Exploitation Of Groundwater Resources Research Articles

Groundwater and Subsidence Modeling Combining Geological and Multi-Satellite SAR Data over the Alto Guadalentín Aquifer (SE Spain)

In the current context of climate change, improving groundwater monitoring and management is an important issue for human communities in arid environments. The exploitation of groundwater resources can trigger land subsidence producing damage in urban structures and infrastructures. Alto Guadalentín aquifer system in SE Spain has been exploited since 1960 producing an average piezometric level drop of 150 m. This work presents a groundwater model that reproduces groundwater evolution during 52 years with an average error below 10%. The geometry of the model was improved introducing a layer of less permeable and deformable soft soils derived from InSAR deformation and borehole data. The resulting aquifer system history of the piezometric level has been compared with ENVISAT deformation data to calculate a first-order relationship between groundwater changes, soft soil thickness, and surface deformation. This relationship has been validated with the displacement data from ERS and Cosmo-SkyMed satellites. The resulting regression function is then used as an empirical subsidence model to estimate a first approximation of the deformation of the aquifer system since the beginning of the groundwater extraction, reaching 1 to 5.5 m in 52 years. These rough estimations highlight the limitations of the proposed empirical model, requiring the implementation of a coupled hydrogeomechanical model.

Assessing the geo-electric characteristics of Basement Complex rocks and its implication for groundwater prospecting in Ilorin Metropolis, Nigeria

Abstract. In Basement Complex rocks where rainfall is seasonal, water provision in dry season depends on regolith aquifer. For effective exploitation of groundwater resources, it is reasonable that geophysical investigation be conducted before development of well. In many instances, geophysical surveys may be expensive or nonexistent. Hence, there is a need for spatial analysis which might advise water engineers within such environments. Vertical Electrical Soundings (VES) data of 53 locations conducted with ABEM SAS-1000 terrameter using Schlumberger electrode configuration were obtained from the hydrogeology Department of Kwara state Ministry of Water Resources and Lower Niger River Basin and Rural Development Authority, Ilorin. VES locational coordinates were recorded using handheld GPS device. Sound curves were evaluated by partial curve matching approach and computer iteration using WinResist. The results depict six geo-electric regional successions, namely: top soil, lateritic clay, weathered basement, fairly-hard basement, thin fractured and hard basement. The geo-electric succession identified was plotted in Surfer 12 environment, using kriging interpolation method to show spatial distribution pattern of this zone. The spatial pattern is expected to give an insight to the nature of spatial variability of geo-electric layers and assist drillers as well as water resources policy makers in their operations. Keywords. Geo-electric, groundwater, basement complex, geophysical, GIS

Pollution and Other Dimensions of Non-Renewable Groundwater in Haryana (India)

<div><p><em>The vital role groundwater plays as a decentralized source of drinking water for millions rural and urban families cannot be overstated. In India, where groundwater is used intensively for irrigation and industrial purposes, a variety of land and water-based human activities are causing pollution of this precious resource. There are no estimates of the public health consequences of groundwater pollution as it involves methodological complexities and logistical problems. The groundwater behavior in the Indian sub-continent is highly complicated due to the occurrence of diversified geological formations with considerable litho-logical and chronological variations, complex tectonic framework, climato-logical dissimilarities and various hydro-chemical conditions. Once contamination starts, very little can be done to check it except a total ban on pumping. But this is very difficult, as millions of rural families in India depend on groundwater for sustaining irrigated agriculture and livelihoods. Manufacturing and service industries have high demands for cooling water, processing water and water for cleaning purposes. Groundwater pollution occurs when used water is returned to the hydrological cycle. Haryana is fast emerging as one of the most favoured investment destinations in India. The State has taken lead in terms of planned industrial and urban growth compared to neighboring States, which has resulted in development of vibrant urban and industrial complexes. They dump the wastes in the rivers which results in water pollution. Management of groundwater resources in the Indian context is an extremely complex proposition as it deals with the interactions between the human society and the physical environment. Unplanned depletion of non-renewable groundwater reserves can undermine and potentially erode the economic and social vitality of any community. Hence, there is need to plan the exploitation of non-renewable groundwater resources and guide their utilization with a view to making communities better prepared socio-economically to cope with increasing water stress as aquifer storage is depleted.</em></p></div>

Mapping interactions between geology, subsurface resource exploitation and urban development in transforming cities using InSAR Persistent Scatterers: Two decades of change in Florence, Italy

Urban expansion and city transformation are increasing reality across the world. Now more than ever it is essential to understand and map at the appropriate scale the processes happening along the verticality and horizontality of cities, to gather robust evidence underpinning strategies for sustainable management of the built environment. This paper explores how established techniques of Persistent Scatterer Interferometry (PSI) can be shaped into a novel dedicated procedure to detect vertical and horizontal urban dynamics including: use and re-use of urban space (new building construction, intentional demolition, renovation projects); exploitation of groundwater resources (induced land subsidence); interactions between new foundations, superficial deposits and bedrock geology (settlement of recent buildings); ground and slope instability affecting settled buildings; susceptibility of heritage assets to structural damages; baseline characterisation prior to planned major infrastructure construction (tunnelling and transportation networks). Florence, central Italy, is used as a demonstration site. This city includes UNESCO World Heritage List historic centre, 20th-century residential, industrial and peri-urban quarters, and is currently in transition to metropolitan area of over 1 million of inhabitants. Velocity decomposition maps were generated based on millimetre-precise estimates of surface displacements retrieved from PSI processing of the full archives of satellite C-band radar images, including 79 ERS-1/2 descending (1992–2000), 70 ENVISAT ASAR ascending and descending (2003–2010) and 101 RADARSAT-1 ascending and descending (2003–2007). 12 macropatterns and 84 micropatterns in the final map of alert areas highlight a dualism which reflects the physical and urban geography of Florence. North-western and south-western quarters show hot spots of new building construction and regeneration projects for residential, business and tertiary service purposes, alongside issues due to groundwater exploitation and induced land subsidence up to 30–40 mm/yr. Local interactions with underlying geology and natural slope instability processes predominate in the southern and north-eastern sectors. At local scale, stable condition was found for the heritage assets and buildings located along the tracks of the planned subway railway and tramway, with motion rates averagely within ±1.5 mm/yr and localised deformation only up to −3.5 mm/yr. Structural assessment based on future PSI monitoring campaign will benefit of this baseline characterisation.

Hydrostructural setting of Riardo Plain: effects on Ferrarelle mineral water type

The exploitation of groundwater resources must always keep in account the geology and hydrogeological settings of the catchment basin for the sustainability of withdrawals, in order not to overexploit the aquifer. Especially, in the case of mineral water extraction, even more attention should be paid to understand what are the water-rock-gases interaction mechanisms, which allow obtaining a specific water chemistry. The case of Ferrarelle mineral water (western sector of Riardo Plain, Caserta) is particularly complex. Through the acquisition of a great amount of former geological and hydrogeological data and by new hydrogeological surveys, it has been possible to distinguish the aquifer levels, distinguishing four circulations over the Roccamonfina Volcano and in the Riardo Plain. The presence of volcanic and volcaniclastic deposits deriving from the Roccamonfina Volcano which cover a highlytectonized carbonate bedrock, allows the formation of two aquifers in hydraulic continuity. This mixing between the two aquifers allows, with the ascent of deep CO2 through faults in the carbonate bedrock, the formation of the typical chemical composition of the mineral water Ferrarelle. In the eastern sector of the plain, it is possible to distinguish the volcanic aquifer from the carbonate one, probably due to the presence of low permeability deposits.

AVALIAÇÃO DOS RECURSOS NATURAIS NA ILHA DA INHACA (OCEANO ÍNDICO, MOÇAMBIQUE): PRIMEIRA APROXIMAÇÃO

Este artigo avalia o estado de degradação ou conservação da terra na Ilha da Inhaca, a partir de uma proposta teórica de degradação da terra e com apoio em geotecnologias. A degradação da terra é concebida como processo de mudanças ordenadas na estrutura e funções da paisagem. Uma parcela de terra é entãosusceptível à desertificação quando aspectos do suporte geoambiental, particularmente as condições hidrogeológicas são afetadas por fenômenos de degradação (como por exemplo, a diminuição do nível dos lençóis freáticos, seja por conta de variação climática, seja por exploração excessiva dos recursos hídricossubterrâneos). A Ilha da Inhaca não é susceptível à desertificação, porém, a degradação da vegetação e do solo é localmente preocupante.Palavras-chave: Ilha da Inhaca, degradação da terra, susceptibilidade à desertificação.

Avaliação da Vulnerabilidade Intrínseca à Contaminação do Aquífero na Bacia do Rio Passo Fundo no Estado do Rio Grande do Sul

The progressive pollution of surface water reserves increasingly generates the exploitation of groundwater resources. Based on this, grows the importance of studies that aim to contribute to the qualitative and/or quantitative analysis of these important sources. The present study aims to determine the natural vulnerability of the aquifer to contamination in the watershed of the Passo Fundo river basin, by applying the GOD system. It has been used information from 439 wells registered on the Groundwater Information System. The river basin under study presents a negligible vulnerability in 73,1% of its total area, low in 25,6 %, an average of 1,3 % and high in only 0,01 %. Thus, it can be concluded that the aquifer has a significant natural protection through the basaltic rocks of the Serra Geral Formation, featuring, for the most part, a confining condition to the aquifer.

Multivariate statistical analysis of the groundwater of Ain Djacer area (Eastern of Algeria)

The intensive exploitation of groundwater resources in the region of Ain Djacer has greatly influenced the hydrochemical functioning of the superficial aquifer. This has resulted in a general decline of the piezometric level of the groundwater, a mineralization of water and calcium facies near limestone and sodium chloride in the center of the plain in liaison with the lithology. To highlight the hydrochemical processes of groundwater, a study by major ions were analyzed in 21 groundwater samples collected from this aquifer during the month of March 2004. Multivariate statistical techniques and cluster and principal component analysis were applied to the data on groundwater quality, with the objective of defining the main controls on the hydrochemistry at the plain. These statistical techniques have shown the presence of three salinity groups with increasing importance according to the direction of flow. The initial facies on the limits as well as infiltration areas is bicarbonate. In the center of the plain, water becomes charged with sodium (Na) and chlorine (Cl) in connection with the dissolution of salt formations. The presence of nitrates is related to agricultural activity.

The formation of shallow fresh groundwater in the north of Yanchi county, Ningxia, China: main influencing factors and mechanism

Shallow fresh groundwater is not common in the middle of basins in arid and semiarid areas with strong evaporation where shallow groundwater is often brackish water or saline water. In this study, the shallow fresh groundwater in the north area of Yanchi county, China was investigated for the main influencing factors and mechanisms of its formation. The results showed that freshwater of HCO3 and SO4 types with mean salinity of 0.78 g/L formed in the north of the study area while brackish and saline water of SO4·Cl–Na type with mean salinity of 2.28 g/L formed in the west and south of the study area. The fresh groundwater formed owing to the special physico-chemical properties of the aeolian sand which has the good permeation of atmospheric precipitation, the weak evaporation of the groundwater, the low salt contents in the vadose zone and aquifer medium, the weak water–rock interaction and the good hydrodynamic condition. The lateral recharge of low salinity groundwater also played a mixing and diluting role in the formation of the fresh groundwater. The findings should provide a scientific basis for the exploitation and utilization of local groundwater resources and be of significance in the exploration and exploitation of fresh groundwater in arid and semiarid regions.

Strategic assessment of groundwater resource exploitation using DPSIR framework in Guwahati city, India

Millions of people on the urban settlements in Asia rely on groundwater for fulfilling daily water needs. And while groundwater storage is vast, its replenishment is limited, and many aquifers are exhibiting signs of inadequately controlled pumping. However, efforts to understand the impacts of a society on the availability, equity, and sustainability of groundwater and its repercussions has received little attention till date. Therefore, using Guwahati city, India, as a case, the aim of this paper is to understand the socio-political factors and their intra and inter-relationships with groundwater which in turn influences the urban households' accessibility to water. Overall methodology used the DPSIR framework for which inputs were generated from questionnaire survey of 150 households and other official, literature records. It is revealed that high population density of 4445 persons/km2, rapid urbanization with haphazard construction, pertaining groundwater rights with land rights, and coverage of only 27% of the population by water supply services have acted as thrusts to exceed groundwater extraction over safe yield. This situation however has a feedback in the form of increasing number of households with reduced accessibility to water as many have stated about declined water levels, increasing issue of water affordability and subsequent emergence of water poor. The paper recommends use of water use fee rate and indirect groundwater pricing through energy tariffs for enhanced conservation of groundwater as opposed to present day method of its regulation.

Evaluation of the Effects of Climate Change on Groundwater Recharge Using a Hybrid Method

In this study, a new framework was developed for the estimation of groundwater recharge based on a hybrid method. In this regard, the homogeneous recharge zones were determined by the analytical hierarchy process (AHP). The recharge rates in these zones were calculated using the Thornthwaite and Mather’s method. These zones and their recharge rates were entered into the MODFLOW model. Next, the modeling processes, modification of recharge, and calibration of empirical models were interactively continued in the MODFLOW. This way, one of the most important disadvantages of conventional empirical models, i.e., ignoring the physical properties of the aquifer, was resolved by considering the main parameters such as soil properties, unsaturated thickness, land cover, irrigation, and precipitation in the resulting nonlinear equations. The low root mean square error values (less than 5.2) for all equations and high values of the coefficient of determinations indicated the accuracy and reliability of the models. The results of this hybrid method were a series of independent, cost-effective, rapid, and simple to use empirical equations for recharge estimation. As an example for the application of this method, the effects of climate change on groundwater recharge were evaluated in the study area. The obtained results showed that climate change would reduce the recharge rates of the homogeneous zones differently. Moreover, the recharge rate had a general decreasing trend in all regions. Overall, the total annual recharge rate would decrease in the plain. This reduction, especially in the west of the plain which is one of the most important sources of recharge supply, is considerable and will turn the entire plain vulnerable. In general, little reduction in rainfall or increase in temperature would have significant effects on groundwater recharge in the region. Therefore, due to the high dependence of this plain on groundwater resources, special planning is required for the exploitation of groundwater resources in the region.

Estimation of Hydrodynamic Parameters of Groundwater Resources in Kouhpayeh- Segzi Watershed Using MODFLOW

Nowadays, due to the high potential of advanced simulation models for groundwater, these models are comprehensively applied in the management and exploitation of groundwater resources. The aim of this study was to investigate and simulate the groundwater resources in Kouhpayeh-Segzi watershed and in particular estimate the hydrodynamic coefficients of unconfined aquifer. After preparation of input layers, efficient parameters in modeling, boundary conditions and aquifer gridding were determined. Then, based on the available data, the model was run and calibrated in a steady state for the water year 2002 and in a transient state for water years between 2002 and 2004. The simulation outputs were confidently verified for the water year 2005. The results indicated that the hydraulic conductivities and storage coefficients were ranged on sub-basin from 15.26 to 19.87 m/day and 0.0107 to 0.0186, respectively. From aquifer's hydrograph for a period from 1995 to 2012, water level dropped about 25 cm. This may be due to two irrigation networks (green area). This leads to rising water level. By ignoring these recharge areas, water level declined up to 80 cm per year. With sensitivity analysis in transient state to evaluate the efficacy of each parameter, the accuracy of the results of calibration model was confirmed. In addition, the hydraulic head values computed by MODFLOW were in good agreement with those that were collected from all piezometers.

A GIS/Remote Sensing-based methodology for groundwater potentiality assessment in Tirnavos area, Greece

The aim of this paper is to assess the groundwater potentiality combining Geographic Information Systems and Remote Sensing with data obtained from the field, as an additional tool to the hydrogeological research. The present study was elaborated in the broader area of Tirnavos, covering 419.4 km2. The study area is located in Thessaly (central Greece) and is crossed by two rivers, Pinios and Titarisios. Agriculture is one of the main elements of Thessaly’s economy resulting in intense agricultural activity and consequently increased exploitation of groundwater resources. Geographic Information Systems (GIS) and Remote Sensing (RS) were used in order to create a map that depicts the likelihood of existence of groundwater, consisting of five classes, showing the groundwater potentiality and ranging from very high to very low. The extraction of this map is based on the study of input data such as: rainfall, potential recharge, lithology, lineament density, slope, drainage density and depth to groundwater. Weights were assigned to all these factors according to their relevance to groundwater potential and eventually a map based on weighted spatial modeling system was created. Furthermore, a groundwater quality suitability map was illustrated by overlaying the groundwater potentiality map with the map showing the potential zones for drinking groundwater in the study area. The results provide significant information and the maps could be used from local authorities for groundwater exploitation and management.

Effects of seasonal change and seawater intrusion on water quality for drinking and irrigation purposes, in coastal aquifers of Dar es Salaam, Tanzania

Groundwater is the major source to meet domestic, industrial and agricultural needs in the city of Dar es Salaam, Tanzania. However, population growth, increasing urbanization, industrialization and tourism, and climatic changes have caused an intensive exploitation of groundwater resources leading the aquifers become more vulnerable to seawater intrusion. The aim of this study is to examine the variations of groundwater chemistry (as resulting from natural and anthropogenic inputs) depending on seasonal changes, in order to evaluate water quality for drinking and irrigation purposes. Physical and chemical data come from the analysis of groundwater samples, collected from 72 wells, used for the evaluation of water quality parameters, during a year of monitoring. Pattern diagrams, geochemical modeling techniques and Principal Component Analysis (PCA) have been used to identify the main factors influencing groundwater composition. Based on the hydrochemistry, the groundwater was classified into three types: (a) Na–Cl, (b) Ca–Cl, (c) mixed Ca–Na–HCO3–Cl (d) mixed Ca–Mg–Cl–SO4. The geochemical modeling results show that groundwater chemistry is mainly influenced by evaporation process, as it is suggested by the increase of Na and Cl ions concentrations. According to irrigation water quality assessment diagrams of USDA, most water samples from dry and rainy seasons, distributed in category C2–S1, C3–S1, C3–S2, C4–S2 highlighting medium to very high salinity hazard and low to medium sodium content class. PCA evidenced the role of seawater intrusion, evaporation process and anthropogenic pollution (i.e. high NO3 levels due to agricultural activities), as the major factors that influenced the water chemistry, and hence the water quality. Based on Pearson correlation matrix, the presence of high correlations (>0.8) among Na, Cl, Mg and SO4, in association with EC, were interpreted as the seawater intrusion effects. In this area groundwater quality is generally low, and often exceeds permissible limits of standard guideline values of WHO and FAO, referred to EC and chloride values. The high salinity and the groundwater level depletion create serious problems for current use of water supplies as well as future exploitation.

The Chemical Dynamic Characteristic Research of Inland Shallow Salt Water

Shallow inland water resources has a large potential for development. To Jiyang shallow groundwater for example, through the regular ion-test analysis, Piper diagram and hydrogeochemical characteristics, the results show that: (1) The type of chemistry of shallow groundwater inland were Cl·SO4-Mg·Na·Ca; (2) The salt water area is relatively fixed, there is no expansion or decreasing trend; (3) The level flow of shallow groundwater is slow and water rock interaction is strong, that is not conducive to the shallow groundwater quality improvement, changing the runoff conditions of shallow groundwater is essential way for shallow groundwater resources exploitation.

INTEGRATION OF GIS TECHNOLOGY FOR FUZZY-DETERMINISTIC MODELING CONDITIONS OF FORMATION AND OPERATION KEGEYLI GROUNDWATER IS ABSTRACTED

Offers scientific and methodological basics for application of fuzzy-deterministic simulation geofiltration processes in single layers on the basis of the application of GIS technology in terms of dominance fuzzy initial information. GIS model of Kegeyli withdrawal of groundwater (KWGV) is carried out on the basis of software including ArcGIS (ArcCatalog, ArcMap). The problems of a situational analysis of the results clearly-deterministic simulation. The proposed information model and information model KWGV filtration process to ensure that the relationship between the object model and the geofiltration, represented as a system of fuzzy-deterministic two-dimensional (quasi three-dimensional) nonlinear differential equations filtering and organizing computational experiments (CE). In this context, discusses aspects of geoinformation approach in the process of fuzzy-deterministic simulation of operating conditions Kegeyli abstraction of groundwater. It is proposed software system that focuses on the study of hydro geological objects, both local and regional scale using data from heterogeneous. Formalization of fuzzy algorithms parameters of underground hydrosphere, the relationship abstraction of groundwater and its model. The algorithms select the solution in the formation and exploitation of groundwater resources, the principles of the information model of the region of the filtering process. The results of solving the problem of formalization of parameters and forecast the state of groundwater Kegeyli withdrawals of groundwater.

Analysis of Groundwater Quality of Aligarh City, (India): Using Water Quality Index

Water is essential for all living organisms for their existence and metabolic process. Unethical human intervention in natural system and over exploitation of groundwater resources induces degradation of its quality. In many instances groundwater is used directly for drinking as well as for other purposes, hence the evaluation of groundwater quality is extremely important. The present study is aimed to analyze the underground water quality at Aligarh. In this study 80 water samples were collected from 40 places and analyzed for 14 water quality parameters for pre-monsoon and post-monsoon seasons (2012). The water quality index of these samples ranges from 18.92 to 74.67 pre-monsoon and 16.82 to 70.34 during post-monsoon. The study reveals that 50 % of the area under study falls in moderately polluted category. The ground water of Aligarh city needs some treatment before consumption and it also needs to be protected from contamination.

Aplicación de SIG para la caracterización hidrogeológica de sistemas dunares (Erg Chebbi, Marruecos)

Hydrogeological studies in remote areas are difficult to tackle and often logistically complicated. However, in some of these areas the exploitation of groundwater resources is essential for the survival of the communities that inhabit them. The dunes of Erg Chebbi configure a free aquifer about 100 km 2 in area. With an average annual rainfall of less than 150 mm, Erg Chebbi represents an extremely delicate hydrological system that requires a very well designed exploitation to enable a sustainable development. This paper addresses the hydrogeological characterization of an erg system by means of Geographic Information Systems (GIS) (ArcGis 9.3 y Global Mapper v.12), Digital Elevation Model (DEM) and geological information analysis. Results allowed the characterization the dune system and the setting of a hydrogeological model, consistent with field data. The results are relevant to the management of the groundwater exploitation in the studied system, and highlight the utility of this methodology to the characterization of other areas with similar characteristics.

Estudios hidrogeológicos en zonas remotas son SIG: Erg Chebbi (Marruecos)

Hydrogeological studies in desert and remote areas are difficult to tackle and often logistically complicated. However, in some of these areas the exploitation of groundwater resources is essential for the survival of the communities that inhabit them. The dunes of Erg Chebbi (Morocco), is a water-table aquifer which supplies drinking and irrigation water for local communities. With an average annual rainfall of less than 150 mm, erg Chebbi represents an extremely delicate hydrological system that requires a very well designed exploitation to enable a sustainable development. This paper addresses the hydrogeological characterization of an erg by applying geography information systems and field visits. The methodology used allowed the characterization the dune system and setting of a hydrogeological model. The results are relevant to the management of groundwater exploitation of the system studied, and for the application of the methodology to other areas with similar characteristics.

Projected groundwater balance as a state indicator for addressing sustainability and management challenges of overexploited crystalline aquifers

In India, particularly in semi-arid regions, groundwater levels are declining at alarming rates due to overexploitation and the sustainable exploitation of groundwater resources is in deep crisis. There is little or no information on groundwater sustainability indicators, which can signal towards the challenges in water management. In this study we downscaled an entire watershed into three zones based on the different hydrodynamic behaviour recorded at the borewell scale. A process-based simple, multi-parameter linear auto-regressive model was developed to predict groundwater levels, which uses recharge, groundwater withdrawal and irrigation return flow as input variables. A comprehensive and predictive long-term groundwater balance is used as a state indicator to evaluate the sustainability and management challenges in the watershed. Two groundwater withdrawal scenarios were designed to assess the impact of groundwater withdrawal on the groundwater balance. We found that geological heterogeneities play a crucial role in controlling groundwater fluctuations. The storage change in two different groundwater withdrawal scenarios shows gradually declining groundwater storage in both scenarios. A long-term assessment of the groundwater balance helps to analyse the state of the groundwater system and to locate priority zones for watershed interventions.