Groundwater Vulnerability

Providing efficient and effective methodologies and technologies for sustainable groundwater resources development and management are the vision of Ground Water Hydrology division of National Institute of Hydrology, Roorkee, Uttarakhand, India. Some of the emerging areas in the field of groundwater hydrology needing inputs to modern science include groundwater storage and resource estimation; groundwater modelling and management; coastal aquifer dynamics; surface water and groundwater interaction; hard-rock and karst hydrology; groundwater sustainability on supply and demand, groundwater protection against contaminants, and impact of environmental changes on groundwater resources. Keeping in view of these thrust areas, the Ground Water Hydrology division is pursuing the basic and applied research pertaining to various aspects of groundwater hydrology such as, aquifer parameter estimation; aquifer responses due to untoward stresses; groundwater assessment, modelling and management; coastal groundwater dynamics; contaminant transport modelling; managed aquifer recharge; bank filtration; and impact of climate change on groundwater resources. This document provides details of groundwater studies and projects completed by Ground Water Hydrology division of National Institute of Hydrology, Roorkee (India) since 2007.

— National Institute of Hydrology is a Government of India society under Ministry of Water Resources, River Development & Ganga Rejuvenation. It has been functioning as a research Institute in the area of hydrology and water resources in the country since December 1978 with headquarters at Roorkee (Uttarakhand, India) and six regional centres located in different physiographic regions of the country. This article presents salient details of groundwater studies undertaken by Ground Water Hydrology division of the Institute during last few years.

Many Arab countries are facing major environmental challenges. Water scarcity and pollution in conjunction with the loss, degradation and contamination of land resources have become core problems affecting public health and the socio-economic development. Water and soil resources represent exhaustible and vulnerable resources.  Thus, a sustainable development of the Arab region requires the implementation of guidelines concerning the protection and sustainable use of groundwater resources and soils. The formulation and dissemination of such guidelines is the main goal of the project. 
The mapping of groundwater vulnerability is widely used in developed countries as a basic tool for the protection of groundwater resources. Such maps are not only used by groundwater specialists but also in the framework of land use planning. The intention of the guideline presented in this report is to facilitate the preparation of groundwater vulnerability maps in the Arab region.
Groundwater vulnerability maps in conjunction with maps showing existing potential hazards to groundwater resources help to identify possible risks. The identification and assessment of risks for the susceptibility of water supply utilities to contamination is needed in order to undertake countermeasures against pollution risks. Therefore, the risk assessment also plays an important role for the protection of groundwater resources.
To provide an effective protection of the groundwater resources, it is also important to convince the land use planning authorities to take the issue of groundwater protection into consideration when deciding about locations and conditions for the establishment of facilities and activities which are possibly hazardous to groundwater, such as waste disposal sites, sewage treatment plants and sewer mains, industrial and commercial estates, storage facilities for oil products and toxic hazardous substances, etc. By locating such sites in areas where a contamination of the groundwater resources cannot occur, a deterioration of the groundwater resources can be actively avoided.
The preparation of groundwater vulnerability maps helps to create awareness among land use planners for the issue of groundwater protection.

ΠΕΡΙΛΗΨΗ

Η διπλωματική εργασία πραγματεύεται τη διερεύνηση της τρωτότητας υπόγειου υδροφόρου συστήματος του πεδινού τμήματος Ξυλαγανής - Ιμέρου του Ν. Ροδόπης  στο πλαίσιο της διαχείρισης των υπόγειων νερών της περιοχής. Οι εργασίες στο πλαίσιο της διπλωματικής, εκτός από τη συγκέντρωση, ανάλυση και σύνθεση σχετικού βιβλιογραφικού υλικού περιέλαβαν και τη συγκέντρωση και αξιολόγηση γεωλογικών, υδρολογικών και υδρογεωλογικών στοιχείων από προγενέστερες έρευνες στην ίδια περιοχή, που αφορούσαν σε σχετικές μετρήσεις πεδίου, εργαστηριακές μετρήσεις και αναλύσεις, όπως και εργασίες γραφείου. Οι θέσεις των γεωτρήσεων παρακολούθησης προέρχονται από λεπτομερή καταγραφή προηγούμενης έρευνας που έγινε με πραγματικές συντεταγμένες και με την ανάπτυξη βάσης δεδομένων με τη βοήθεια Γεωγραφικού Συστήματος Πληροφοριών (GIS), ενώ ο σχεδιασμός των χαρτών κατανομής διαφόρων παραμέτρων έγινε με τη χρήση σχετικών λογισμικών (Surfer 9). Οι χημικές αναλύσεις πραγματοποιήθηκαν στο Εργαστήριο Τεχνικής Γεωλογίας του Τμήματος Πολιτικών Μηχανικών του Δ.Π.Θ., σε προηγούμενη έρευνα.
Πιο αναλυτικά, στο Κεφάλαιο 1 γίνεται βιβλιογραφική προσέγγιση στο θέμα της τρωτότητας- διακινδύνευσης ρύπανσης υπόγειων υδροφόρων συστημάτων αλλά και στο πρόβλημα της διείσδυσης της θάλασσας σε παράκτια υδροφόρα στρώματα. Στο Κεφάλαιο 2 παρουσιάζεται το γεωλογικό και γεωμορφολογικό περιβάλλον της περιοχής έρευνας. Το Κεφάλαιο 3 παρουσιάζει τα βασικά υδρολογικά στοιχεία της περιοχής έρευνας. Στο Κεφάλαιο 4 αναφέρονται οι υδρογεωλογικές συνθήκες της περιοχής έρευνας και παρατίθενται τα αποτελέσματα και η ερμηνεία των αποτελεσμάτων από σχετικές μετρήσεις προηγούμενων ερευνών στην περιοχή. Το Κεφάλαιο 5 αφορά στην παράθεση ποιοτικών χαρακτηριστικών δειγμάτων νερού από τον υδροφόρο της περιοχής έρευνας που εκτιμήθηκαν σε προηγούμενες έρευνες. Στο Κεφάλαιο 6 καταγράφονται τα αποτελέσματα από την εφαρμογή της μεθόδου DRASTIC με τον λεπτομερή υπολογισμό των τιμών του δείκτη τρωτότητας DRASTIC, παρουσιάζονται χάρτες τρωτότητας - διακινδύνευσης ρύπανσης των υπόγειων νερών της περιοχής έρευνας κυρίως από το έδαφος προς τον υδροφόρο και μέσω της ακόρεστης της περιοχής και συγκρίνονται τα αποτελέσματα αυτά με τη συγκέντρωση των νιτρικών ιόντων στην περιοχή για την αποτίμηση της αξιοπιστίας της μεθόδου. Στο Κεφάλαιο 7 παρουσιάζονται τα αποτελέσματα από την εφαρμογή της μεθόδου GALDIT με τον λεπτομερή υπολογισμό των τιμών του δείκτη τρωτότητας GALDIT, παρουσιάζονται χάρτες τρωτότητας-διακινδύνευσης ρύπανσης των υπόγειων νερών της περιοχής έρευνας, της περιοχής από θαλάσσια διείσδυση και συγκρίνονται τα αποτελέσματα αυτά με τις τιμές του δείκτη Revelle στην περιοχή έρευνας για την αποτίμηση της αξιοπιστίας της μεθόδου. Τέλος στο Κεφάλαιο 8 παρουσιάζονται τα συμπεράσματα που προέκυψαν από την εκπόνηση της διπλωματικής εργασίας στην υπό εξέταση περιοχή καθώς και προτάσεις για περαιτέρω έρευνα στην περιοχή, όπως και διαχειριστικές προτάσεις που θα μπορούσαν να εφαρμοστούν από τους αρμόδιους φορείς.


ABSTRACT

The thesis discusses the research of the vulnerability of an aquifer system in Xilagani – Imeros palin region of Rhodope Prefecture, in the framework of the groundwater management in the region. The work in this thesis, apart from the collection, analysis and synthesis of relevant bibliographic material, included the collection and analysis of geological, hydrological and hydrogeological data from previous research in the study area which concerned field measurements, laboratory measurements and analysis, as well as office work. The locations of monitoring wells came up from detailed previous research, done with real coordinates and the development of a database with the use of Geographic Information System (GIS), while the design of the relevant maps of various parameters distribution was done with the use of relevant software (Surfer 9). The chemical analysis was carried out, in a previous research, at the Laboratory of Engineering Geology in the Department of Civil Engineering, Democritus University of Thrace.
In detail, Chapter 1 includes a bibliographic approach to vulnerability - risk of pollution of aquifer systems and the problem of seawater intrusion in coastal aquifers. Chapter 2 presents the geological and geomorphological environment of the study area. Chapter 3 presents the main hydrological elements of the study area. In Chapter 4 the hydrogeological conditions of the study area are stated, as well as the results and interpretation of results from related measurements of previous researches in the region. Chapter 5 deals with the quoting of groundwater quality data of the study area as estimated in previous surveys. In Chapter 6, the results recorded by applying the DRASTIC method for the detailed calculation of the DRASTIC index of vulnerability are presented. Vulnerability maps are also presented, concerning the risk of pollution of groundwater in the study area mainly from the ground to the aquifer through the unsaturated zone and these results are compared with the concentration of nitrates in the region to assess the reliability of the method. Chapter 7 presents the results of the GALDIT method by the detailed calculation of the values of the GALDIT index of vulnerability. Vulnerability maps are also presented concerning the risk of groundwater pollution from sea water intrusion and these results are compared with those of the Revelle index in the study area, so as to assess the reliability of the method. Finally, Chapter 8 presents the conclusions drawn from the development of this thesis in the examined region and suggestions for further research in the area, as well as management proposals that could be implemented by relevant institutions and stakeholders.

Mounding often occurs beneath engineering structures designed to infiltrate reuse water. AQTESOLV software and a spreadsheet solution for Hantush, together with soil moisture water balance (SWAGMAN farm model), were used for quantitatively predicting the height and extent of groundwater mounding underground to assess the groundwater-flow simulations of infiltration from a hypothetical irrigation site. Horizontal and vertical permeability, aquifer thickness, specific yield, and basin geometry are among the aquifer and recharge properties inputs. For 2.2 ha sites, the maximum heights of the simulated groundwater mound ranges up to 0.29 m. The maximum areal extent of groundwater mounding measured from the edge of the infiltration basins of 0.24 m ranges from 0 to 75 m. Additionally, the simulated height and extent of the groundwater mounding associated with a hypothetical irrigation infiltration basin for 2.2 ha development may be applicable to sites of different sizes, using the recharge rate estimated from the SWAGMAN farm model. For example, for a 2.2 ha site with a 0.0002 m/day recharge rate, the irrigation infiltration basin design capacity (and associated groundwater mound) would be the same as for a 1.1 ha site with a 0.0004 m/day recharge rate if the physical characteristics of the aquifer are unchanged. The study claimed that the present modelling approach overcomes the complications of solving the Hantush equation for transient flow. The approach utilised in this study can be applied for other purposes such as measuring the feasibility of infiltrating water, attenuation zone, risk mitigation essential for decision-makers and planning regulators in terms of environmental effects and water use efficiency.

This thesis clarifies the potential impacts of climate change and sea-level rise under future climate scenarios on groundwater recharge and surface leakage, and consequently on the groundwater vulnerability of a shallow, unconfined, low-lying coastal sedimentary aquifer in southern Finland. The study utilised multiple approaches, including field investigations, well monitoring, three-dimensional (3D) geological modelling, 3D groundwater flow modelling, multivariate statistical approaches (principal component analysis (PCA) and hierarchical cluster analysis (HCA)), the stable isotopes δ2H and δ18O, conventional hydrogeochemistry and groundwater intrinsic vulnerability assessment methods. The UZF1 model was coupled with the 3D groundwater MODFLOW model to simulate flow from the unsaturated zone through the aquifer. The well-calibrated groundwater flow model was used to simulate and predict the potential impacts of climate change on groundwater recharge under future climate and sea-level rise scenarios. The results indicate changes in the groundwater recharge patterns during the years 2071–2100, with recharge occurring earlier in winter and early spring. Because the aquifer is located in a cold snow-dominated region, the seasonal impacts of climate change on groundwater recharge were more significant, with land surface overflow resulting in flooding during the winter and early spring and drought during the summer. Rising sea levels would cause some parts of the aquifer to be submerged under the sea, compromising groundwater quality due to the intrusion of seawater. This, together with increased groundwater recharge, would raise the groundwater level and consequently contribute to more surface leakage.
The groundwater geochemistry of the coastal aquifer in Hanko is very similar to that of inland shallow aquifers generally in Finland, where the groundwater is mainly of the Ca–HCO3 type, with low dissolved element concentrations, low pH and alkalinity, and low Ca and Mg concentrations due to rapid percolation or the short residence time. The stable isotopes δ2H and δ18O clearly suggest that the Hanko aquifer recharges directly from meteoric water (snowmelt and rainfall), with minor or insignificant contributions from the Baltic Sea and surface water. However, the geochemistry of the groundwater suggests sulphate reduction in the mixed zone between freshwater and seawater, indicating that local seawater intrusion may temporarily take place, although the contribution of seawater was found to be very low. Further inland, the influence of surface water could be observed from higher levels of KMnO4 consumption in wells near the lake above the aquifer. The findings also demonstrated that the use of stable isotopes δ2H and δ18O alone to identify seawater–aquifer interaction is not sufficient to determine the rate of water exchange. The high temporal variation in groundwater chemistry directly corresponded to groundwater recharge. With an increase in groundwater recharge, KMnO4 consumption, EC, alkalinity and Ca concentrations also increased in most wells, while Fe, Al, Mn and SO4 were occasionally increased during the spring after snowmelt under specific geological conditions. Based on the future climate scenarios, precipitation in the Hanko area is expected to increase and the Baltic Sea level to rise. This could cause increased recharge of the aquifer from surface water, but also some seawater intrusion due to the sea-level rise and storm surges, as well as increased groundwater abstraction. An increase in the concentrations of some dissolved elements and changes in groundwater geochemistry along the coastline can be expected in the future. Thus, in coastal aquifers with low hydraulic gradients, the hydrogeochemistry should be used to confirm the intrusion of seawater. The PCA and HCA multivariate statistical approaches are useful tools to extract the main components that are able to identify the vulnerable areas of the aquifer impacted by natural or human activities, either on regional or site-specific scales. The integration of PCA and HCA with conventional classification of groundwater types, as well as with the hydrogeochemical data, provided an understanding of the complex groundwater flow systems, supporting aquifer vulnerability assessment and groundwater management in the future.
The degree of groundwater vulnerability in the Hanko aquifer has been greatly impacted by seasonal variations in groundwater recharge during the year, and will also vary depending on climate change variability in the long term. The potential for high groundwater vulnerability to contamination from sources on the ground surface occurs during the period with a high groundwater recharge rate after snowmelt, while high vulnerability to seawater intrusion could occur when there is a low groundwater recharge rate in the dry season. This thesis study highlighted the importance of the integration of groundwater vulnerability assessment methods for shallow, unconfined, low-lying coastal aquifers from a comparison of three intrinsic vulnerability mapping methods: the AVI, a modified version of SINTACS and the GALDIT method. The modified SINTACS could be used as a guideline for groundwater vulnerability assessment of glacial and deglacial deposits in inland aquifers, and in combination with GALDIT, it could provide a useful tool for assessing groundwater vulnerability to both contamination from sources on the ground surface and to seawater intrusion for shallow, unconfined, low-lying coastal aquifers under future climate change.

A groundwater resources assessment has been carried out for the Lake Nyasa Basin east Africa, with reference to sub catchments further to the whole basin wise analysis, including quantification of potential yields from the aquifers. Numerical groundwater models, MODFLOW-SURFACT coupled with Visual MODFLOW, were used to assess sub-basin groundwater sustainability (Via “Zone Budget” software package). The model has been calibrated to observed hydraulic head and processed baseflow estimate. It is concluded that the aquifer system is sustained by episodic recharge and the long-term gaining storage which represents the maximum extractable volume. Future predictions of groundwater usage indicate that by 2035 the percentage of annual safe yield extracted will increase to between 11.3 and 103%. Model result suggests that there is a need to revise the current estimate of sustainable yield based on future climate change conditions and projected population growth, which would decrease spring flows substantially and decrease hydraulic head basin-wide. It also suggests that by 2035 some sub catchments will be nearly at or exceeding the annual safe yield leaving no room for socio-economic development, or the need to reduce existing socio-economic demands to meet domestic demands. Besides to improving the natural replenishment capacity through artificial recharge technique, the other option is to increase the percentage of total recharge allocated to the annual safe yield from 10% of the total annual recharge to 20% in these catchments. This provides a basis for management of individual groundwater scheme in sustaining livelihood activities or implications of policies and to develop a plan for potential groundwater extraction scenarios pertaining to water use and allocation.

This study characterize groundwater yield and flow pattern on a shallow overburden aquifers of a basement complex rock in Ilara-mokin and its’ environs, southwestern Nigeria. A total of 40 wells were sampled by using a handheld GPS and well estimator to collect data on the wells parameters and the physiographic characteristics of the well’s locations. The data collected include: elevation, longitude, latitude, well depth, depth to water and well diameter of the sampled wells. The mean yield of the well has revealed by this study is 1.21m3, with high variability in yield depending on the nature of the underlying overburden aquifers of the sampled well. The static water level, groundwater flow direction, surface profile and 3-D elevation model of the study area were produced from the data collected using ArcGis 9.3 and surfer 8 GIS software. The groundwater flow direction in the study is towards the southwestern part of the study area with few exceptions as the case of Ikota in the eastern part of the study area. The study concluded that Ilara-mokin and it’s’ environs have poor groundwater yield that can sustain the increasing population. It is therefore recommended that there should be proper development, management and advance exploration of the groundwater in areas where water level is close to the surface especially within the lowland areas and isolated marginally thick overburden as confirmed by a previous hydro-geophysical studies carried out in the area.

Jeita spring is the most important spring of Lebanon. It provides drinking water to almost 50 % of the Lebanese population. The uncontrolled and rapid development over the past two decades has lead to a continuously high level of pollution of this most important water source of the country (RAAD & MARGANE, 2013). Until now, wastewater in the Jeita catchment is not collected and treated. Only through the implementation of rigorous measures this pollution load could be reduced. The implementation of a wastewater scheme, supported by the German Government, is currently underway (MARGANE, 2011; MARGANE & MAKKI, 2012; MUELLER & MARGANE, 2011). Although wastewater can be considered the main pollution source, there is a large number of other potential pollution sources which also endanger groundwater quality (RAAD et al., 2012, 2013). The implementation of groundwater protection zones, as proposed in this document, is the only effective measure that could ensure in the long-term an improvement of drinking water quality for the water supply of the Greater Beirut Area. It requires the adoption and enforcement of very strict landuse restrictions.

Hydro-geology (hydro- meaning water, and -geology meaning the study of the Earth) is the area of geology that deals with the distribution and movement of groundwater in the soil and rocks of the Earth's crust (commonly in aquifers). The term hydrology is often used interchangeably. Some make the minor distinction between a hydrologist or engineer applying themselves to geology (hydrology), and a geologist applying themselves to hydrology (hydro geology).Hydrogeology is an interdisciplinary subject; it can be difficult to account fully for the chemical, physical, biological and even legal interactions between soil, water, nature and society. The study of the interaction between groundwater movement and geology can be quite complex. Groundwater does not always flow in the subsurface down-hill following the surface topography; groundwater follows pressure gradients (flow from high pressure to low) often following fractures and conduits in circuitous paths. Taking into account the interplay of the different facets of a multi-component system often requires knowledge in several diverse fields at both the experimental and theoretical levels. The following is a more traditional introduction to the methods and nomenclature of saturated subsurface hydrology, or simply the study of ground water content.Hydrogeology, as stated above, is a branch of the earth sciences dealing with the flow of water through aquifers and other shallow porous media (typically less than 450 m or 1,500 ft below the land surface.) The very shallow flow of water in the subsurface (the upper 3 m or 10 ft) is pertinent to the fields of soil science, agriculture and civil engineering, as well as to hydrogeology. The general flow of fluids (water, hydrocarbons, geothermal fluids, etc.) in deeper formations is also a concern of geologists, geophysicists and petroleum geologists. Groundwater is a slow-moving, viscous fluid (with a Reynolds number less than unity); many of the empirically derived laws of groundwater flow can be alternately derived in fluid mechanics from the special case of Stokes flow (viscosity and pressure terms, but no inertial term). The mathematical relationships used to describe the flow of water through porous media are the diffusion and Laplace equations, which have applications in many diverse fields. Steady groundwater flow (Laplace equation) has been simulated using electrical, elastic and heat conduction analogies. Transient groundwater flow is analogous to the diffusion of heat in a solid, therefore some solutions to hydrological problems have been adapted from heat transfer literature.Traditionally, the movement of groundwater has been studied separately from surface water, climatology, and even the chemical and microbiological aspects of hydrogeology (the processes are uncoupled). As the field of hydrogeology matures, the strong interactions between groundwater, surface water, water chemistry, soil moisture and even climate are becoming more clear.For example: Aquifer drawdown or overdrafting and the pumping of fossil water may be a contributing factor to sea-level rise

A modified DRASTIC model in a geographic information system (GIS) environment coupled with an information-analytic technique called ‘rough  sets’ is used to understand the aquifer vulnerability characteristics of a segment of the lower Kali watershed in western Uttar Pradesh, India. Since the region is a flat plain, topography (T) is removed as a potential control. Other parameters are the same as in DRASTIC, hence the new model is termed as DRASIC. The rough set technique is employed to provide insight into the relative vulnerabilities of different administrative units (blocks) within the study area. Using rough sets, three important factors are computed: strength, certainty and coverage. Strength indicates how the vulnerability characteristics vary in the entire area, certainty gives the relative fractions of low, medium and high vulnerability regions within a particular block, and coverage computes the percentage of a particular vulnerability state in each block. The purpose of the work is to demonstrate the utility of this integrated approach in classifying different administrative blocks in the study area according to their aquifer vulnerability characteristics. This approach is particularly useful for block-level planning and decision making for sustainable management of groundwater resources.

This study deals with the intrinsic vulnerability of groundwater reservoirs to pollution, by the use of two models DRASTIC and GODS, this study is done by taking samples from 17 water resources of Malayer plain Aquifer area of southern Hamedan Province, Iran. 30 physicochemical parameters and heavy metals have been studied and vulnerability of this aquifer to the nitrate concentration, was determined. The study showed that results from DRASTIC were better than GODS in Assessment and Estimating groundwater vulnerability to pollution, also DRASTIC model has been corrected, and compared the ability of these two models in vulnerability zoning has been evaluated. According to high correlation between DRASTIC index and nitrate concentration, ranking and weighting of nitrate pollutant is inserted in the DRASTIC equation, and zoning map of DRASTIC method has been calibrated by nitrate concentration. By this method, vulnerability zoning is determined between very low to very high, which shows the increase of DRASTIC index by nitrate concentration. DRASTIC parameters uncertainty has affected the zoning results in this method, but its calibration with nitrate concentration, gives more accurate vulnerability results.

Domestic, industrial and agricultural sewage contaminates the limited groundwater reservoirs, and makes water extraction more cumbersome in numerous parts of Iran. Impurity was affected by effluent depletion wealthy in ammonia. The alteration in ammonia condensation was mostly governed by the immigration of the contamination plume under nitrification in groundwater. The nitrification level was presumably traced by alters in dissolved oxygen and potentially manganese. Nitrogen pollution of natural water is a typical obstacle for diverse lands throughout the universe. Computer simulation and ground perceptions demonstrate the detracting situations organized under joint effects of anthropogenic items and suitable natural conditions, such as the low-level topography in which reduced water exchange rate can happen. In European Union countries, exposure sewage mud on agricultural terrains is surrounded by guidance. It was established that solitary usage of waste-water mud was useful for extension of herbage cover. Waste-water mud from food industry prepared herbage nutrients effectively used by the herbs. Therefore, the consequences of the experiences displayed that the imperceptible extrication of macronutrients from waste water mud was fully applied by herbages to stimulate their formation and extension. The rapid growth of proactive industries in this country, which is by and large due to ignorance towards the adequate water sources, has augmented the complications and has overshadowed the underground water in plains. Refined water (treated wastewater) can possibly help preserve the subterranean water since overtreatment ensures decent sewage management. Natural filtration under the ground eliminates the need for costly advanced treating procedures. Furthermore, aquifers provide a natural mechanism to transport the treated subterranean water and eliminate the surface storage and its problems, such as evaporation and algal growth. Supplementing water into a geological formation through various methods and equipment is called “Artificial Feeding”. This study deals with the strategies, challenges, and the mechanisms to remove the soil pollutants.

The growth of human population often corresponds with change in land use, including expansion of urban areas, which necessitates increasing the available amount of drinking water. As the surface water sources are more amenable to pollution, it has become necessary to use groundwater at an increasing rate. Groundwater is normally abundant in the alluvial region where the urban areas are often located. Such areas face a greater risk of pollution of groundwater due to several factors. Surface water resources are becoming more scares in Iraq which gave a tendency to use groundwater. In this research, groundwater vulnerability in part of the western desert had been studied. It was noticed that the area has low risk for the contamination of ground water.

The deleterious impacts of dumpsite activities and the associated risk on both the environment and human is consequential, hence this study assessed groundwater vulnerability to pollution from dumpsite using a modified DRASTIC model.  Six hydrogeological factors: D- Depth to water,  R- Net Recharge, A- Aquifer media, L- Distance of well to dumpsite, T- Topography, and  C- Clay content were  used  in the modification (DRALTC) based on peculiarity of the study area. Cluster analysis of groundwater data and Water Quality Index (WQI) were also evaluated. The groundwater vulnerability index was characterized by two zones; forty five percent (45%) moderate and fifty five percent (55%) high zones. The dendogram showed three clusters of chemical dissimilarities. The WQI showed values between 61.8 and 205, indicating good–poor–very poor class of water. The analysis of the groundwater samples showed nitrate concentration ranging from 7.60 to 35.6 mg/L and from 8.56 to 32.4 mg/L in dry and rainy seasons, respectively. The DRALTC model was validated using nitrate concentration. Though, there appeared relative groundwater protection from contamination, there is still need for measures to mitigate further contamination and associated risk in the moderate vulnerability zones. DRALTC model is proved a good tool in groundwater management.

[En] Groundwater Vulnerability Index to Contamination – VIX. Identification of areas with greater vulnerability of groundwater to contamination is essential for planning human activities in geographic space, as well as for the adoption of measures to mitigate its possible negative impacts. In this Technical Bulletin the Groundwater Vulnerability Index to Contamination - VIX is described and an application example is provided.

The growth of human population often corresponds with change in land use, including expansion of urban areas, which necessitates increasing the available amount of drinking water. As the surface water sources are more amenable to pollution, it has become necessary to use groundwater at an increasing rate. Groundwater is normally abundant in the alluvial region where the urban areas are often located. Such areas face a greater risk of pollution of groundwater due to several factors. Surface water resources are becoming more scares in Iraq which gave a tendency to use groundwater. In this research, groundwater vulnerability in part of the western desert had been studied. It was noticed that the area has low risk for the contamination of ground water.

The main objective of this study was to obtain the relationship oftopography and Land Use/Land Cover (LU/LC) classes ongroundwater pollutionvulnerability using RS and GIS for Bangalore District. Here ArcGIS software and ERDAS IMAGINE software are used withAnalytical Hierarchy Process (AHP) to process different layers such as drainage map, a relief map, a Digital elevation map, and drainage network map. Topographic features like drainage network and relief likely have a substantial impact on groundwater pollution with Land Use/Land Cover classes which was divided into seven categories water bodies, forest land, grass, wasteland, wetlands, agriculture built-up, built-up area with very low, low, medium and high density. The urbanization index map was developed by overlaying all the maps to explain topographic impacts on groundwater contamination.Our research shows that due to urbanization, industrialization, and anthropogenic activities, topography has a major effect on groundwater pollution. Water distribution in the study region showed a falling drift with a 59 percent decrease. The vegetation distribution also showed a declining trend with a 49 percent fall. The combined distribution showed a significant 109 percent rise. Other areas decreased by 40 percent in total. The development of form land and open spaces into developed areas on the outskirts of the city demonstratesan unsustainable growth of the town, which must be resolved, and there must be immediate action taken by the concerned authorities and eradicating the future damages at the earliest.

Research conducted between 1999 and 2004 to assess pressure on coastal zone focused on three main objectives: first, the evaluation of seawater intrusion in southern coastal wells, second, the soil salinization in greenhouses irrigated by well waters, and third the management of saline water in two soil textures. Groundwater contamination was assessed by regular sampling of six wells for 30 months. The salinity of water fluctuated around 3 dS m-1 and the Simpson index (Cl/HCO3) indicated levels of moderate to injurious  contaminations. The Na/Cl ratios remained < 1, suggesting a seawater intrusion rather than an anthropogenic origin. In all sites, greenhouse growers had to rely on other water sources (e.g. rainwater, domestic) to supply the crop needs. In some cases, the crop had to be interrupted as salinity decreased yields. Improving the management of water and nutrients was studied in a tomato/Jew’s-mallow sequence. Three levels of water salinity (1, 2.5 and 5 dS m-1) were tested in sandy and clay soils. Under sound management of fertilizers input and a leaching fraction, the salinity had no obvious negative effect on tomato in the clay soil. The Jew’s mallow had a role in the removal of residual salts.

High  arsenic  (As)  concentrations in groundwater in different zones  of Cambodia have become  a
major  concern in recent years.  This paper attempts to review,  synthesize, and analyze data from
available literature in order to give  an insight view  on the  spatial  arsenic contamination in Cambodia,
particularly  in the province along Mekong  River.  These regions  are  located  in the low land  areas
where groundwater is heavily used in domestic activities. The review covered 7 provinces; Kandal,
Prey Veng, Kampong Cham, Kampong Chhnang, Kampong Thom, Kratie, and Peri-urban of Phnom
Penh. The data showed that  The Mekong lowlands consist broadly of alluvial material overlying
shale, slate and sandstone bedrock.  Monitoring of groundwater quality has shown that  arsenic in
drinking  water  has  been  failed  to  meet  WHO  guideline  (0.01mg/l)  or  the  prevailing  national
standards  for arsenic.  It was found that  during the period from  2005  to  2009,  30,839  of  47,950  of
national  wells  in  7 provinces  have been  tested  for arsenic  using  field test  kits.  The results  have
revealed that  t  up to 35-38% of tube-wells within these  areas  are contaminated with arsenic above
the Cambodian National Standard (50ppb).  About  2.8-3% of wells along  the Stung Saen River in
Kampong Thom  and about 50% of the  tube-wells in  the lower floodplains of the Mekong and Bassac
Rivers in Kandal are contaminated.  The most highly affected province is Kandal.  In order to address
the  issue,  area wise assessment of groundwater contamination, community education,  provision of
preventative  medicine,  development  of  safe  rural  water  supply  mechanisms,  and  program
monitoring and evaluation are of paramount importance.

ABSTRACT The concept of Integrated Constructed Wetlands (ICW) promotes in-situ soils to construct and line wetland cells.The integrity of soil material, however, may provide a potential pathway for contaminants to flow into the underlying groundwater. This study assessed the extent of groundwater quality deterioration due to the establishment of a full-scale ICW system treating domestic wastewater in Ireland. The ICW is located at Glaslough in Co. Monaghan, Ireland. It consists of two sedimentation ponds and a sequence of five shallow vegetated wetland cells. The ICW cells were lined with 500 mm thick local subsoil material, which comprised a mixture of alluvium, organic soils, tills and gravel. Groundwater samples and head data were collected from eight piezometers, which were installed around the ICW cells. The groundwater and wetland water samples were analysed for water quality parameters such as bulk organic matter, nutrients and pathogens. Overall, significantly higher contaminant concentrations were recorded in monitoring wells up-gradient and near to the distal wetland cells than down-gradient ones, which were near to the proximal cells. For the down-gradient piezometers, concentrations seldom exceeded the natural background levels. Detailed analyses through the application of chemometrics models indicated that the source of contamination was largely of geogenic origin. Findings suggest that ICW systems pose a minimal risk to the groundwater quality; the greatest risk was associated with the distal wetland cells.

Groundwater is the main source of water for different purposes in the desert areas of Egypt. The agricultural and different human activities in line with hydrological characteristics have influenced the quality of this water resource. The main aim of this work was the determination of groundwater quality and vulnerability to pollution in west Luxor Governorate, Egypt. For completion of this work, 50 boreholes were sampled during October 2014 and groundwater samples were analyzed chemically. Hydrological, topographic, lithological, climatic conditions and land use data, which are considered key factors for pollutants transport, were also collected for building groundwater vulnerability maps. The results revealed high levels of groundwater pollution with NO3¯, Cd and Pb, as well as increased levels of total dissolved solids. The map of intrinsic groundwater vulnerability (based on the IV index; Arauzo 2017) showed medium and high levels of vulnerability associated with natural factors in 62% and 38% of the area, respectively. The map of specific groundwater vulnerability (based on the LU-IV procedure; Arauzo 2017) indicated that 52% of the area showed high to extreme levels of vulnerability to nitrate pollution from nonpoint sources. From this, it was concluded that the study area can be considered a Nitrate Vulnerable Zone (NVZ) and, therefore, specific measures (including optimization of water and N-fertilizers applications) must be taken in order to restore water quality.

The main objective of this study was to assess aquifer vulnerability using a modified DRASTIC model (DRASTICA) to develop vulnerability mapping in Hoskote Taluk, Bengaluru. Here ERDAS IMAGINE software and ArcGIS software are used. The DRASTIC parameters such as Depth of water level (D), Recharge( R), Aquifer media (A), Soil media (S), Topography (T), Impact of vadose zone (I), Hydraulic conductivity (C) were all referred. In ‘DRASTICA’ ‘A’ refers to a new parameter called ‘impact of anthropogenic activities (A)’ to access the human impact on the groundwater resources in the study area.  Step by step Basic data was collected, that is Satellite data, Population density, Water level, recharge, borehole data, soil data, and Digital elevation model (DEM). The original ‘DRASTIC’ model was altered by including anthropogenic impact ‘A’ using Analytical Hierarchy Process (AHP) which is used for determining the ratings of each parameter in the modified-DRASTIC method and was processed in GIS to generate groundwater vulnerable zones. As GIS enables in the visual interpretation of data, this has given specific maps for specific analysis, and as a result, 80 percent of the study lies under very high vulnerable zone while in other areas, the potential to pollution is comparatively less.  Spatial analysis indicated that anthropogenic impact influenced pollution, thereby human activities as to be addressed. It was observed that the modified ‘DRASTICA’ model is more suitable and precise for the present study.

An approach to solving the challenges encountered in groundwater vulnerability assessment in Sub-Saharan African countries is discussed in this paper. The aim of this review is to highlight the gaps and difficulties encountered and provide guidelines for groundwater protection measures in sub-Saharan African countries, particularly countries without specific regulations and methodology of carrying out aquifer vulnerability assessments. Highlighted difficulties in groundwater vulnerability mapping in Sub-Saharan Africa include limited data, shortage of skilled professionals, inapplicability of most existing vulnerability methods and non-availability of funds. The numerical, travel time and parametric vulnerability approaches were recommended for use in sub-Saharan Africa based on the unique geomorphological features of the African continent. The goal of outlining the challenges and providing a guideline was to minimise the impact of groundwater pollution and to prioritise groundwater mapping in an aquifer protection assessment.

The efficient use of water resources in arid region has become highly relevant in the evaluation and mining planning, since the exploration phase to closure. The objective of the numerical groundwater model was to assess the potential for groundwater extraction to meet mine water demand from one of the driest area in the world. Numerical groundwater models were used to assess groundwater resource. Modelling was undertaken using MODFLOW-SURFACT code, an advanced MODFLOW based code, within the framework of Visual MODFLOW version 4.6. A steady state model was developed to assess the regional groundwater flow pattern and to calibrate the recharge and hydraulic conductivity parameters in the model. The model was calibrated with a correlation of coefficient of 0.997, and root-mean-squared error is 0.3 m. A transient simulation model was used to predict the impact of 1.5 million cubic metre/year extraction for 10 years on the main aquifer hydrogeological regime, including after cession of pumping. Modelling simulated four hydrogeological scenarios. Model results for the ‘worst case’ scenario suggested that the Saq Sandstone aquifer should be capable of supplying the mine water demand (1.5 million cubic metre (MCM)/year) for 10 years. However, the long-term water-level drawdown shows a continuous decrease without achieving steady state conditions; thus, the majority of water is being taken from aquifer storage, and in the long term, there will be a mutual interference from a borefield located to the north of the model area. In this area, the hydraulic gradient is relatively steep and over-pumped for more than 28 years. Other scenario shows that there will be a recovery of around 8 m out of the 11.6-m drawdown, after 18 years of cession of pumping, implying that the aquifer will be stressed and a large percentage of water taken from aquifer storage. To minimise hydrogeological impacts, it is recommended to laterally spread out production bores, bores should be located where the Saq Sandstone is deepest, and operate the bores at low extraction rates. Overall, this study presents a useful numerical model output for mine water supply assessment and will contribute towards improving water resources management under different conditions in one of the world driest area.

This study assesses and characterizes the vulnerability of unregulated groundwater systems to microbial contamination in 18 counties in the state of Georgia using a contamination risk screening strategy based on watershed characteristics and elements of the Safe Drinking Water Act's Wellhead Protection program. Environmental data sources analyzed include septic systems, elevation, land use and land cover data, soil, vegetation coverage, demographics, and livestock. A geospatial overlay/index modeling approach was developed to identify areas of higher vulnerability for groundwater pollution by taking into consideration watershed land use, hydrology, and topography (LHT). Sensitivity analysis was used to evaluate the effectiveness of model variables. The results of the model were validated by using field data and output from U.S. EPA's DRASTIC model, a widely used intrinsic vulnerability assessment tool. The validation showed a higher risk of microbial contamination for wells located in a high to medium LHT vulnerability zones. LHT provided a clear distribution of satisfactory and unsatisfactory wells in the three vulnerability zones; however, the majority of wells (>75%), with both satisfactory and unsatisfactory test results, are located in medium DRASTIC vulnerability zone. This difference between LHT and DRASTIC can be attributed to the microbial contamination specific factors incorporated into LHT index. It is concluded that although inclusion of potential contamination sources on adjacent land uses in the vulnerability assessment framework adds to the complexity of the processes involved in a vulnerability assessment, such inclusion provides a meaningful perspective to groundwater protection efforts as an effective screening tool.

Abstract An approach to solving the challenges encountered in groundwater vulnerability assessment in Sub-Saharan African countries is discussed in this paper. The aim of this review is to highlight the gaps and difficulties encountered and provide guidelines for groundwater protection measures in sub-Saharan African countries, particularly countries without specific regulations and methodology of carrying out aquifer vulnerability assessments. Highlighted difficulties in groundwater vulnerability mapping in Sub-Saharan Africa include limited data, shortage of skilled professionals, inapplicability of most existing vulnerability methods and non-availability of funds. The numerical, travel time and parametric vulnerability approaches were recommended for use in sub-Saharan Africa based on the unique geomorphological features of the African continent. The goal of outlining the challenges and providing a guideline was to minimise the impact of groundwater pollution and to prioritise groundwater mapping in an aquifer protection assessment.

Nataša Ravbar & Nico Goldscheider: Proposed methodology of vulnerability and contamination risk mapping for the protection of karst aquifers in Slovenia On the basis of work accomplished by the European COST Action 620, a comprehensive approach to groundwater vulnerability and contamination risk assessment is proposed, taking into account the special characteristics of Slovene karst aquifer systems. The Slovene Approach is consistent with national environmental legislation and enables comparison across European countries. The method integrates temporal hydrological variability in the concept of groundwater vulnerability and offers a new possibility to combine surface and groundwater source and resource protection, which required the development of a new K factor (karst groundwater flow within the saturated zone). The risk analysis considers intrinsic vulnerability, contamination hazards and the importance of the source or resource. It has been first applied to the Podstenjšek spring...

Edi tor ’s Note : NEHA strives to provide up-to-date and relevant information on environmental health and to build partnerships in the profession. In pursuit of these goals, we feature a column from the Environmental Health Services Branch (EHSB) of the Centers for Disease Control and Prevention (CDC) in every issue of the Journal. In this column, EHSB and guest authors from across CDC will highlight a variety of concerns, opportunities, challenges, and successes that we all share in environmental public health. EHSB’s objective is to strengthen the role of state, local, tribal, and national environmental health programs and professionals to anticipate, identify, and respond to adverse environmental exposures and the consequences of these exposures for human health. The conclusions in this article are those of the author(s) and do not necessarily represent the views of CDC. Mansoor Baloch is a consultant hydrologist/environmental engineer with the Environmental Health Specialists Ne...

Background and objectives: Groundwater pollution is a complex and full of uncertainty process, on a regional scale. Development of an integrated method for assessing groundwater vulnerability, can be efficient in order to optimized management and protection of them. Because of fertile soil and sufficient water resources, Ramhormoz plain is suitable area for agriculture that by development of agriculture, use of chemical fertilizers and pesticide, this plain always is at risk of contamination. One of the suitable approach to prevent groundwater contamination, identify areas of potential contamination. The aim of this study is to produce vulnerability map of Ramhormoz plain alluvial aquifer using DRASTIC model, and then use artificial intelligence techniques to improve the results of the DRASTIC model. Due to the importance of groundwater resources in the study area that are used for various purposes including agriculture, Aquifer vulnerability study and protect these areas for development and management of water resources is essential.
Materials and methods: In this study, first, vulnerability evaluation of Ramhormoz alluvial aquifer plain was performed using DRASTIC model and in the following, artificial intelligence methods was used to optimize the model. DRASTIC model includes the following parameters: depth to water table, net recharge, aquifer media, soil media, topography, impact of vadose zone and hydraulic conductivity that are effective in groundwater vulnerability assessment. This method, based on the standard weights of DRASTIC model and obtained layers for each of the seven parameters, calculates the amount of aquifer vulnerability. After preparation of the layers, vulnerability of Ramhormoz alluvial aquifer plain was determined using drastic model. Also the groundwater vulnerability map and DRASTIC index was calculated for the entire area. In order to evaluation of accuracy of the obtained results from the model, nitrate concentration data existing in groundwater have been used for verification. Following In order to improve results, DRASTIC model was integrated by artificial neural networks, fuzzy logic (Sugeno and Mamdani) and Adaptive Neuro-Fuzzy Inference System methods and four vulnerability maps was obtained using different models of artificial intelligence.
Results: the groundwater vulnerability map toward the contamination was prepared by the division into three vulnerability ranges including low, medium and high and DRASTIC index was calculated for the entire area between 48 and 156. Correlation coefficient 0.97 between DRASTIC index and nitrate concentration reflects the relatively good accuracy of this method. Also, the results of the implementation of these models showed that the used artificial intelligence models have the ability to improve the primary DRASTIC model results. By comparing the results of the models can be concluded that the Adaptive Neuro-Fuzzy Inference System model has the best result.
Conclusion: The determination coefficient, R2, for the Adaptive Neuro-Fuzzy Inference System, neural networks and Mamdani fuzzy and Sugeno fuzzy models, is 0.99, 0.94, 0.98 and 0.87 respectively. According to the final model, South- Southeast regions have the highest potential for contamination.

An approach to solving the challenges encountered in groundwater vulnerability assessment in Sub-Saharan African countries is discussed in this paper. The aim of this review is to highlight the gaps and difficulties encountered and provide guidelines for groundwater protection measures in sub-Saharan African countries, particularly countries without specific regulations and methodology of carrying out aquifer vulnerability assessments. Highlighted difficulties in groundwater vulnerability mapping in Sub-Saharan Africa include limited data, shortage of skilled professionals, inapplicability of most existing vulnerability methods and non-availability of funds. The numerical, travel time and parametric vulnerability approaches were recommended for use in sub-Saharan Africa based on the unique geomorphological features of the African continent. The goal of outlining the challenges and providing a guideline was to minimise the impact of groundwater pollution and to prioritise groundwater...

Droughty areas formed about 1/3 of earth’s surface. The rate of rainfall in these areas is low and rate of evaporation is high that it sometimes arrives to 40 times more than rainfall. With this situation, droughty areas are in difficulty of water sources. Since surface waters are not trustable in these areas (because of low and irregular rainfall), human has tried to turn to sources of groundwater that has less environmental changes. Yazd- Ardakan plain is one of the areas that has groundwater tension and actually has faced to dropping of groundwater’s level and land settlement. According to negative conclusions and consequences of land settlement and vital importance of groundwater reservoirs in droughty areas, in this article, it’s been tried to do research and explore in this field and do analyze about effective factors of this field. Since agriculture has most consuming water volume, in this article, the basis of work was stayed on studying of agricultural activities, moreover developing of industry and population and some of performed plans in area were mentioned too. Obtained conclusions show that excavating of numerous wells through the revolution occurrence that there wasn’t accurate observe on excavating wells and also policies of government are main factors of increasing of cultivated surface and as result of that, increasing of exploiting from reservoir. Also agricultural activities especially traditional agriculture is main factor of losses and wasted water because of their low efficiency. Developing of industry and population are couple of effective factors of increasing consuming water.

Droughty areas formed about 1/3 of earth’s surface. The rate of rainfall in these areas is low and rate of evaporation is high that it sometimes arrives to 40 times more than rainfall. With this situation, droughty areas are in difficulty of water sources. Since surface waters are not trustable in these areas (because of low and irregular rainfall), human has tried to turn to sources of groundwater that has less environmental changes. Yazd- Ardakan plain is one of the areas that has groundwater tension and actually has faced to dropping of groundwater’s level and land settlement. According to negative conclusions and consequences of land settlement and vital importance of groundwater reservoirs in droughty areas, in this article, it’s been tried to do research and explore in this field and do analyze about effective factors of this field. Since agriculture has most consuming water volume, in this article, the basis of work was stayed on studying of agricultural activities, moreover developing of industry and population and some of performed plans in area were mentioned too. Obtained conclusions show that excavating of numerous wells through the revolution occurrence that there wasn’t accurate observe on excavating wells and also policies of government are main factors of increasing of cultivated surface and as result of that, increasing of exploiting from reservoir. Also agricultural activities especially traditional agriculture is main factor of losses and wasted water because of their low efficiency. Developing of industry and population are couple of effective factors of increasing consuming water.

Today geology faces new challenges but also great chances brought on by the increased use of digital information. On one hand in the last decade the increase in data volume has been enormous, on the other hand the data sources are still neither homogeneous nor widely distributed. Furthermore often the only available data for a survey were acquired for completely different purposes. Especially when tasks become more complex, the usage of distributed not homogeneous data is essential and leads to considerable problems.
One possible solution is the development of data warehouses, integrating all available and needed data. The disadvantage of this concept is a reduced flexibility and the investments to build up and run this data environment. Another solution is provided by recent developments in Geoinformatics: the use of Spatial Data Infrastructures (SDI) for management of huge amounts of spatially related data. In contrast to the data integration approach, SDIs foster the re-use of already existing data inventories for future uses that are not known yet. The approach aims at just-in-time integration of data in a distributed computing environment. The main building block of any SDI is the web service technology, an industrial standard in the field of Information Technology (IT).
Most tasks related to engineering geology are dependent on a broad variety of data, not necessarily assembled in one place In this paper problems resulting from this fact will be discussed and shown where engineering geologist may profit from the application of SDI. Typical approaches for the usage will be shown and an established case study (groundwater vulnerability assessment) is discussed to demonstrate the capabilities the potential of this technique in Engineering Geology.