Climate Change and its Effects on Water Resources

The purpose of this paper is to provide an overview of the application of the resilience methodology to analyze quantitative engineering problems and demonstrate how this analysis can be used in making policy decisions in water quality and climate change problems. The resilience thinking is a relatively new paradigm which has found its roots in the analysis of social-ecological systems. Engineering and thus quantitative applications of this conceptual framework is at its infancy and the topics discussed in this paper may shed some light to this path which is full of mathematical and computational difficulties.

Throughout the Mediterranean Region, a combination of population growth and climate change will compromise our ability to manage available water resources. Pro-active resource management decisions are required; however, these efforts will prove futile unless reliable predictions can be made of the impact that changing conditions will impart upon the hydrologic cycle and water reserves. Groundwater is a particular concern as its unique characteristics are rarely adequately accommodated within IWRM (Integrated Water Resource Management). Moreover, few studies have considered the potential impacts of climate change on groundwater resources in a region where meteorological conditions and sea and lake levels are expected to change at rates that are unprecedented in modern times. Time is of the essence. Groundwater is resilient to drought and promises to play a crucial role in regions where climate change threatens renewable water resources. Questions that need to be addressed are: (1) How will climate change affect the nature and seasonality of aquifer recharge? (2) How will fresh groundwater levels beneath coastal areas respond to changing sea/lake levels, and to what extent will rising sea levels promote the intrusion of seawater? (3) Will a decline in sea/lake levels accelerate the release of contaminants stored in coastal aquifers to receiving water bodies? (4) Over what time frame will changes to the groundwater system occur?

Climate change is one possible external driver of ecosystem services. In the tropical Pacific, short-term climate change is influenced by oceanic Kelvin waves that induce remote temperatures to rise (El Niño event) or decrease (La Niña event). This teleconnection is not globally uniform; in the United States (U.S.) drought conditions induced by El Niño commonly appear in the northern latitudes, whereas drought induced by La Niña occurs in the southern latitudes. Should natural or anthropogenic climate forcing influence the frequency or intensity of drought, there is a potential for catastrophic events to occur placing our national and global security at risk. Because climate forcing interacts with ecosystems characterized by nonlinear and multivariate processes over local-to-global and immediate-to-long-term scales, their assessment and prediction are challenging. This study demonstrates the efficacy of an alternative modeling paradigm based on using a self-organizing map to examine and predict the role that climatic change has on water-resource related ecosystem services. Examples include: (1) hindcasting 2,000 years of temperature and precipitation across states in the south-central and southwestern U.S.; (2) forecasting climate-induced groundwater recharge variability across subbasins in mid-western U.S.; and, (3) forecasting climate-change effects on post-fire hydrology and geomorphology in the western U.S.

On a global scale, there is increasing evidence that climate is changing and of a discernible human influence. Many of scientists are confident that if current emissions of greenhouse gases continue, the world will be warmer, sea levels will rise and regional climate patterns will change. According to some scientist, global temperatures are expected to rise faster over the next century than over any time during the last 10,000 years. From this token, geothermal energy is now considered to be one of the most important alternative energy sources to minimize climate change. Geothermal technologies for power generation or direct use operate with little or no greenhouse gas emissions. Geothermal energy is generally accepted as being an environmentally-friendly energy source, particularly when compared to fossil fuel energy sources. Geothermal resources have long been used for direct heat extraction for district urban heating, industrial processing, domestic water and space heating, leisure and balneotherapy applications. Geothermal energy is used in more than 80 countries for direct heat application and 24 countries for power generation. Re-injection of fluids maintains a constant pressure in the reservoir, thus increasing the field’s life and reducing concerns about environmental impacts. Geothermal energy has several significant characteristics that make it suitable for climate change mitigation.

The geological view to the issue of impact climate change on water resources on the Earth is the main objective of the paper. The geological excursion into the past of the Earth clearly shows that the climate cannot be stabilized. The volume of water existing on the Earth is stable and has never changed. About 96% of countries have sufficient resources of water. The major reason for water scarcity on the Earth is not unfavorable distribution of natural resources but poverty and lack of education.

Groundwater is a vital resource for living and food security for at least two billion people worldwide. Ever increasing demand on groundwater has led to overexploitation of the aquifers and degradation of groundwater quality. Climate change will exacerbate these problems by producing reduced recharge rates in some areas, more reliance on groundwater resources due to decrease in reliability of surface waters, farther inland penetration of saltwater intrusion in response to both sea-level rise and excessive groundwater extraction and deterioration of groundwater quality by increased flushing of urban and agricultural waste due to more frequent flooding. These problems emerged the concern about the sustainable management of groundwater so that it is not depleted while the increasing demand is satisfied under the pressures exerted by the climate change. This paper examines one of the most significant consequences of climate change, decreasing recharge rates, on the sustainable management of groundwater resources using a hypothetical case study.

Israel is a developed, water-scarce country, with problems of increasing aquifer water salinity resulting from its exploitation of groundwater resources. To address this problem, we developed a model for planning water supply from diverse sources, including groundwater, the National Water Carrier, wastewater and seawater, and implemented it on two case studies in Israel. The model integrates hydrological, technological and economic considerations, and estimates the economic and environmental impacts of alternative water management policies. The hydrological model forecasts the concentration of chlorides in the aquifer under alternative scenarios in the short term and long term. The economic model estimates the costs of various desalination processes under the regional conditions, and the total costs of the water supply to the region under these scenarios. The conclusions are that desalination of brackish water involves lowest costs; desalination of National Carrier water is effective when there is large-scale use; desalination of wastewater is significant for maintaining the chloride concentration threshold in water for agriculture; and desalination of seawater is recommended when it makes an important contribution to maintaining the national water balance. Most importantly, we conclude that the economic cost of improving the quality of the supplied water and of the aquifer water should be considered in decision making.

Climate change is a potential stressor of groundwater resources and its effects on the availability of groundwater need to be understood and determined. The impacts of climate change on groundwater systems are conceptually known, however in the context of climate change impact assessment there has been little research conducted on groundwater compared to surface water resources. One of the tools used to quantify the effects of climate change is to use groundwater flow models in conjunction with downscaled GCM (global circulation model) results and groundwater recharge estimation. The purpose of this study is to present an overview of groundwater modeling approaches to assess the impacts of climate change on groundwater resources. Basic requirements, challenges and different approaches to overcome them are presented. The principal challenge of any climate change impact study is the downscaling of GCM results to the basin scale. Furthermore, the estimation of the impacted groundwater recharge is particularly important in groundwater modeling studies. A summary of case studies demonstrating the various methodologies are provided, following with an overview of a recent climate change impact study conducted for Tahtalı stream basin in Turkey.

Among several other factors, spatial and temporal variability of some basic characteristics is of primary importance in defining the vulnerability of a hydrogeological system against external/internal stresses. Response of a hydrogeological system to climatic changes is reflected in dynamics of recharge, storage and flow, which consequently alters water quality. Managing karst aquifers is more difficult compared to non-karstic aquifers, due to the fact that recharge-storage-flow mechanism is not as straightforward as in non-karstic aquifers. In this paper, management of karst aquifers, with special emphasis on climatic changes, is discussed, based on some examples from Turkish karst. It was demonstrated that well karstified rock masses, which normally do not contain significant phreatic zones, can be developed, in order to capture and store the flush waters of floods for later use.

Due to climate change, water availability for different uses such as domestic water supply, hydropower production and agricultural irrigation could be significantly reduced in the near future mainly in regions with arid and semi-arid climate. Precipitation data in the form of time series from different stations in South East Europe (SEE) as well as results from global atmospheric circulation models indicate that climate change will reduce water availability in this part of the Mediterranean. In this presentation the coupling of hydrological, hydraulic and climate change models is suggested in order to explore the impact of climate change on water resources at the river basin level. The methodology is illustrated for the Mesta/Nestos river basin, which is shared between Bulgaria and Greece. The case study is part of the worldwide UNESCO-HELP initiative.

The relationship between climate change and floods frequency is of great interest for addressing the complex analysis on the hydrologic cycle evolution. In this context, this study aims to assess, by a preliminary investigation, the climate change effects on the floods frequency in several basins of the upper Tiber River, whose area is ranging from 100 to 300 km

2

. For that, a continuous hydrological model coupled with a stochastic generation of rainfall and temperature has been used. Therefore, a long synthetic series of discharge were generated from which the annual maximum discharges were extracted and, hence, the flood frequency curves were defined. For the stochastic generation of precipitation, the Neyman-Scott Rectangular Pulse model was used, while for the synthetic generation of temperature, an ARIMA model with fractional differentiation was applied. The time series of discharge was assessed by applying a continuous hydrological model developed ad hoc for the investigated basins. The model structure was inferred by investigating the effects of antecedent wetness conditions on the outlet response of several experimental basins located in Central Italy. The analysis proposed here compares the actual time series of precipitation and temperature and the perturbed ones by assuming two different future scenarios obtained by the Global Circulation Model HadCM3. Results showed that geo-morphological and land-use characteristics of basins might have a paramount role in the changing of floods frequency.

Water resources are mainly controlled by the climate conditions. Global warming will therefore have evolving impacts on water resources and poses important challenges for sustainable development. Studies are rapidly emerging with focus on potential implications of climate change on Turkish water resources. These studies can be grouped into two major fields: (1) Studies investigating the degree of climate change reflected in the past observed hydro-meteorological records, and (2) studies investigating potential future impacts of climate change on water resources. In this paper, we present a summary of the current knowledge in the area of climate change impacts on Turkish water resources with emphasis on the two major fields listed above. Overall conclusion of the review is that climate change will put additional pressure on already stressed water resources in Turkey. The credibility of water management scenarios – whether focused on maintaining ecosystems or on food and energy security – largely depends on improved consideration of plausible climate change scenarios, and their potential uncertainties, in decision making.

Groundwater and surface water are the sources of water supply in Azerbaijan. The hydroeconomic balance of Azerbaijan is characterized by annual and seasonal deficits arising from the implementation of hydroeconomic measures for increasing the water supply to different branches of the national economy. When almost all available surface water resources are involved in the national economical production, the optimal use of aquifers’ fresh groundwater resources are currently playing pivotal role. That is the reason that the interest in the impacts of climate change on groundwater resources in Azerbaijan has developed greatly. This paper examines the scientific and technical aspects of evaluating the fresh groundwater resources formation in the hydrogeological structures, such as deposits in the mountainous regions, foothill and intermountain plains. It also investigates the role of the climatic factors and impacts of climate change on groundwater resources.

The global climate change impact on water resources of Armenia is shortly reviewed. The mountainous character of Armenia causes the great differentiation in landscape types, as well as geological characteristics, climate, soils and water resources. The present day Armenia is disposed to significant ecological risks and becomes a country which economy is based on the intensive use of natural resources which eco security vulnerability is continually increasing. It is noted that the strategy of ecological security is based on the defensive, adaptation, cooperative and other approaches but the country needs to have ecological security concept based on the ecological ideology in beforehand. We highlighted in this presentation that the reduction of water reserves will coincide with the growth of the demand on water resources, since due to the climatic peculiarities namely due to the high air temperature the households will require more potable water and the needs of agriculture in irrigation water supplies will increase. Corresponding risk assessments are preliminary evaluated and some possible recommendations to be done are presented.

The results of long-term researches of the atmosphere temperature changes above middle latitudes of Central Asia region and the causes of climatic changes in atmospheric parameters considering man caused and natural factors are presented. In recent years global temperature has sharply dropped by 0.6°C, compensating the temperature increase by 0.6–0.7°C in the 100 previous years. The restoration of the equilibrium is an indirect confirmation of solar factor influence on the Earth’s climate. Recently detected tendencies of temperature increase and small decrease of its average values in Kyrgyzstan, do not promote water inflow increase in mountain rivers, enhancing a water resources deficit in future in Central Asia.

Although climate change is potentially a major threat to the security of water resources, other possible new threats should not be ignored. Nanotechnology is a rapidly expanding industry, and already manufactured nanoparticles (mNPs) are being used in many products. Past experience suggests that use of new chemicals leads to subsurface pollution. The seriousness of this threat depends on two factors: the toxicity of mNPs and their mobility. Many mNPs, particles typically <100 nm across, are composed of metals, metal compounds (e.g. Ag, ZnO, CdSe) or carbon (e.g. carbon nanotubes). An active research area, nanotoxicology is showing toxic effects can occur under some conditions for bacteria, invertebrates, and vertebrates from low ppm concentrations upwards. Factors affecting mNP mobility in groundwater include aggregation, interactions with other particles, attachment to rock, and straining, with behaviour being very dependent on solution chemistry. The limited research available on intact rock samples indicates an encouraging degree of attenuation, at least in matrix flow systems, but field evidence suggests that a small proportion of particles can travel considerable distances.

This paper introduces a novel method for controlling of the cyanobacteria concentration in open water reservoirs during periods of global warming. The technology is based on usage of nanophotocatalysts made from nanocarbon-metal composition with titanium as the metal. Under the natural ultraviolet radiation, the nanophotocatalysts form OH-radicals in water that destroy cyanobacteria. Field tests in natural water revealed it to be efficient with low consumption of nanocompositions (about 10 g/ha or 50 l of aqueous solution of the nanocomposition with the concentration of 200 mg/l), OH-radicals formed only in the upper water layers where cyanobacteria grow, and nanocompositions coagulate and precipitate harmless water-insoluble particles within the first day.

Radionuclide contaminants of most environmental significance are those taken up by plants; and have high rates of transfer to vegetable and animal products, such as crops, milk and meat, and have relatively long radiological half-lives. Soil type (particularly clay mineral composition and organic matter content), tillage practice, and climate affect radionuclide transport to rivers and groundwater. Prior to the Chernobyl accident, the respective concentrations of the

90

Sr and

137

Cs in the Pripyat water averaged 0.011 and 0.007 Bq/l. After some rainfalls, the respective concentrations of

90

Sr and

137

Cs in the Dnipro and Pripyat rivers ranged from 1.59 to 2.70 Bq/l and from 3.35 to 5.95 Bq/l. In contrast to

137

Cs, the radionuclide

90

Sr is transported by streams as a soluble compound (50–99%). Rainfall exacerbated contamination at the Chernobyl site by the addition of airborne radioactive particles (micro- and/or nano-sizes) to surface and ground-water system increasing genotoxicity to plants.

In 1982, the Ministry of melioration and water industry (now called the Ministry of agriculture and water industry) began conducting the cadastre of meliorative condition of irrigated areas and technical condition of hydrameliorative systems. This cadastre is still performed according to methods created during the former USSR. Today, these methods do not meet requirements of practice under conditions of increasing deficiency of water resources, their deterioration, and climate change. In this study, the acceptable depth to ground water (LGW) for different hydrogeologic and soil conditions is investigated. Methods for ensuring that a sufficient water supply exists for irrigated areas are developed based on irrigation and climatic factors and degree of area drainage. In the assessment of meliorative condition indicators, we suggest that investigators analyze the evolution over the most recent 3–5 years taking into account their degree of stability during and crop capacity. To justify the repair-and-renewal operations and construction work on irrigational-drainage systems, the new methods are based on actual fluid-and-electrolyte balances and engineering of the hydraulic structures.

The climatic change hazard in the Kyrgyz Republic is the potential reduction of mountain runoff to rivers. This is because agriculture, a basis of state economy, depends on irrigation water from mountainous rivers. The current shortage in surface water resources provides a motivation for increasing the irrigation system efficiency and use of ground waters for irrigation. The surface and ground waters of intermountain valleys of Kyrgyzstan are interdependent. The efficiency improvement of irrigation systems reduces recharge of ground waters and, from the point of view of their budget, is the same as using ground waters for irrigation. These factors reduce flow of ground waters into downstream areas, where they discharge into surface water sources. That is, the replenishment of surface water resources at the expense of ground waters leads to reduction of surface and ground water resources in the underlying areas. This paper shows demonstrates the mentioned process occurs but with a long time delay. The periods of delay may be more than 20 years, giving time for the introduction of agriculture technologies intended for use of smaller quantities of water. The equations suggested here can be used for similar calculations in other intermountain valleys of Central Asia.

This paper analyzes and emphasizes the importance of groundwater evapotranspiration (

ETg

) in groundwater balances. The

ETg

diminishes the net groundwater recharge that constrains groundwater flow and replenishment of groundwater resources. The

ETg

consists of two different components, groundwater transpiration (

Tg

) and groundwater evaporation (

Eg

), both not yet well identified in hydrogeology. The

ETg

values are the largest in dry locations with shallow groundwater table. The significance of the

ETg

however is the largest when its relative contribution to groundwater balance is high i.e. when its rate is comparable with groundwater recharge.

As it is widely known the earth is experiencing a climate change. The primary effect of this change is the increase trend in global temperature. This, in turn, results in increased number of events in flooding, and drought in different parts of the world. A secondary effect is the change in water and soil salinity. A considerable portion of the cultivated land in the world is affected by salinity, limiting productivity potential. About 20 million ha of total 230 million ha of irrigated land in the world are salt affected. The climate change is expected to worsen this situation. This study explores the water stress effect on soil salinity. For this purpose, a model is developed to simulate salt transport in a layered soil column. The soil salinity transport model development involves two parts: (1) modeling salt movement through sail layers due to runoff, percolation, and lateral subsurface flow, and (2) modeling dissolution and precipitation of gypsum which acts as sink or source for salts in soil. The model is calibrated and validated with measured data. The soil is irrigated under optimal and water stress irrigation conditions. The major model parameters affecting the soil salinity are found to be wilting point, field capacity, hydraulic conductivity, initial soil salinity, and soil gypsum concentration. The results have revealed that water stress results in high concentration of salt accumulation in soil columns.

The chapter comprises updated results from research on projected climate change in Republic of Macedonia in the course of twenty-first century related to previously elaborated National Communications on Climate Change as obligation under the United Nation Frame Convention on Climate Change. The results refer to air temperature and precipitation analysis on seasonal and annual base according to various emission scenarios for years 2025, 2050, 2075 and 2100 for the entire country as well as for diffe rent climatic regions of Macedonia. Also, presented are first estimations of the water resources vulnerability assessment and the status of the available information on the transboundary aquifers in Republic of Macedonia.

This paper analyzes evolution and efficiency of water governance in Bulgarian agriculture during post-communist transition and EU integration. First, it defines the water governance and the scope of analysis. Next, it presents the process of transformation of agricultural water governance embracing all mechanisms and modes including institutional environment, market, private, public, and hybrid. Third, it assesses impacts of newly evolved system of governance on efficiency and sustainability. Finally, it suggests recommendations for improvement of public policies.

Alluvial groundwater systems are extremely vulnerable to changes in precipitation amounts as they are typically recharged from above. Thus, any change in precipitation patterns due to climate change is likely to influence such systems first. Dynamic behavior of these systems is clearly seen from large fluctuations in the declining and rising curves of groundwater level time series graphs. An example of such a system is analyzed within the scope of this study that is located in Western Anatolia near Izmir, Turkey. Data collected from 21 monitoring wells were used to assess the long term general trend in the groundwater levels of Torbali-Bayindir plain, an alluvial system near Izmir city. The results demonstrated an average declining pattern of 0.75 m/year in groundwater levels where strong seasonal fluctuations in some wells could reach as high as 30 m. Considering this dynamic behavior, such systems, which are highly dependent on timing, persistence and total amounts of precipitation, are extremely vulnerable to changes in precipitation patterns, particularly in areas where climate change effects are towards increased temperature values and reduced precipitation totals.

In countries with advanced environmental management systems, nume­rical models are often used in the planning and management of sustainable groundwater resources. Toward that end, we evaluated the influence of climate change on karstic groundwater resources of the Escusa (Castelo de Vide) aquifer using a finite-element discrete continuum flow model, allowing the use of 1-D, 2-D and 3-D finite elements in the same computational mesh. The model was calibrated by the regional field measurements. Since this coupled model simulates fluid movement in, and exchange between, multiple domains, it was possible to monitor flow processes such as recharge (diffuse and concentrated infiltration), flux inside the aquifer (quick in caves and conduits and slow in the rock mass), and concentrated discharge (karstic springs) and diffuse discharge to wetlands and other porous hydrogeological units. Four different climate scenarios were analyzed with respect to their influence on future aquifer discharge rates. These scenarios (by the Hadley Centre for Climate Prediction and Research) reflected global and regional climate predictions for 50 and 100 year periods. The variation in groundwater discharge rates from the Escusa aquifer was evaluated in relation with discharge to the Sever River and granitic rocks in contact with the aquifer in its northern part. All the climate-based simulations show a decline in the discharge rates of the groundwater aquifer. Another important finding is that the discharge rates per month change and sometimes it is possible to have an increase in the discharge during the first half of the year and a reduction in the second half of the year.

Groundwater quality is becoming an important issue in many parts of the world. The status of groundwater quality in the given groundwater system can be addressed through quantitative analysis of its hydrogeochemical field in temporal and spatial domain. A quantitative, multi-stage classification of groundwater quality adopted in Poland is presented and compared with the approach recommended by EU. It helps to guard pristine water quality and to detect early stages of deterioration of groundwater quality, thus allowing timely measures to achieve trend reversals.

Constanta city is located on the Black Sea coast in the eastern part of the Romanian South Dobrogea region. Global warming in the Dobrogea region promotes drought conditions that decrease groundwater levels and increase abstraction rates in the shallow unconfined aquifers (loess deposits and karstified Sarmatian limestones) being used for public supply. This study advocates using an alternative confined and high quality groundwater source in the zone adjacent to the tectonic blocks 5 and 10, where the Senonian aquitard ensures delays to climate change and provides protection from potential anthropogenic contaminants. Our review of the hydrogeologic and technical conditions further suggest that abstraction wells need to be developed within the Constanţa city limits and Upper Jurassic–Lower Cretaceous aquifer (400–1,200 m thick). Suggested optimal exploitation characteristics are proposed.

Borjomi mineral waters field is a source of famous mineral water, which is exported to dozens of countries and forms a significant part of budget of Georgia. Currently, in connection with construction of Baku-Tbilisi-Ceyhan pipeline by British Petroleum (BP), serious concerns arise with respect to vulnerability of water supply of the city of Borjomi to possible oil spills related to operation of the pipeline. In this paper, we consider mainly the interaction between surface water and groundwater of the Bakuriani-Borjomi lava flow and the possibility of their pollution with hydrocarbons in case of oil spilling. In order to define the possible pollution propagation, we apply stable isotope technology and other modern hydro-geophysical methods that we have created.

Georgia is rich with natural thermal waters and has a long tradition of their exploitation. Approximately 250 thermal springs and artificial wells are known, as well as spring clusters with water temperatures between 30°C and 108°C. The majority of these thermal water deposits have decreased well pressures due to irrational exploitation and climate change effects. In some cases, the complete termination of outflow has been observed. Based on the number of observed resources and their thermal potential, exploitation of thermal water deposits in the Tbilisi region is the most promising; thus, the assessment of its conditions are regarded as an important national priority. This paper summarizes the geothermal potential of the Tbilisi region based on development and application of a coupled 3D groundwater model using existing and newly obtained geologic, hydrogeologic, and geophysical data. Our modeling work resulted in a 10 year exploitation perspective of Tbilisi thermal deposits.

Having a water potential of 1,500 m

3

/capita-year, Turkey cannot be classified as a water rich country. It is estimated that in 2030 the population will reach 100 million and consequently the water potential will drop down to 1,000 m

3

/capita-year. Considering the predictions about regional and global climate change trends these figures obviously indicate a probable water scarcity in the nearest future and the importance of efficient wastewater reuse in Turkey. In Turkey, wastewater reuse for irrigation purposes was done in the past by direct use or after mixing with river water. But, recently, more conscious wastewater reuse applications are practiced, considering the predictions and protection of water resources from pollution. In this paper, a general view of current water resources and wastewater reuse activities in Turkey are given. Also the future predictions and planned activities are mentioned.

The lagoon of Messolonghion is a fragile ecosystem that is protected as a Nature wetland under the Ramsar Treaty. The need for environmental protection of the wetlands has proven to be necessary because of continued human interference as well as climate changes recorded in recent years. Studies show that the lagoon of Messolonghion is an ecosystem that has been burdened by human activities (pesticides, fertilizers, overexploitation of underground aquifers, intrusion and land use change), and also by climatic changes (temperature, precipitation, sea level). Human activities and climatic changes together adversely affect the hydrodynamic and ecological balance of the entire ecosystem. The Messolonghion lagoon ecosystem is also the recipient of the effluent output of the locally operating Wastewater Processing Plant (WWTP), and has been over-enriched in macro-nutrients N, P, K. The potential of urban wastewater reuse for soil and crop irrigation in the protected area appears to be an environmentally acceptable solution for alleviating the natural water shortage, since it will save significant amounts of irrigation water, as well as it will reduce the adverse effects of the treated effluents discharged into the aquatic ecosystem. A prerequisite for safe reuse of urban wastewater is a series of studies of parameters that have to do with the geotechnical characteristics (geology, hydrology, soil characteristics of the reuse area) and climatic factors (temperature, humidity, sunshine, precipitation). The study of cultivated areas and the soil parameters for each crop will allow us to calculate the water requirements of crops and the final percentage of reuse of effluent water on soils and crops. The implementation of the methodology is important for the countries of the southern Mediterranean, especially in coastal areas, facing environmental problems and threatened by declining of the irrigation water resources due to climate changes.