studied system contains three major groundwater types, namely Ca–Mg–HCO₃, Na–Cl, and non-dominant water, based on the analysis of the major ions. The main processes contributing to chemical compositions in the groundwater are the dissolution along the flow path, dedolomitisation, ion exchange reactions, and the mixing with wastewater. According to the computed water quality index (WQI) ranging from 25.45 to 194.35, the groundwater in the plain can be categorized into “excellent water”, “good water”, and “poor water”. There is a resemblance between the spatial distribution of the WQI and hydrochemical water types in the Piper diagram. The “excellent” quality water broadly coincides with the Ca-Mg-HCO₃ water type. The “poor” water matches with the Na–Cl water type, and the “good” quality water coincides with blended water. The results indicate that this aquifer suffers from intense human activities which are forcing the aquifer into a critical condition.     

Groundwater Resources in Lebanon: A Vulnerability Assessment

This paper presents a regional groundwater vulnerability assessment for Lebanon using the DRASTIC model coupled with a GIS‐based framework to prioritize protection efforts, whereby the most vulnerable areas to groundwater are targeted first, thus optimizing the allocation of financial and human resources. The objective of the study is to initiate a systematic approach to better manage and protect the country's groundwater resources.     

基于概率数学方法与GIS的泥石流敏感性分析及评价——以汶川县为例

以汶川县为研究区,通过对震后的高分辨遥感影像的遥感解译,获得了145条泥石流沟及流域中的崩滑物源的分布图。选择了坡度、坡向、地层岩性、地震峰值加速度、距水系距离、距断层距离作为评价因子,利用概率数学方法与GIS的空间分析功能,获得145条泥石流沟在上述6个评价因子上的分值;再利用层次分析法计算得到各评价因子权重,建立泥石流敏感性评价模型,得到了研究区泥石流沟敏感性分级图。结果表明:研究区145条泥石流沟中,有60条泥石流沟属于高敏感性,43条泥石流沟为中敏感性,其余42条泥石流沟敏感性较低,研究成果对于认识该地区泥石流灾害现状及发展趋势与防灾减灾有一定的参考意义。     

Spatio-Temporal Groundwater Vulnerability Assessment - A Coupled Remote Sensing and GIS Approach for Historical Land Cover Reconstruction

This paper presents a spatial-temporal groundwater vulnerability assessment, based on a coupled remote sensing and GIS approach for historical land cover reconstruction. This flexible methodological tool can be used for spatiotemporal vulnerability assessment in fresh water systems. The transboundary watershed of the Águeda River was used as an experimental case study where the DRASTIC and DRASTIC pesticide indices and the Susceptibility Index (SI) were used for vulnerability assessment. Land-use temporal evolution was mapped using remote sensing, taking into account the aerial frames of the historical American Flight of 1956/59, the IGN’s 1984 Flight and CORINE Land Cover (1990, 2000 and 2006) as spatial information. Four new land-use layers were considered in the SI’s temporal evolution assessment, namely for 1959, 1990, 2000 and 2006, respectively. In the last 50 years, the highest vulnerable areas to groundwater contamination have been concentrated mainly in the central zone of the watershed where the tertiary aquifer and the largest urban area are located. Future research will involve feasibility studies of different treatment schemes and the development of specific monitoring activities.     

农业生态系统对气候变化的脆弱性评价——以河北省农业综合开发项目区为例

选取河北省农业综合开发项目区农业生态系统作为研究对象,将其划分为2个一级区8个亚区。通过采用实地调查与专家推荐的方法,确定了河北省农业对气候变化的脆弱性评价体系;采用专家打分和层次分析法完成了现状条件下农业对气候变化的脆弱性评价。评价结果表明坝上高原和冀西北山间盆地亚区农业对气候变化非常脆弱,山麓平原亚区农业对气候变化较为适中,滨海平原亚区农业对气候变化脆弱性逐渐变缓。评价结果基本上反映出河北省农业开发项目区生态系统气候脆弱性现状的一个大致轮廓,可供进一步研究借鉴和参考。     

阶梯状抽水试验水文地质参数确定

针对传统阶梯状抽水试验参数计算过程中,通常只选择抽水阶段的部分试验数据等问题,应用Theis公式及叠加原理,利用抽水试验所有降深数据(抽水和水位恢复阶段全部资料)求解水文地质参数,利用承压含水层抽水试验数据计算得出导水系数、储水系数,利用潜水含水层抽水试验数据计算得出渗透系数和给水度,此外在低效率抽水井中利用抽水试验数据计算得出井损系数和井流量指数。计算过程中,利用Excel计算并绘制计算水位降深和观测水位降深的拟合曲线,计算过程简单快捷。整个抽水试验过程中,不必再分别提出抽水、水位恢复期的计算公式,可以避免人为选择单个水位降深数据对参数求解带来的影响。     

A Systematic Review of Water Vulnerability Assessment Tools

The important relationship between health and water necessitates consideration of water vulnerability. Water vulnerability is contingent upon biophysical and social drivers operating at multiple scales, and is difficult to assess. This paper offers a systematic review of 50 water vulnerability assessment tools. We identify and synthesise the contents of these assessment tools (710 indicators) into five dimensions and 22 sub-dimensions and consider the extent to which they reflect environmental and social aspects. The findings are discussed in light of a holistic approach to water resources management, and specifically Integrated Water Resources Management (IWRM). Significant opportunities exist to enhance the efficacy of water vulnerability assessment tools by incorporating indicators and operational measures for social considerations (e.g., adaptation, institutions, governance) that are developed outside the context of water.     

Geostatistical Assessment of Groundwater Nitrate Contamination with Reflection on DRASTIC Vulnerability Assessment: The Case of the Upper Litani Basin, Lebanon

Groundwater constitutes the largest single source of fresh water in many parts of the world and provides a risk buffer to sustain critical water demands during cyclic and prolonged dry periods, especially in semi-arid and arid regions. However, unprecedented socio-economical growths are threatening the viability of these precious resources through fast depletion of already critically low stocks accompanied by persistent degradation of water quality due to salinization, and contamination by pesticides and fertilizers, urban sewage and industrial waste. These circumstances are particularly true of the Upper Litani Basin (ULB), which houses over 500,000 of Lebanon’s 4 million population and provides the bulk of the country’s agricultural output. Uncontrolled urban, agricultural and industrial growths following a prolonged civil strife and foreign occupation have resulted in the deterioration of the quality of the basin’s surface water and potentially its groundwater resources. An assessment study of groundwater quality conditions in the ULB was conducted in support of efforts to manage water quality in the basin. Geostatistical analysis of groundwater nitrate levels was conducted using data collected through an extensive basin-wide water quality survey sponsored by the USAID and covered two periods representing the summer and winter periods. The results of analysis include maps of nitrate contamination and probability of exceedance of drinking-water nitrate regulatory limit. The results indicate a significant, widespread and persistent nitrates contamination of groundwater in the ULB. Nitrate levels in groundwater exceed standard limits for drinking water in many parts of the basin. These findings were examined with respect to those of a DRASTIC groundwater vulnerability assessment conducted by the USAID BAMAS project. Comparative analysis of the two assessments shed the light on several issues related to the application and interpretation of DRASTIC scores and the groundwater nitrate contamination process.     

Rapid Economic Assessment of Flood-control Failure along the Rio Grande: A Case Study

Recent flood events along the international border between the USA and Mexico resulted in significant economic damage and loss of human life. The International Boundary and Water Commission, the agency responsible for monitoring US–Mexican flood control levees, had requested funding for maintenance and improvement of these levees. However, the Office of Management and Budget requires agencies to provide benefits or in this case avoided loss estimates to justify the budget request. Due to severe time constraints in the budgetary process there was a need for a rapid assessment of the potential economic impacts from a failure of this ageing flood-control infrastructure. The economic losses avoided by four major flood-control projects on the Rio Grande were estimated using an innovative combination of satellite imagery, geographic information systems, and economic methods. The control projects apply to about 547 km (340 miles) of levees from Caballo Reservoir in New Mexico to Brownsville, Texas, and include several million people, extensive industry, and agricultural production. High resolution imagery was used to identify and quantify potential flood inundation areas, types of land use, and impacts of flood-control infrastructure failure. Value estimates of residential, industrial, and commercial property, and agricultural production at risk were developed from property assessment data, crop enterprise budgets, census data, and community leaders. Damage factors accounting for flood inundation levels and building contents were then used to develop gross economic losses avoided by flood-control infrastructure for each of the different property and land use types in each project area. The baseline analysis indicates that the four projects cumulatively prevent one time losses of US$322.9 million in flood-control protection.     

Drought Vulnerability Assessment Based on a Multi-criteria Integrated Approach and Application of Satellite-based Datasets

Water Resources Management - Drought as a complex event depends on some geo-environmental parameters. The impact of this phenomenon on the economy and environment can be devastating. Recognizing...     

A Superposed Model for the Pipe Failure Assessment of Water Distribution Networks and Uncertainty Analysis: A Case Study

Pipe failure often occurs in water distribution networks (WDNs) and results in high levels of water loss and socio-economic damage. Physical-based, statistical and data-driven models have been developed to estimate pipe failure rates (failures per km of pipe per year) to efficiently manage water losses from WDNs and to ensure safe operations. Due to the complexities of pipe failure patterns, we develop a superposed statistical model to depict the relationship between pipe failure rate and pipe age. The model’s level of uncertainty was then quantified by simulating pipe failures as Poisson numbers. Part of Beijing’s WDN is taken as a study case, and pipe failure data for a 4-year period, as well as pipe properties, are collected to develop the pipe failure model. The case study results show that the pipe failure rates vary with time in a non-monotonic manner and that the proposed model captures pipe failure behaviour with an R² value of 0.95. A 95% confidence interval of modelled pipe failures for each pipe age group is used to describe the uncertainty level of the model. We find that 88% of the observations fall under the 95% confidence interval. The established model could be applied to prioritize pipes with higher failure rates to optimize pipe replacement/rehabilitation strategies. Our uncertainty analysis of this model can help utility managers understand the model’s reliability and formulate reasonable WDN management plans.     

基于熵权法的流域水资源脆弱性评价——以淮河流域为例

流域水资源脆弱性评价可以量化表现出水资源的脆弱性程度,客观地反映研究区的水安全状况。根据水资源脆弱性的表现形式及成因,设置了水量、水质、洪涝灾害、旱灾4个一级指标,自然因素、人为因素、承载因素3个二级指标,分级构建了水资源脆弱性评价指标体系,在线性加权法的基础上采用熵权法构建了水资源脆弱性评价模型。以淮河流域为例进行实证分析,从时间、空间2个维度上对2003—2012年淮河流域整体及流域内的4个省份进行水资源脆弱性评价。结果表明时间上,10 a间淮河流域整体水资源脆弱度数值逐年减小,水资源脆弱性呈现好转趋势,流域内河南、安徽、江苏、山东4省的水资源脆弱性在10 a间均有所缓解;空间上,淮河流域水资源自西向东越来越脆弱。研究结果表明目前淮河流域水资源脆弱性状况呈现好转趋势,但仍然存在一些问题,有待进一步管理和调控。     

A Particle Swarm Optimization Assessment for the Determination of Non-Darcian Flow Parameters in a Confined Aquifer

Being one of the preliminary in-situ testing methods, aquifer pumping tests would provide significant insights which form a basis for the aquifer characterization. The use of Darcian based flow models to describe the groundwater flow would be ineffective for the aquifer pumping tests under certain circumstances. Non-Darcian flow models could therefore construct more accurate portrayal of physical reality for the assessment of aquifer testing. The interpretation of flow parameters obtained from non-Darcian flows via classical curve matching methods seems extremely difficult to acquire a unique match since the well-defined type curves have not been developed. In this study, an evolutionary optimization based algorithm, called as Particle Swarm Optimization (PSO), was established to determine the flow parameters namely power index, storativity and the turbulent factor which serves as an apparent hydraulic conductivity. The proposed PSO based parameter estimation scheme was implemented for a number of numerical test cases and the estimation performance was evaluated by comparing with available population based algorithms. The results reveal that the PSO based estimation approach is successfully able to identify the flow parameters in an accurate and fast manner. A number of sensitivity analyses were also conducted to draw the limitations of the introduced PSO based technique. The positive findings from this study pointed the potential capability of using PSO as a viable algorithm to process the complex relations in the flow.