The salination problem of the Guzelyurt aquifer, Cyprus

Journal of Hydrology, 2004

In coastal aquifers which are exploited for agricultural purposes, salinisation by salt recycling from irrigation is superimposed on the effects of seawater intrusion. Water quality degradation of irrigation pumping wells caused by seawater intrusion further enhances salinisation by irrigation, as the extracted solute mass is recycled and is not withdrawn from the system. The main objective of this study is the investigation and quantification of the impact of solute recycling from irrigation relative to seawater intrusion. A solute mass budget was established by expressing the solute mass return flow as fraction of the extracted solute mass from wells by means of a solute mass return flow ratio ðr r Þ: The obtained expression for the relative contribution of solute recycling from irrigation is an exponential function of the return flow ratio r r and normalised time t only (time versus system turnover time). This expression was applied to an example, the Kiti aquifer (Southern Cyprus), where field observations suggest that solute return flow is a superimposed salinisation mechanism. The contribution from solute recycling normalised with the solute mass flux entering from the sea after 20 years was found to be 1.5-8.5% in the extracted solute mass flux, depending on the estimation of the system turnover time. Subsequently, a coupled finite element model, reflecting the main features of the Kiti aquifer was used as a possible 'synthetic reality', to test the relative impact of solute recycling on the spatial salinity distribution in a complex hydrogeological and geometrical setting. This was done by running two simulation scenarios: (1) recycling all the extracted solute back into the system and (2) leaving solute recycling aside and comparing the results of these two scenarios relative to each other and to patterns observed in the field. The results showed, that by introducing solute recycling into the numerical model as coupled boundary condition does not only respect the overall solute mass balance but can have an important impact on the salinity distribution, leading to a significant spreading of the mixing zone, similar to what was observed in the field.

2005

I also want to thank all people working at Chyn for creating such a pleasant and amusing working environment, which makes it almost the 'second home'. In particular, I would like to thank Daniel Hunkeler, Heinz Surbeck and Pierre Schnegg for their involvment in this project, leading to numerous results and very fruitful discussions. Without the close collaboration with the Cyprus Water Development Department, field work in Cyprus would not have been possible. Their interest and support and fruitful discussions were very much appreciated. Special thanks go to Dr. Andreas Christodoulides, whose personal involvement in helping us with anything we needed during the field campaigns in Cyprus will remain unforgettable. Special thanks go to the managements of the Lanitis and Phasouri plantations, who authorised the implementation of the monitoring wells and who provided a lot of logistical support. A very special thank goes to Fabien Cornaton for all the support and help he has given me throughout these years, with many discussions leading onto new tracks. Also, I want to thank him for all the long-distance trouble-shooting and debugging across the oceans and corrections he did for me in the last phase of the work. My parents and family I want to thank so much for all the unforgettable support I got from them, particularly in the very last and difficult phase of the work. My father's patience in correcting my 'awkward' english and his pertinent comments and advice kept me going.

Water Supply, 2017

The purpose of this study is to investigate the saltwater intrusion phenomenon in the alluvial aquifer of Katapola, on Amorgos Island, under current and future climatic conditions and to provide groundwater management options for alleviating this problem. To this end, a groundwater flow model was developed and the sharp-interface approximation combined with the Ghyben–Herzberg equation was used. A correction factor that accounts for the hydrodynamic dispersion occurring at the brackish zone was also incorporated in the analysis. The model results show that under the current pumping strategy, the saltwater intrusion front extent is vast, posing a serious threat to the quality of groundwater used for drinking and irrigation in the area. The management goal is to find the alternative pumping scenarios for the existing well network that will prevent further spreading of saltwater intrusion. Several water management scenarios were developed, taking into account the effects of climate cha...

Journal of Hydrology, 2011

Groundwater salinisation is a major groundwater contamination issue worldwide and can be caused by different processes, such as seawater intrusion, agrochemical pollution, geogenic contamination and irrigation-induced salinisation. In many areas, several salinisation processes are superimposed. Since remedial measures vary for different salinisation processes, correct identification is fundamental for adequate design of management strategies: different strategies may be required in one and the same aquifer, depending on which salinisation process is active where in the domain. A simulation-based salinisation risk assessment methodology is proposed, based on the principle of linear superposition of total dissolved solutes in groundwater. In a first step, the measured bulk salinity distribution is used to calibrate a numerical groundwater flow and transport model, accounting for all identified salinisation processes. Then, the bulk salinity distribution is decomposed into different salinity components by adapting the boundary conditions, running a simulation for each salinisation process separately. These simulation results yield the necessary components to calculate the risk index distributions, which are a measure of the respective future potential salinity increase. Overlaying the risk index distributions with a defined threshold concentration reveals risk areas requiring remediation or conservation measures with respect to each process. The risk area maps resulting from this methodology are a promising tool for the design of groundwater management schemes. They condense relevant information from complex dynamic processes obtained from numerical simulations and visualise the results in simple and static maps, accessible to decision makers who are not familiar with groundwater dynamics. The different steps of the salinisation risk assessment procedure are first described and illustrated on a synthetic example and then applied to a real aquifer system in Southern Cyprus (Akrotiri), where three major salinisation processes are superimposed.

Euro-Mediterranean Journal for Environmental Integration, 2020

The Gareb-Bouareg aquifer is located in northeastern Morocco. This aquifer extends continuously and expansively under the two plains of Gareb and Bouareg. The introduction of irrigated agriculture utilizing only surface water to these plains has resulted in an alarming rise in the level of the water table, leading to waterlogging and salinization, which have adversely affected crop growth and rendered large areas of the plains unproductive. Therefore, a study of the water-table fluctuations in response to the agricultural development of this area was carried out. Two potential methods of lowering the water table of the brackish alluvial aquifer-the installation of subsurface and deep drainage networks-were proposed. Due to a lack of sufficient data at the local scale (agricultural parcels), it was not possible to simulate the functioning of the agricultural drainage system, so a regional MODFLOW model based on a hydrodynamic modeling approach was used to determine the optimal method of lowering the groundwater level and preventing it from rising above safe levels, thus preserving the quality of the soil and improving growing conditions for crops. After successful calibration and validation of the model, several pump-draining scenarios were simulated to evaluate their impacts on the water table in an area of the plains that suffers from waterlogging. The results for the most realistic scenario revealed that pump draining performed via 10 wells at a rate of 30 l/s per well (i.e., 300 l/s overall) would lower the water table by a maximum of 5.42 m, which would approximate its original level before the water table began to rise due to irrigation. The zone sensitive to this abstraction process would cover an area of approximately 14 km 2. This technique could be improved by reducing inflows through the use of water-saving irrigation practices and/or applying corrective measures to increase groundwater outflows, which would eventually be demineralized.

2017

Two challenges related to improving the management of the Germasogeia aquifer were presented to the Study Group by the Cyprus Water Development Department (WDD), the public organisation responsible for managing the water resources in Cyprus. The first challenge was how to optimally recharge the aquifer in order to compensate for the extraction of drinking and irrigation water whilst preventing sea water intrusion. In order to address this challenge we developed model for the water in the aquifer. Note that by exploiting the long, thin nature of the aquifer we only develop two-dimensional models in this work. We first develop a simple model based on Darcy flows for porous media which gives the water table height for given dam seepage rate, recharge and extraction rates; we neglect seawater intrusion. We then use the steady version of this model to develop an optimized recharge strategy with which we can identify minimal recharge required for a desired extracted water volume such that...

2005

I also want to thank all people working at Chyn for creating such a pleasant and amusing working environment, which makes it almost the 'second home'. In particular, I would like to thank Daniel Hunkeler, Heinz Surbeck and Pierre Schnegg for their involvment in this project, leading to numerous results and very fruitful discussions. Without the close collaboration with the Cyprus Water Development Department, field work in Cyprus would not have been possible. Their interest and support and fruitful discussions were very much appreciated. Special thanks go to Dr. Andreas Christodoulides, whose personal involvement in helping us with anything we needed during the field campaigns in Cyprus will remain unforgettable. Special thanks go to the managements of the Lanitis and Phasouri plantations, who authorised the implementation of the monitoring wells and who provided a lot of logistical support. A very special thank goes to Fabien Cornaton for all the support and help he has given me throughout these years, with many discussions leading onto new tracks. Also, I want to thank him for all the long-distance trouble-shooting and debugging across the oceans and corrections he did for me in the last phase of the work. My parents and family I want to thank so much for all the unforgettable support I got from them, particularly in the very last and difficult phase of the work. My father's patience in correcting my 'awkward' english and his pertinent comments and advice kept me going.

Environmental Earth Sciences

Seawater intrusion is a major problem to freshwater resources especially in coastal areas where fresh groundwater is surrounded and could be easily influenced by seawater. This study presents the development of a conceptual and numerical model for the coastal aquifer of Karareis region (Karaburun Peninsula) in the western part of Turkey. The study also presents the interpretation and the analysis of the time series data of groundwater levels recorded by data loggers. The SEAWAT model is used in this study to solve the density-dependent flow field and seawater intrusion in the coastal aquifer that is under excessive pumping particularly during summer months. The model was calibrated using the average values of a 1-year dataset and further verified by the average values of another year. Five potential scenarios were analyzed to understand the effects of pumping and climate change on groundwater levels and the extent of seawater intrusion in the next 10 years. The result of the analysis demonstrated high levels of electrical conductivity and chloride along the coastal part of the study area. As a result of the numerical model, seawater intrusion is simulated to move about 420 m toward the land in the next 10 years under "increased pumping" scenario, while a slight change in water level and TDS concentrations was observed in "climate change" scenario. Results also revealed that a reduction in the pumping rate from Karareis wells will be necessary to protect fresh groundwater from contamination by seawater.

Water Resources Research, 2004

1] Overexploitation of aquifers may impair groundwater quality and cause salinization, as occurs in the sloping Coastal Aquifer in Israel. The current management policy risks the future of the aquifer as the country's most important water reservoir. The paper examines a variety of policies and studies their impact on the salinization of the aquifer. Two quantitative approaches were applied: (1) a balance approach which was used to calculate the mean salinity of the aquifer water and (2) a 2-D numerical solution of the flow and transport equations in a 10 Â 15 km cell representing a portion of the aquifer. The policy alternatives include desalination of imported freshwater (180-250 ppm Cl À ), desalination of treated wastewater, and injection of the desalinated water. An increased pumping from the aquifer compensates for the injection of these waters. The results show that desalination of imported freshwater or wastewater with no injection would reduce the salinization rate of the aquifer only slightly, and that the effect would be noticeable only after a period corresponding to the retention time of the vadose zone. The alternatives that involve injection of desalinated water would stop the salinization process; the aquifer mean salinity would stabilize around the level that prevailed at the time of implementation of the injection policy. The numerical solution confirmed the conclusions of the balance approach while including the complex effect of the highsalinity boundary condition on the east and the role of thickness variations in a sloping aquifer. This approach addressed the influence of the spatial densities of pumping and of injection and showed that as the density increases, the numerical and balance solutions converge. It is shown that the numerical simulation should be used for future planning of the injection and pumping layout. Finally, calculations based on our results show that the alternatives involving injection of desalinated freshwater provide the lowest cost of improving the aquifer water salinity.

International Journal of Environmental Science and Technology, 2018

The integration of the statistical approaches and GIS tools with the hydrogeological and geological contexts allowed the assessment of the processes that cause groundwater quality deterioration in the great important deltaic aquifer in the northeastern Tunisia (Medjerda Lower Valley Aquifer). The spatial variation of the groundwater parameters and the molar ratio (Cl − /Br −) were also used to determine the possible impacts from seawater intrusion and from the septic tank leachate. Sixty shallow groundwater samples were collected in 2014 and analyzed for major and trace ions over an area of about 1090 km 2 to determine the suitability for drinking or agricultural purposes. The total dissolved solids (TDS) content ranges from 1005 to 19,254 mgl −1 with a mean value of 3477.18 mgl −1. The chemistry is dominated by the sodium-chloride waters (55%). Mapping of TDS, Cl − , Na + , SO 4 2− and NO 3 − using kriging method shows a clear increase in salinity toward the coastline accompanied by Na + and Cl − increase which may be related to seawater intrusion and halite dissolution. Locally, higher nitrate concentration is related to the agricultural activities inducing contribution of chemical fertilizers and irrigation with treated wastewater. The saturation indices indicate that all carbonate minerals tend to reach saturation equilibrium confirming water-rock interactions, while evaporitic minerals are still in sub-saturation state and may increase the salinity of the groundwater. The principal component analysis proves the occurrence of groundwater contamination principally by seawater intrusion in the factor I (74.15%) and secondary by an anthropogenic source in the factor II (10.35%).

2015

Groundwater is an important natural resource; as of today, more than 2 billion people depend on gro undwater. Determination of the quantity of available water resources is crucial due to continuously increasing water demand and unequal spatial distribution of water in the world. Coastal areas are typically considered to be areas of limited supply and large demand and groundwater is mostly the resource that is used for water supply purposes for coastal communities. Thus, there exist numerous studies in literature that focus on the determination of the groundwater characteristics in coastal regions with particular emphasis on the geological, hydrogeological and hydrochemical properties of coastal groundwater. Coastal aquifers are considered to be significant water resources and are mostly under threat due to salt water intrusion. The reason for salt water intrusion is mostly anthropogenic such as over exploitation but occasionally natural causes like tectonic boundaries or fault lines could be influential. When coupled with low recharge rates that are common in semi-arid regions such as the Mediterranean, effective and sustainable supply of water with sufficient quality and quantity becomes a real challenge for coastal communities.

Applied Geochemistry, 2008

There are numerous springs and wells within the context of this research about the part of northern and northeastern in The Mandalia Bay which has an important role regarding tourism and agriculture in Turkey's Southeastern Aegean coasts. There are an important springs in this basin, as the high discharge with values Ekinambari springs for 5385 l/s, Savrankoy springs for 4215 l/s, Avsar springs for the 1000 l/s, Sucikti springs (Karacahisar) to 400 l/s. The change of the total annual flow observations compatible with each other, an increase was observed in springs of Ekinambari, Savrankoy and Sucikti. The springs group of Ekinambari, is located from the sea about 10 km away in the alluvium. These springs were at the foot of the hill at various points at 46 m altitude, different flow rates and temperatures, allochthonous limestone flows from the broken system. The springs in the investigation area, which was measured in the high current values, of Savrankoy and Ekinambari springs monthly average current value of resources are examined, the difference between the current value is less than by months. In this spring waters of high salinity values (0,5 to 36,2‰) was determined. In this study were questioned as origin of ground water salinity from deep aquifer formations or from current sea water? In the case of salinity, in spring waters have occurred on deep towards the karstic levels of limestones from sea water is saturation. Examined the water was fed by a high level, the transition period is short and in aquifer in contact with shallow circulating water for a short time is. They could say that mixing different amounts of surface water were also. Given these results, the most important spring waters for the region (Savrankoy, Ekinambarı, etc.,) of ground water movement in karstic system pressure and decreasing/increasing rate of interventions performed in the presence of a seawater can be mentioned.

Environmental Earth Sciences, 2013

The groundwater of the deep Yes ¸ilko ¨y aquifer is the only water resource for agricultural and domestic consumption at the Karpaz Peninsula of Cyprus, which stretches approximately 100 km from the northeast of capital Nicosia to the northern tip of Cyprus. During the last decade, over-pumping and following dry periods have depleted the groundwater resources and the water surface elevation of the aquifer has dropped. The aim of this study is to understand the behavior of the Yes ¸ilko ¨y aquifer in the last decade for the proper management of groundwater resources. This has been achieved based on well survey and field survey studies, monitoring programs followed by pumping tests, and safe yield analysis. Most of the research effort has been focused on field and well survey studies to quantify agricultural water consumption and abstraction rates from the aquifer. A long-term groundwater level monitoring program, short-term continuous groundwater monitoring and pumping tests provided information for the regression analyses while deriving a sixth order polynomial relationship between the period parameter and the head parameter. The equation was helpful to predict the shortterm behavior of the water level when the present hydrogeological conditions prevail. The pumping test results satisfied the hydraulic properties of calcarenite formation yielding T = 1,782 m 2 /day and S = 0.0012. The results of safe yield analysis show that the annual deficit of the aquifer is 0.496 million cubic meters (MCM), which is equivalent to a 0.6 m drop in groundwater levels per year. Finally, the resultant annual safe yield of the aquifer is estimated as 0.84 MCM.

2001

An optimization model was developed to manage the supplemental use of groundwater in the coastal aquifer subject to saltwater intrusion in the Goksu Delta at Silifke, Turkey. The response of the aquifer system was linked to the optimization model using the response matrix method. A calibrated groundwater simulation model using the SUTRA (Saturated-Unsaturated Transport) code was run to generate aquifer response coefficients at specific well locations. It was assumed that pumping occurs from two wells, and a linear optimization model was constructed under steady-state conditions to maximize the total pumping rates from these two wells subject to water demands and chloride concentration and drawdown limitations.

Aquifer salinization has recently increased significantly due to human activity and has caused irreparable environmental and economic effects. In this research, a new method is proposed for modeling the vulnerability to salinity for the Ghaemshahr-juybar aquifer. Specifically, the GALDIT (Sea water intrusion) and TAWLBIC (Saltwater up-coning) indices were combined to produce a map of vulnerability (Comprehensive Salinity Index or CSI) to seawater intrusion of a region near the coast and saltwater up-coning away from the coast, respectively. Single parameter and removal layer sensitivity analysis were performed in order to identify the sensitive parameters and achieve optimal weights (through the single-parameter method) of contributing factors in all three methods. The three optimized methods produced were GALDIT-Opt, TAWLBIC-Opt and CSI-Opt. To assess the accuracy of the original maps and optimal ones, the Pearson correlation was used. Results indicated that the Pearson correlation of the optimized GALDIT, TAWLBIC and CSI model was better than GALDIT, TAWLBIC and CSI. The results show that the increase in correlation between EC (Electrical Conductivity), TDS (Total Dissolved Solids) and SAR (Sodium Adsorption Ratio) from the GALDIT model to the CSI-Opt model from values of 0.64, 0.56 and 0.68 has improved to values of 0.81, 0.88 and 0.91, respectively. The highest concentration of EC, with a value of 7050 ms/cm, is sampled in the areas of the east and northwest of the Ghaemshahr-juybar aqui-fer, which are classified in the CSI-Opt model as high and very high vulnerability levels. The highest concentration of TDS and SAR has been found in the east, northwest and northeast of the Ghaemshahr-juybar aquifer with a value of 4724 ppm for TDS and 14 mg/l for SAR that have been modeled in the CSI-Opt index as highly vulnerable areas. Eventually, CSI mapping can be used as an efficient tool in prioritizing in terms of the vulnerability to aquifer salinity, carrying out adjustments, recharge, and adaptation policies for this issue.