Search results for: groundwater level

Authors: Aziza Barrek, Mohamed Haythem Msaddek, Ismail Chenini

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Excessive groundwater pumping due to the increasing water demand, especially in the agricultural sector, causes groundwater scarcity. Groundwater recharge is the most important process that contributes to the water's durability. This paper is based on the Analytic Hierarchy Process multicriteria analysis to establish a groundwater recharge susceptibility map. To delineate aquifer suitability for groundwater recharge, eight parameters were used: soil type, land cover, drainage density, lithology, NDVI, slope, transmissivity, and rainfall. The impact of each factor was weighted. This method was applied to the El Fahs plain shallow aquifer. Results suggest that 37% of the aquifer area has very good and good recharge suitability. The results have been validated by the Receiver Operating Characteristics curve. The accuracy of the prediction obtained was 89.3%.

Keywords: AHP, El Fahs aquifer, empirical formula, groundwater recharge zone, remote sensing, semi-arid region

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Authors: Moses Oghnennyoreme Eyankware, Christian Ogubuchi Ede

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Groundwater is the principal source for various uses in this study area. The quality and availability of groundwater depend on rock formation within the study area. To effectively study the quality of groundwater, 24 groundwater samples were collected. The study was aimed at investigating the hydrogeochemistry of groundwater, and additionally its suitability for drinking and irrigation purposes. The following parameters were analyzed using the American Public Health Association standard method: pH, turbidity, Ec, TDS, Mg2+, SO42-, NO3¯, Cl-, HCO3¯, K+, Na2+ and Ca2+. Results obtained from Water Quality Index revealed that the groundwater sample fell within good water quality that implies that groundwater is considered fit for drinking purposes. Deduced results obtained from irrigation indices revealed that Permeability Index (PI), Soluble Sodium Percentage (SSP), Sodium Percentage (Na %), Sodium Absorption Ratio (SAR), Kelly Ratio (KR), Magnesium Hazard (MH) ranges from 0.00 to 0.01, 4.04 to 412.9, 0.63 to 257.7, 0.15 to 2.34, 0.09 to 2.57 and 6.84 to 84.55 respectively. Findings from Total hardness revealed that groundwater fell within soft, moderately hard and hard categories. Estimated results obtained from CSMR, RI and LSI showed that groundwater showed corrosion tendency, salinization influenced groundwater at certain sampling points and chloride and sulfate unlikely to interfere with natural formation film.

Keywords: water, quality, suitability, anthropogenic, Nigeria

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Authors: Lanja F. Rauf, Salahalddin S. Ali, Nadhir Al-Ansari

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Evolving groundwater vulnerability from DRASTIC to modified DRASTIC methods helps choose the most accurate areas that are most delicate toward pollution. This study aims to modify DRASTIC with land use and water quality index for groundwater vulnerability assessment in the Halabja-Khurmal sub-basin, NE/Iraq. The Halabja- Khurmal sub-basin groundwater vulnerability index is calculated from nine hydrogeological parameters by the overlay weighting method. As a result, 1.3 % of the total area has a very high vulnerability value and 46.1 % with high vulnerability. The regions with high groundwater vulnerability have a high water table and groundwater recharge. Nitrate concentration was used to validate the result, and the Pearson correlation and recession analysis between the modified DRASTIC index and nitrate concentration depicted a strong relation with 0.76 and 0.7, respectively.

Keywords: groundwater vulnerability, modified DRASTIC, land-use, nitrate pollution, water quality index

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Authors: S. K. Maanju, K. Saha, Sonam Yadav

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Rapid urbanization growth and multi-faceted regional level industrialization is posing serious threat to natural groundwater resource in State of Rajasthan which constitute major semi-arid part of India. The groundwater resources of the State are limited and cannot withstand the present rate of exploitation for quite a long time. Recharging of groundwater particularly in the western part, where annual precipitation does not exceed a few centimeters, is extremely slow and cannot replenish the exploited quantum. Hence, groundwater in most of the parts of this region has become an exhausting resource. In major parts water table is lowering down rapidly and continuously. The human beings of this semi-arid region are used to suffering from extreme climatic conditions of arid to semi-arid nature and acute shortage of water. The quality of groundwater too in many areas of this region is not up to the standards prescribed by the health organizations like WHO and BIS. This semi-arid region is one of the highly fluoride contaminated area of India as well as have excess, nitrates, sulphates, chlorides and total dissolved solids at various locations. Therefore, concerted efforts are needed towards sustainable development of groundwater in this State of India.

Keywords: Rajasthan, water, exploitation, sustainable, development and resource

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Authors: Akhtar Malik Muhammad, Agha Mirwais

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Dams are considered to recharge aquifers by raising the water table, especially the ones near wells. The present study investigates the impact of dams on groundwater recharge in Jilga, Pakistan. The comparative analysis of changes in the groundwater table of the year 2012 and 2019 was carried out using ArcGIS 10.5 through the kriging method and remote sensing techniques to evaluate the mini dam's impact on the upstream area. Arc Info Spatial Analyze extension was used to find static water level maps of the years. The water table was observed minimum 67.08 feet and maximum 130.09 feet in 2012 whereas in 2019 the minimum water table level 49.89 feet and maximum 115.85 feet. Groundwater recharge with different ratio was noted, but the most significant was at Rabbani dam with 26ft due to supported lithology conditions and the lowest recharge was found at Garang dam14ft. The overall positive trend indicates the rehabilitation of dead karez and agriculture activities by increasing 36% the vegetation area in 2019. An over 6% increase in human settlement indicates socioeconomic development. Thus, it highlights the need for preferential focus on the construction of the dam so that the water level could be sustained to cater to the agricultural and domestic needs of the local population around the year

Keywords: water table, GIS, land cover, mini dams, agriculture

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Authors: Syed Adnan, Javed Iqbal

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In urban and rural areas groundwater is the most economic natural source of drinking. Groundwater resources of Pakistan are degraded due to high population growth and increased industrial development. A study was conducted in district Peshawar to assess groundwater vulnerable zones using GIS based DRASTIC model. Six input parameters (groundwater depth, groundwater recharge, aquifer material, soil type, slope and hydraulic conductivity) were used in the DRASTIC model to generate the groundwater vulnerable zones. Each parameter was divided into different ranges or media types and a subjective rating from 1-10 was assigned to each factor where 1 represented very low impact on pollution potential and 10 represented very high impact. Weight multiplier from 1-5 was used to balance and enhance the importance of each factor. The DRASTIC model scores obtained varied from 47 to 147. Using quantile classification scheme these values were reclassified into three zones i.e. low, moderate and high vulnerable zones. The areas of these zones were calculated. The final result indicated that about 400 km2, 506 km2, and 375 km2 were classified as low, moderate, and high vulnerable areas, respectively. It is recommended that the most vulnerable zones should be treated on first priority to facilitate the inhabitants for drinking purposes.

Keywords: DRASTIC model, groundwater vulnerability, GIS in groundwater, drinking sources

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Authors: Serin Darwish, Hakim Saibi, Amir Gabr

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The United Arab Emirates (UAE) is situated within an arid zone where the climate is arid and the recharge of the groundwater is very low. Groundwater is the primary source of water in the United Arab Emirates. However, rapid expansion, population growth, agriculture, and industrial activities have negatively affected these limited water resources. The shortage of water resources has become a serious concern due to the over-pumping of groundwater to meet demand. In addition to the deficit of groundwater, the UAE has one of the highest per capita water consumption rates in the world. In this study, a combination of time-lapse measurements of microgravity and depth to groundwater level in selected wells in Al Ain city was used to estimate the variations in groundwater storage. Al-Ain is the second largest city in Abu Dhabi Emirates and the third largest city in the UAE. The groundwater in this region has been overexploited. Relative gravity measurements were acquired using the Scintrex CG-6 Autograv. This latest generation gravimeter from Scintrex Ltd provides fast, precise gravity measurements and automated corrections for temperature, tide, instrument tilt and rejection of data noise. The CG-6 gravimeter has a resolution of 0.1μGal. The purpose of this study is to measure the groundwater storage changes in the shallow aquifers based on the application of microgravity method. The gravity method is a nondestructive technique that allows collection of data at almost any location over the aquifer. Preliminary results indicate a possible relationship between microgravity and water levels, but more work needs to be done to confirm this. The results will help to develop the relationship between monthly microgravity changes with hydrological and hydrogeological changes of shallow phreatic. The study will be useful in water management considerations and additional future investigations.

Keywords: Al-Ain, arid region, groundwater, microgravity

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Authors: G. Gnanachandrasamy, Y. Zhou, S. Venkatramanan, T. Ramkumar, S. Wang

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The natural resources of groundwater are the most precious resources around the world that balances are shrinking day by day. In connection, there is an urgency need for demarcation of potential groundwater zone. For these rationale integration of geographical information system (GIS) and remote sensing techniques (RS) for the hydrological studies have become a dramatic change in the field of hydrological research. These techniques are provided to locate the potential zone of groundwater. This research has been made to indent groundwater potential zone in Ariyalur of the southern part of India with help of GIS and remote sensing techniques. To identify the groundwater potential zone used by different thematic layers of geology, geomorphology, drainage, drainage density, lineaments, lineaments density, soil and slope with inverse distance weighting (IDW) methods. From the overall result reveals that the potential zone of groundwater in the study area classified into five classes named as very good (12.18 %), good (22.74 %), moderate (32.28 %), poor (27.7 %) and very poor (5.08 %). This technique suggested that very good potential zone of groundwater occurred in patches of northern and central parts of Jayamkondam, Andimadam and Palur regions in Ariyalur district. The result exhibited that inverse distance weighting method offered in this research is an effective tool for interpreting groundwater potential zones for suitable development and management of groundwater resources in different hydrogeological environments.

Keywords: GIS, groundwater potential zone, hydrology, remote sensing

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Authors: H. J. Kim, K. H. Kim, N. H. Park, K. T. Nam, Y. H. Jung, T. H. Kim, J. H. Shin

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Underground excavations in an urban area can cause various geotechnical problems such as ground loss and lowering of groundwater level. When the ground loss becomes uncontrollably large, sinkholes can be developed to the ground surface. A sinkhole is commonly known as the natural phenomenon associated with lime rock areas. However, sinkholes in urban areas due to pressurized sewers and/or tunneling are also frequently reported. In this study, mechanism of a sinkhole developed at the site ‘A’ where a tunneling work underwent is investigated. The sinkhole occurred in the sand strata with the high level of groundwater when excavating a tunnel of which diameter is 3.6 m. The sinkhole was progressed in two steps. The first step began with the local failure around the tunnel face followed by tons of groundwater inflow, and the second step was triggered by the TBM (Tunnel Boring Machine) chamber opening which led to the progressive general failure. The possibility of the sinkhole was evaluated by using Limit Equilibrium Method (LEM), and critical height was evaluated by the empirical stability chart. It is found that the lowering of the face pressure and inflow of groundwater into the tunnel face turned to be the main reason for the sinkhole.

Keywords: limit equilibrium method, sinkhole, stability chart, tunneling

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Authors: S. M. Moustafa, A. Ezzat, Y. S. Taha, G. H. Hassib, S. Hamada

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After the occurrence of 14, Nov, 1981 earthquake (M = 5.3), on Kalabska fault, south of Egypt, seismic stations distributed in and around the Kalabsha area, in order to monitoring, recording and studying the seismic activity in the area. In addition of that, from 1989 a number of piezometer wells drilled in the same area, distribed on at the both side of the active faults area and in different water bearing formations, in order to measuring the groundwater parameters (level, temperature, ph, and conductivity) to monitoring the relationship between those parameters and the seismic activity at Kalabsha area. The behavior of groundwater due to seismic activity over the world studied by several scientists i.e. H. Wakita (1979) on Izu-Oshima earthquake (M= 7.0) at Japan, M. E. Contadakis & G.asteriadis (1972), and Evans (1966), they found an anomalies on groundwater measurements prior, co, and post the occurrence of bigger earthquakes, referring to the probability of precursory evidence of impending earthquakes. In Kalabsha area south of Egypt, this study has been done using recorded seismic data, and the measurements of underground water parameters. same phenomena of anomalies founded on groundwater measurements pre, co. and post the occurrence of earthquakes with magnitude bigger than 3, and no systematic regularity exists for epicenter distance, duration of anomalies or time lag between anomalies appear and occurrence of events. Also the results found present strong relation between the groundwater in the upper unconfined aquifer Nubian Sandstone formation, and Kalabsha seismic activity, otherwise no relation between the seismic activities in the area with the deep groundwater in the lower confined aquifer Sandstone.

Keywords: seismicity, groundwater, Aswan, Egypt

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Authors: Sakshi Dhumale, Madhushree C., Amba Shetty

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The effect of station density on the geostatistical prediction of groundwater levels is of critical importance to ensure accurate and reliable predictions. Monitoring station density directly impacts the accuracy and reliability of geostatistical predictions by influencing the model's ability to capture localized variations and small-scale features in groundwater levels. This is particularly crucial in regions with complex hydrogeological conditions and significant spatial heterogeneity. Insufficient station density can result in larger prediction uncertainties, as the model may struggle to adequately represent the spatial variability and correlation patterns of the data. On the other hand, an optimal distribution of monitoring stations enables effective coverage of the study area and captures the spatial variability of groundwater levels more comprehensively. In this study, we investigate the effect of station density on the predictive performance of groundwater levels using the geostatistical technique of Ordinary Kriging. The research utilizes groundwater level data collected from 121 observation wells within the semi-arid Berambadi watershed, gathered over a six-year period (2010-2015) from the Indian Institute of Science (IISc), Bengaluru. The dataset is partitioned into seven subsets representing varying sampling densities, ranging from 15% (12 wells) to 100% (121 wells) of the total well network. The results obtained from different monitoring networks are compared against the existing groundwater monitoring network established by the Central Ground Water Board (CGWB). The findings of this study demonstrate that higher station densities significantly enhance the accuracy of geostatistical predictions for groundwater levels. The increased number of monitoring stations enables improved interpolation accuracy and captures finer-scale variations in groundwater levels. These results shed light on the relationship between station density and the geostatistical prediction of groundwater levels, emphasizing the importance of appropriate station densities to ensure accurate and reliable predictions. The insights gained from this study have practical implications for designing and optimizing monitoring networks, facilitating effective groundwater level assessments, and enabling sustainable management of groundwater resources.

Keywords: station density, geostatistical prediction, groundwater levels, monitoring networks, interpolation accuracy, spatial variability

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Authors: Isiya Aminu Dabai, Adebola Kayode, Adeosun Kayode Daniel

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Rural water supply relies mainly on groundwater exploitation, because it is more accessible, reliable, cheaper to develop and maintain, also with good quality compared to the surface water. Despite these advantages, groundwater has come under pollution threats like waste dumps, mineral exploitation, industrialization etc. This study investigates the effects of an open dumping to the surrounding groundwater. Ten hand dug well water samples were collected from the surroundings and tested. The average result shows that temperature, colour and turbidity to be 8.50 c, 6.1 TCU and 3.1 NTU respectively and pH, conductivity, total dissolved solids, chloride content and hardness to be 7.2, 4.78, 1.8, 5.7, and 3.4 respectively while in the bacteriological test well no. 1, 2, 3, and 5 shows the presence of coliforms and E. Coli bacteria.

Keywords: groundwater, pollution, waste, dump site, unsafe, quality

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Authors: Siamak Feizi, Gunvor Baardvik

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Soil erosion has special consequences for landfills that are more serious than those found at conventional construction sites. Different potential heads between two sides of a landfill and the subsequent movement of water through pores within the soil body could trigger the soil erosion and construction instability. Such a condition was encountered in a landfill project in the southern part of Norway. To check the risk of internal erosion due to changes in the groundwater level (because of seasonal flooding in the river), a series of numerical simulations by means of Geo-Seep software was conducted. Output of this study provides a total picture of the landfill stability, possibilities of erosions, and necessary measures to prevent or reduce the risk for the landfill operator.

Keywords: erosion, seepage, landfill, stability

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Authors: Babatunde Adebo, Adedeji Adetoyinbo

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Groundwater is an important constituent of the hydrological cycle and plays a vital role in augmenting water supply to meet the ever-increasing needs of people for domestic, agricultural and industrial purposes. Unfortunately, this important resource has in most cases been contaminated due to the advancement of seawater into the fresh groundwater. This is due to the high volume of water being abstracted in these areas as a result of a high population of coastal dwellers. The knowledge of salinity level and intrusion of saltwater into the freshwater aquifer is, therefore, necessary for groundwater monitoring and prediction in the coastal areas. In this work, an advection-dispersion saltwater intrusion model is used to study and simulate saltwater intrusion in a typical coastal aquifer. The aquifer portion was divided into a grid with elements and nodes. Map of the study area indicating well locations were overlain on the grid system such that these locations coincide with the nodes. Chlorides at these well were considered as initial nodal salinities. Results showed a highest and lowest increase in simulated chloride of 37.89 mg/L and 0.8 mg/L respectively. It also revealed that the chloride concentration of most of the considered well might climb unacceptable level in the next few years, if the current abstraction rate continues unabated.

Keywords: saltwater intrusion, coastal aquifer, nodal salinity, chloride concentration

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Authors: Shobha Kumari Yadav, Yubaraj Satyal, Ajaya Dixit

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In addressing groundwater depletion, it is important to develop evidence base so to be used in assessing the state of its degradation. Groundwater data is limited compared to meteorological data, which impedes the groundwater use and management plan. Monitoring of groundwater levels provides information base to assess the condition of aquifers, their responses to water extraction, land-use change, and climatic variability. It is important to maintain a network of spatially distributed, long-term monitoring wells to support groundwater management plan. Monitoring involving local community is a cost effective approach that generates real time data to effectively manage groundwater use. This paper presents the relationship between rainfall and spring flow, which are the main source of freshwater for drinking, household consumptions and agriculture in hills of Nepal. The supply and withdrawal of water from springs depends upon local hydrology and the meteorological characteristics- such as rainfall, evapotranspiration and interflow. The study offers evidence of the use of scientific method and community based initiative for managing groundwater and springshed. The approach presents a method to replicate similar initiative in other parts of the country for maintaining integrity of springs.

Keywords: citizen science, groundwater, water resource management, Nepal

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Authors: Maged El Osta, Milad Masoud

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Al Jabal Al Akhdar in the north-eastern part of Libya represents a region with promising ecological underpinning for grazing and other agricultural developments. The groundwater potential of both Upper Cretaceous and Eocene aquifers was studied based the available literature and a complete database for about 112 water wells drilled in the period 2003-2009. In this research, the hydrogeological methods will be integrated with the Geographic Information System (GIS) that played a main role in highlighting the spatial characteristics of the groundwater system. The results indicate that the depth to water for the Upper Cretaceous aquifer ranges from 150 to 458 m, and the piezometric surface decreases from over 500 m (m.s.l) in the northern parts to -20 m (m.s.l) in southeastern part. Salinity ranges between 303 and 1329 mg/l indicating that groundwater belongs to the slightly fresh water class. In the Eocene aquifer, the depth to groundwater ranges from 120 to 290.5 m and the potentiometric level decreases gradually southwards from 220 to -51 m (m.s.l) and characterized by steep slope in the southeastern part of the study area, where the aquifer characterized by relatively high productivity (specific capacity ranges between 10.08 and 332.3 m2/day). The groundwater salinity within this aquifer ranges between 198 and 2800 mg/l (fresh to brackish water class). The annual average rainfall (from 280 to 500 mm) plays a significant role in the recharge of the two aquifers. The priority of groundwater quality and potentiality increases towards the central and northern portions of the concerned area.

Keywords: Eocene and Upper Cretaceous aquifers, rainfall, potentiality, Geographic Information System (GIS)

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Authors: Hritik Bhattarai, Vivek Dumre, Ananya Neupane, Poonam Koirala, Anjali Singh

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The availability of clean and reliable groundwater is essential for the sustainment of human and environmental health. Groundwater is a crucial resource that contributes significantly to the total annual supply. However, over-exploitation has depleted groundwater availability considerably and led to some land subsidence. Determining the potential zone of groundwater is vital for protecting water quality and managing groundwater systems. Groundwater potential zones are marked with the assistance of Geographic Information System techniques. During the study, a standard methodology was proposed to determine groundwater potential using an integration of GIS and AHP techniques. When choosing the prospective groundwater zone, accurate information was generated to get parameters such as geology, slope, soil, temperature, rainfall, drainage density, and lineament density. However, identifying and mapping potential groundwater zones remains challenging due to aquifer systems' complex and dynamic nature. Then, ArcGIS was incorporated with a weighted overlay, and appropriate ranks were assigned to each parameter group. Through data analysis, MCDA was applied to weigh and prioritize the different parameters based on their relative impact on groundwater potential. There were three probable groundwater zones: low potential, moderate potential, and high potential. Our analysis showed that the central and lower parts of the Bagmati River Basin have the highest potential, i.e., 7.20% of the total area. In contrast, the northern and eastern parts have lower potential. The identified potential zones can be used to guide future groundwater exploration and management strategies in the region.

Keywords: groundwater, geographic information system, analytic hierarchy processes, multi-criteria decision analysis, Bagmati

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Authors: Punitha Periyasamy, Mahalingam Sudalaimuthu, Sachikanta Nanda, Arasu Sundaram

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India holds 17.5% of the world’s population but has only 2% of the total geographical area of the world where 27.35% of the area is categorized as wasteland due to lack of or less groundwater. So there is a demand for excessive groundwater for agricultural and non agricultural activities to balance its growth rate. With this in mind, an attempt is made to find the groundwater potential zone in Gomukhi river sub basin of Vellar River basin, TamilNadu, India covering an area of 1146.6 Sq.Km consists of 9 blocks from Peddanaickanpalayam to Villupuram fall in the sub basin. The thematic maps such as Geology, Geomorphology, Lineament, Landuse, and Landcover and Drainage are prepared for the study area using IRS P6 data. The collateral data includes rainfall, water level, soil map are collected for analysis and inference. The digital elevation model (DEM) is generated using Shuttle Radar Topographic Mission (SRTM) and the slope of the study area is obtained. ArcGIS 10.1 acts as a powerful spatial analysis tool to find out the ground water potential zones in the study area by means of weighted overlay analysis. Each individual parameter of the thematic maps are ranked and weighted in accordance with their influence to increase the water level in the ground. The potential zones in the study area are classified viz., Very Good, Good, Moderate, Poor with its aerial extent of 15.67, 381.06, 575.38, 174.49 Sq.Km respectively.

Keywords: ArcGIS, DEM, groundwater, recharge, weighted overlay

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Authors: Abdalraheem Huwaysh, Khalil Al Samarrai, Yasmin ElAhmar

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Water quality is an important factor that determines its usage for domestic, agricultural and industrial uses. This study was carried out through the Tajoura Area, Jifarah Plain, Northwest Libya. Chemical and physical parameters were measured and analyzed for groundwater samples collected in 2021 from twenty-six wells distributed throughout the investigation area. Overexploitation of groundwater caused considerable deterioration in the water quality, especially at Tajoura Town (20 Km east of Tripoli). The aquifer shows an increase in salinization, which has reached an alarming level in many places during the past 25 years as a result of the seawater intrusion. The chemical composition of the water samples was compared with the drinking water standards of WHO and Libyan Standards. Groundwater from this area was not suitable to be a source for direct drinking based on Total Dissolved Solids. The dominant cation is sodium, while the dominant anion is chloride. Based on the Piper trilinear diagram, most of the groundwater samples (90%) were identified as sodium chloride type. The best groundwater quality exists at the southern part of the study area. Serious degradation in the water quality, expressed in salinity increase, occurs as we go towards the coastline. The abundance of NaCl waters is strong evidence to attribute the successive deterioration of the water quality to the seawater intrusion. Considering the values of Cl- concentration and the ratio of Cl-/HCO3-, about 70% of the groundwater samples were strongly affected by the saline water. Car wash stations in the study area as well as the unlined disposal pond used for the collection of untreated wastewater, contribute significantly to the deterioration of water quality. The water quality in this area needs to be monitored regularly and it is crucial to treat the water before consumption.

Keywords: Tajoura, groundwater, seawater intrusion, water quality

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Authors: Emna Bahri Hammami, Zammouri Mounira, Tarhouni Jamila

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The Nadhour Saouaf Sisseb El Alem (NSSA) system comprises some of the most intensively exploited aquifers in central Tunisia. Since the 1970s, the growth in economic productivity linked to intensive agriculture in this semiarid region has been sustained by increasing pumping rates of the system’s groundwater. Exploitation of these aquifers has increased rapidly, ultimately causing their depletion. With the aim to better understand the behavior of the aquifer system and to predict its evolution, the paper presents a finite difference model of the groundwater flow and solute transport. The model is based on the Groundwater Modeling System (GMS) and was calibrated using data from 1970 to 2010. Groundwater levels observed in 1970 were used for the steady-state calibration. Groundwater levels observed from 1971 to 2010 served to calibrate the transient state. The impact of pumping discharge on the evolution of groundwater levels was studied through three hypothetical pumping scenarios. The first two scenarios replicated the approximate drawdown in the aquifer heads (about 17 m in scenario 1 and 23 m in scenario 2 in the center of NSSA) following an increase in pumping rates by 30% and 50% from their current values, respectively. In addition, pumping was stopped in the third scenario, which could increase groundwater reserves by about 7 Mm3/year. NSSA groundwater reserves could be improved considerably if the pumping rules were taken seriously.

Keywords: pumping, depletion, groundwater modeling system GMS, Nadhour Saouaf

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Authors: Faisal Aburub, Wael Hadi

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Data mining is the process of extracting useful or hidden information from a large database. Extracted information can be used to discover relationships among features, where data objects are grouped according to logical relationships; or to predict unseen objects to one of the predefined groups. In this paper, we aim to investigate four well-known data mining algorithms in order to predict groundwater areas in Jordan. These algorithms are Support Vector Machines (SVMs), Naïve Bayes (NB), K-Nearest Neighbor (kNN) and Classification Based on Association Rule (CBA). The experimental results indicate that the SVMs algorithm outperformed other algorithms in terms of classification accuracy, precision and F1 evaluation measures using the datasets of groundwater areas that were collected from Jordanian Ministry of Water and Irrigation.

Keywords: classification, data mining, evaluation measures, groundwater

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Authors: Ebissa Gadissa Kedir

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This paper presents the potential groundwater assessment and sustainable management in the selected study area. It is the most preferred water source in all climatic zones for its convenient availability, drought dependability, excellent quality, and low development cost. The rural areas, which account for more than 85% of the country's population, are encountered a shortage of potable water supply which can be solved by proper groundwater utilization. For the present study area, the groundwater potential is assessed and analysed. Thus, the study area falls in four potential groundwater zones ranging from poor to high. However, the current groundwater management practices in the study area are poor. Despite the pervasive and devastating challenges, immediate and proper responses have not yet been given to the problem. Thus, such frustrating threats and challenges have initiated the researcher to work in the project area.

Keywords: GW potential, GW management, GW sustainability, South gonder, Ethiopia

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Authors: Akbar Khodavirdizadeh

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Gougerd village landslide with area about 150 hectares is located in southwest of Khoy city in northwest of the Iran. This Landslide was commenced more than 21 years and caused some damages in houses like some fissures on walls and some cracks on ground and foundations. The main mechanism of landslide is rotational with the high different of top and foot is about 230 m. The thickness of slide mass based on geoelectrical investigation is about 16m obtained. The upper layer of slope is silty sand and the lower layer of clayey gravel. In this paper, the stability of landslide are analyzed based in static analysis under different groundwater surface conditions and at slope angle changes with limit eqlibrium method and the simplified Bishop method. The results of the 72 stability analysis showed that the slope stability of Gougerd landslide increased with increasing of the groundwater surface depth of slope crown. And especially when decreased of slope angle, the safety facter more than in previous state is increased. The required of safety factor for stability in groundwater surface depth from slope crown equal 14 m and with decreased of slope angle to 3 degree at decrease of groundwater surface depth from slope crown equal 6.5 m obtained. The safety factor in critical conditions under groundwater surface depth from slope crown equal 3.5 m and at decreased of slope angle to 3 degree equal 0.5 m obtained. At groudwater surface depth from slope crown of 3 m, 7 m and 10 m respectively equal to 0.97, 1.19 and 1.33 obtained. At groudwater surface depth from slope crown of 3 m, 7 m and 10 m with decreased of slope angle to 3 degree, respectively equal to 1.27, 1.54 and 1.72 obtained. According to the results of this study, for 1 m of groundwater level decrease, the safety factor increased by 5%, and for 1 degree of reduction of the slope angle, safety factor increased by 15%. And the effect of slope angle on Gougerd landslide stability was felt more than groundwater effect.

Keywords: Gougerd landslide, stability analysis, slope angle, groundwater, Khoy

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Authors: M. Meddi, A. Boufekane

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The Mitidja coastal groundwater which extends over an area of 1450 km2 is a strategic resource in the Algiers region. The high dependence of the regional economy on the use of this groundwater forces us to have recourse to its artificial recharge from the Wadi El Harrach in its upstream part. This system of artificial recharge has shown its effectiveness in the development of water resource mentioned in the succeeding works in several regions of the world. The objective of this study is to: Increase the reserves of water inputs by infiltration, raise the water level and its good quality in wells and boreholes, reduce losses to the sea, and address seawater intrusion by maintaining balance in the freshwater-saltwater interface in the downstream part of the groundwater basin. After analyzing the situation, it was noticed that a qualitative monitoring of the Wadi water for the groundwater recharge has to be done. For this purpose, we proceeded during three successive years (2010, 2011, and 2012) to the monthly sampling of water in the upstream part of the Wadi El Harrach for chemical analysis. The variation of the sediment transport concentration will be also measured. This monitoring aims to characterize the water quality and avoid clogging in the proposed recharge area. The results of these analyses showed the good chemical quality according to the analyses we performed in the laboratory during the three years, but they are too loaded with suspended matters. We noticed that these fine particles come from the grinding of limestone of sandpit located upstream of the area of the proposed recharge system. This problem can be solved by a water supply upstream of sandpit. For the recharge, we propose the method of using two wells for dual use, which means that it can be used for water supply and extraction. This solution is inexpensive in our case and could easily be used as wells are already drilled in the upstream part. This solution increases over time the piezometric level and also reduce groundwater contamination by saltwater in the downstream part.

Keywords: water quality, artificial groundwater recharge, Mitidja, North Algeria

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Authors: Modreck Gomo

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The evolution of groundwater chemistry and its quality is largely controlled by hydrogeochemical processes and their understanding is therefore important for groundwater quality assessments and protection of the water resources. A study was conducted in Bloemfontein town of South Africa to assess and compare the groundwater chemistry and quality characteristics in an alluvial aquifer and single-plane fractured-rock aquifers. 9 groundwater samples were collected from monitoring boreholes drilled into the two aquifer systems during a once-off sampling exercise. Samples were collected through low-flow purging technique and analysed for major ions and trace elements. In order to describe the hydrochemical facies and identify dominant hydrogeochemical processes, the groundwater chemistry data are interpreted using stiff diagrams and principal component analysis (PCA), as complimentary tools. The fitness of the groundwater quality for domestic and irrigation uses is also assessed. Results show that the alluvial aquifer is characterised by a Na-HCO₃ hydrochemical facie while fractured-rock aquifer has a Ca-HCO₃ facie. The groundwater in both aquifers originally evolved from the dissolution of calcite rocks that are common on land surface environments. However the groundwater in the alluvial aquifer further goes through another evolution as driven by cation exchange process in which Na in the sediments exchanges with Ca²⁺ in the Ca-HCO₃ hydrochemical type to result in the Na-HCO₃ hydrochemical type. Despite the difference in the hydrogeochemical processes between the alluvial aquifer and single-plane fractured-rock aquifer, this did not influence the groundwater quality. The groundwater in the two aquifers is very hard as influenced by the elevated magnesium and calcium ions that evolve from dissolution of carbonate minerals which typically occurs in surface environments. Based on total dissolved levels (600-900 mg/L), groundwater quality of the two aquifer systems is classified to be of fair quality. The negative potential impacts of the groundwater quality for domestic uses are highlighted.

Keywords: alluvial aquifer, fractured-rock aquifer, groundwater quality, hydrogeochemical processes

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Authors: Priti Saha, Biswajit Paul

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Rapid urbanization and industrialization have increased the demand of groundwater. However, the present era has evident an enormous level of groundwater pollution. Therefore, water quality assessment is paramount importance to evaluate its suitability for drinking, irrigation and industrial use. This study focus to evaluate the groundwater quality of an industrial city in eastern India through interdisciplinary techniques. The multi-purpose Water Quality Index (WQI) assess the suitability for drinking as well as irrigation of forty sampling locations, where 2.5% and 15% of sampling locations have excellent water quality (WQI:0-25) as well as 15% and 40% have good quality (WQI:25-50), which represents its suitability for drinking and irrigation respectively. However, the industrial water quality was assessed through Ryznar Stability Index (LSI), which affirmed that only 2.5% of sampling locations have neither corrosive nor scale forming properties (RSI: 6.2-6.8). These techniques with the integration of geographical information system (GIS) for spatial assessment indorsed its effectiveness to identify the regions where the water bodies are suitable to use for drinking, irrigation as well as industrial activities. Further, the sources of these contaminants were identified through factor analysis (FA), which revealed that both the geogenic as well as anthropogenic sources were responsible for groundwater pollution. This research demonstrates the effectiveness of statistical and GIS techniques for the analysis of environmental contaminants.

Keywords: groundwater, water quality analysis, water quality index, WQI, factor analysis, FA, spatial assessment

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Authors: Shuo Wang

Abstract:

The hydrogeological parameters of the engineering site and the hydraulic connection between the aquifers can be obtained by the pumping test. Through the recovery test, the characteristics of water level recovery and the law of surface subsidence recovery can be understood. The above two tests can provide the basis for subsequent engineering design. At present, the deformation of deep soil caused by pumping tests is often neglected. However, some studies have shown that the maximum settlement subject to groundwater drawdown is not necessarily on the surface but in the deep soil. In addition, the law of settlement recovery of each soil layer subject to water level recovery is not clear. If the deformation-sensitive structure is deep in the test site, safety accidents may occur. In this study, the pumping test and recovery test of a confined aquifer in Shanghai are introduced. The law of measured groundwater changes and surface subsidence are analyzed. In addition, the fluid-solid coupling model was established by ABAQUS based on the Biot consolidation theory. The models are verified by comparing the computed and measured results. Further, the variation law of water level and the deformation law of deep soil during pumping and recovery tests under different site conditions and different times and spaces are discussed through the above model. It is found that the maximum soil settlement caused by pumping in a confined aquifer is related to the permeability of the overlying aquitard and pumping time. There is a lag between soil deformation and groundwater changes, and the recovery rate of settlement deformation of each soil layer caused by the rise of water level is different. Finally, some possible research directions are proposed to provide new ideas for academic research in this field.

Keywords: coupled hydro-mechanical analysis, deep ground settlement, numerical simulation, pumping test, recovery test

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Authors: Tamas Garamhegyi, Jozsef Kovacs, Rita Pongracz, Peter Tanos, Balazs Trasy, Norbert Magyar, Istvan G. Hatvani

Abstract:

Like most environmental processes, shallow groundwater fluctuation under natural circumstances also behaves periodically. With the statistical tools at hand, it can easily be determined if a period exists in the data or not. Thus, the question may be raised: Does the estimated average period time characterize the whole time period, or not? This is especially important in the case of such complex phenomena as shallow groundwater fluctuation, driven by numerous factors. Because of the continuous changes in the oscillating components of shallow groundwater time series, the most appropriate method should be used to investigate its periodicity, this is wavelet spectrum analysis. The aims of the research were to investigate the periodic behavior of the shallow groundwater time series of an agriculturally important and drought sensitive region in Central-Eastern Europe and its relationship to the European pressure action centers. During the research ~216 shallow groundwater observation wells located in the eastern part of the Great Hungarian Plain with a temporal coverage of 50 years were scanned for periodicity. By taking the full-time interval as 100%, the presence of any period could be determined in percentages. With the complex hydrogeological/meteorological model developed in this study, non-periodic time intervals were found in the shallow groundwater levels. On the local scale, this phenomenon linked to drought conditions, and on a regional scale linked to the maxima of the regional air pressures in the Gulf of Genoa. The study documented an important link between shallow groundwater levels and climate variables/indices facilitating the necessary adaptation strategies on national and/or regional scales, which have to take into account the predictions of drought-related climatic conditions.

Keywords: climate change, drought, groundwater periodicity, wavelet spectrum and coherence analyses

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Authors: Keisuke Konishi, Yoshinari Hiroshiro, Kento Terashima, Atsushi Tsutsumi

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Imazu Bay plays an important role for endangered species such as horseshoe crabs and black-faced spoonbills that stay in the bay for spawning or the passing of winter. However, this bay is semi-enclosed with slow water exchange, which could lead to eutrophication under the condition of excess nutrient inflow to the bay. Therefore, quantification of nutrient inflow is of great importance. Generally, analysis of nutrient inflow to the bays takes into consideration nutrient inflow from only the river, but that from groundwater should not be ignored for more accurate results. The main objective of this study is to estimate the amounts of nutrient inflow from river and groundwater to Imazu Bay by analyzing water budget in Zuibaiji River Basin and loads of T-N, T-P, NO3-N and NH4-N. The water budget computation in the basin is performed using groundwater recharge model and quasi three-dimensional two-phase groundwater flow model, and the multiplication of the measured amount of nutrient inflow with the computed discharge gives the total amount of nutrient inflow to the bay. In addition, in order to evaluate nutrient inflow to the bay, the result is compared with nutrient inflow from geologically similar river basins. The result shows that the discharge is 3.50×107 m3/year from the river and 1.04×107 m3/year from groundwater. The submarine groundwater discharge accounts for approximately 23 % of the total discharge, which is large compared to the other river basins. It is also revealed that the total nutrient inflow is not particularly large. The sum of NO3-N and NH4-N loadings from groundwater is less than 10 % of that from the river because of denitrification in groundwater. The Shin Seibu Sewage Treatment Plant located below the observation points discharges treated water of 15,400 m3/day and plans to increase it. However, the loads of T-N and T-P from the treatment plant are 3.9 mg/L and 0.19 mg/L, so that it does not contribute a lot to eutrophication.

Keywords: Eutrophication, groundwater recharge model, nutrient inflow, quasi three-dimensional two-phase groundwater flow model, submarine groundwater discharge

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Authors: Pedro Martinez-Santos, Víctor Gómez-Escalonilla, Silvia Díaz-Alcaide, Esperanza Montero, Miguel Martín-Loeches

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Groundwater monitoring networks are critical in evaluating the vulnerability of groundwater resources to depletion and contamination, both in space and time. Groundwater monitoring networks typically grow over decades, often in organic fashion, with relatively little overall planning. The groundwater monitoring networks in the Madrid area, Spain, were reviewed for the purpose of identifying gaps and opportunities for improvement. Spatial analysis reveals the presence of various monitoring networks belonging to different institutions, with several hundred observation wells in an area of approximately 4000 km2. This represents several thousand individual data entries, some going back to the early 1970s. Major issues included overlap between the networks, unknown screen depth/vertical distribution for many observation boreholes, uneven time series, uneven monitored species, and potentially suboptimal locations. Results also reveal there is sufficient information to carry out a spatial and temporal analysis of groundwater vulnerability based on machine learning applications. These can contribute to improve the overall planning of monitoring networks’ expansion into the future.

Keywords: groundwater monitoring, observation networks, machine learning, madrid

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