Water Resources in Arid Lands: Management and Sustainability

Surface water quality is a vital issue worldwide due to increasing population and development plans. The objective of this study is to develop a statistical approach for assessing irrigation water canals through monitoring pollutant concentrations and a water quality index. Water samples were collected monthly for the two years 2012/2013 and 2013/2014, from fixed locations along the studied canals in Eastern Delta as a case study. The statistical approach used in this work includes weighted arithmetic water quality index (WAWQI), hierarchical clustering analysis (HCA) and principal component/factor analysis (PC/FA). The study revealed that according to the cluster analysis considering WAWQI, 61.11% of the monitoring locations were grouped under cluster A which has the best water quality among the cluster groups. Furthermore, the results of the principal component analysis identified five principal components which were responsible for 81.24% of water quality status in the studied locations. The results obtained from this study can assess the decision makers in applying water quality strategy to control the presence of pollutants from different sources.

Four coastal lakes fringe the north coast of the Nile Delta, Egypt: Manzala, Maruit, Edku and Burullus. These lakes receive huge amounts of direct and indirect drainage: agriculture, industrial and domestic. Eutrophication of these lakes can have significant negative ecological, social and economic impacts on human. The objective of this paper is to quantify and classify the Carlson trophic state index of the Egyptian northern lakes. Also, control actions to reduce deterioration of northern lakes will be recommended. Data of water quality variables of different lakes are taken from the formal reports of the Egyptian Environmental Affairs Agency (EEAA) Web site. The calculation and classification of Carlson trophic state index (CTSI) are made for the period from 2011 until 2015 according to Carlson method, United States Environmental Protection Agency (USEPA) classification and other variables associated with trophic levels in lakes. These variables are total phosphorus, total nitrogen, chlorophyll-a and Secchi depth. The study revealed that northern lakes suffer from different degrees of eutrophication. Regression analysis results showed that Carlson trophic state index trend is increasing which indicates deteriorating water quality in Lake Maruit, Burullus and Bardawil, declining or improving in Lake Edku and Lake Manzala.

System dynamics modeling facilitates the integrated and sustainable management of soil and water resources by enhancing the understanding of watershed systems. The Hableh-Rud river basin, an important watershed of Iran located across Tehran and Semnan provinces, was chosen for the present research. Reference diagrams were created to represent causal relationships and feedbacks based on which the conceptual model for the integrated management of soil and water resources of the Hableh-Rud river basin was developed. The conceptual model was then converted into a model of stocks and flows and run in the Vensim software. The model is comprised of by the biophysical and the economic subsystems. The main components of the physical subsystem include water balance, groundwater, erosion, sedimentation and water quality. In the economic subsystem, total costs and benefits were taken into account. Model verification was carried out through extreme condition tests and behavior reproduction tests. Having the Nash–Sutcliffe and R² coefficients with greater values than 0.62 and 0.63, respectively, model tested. Different scenarios including vegetation management, climate, water resources management and cropping patterns were simulated, and the outputs of each scenario were compared to the outputs of the existing condition. The results of scenario analyses for a 30-year period reveal that payment for 50% of the ecosystem services by the government to expand alternative jobs and reduce damage to natural resources was determined as the best scenario. Scenario of payment for 25% of the ecosystem services by the government to expand alternative jobs and reduce damage to natural resources was chosen as the next best scenario. After evaluating the vegetation management scenarios, it was determined that farm management actions were considered as the best vegetation scenario. The research indicates that the system dynamic model, as an integrated approach for management of water resources in a basin, is pragmatic.

Groundwater quality and availability is one of the most important environmental and sustainability issues of the twenty-first century. Over the last few years, trace elements have increased in groundwater by human activities, such as agriculture, mining, fossil fuel burning and industrial effluent. The present study is focused on the pollution of groundwater by heavy metals. Seasonal variations of groundwater quality studies have been performed in Pissurlem, Sonshi, Cudnem, Velguem and Surla Watersheds, which are the primary watersheds of Mandovi and Cudnem rivers in Goa State. A maximum of 98 samples has been obtained at a rate of 49 samples per season (summer and winter). Trace elements are measured using the atomic absorption spectrophotometer (AAS). Measured groundwater traces of metals results were brought to the GIS to create spatial maps. Aluminum, barium, boron, copper, manganese, selenium, zinc, cadmium, lead, nickel, arsenic and chromium spatial maps shows that all groundwater levels in the study area were within the allowable limit. Iron spatial maps show all groundwater Fe research areas within the limit quality except in and around Kumbharwada, Vagheri and Morlem Colony sites (4.62 km²/summer and 5.96 km²/winter) for WHO 2011 norm. The study area is situated in the lower part of the Cudnem River with the Mandovi river portion. Research region for groundwater Trace metals contamination within the limits except iron for the WHO 2011 standard. Trace elements in groundwater are characterized as chemical components dissolved in very small quantities in water. The levels of aluminum, barium, boron, copper, manganese, selenium, zinc, cadmium, lead, nickel, arsenic and chromium are well within the permissible limits. All the water samples are favorable for drinking in both of the seasons. Iron levels in groundwater are distinguished by a favorable quality for drinking in all samples, except for three test sites, such as Kumbharwada (S. No. 17), Vagheri (S. No. 22) and Morlem Colony (S. No. 40) in both seasons. The entire study area is widely distributed for the occurrence of iron ore and falls in the active mining belt.

This study aims to understand the mechanism of cohesive sediment transport in irrigation canals when adopting different design approaches. This was achieved through developing a mathematical model to design unlined irrigation canals using three design approaches: regime theory, tractive force and maximum permissible velocity. The latter was modified by the authors to overcome some of its limitations. The model, named ICDesign, was developed using C Sharp language to design the irrigation canals and generate cross sections and a longitudinal profile. Then it was applied to design Zananda Major Canal in the Gezira scheme, Sudan, as a case study. HEC-RAS model was used to simulate the sediment transport based on different design approaches. It was found that the design obtained from the modified maximum permissible velocity gives the least amount and distribution of sediment accumulation along the canal. Thus, it was concluded that the developed software can be used in the design of a variety of irrigation canals. The extent of the applicability and use of the software shall be determined in the future studies.

The conventional physical- and climatological-based models estimating actual evapotranspiration (ETa) do not provide accurate ETa, especially for regional-scale which is a challenge that needs to be tackled for the accurate assessment of irrigation practices. In this study, two energy balance models (1) Surface Energy Balance Algorithm for Land (SEBAL) and (2) Mapping Evapotranspiration at High Resolution with Internalized Calibration (METRIC) were applied in the Al Hamra region of Oman to estimate ETa using Landsat 8 satellite imagery. The aim of the study was to estimate ETa using the SEBAL and METRIC model for the period of two years and validate the outcome against modified Penman–Monteith (PM) model. In addition, this study highlighted procedural differences between METRIC and SEBAL models. The results showed that METRIC model estimated ETa successfully with a R² value of 0.81 as compared to SEBAL model (R² = 0.17). Study validated against PM model showed that the METRIC model outperformed the SEBAL with MAE and RMSE values of 0.30 and 0.36 mm as compared to 2.67 and 1.42 mm, respectively. Study concluded that the SEBAL model used cumulative daily net radiation, while METRIC used cumulative reference evapotranspiration to extrapolate ETa on daily basis. Although METRIC performed well than SEBAL, the manual selection of hot and cold pixel in METRIC was a difficult process and it creates vulnerability of inaccurate estimates of ETa. However, from this study, we can conclude that the METRIC model can be useful in providing high spatial and temporal ETa estimates. Furthermore, the approach used in this paper can be generalized and pave the way for further developments of the studied models.

Cost-effective and efficient techniques of geoelectrics for groundwater exploration, especially in karstic regions, can be used to as an appropriate tool to recognition of karst hydrogeological potential. This paper provides a method based on the geoelectrical tomography to precise determination of the water well drilling location in karstic limestones of Izeh, southwest Iran. The geoelectrical operation done in 98 VES of Schlumberger and two profiles using dipole–dipole and Wenner–Shlumberger arrays. The 1D interpretation of VES using IPI2win followed by 2D electrical resistivity and induced polarization (IP) tomography using Res2Dinv in two sites, Naale Asbi syncline and the west of Izeh limestones, is carried out in order to propose the best locations for drilling of water wells. The results of the geoelectrical study of Asmari limestone of Izeh show the high electrical resistivity (between 200 and 1000 ohms-m) and low IP (lower than 3 Mv%V) indicates dry limestone, which decreases electrical resistivity (between 50 and 150 ohms-m) and stability in IP values, while the layers become water bearing. The dry cavities are characterized by very high electrical resistivity anomalies (ranging from 1500 to higher than 2000 ohms-m) with low IP values in the matrix of limestone with medium high electrical resistivity. The marl and marly limestone layers with low permeability can be detected by very low electrical resistivity (lover than 20 ohms-m) and high IP (higher than 10 Mv%V). The tomography of electrical resistivity and IP have strongly confirmed each other especially in the dipole–dipole array, and however, in some cases of Schlumberger array, the deviations are seen in the depth that can arise due to the high sensitivity of the IP data in high depths.

The objective of the present study is the characterization of drought conditions in two important peninsular states of India namely Tamil Nadu and Karnataka through assessment of meteorological drought indices namely drought index (DI), Palmer index (PI), and standardized precipitation index (SPI). For this, monthly and yearly data of precipitation and temperature have been considered for 110 years (1901–2010). Precipitation deficit conditions have been estimated and compared for both regions using annual rainfall classification thresholds. The annual variability of rainfall and associated trend were estimated using Mann-Kendall test and comparative analysis was done to assess the regional variation during the last 110 years. Comparative study on results implied that drought characterization using SPI may amply facilitate the standardization of threshold classification for severity and frequency that was good agreement with observed events. The application of trend detection framework resulted in the identification of significant trends in those districts which were reported to be drought prone regions. Study amply suggested that drought vulnerability in Tamil Nadu was relatively more than that of Karnataka region depending upon the number of dry and wet years in terms of SPI threshold values and areal extend within 110 years of study period however in terms of severity and number of occurrence, Karnataka was more vulnerable. Analysis based on droughts indices suggests that SPI is simple to evaluate and may relatively more meaningful and conclusive in terms of decision making for the study region if compared with other indices.

In the arid and Semi-arid regions of Pakistan uncertainties in rainfall, projections are high due to the large fluctuation of climate and lack of observed quality of rainfall data. An extremely dry and wet event of rainfall directly impacts water resources, soil, agricultural yields, and human activities, especially in the arid region. In this study, a short- and long-term wet and dry period in the selected region of Pakistan was expressed using the standardized precipitation index (SPI) based on the 35 years of monthly rainfall data collected from six meteorological stations. In the first step, the short term (SPI-3 and SPI-6) and the long term (SPI-12 and SPI-24) were computed. Results of the study investigated that extreme drought occurred 0–3%, a severe drought occurred 2–7%, and moderate drought occurred 6–15% for the period 3- to 24-month SPI within the study area. Then SPI values trends were detected using a new graphical approach innovative trend analysis (ITA). ITA test shows that in five stations subject to wet conditions trend decrease and severe drought at three stations increase for the period 3-month SPI. Overall results show that the drought trend especially in Lahore, Multan, and Mianwali stations were detected negative (heavier drought) under 3- to 24-month SPI. This study assessment showing that policymaker is required to launch a monitoring program to find out the local or national drought impacts on wheat, rice, and cotton agriculture land as well as on many other sectors, especially in this study region of the country. The general reduction in SPI values is at some stations that is, a propensity toward heavier dry seasons. These investigated results would also be significant and beneficial for rural agriculture zone where no observed data information exists.

Runoff is affected by several parameters such as soil type, and Land-use/cover changes, which include vegetation cover and level of urbanization. The current study assesses the impact of Land-use/cover change between 1994 and 2018, on the runoff characteristics of Wadi Al-Mulaikhy Sub-watershed in the Sana'a basin, Yemen by integrated GIS, HEC-GeoHMS extension, and HEC-HMS model. Remote sensing data, land-use/cover, soil type, and rainfall are the main input data. The study results show that the agricultural area was reduced by 5.67%. Conversely, the surface runoff for the overall study area has been increased by 1.65%. It was found that there is no significant change in runoff volume relative to Land-use/cover change due to some agricultural general class changes to other classes (shrubs/brush), which have similar runoff characteristics. The second change, agricultural general class changes to urban classes (urban high density, urban medium to low density and roads) which occurred at the north of the study area near the boundary of the city of Sana'a which has an urban expansion. The changes in runoff parameters were found in the sub-basin (W300, W310, and W320) which are located in the north of the study area due to the changes of agricultural general class to urban classes (urban high density, urban medium to low density, and roads).

The current study investigates the water quality of the water resources in Qa’Jahran basin, Dhamar, Yemen. Thirty water wells with a depth ranging from 100 to 600 m below ground level were used to collect water samples. A total of seventeen water quality parameters were measured during 2019, allowing investigation of spatial variation and indication of potential pollution sources. It is essential to have adequate understanding on the interaction effect, trends, and the correlation structure of these parameters to control water quality. Geographical Information System (GIS) and multivariate statistics techniques were used to understand the water resource quality and generate a water quality index map of Qa’Jahran basin. Based on multivariate statistical analysis, strong correlations were observed between total dissolved solids (TDS), conductivity, chloride, total alkalinity, bicarbonate, sodium, and chloride. Sodium has strong correlation with total alkalinity, chloride, and bicarbonate, while it has moderate correlation with fluoride. On the other side, principal component analysis shows that 85.22% of the overall variances were explained by four major principal components. Accordingly, 52% of the data were required to explain 85.22% of total variances as shown by the factor analysis indicating significant data reduction was resulted in this study. According to the water quality index (WQI), most of the water samples were classified as excellent to good for drinking purpose.

Al Kufrah basin, which is a part of the huge trans-boundary Nubian Sandstone Aquifer System (NSAS) shared by Libya, Egypt, Sudan and Chad, is a major water resource in North Africa. The NSAS consists of a number of aquifers laterally and /or vertically interconnected, extending over more than 2 × 10⁶ km². In recent years, the demand in some areas has resulted in withdrawals that substantially exceed replenishment of the aquifers. A 3-D groundwater flow model was constructed and calibrated to simulate the subregional groundwater flow during the pre- and post-development periods in response to stresses within Al Kufrah Region. The developed model utilized PMWIN^® software, a fully integrated modeling platform that uses the USGS Modular MODFLOW2000^®. The entire simulated thickness of 300 m was modeled as three hydraulically connected horizontal layers; each layer consists of 181 rows and 181 columns with grid spacing of 500 m by 500 m to cover a total area of 8190 km². General head boundaries (GHBs) were assigned to the southern and eastern nodes to simulate the groundwater inflow and outflow. Evapotranspiration was assigned to the upper model layer, with a maximum rate of 2750 mm/yr and an extinction depth of 2 m below the ground surface. Groundwater flow parameters (principally hydraulic conductivities, boundary conditions and recharge) were set during the steady-state calibration process. Calibration proceeded by varying these input parameters until the model results in most closely matched field measurements. In addition, the simulated hydraulic heads were consistent within the model domain with the actual field measurements (before the year 1968). Five stress periods—transient-state flow model, were constructed and calibrated using all available data from 1968 to 2010. Specific storage values range from 10⁻⁵ to 10⁻² for the middle and the lower layers, and specific yield range between 2 × 10⁻³ and 2 × 10⁻¹ for the upper layer was initially assigned based on the previous hydrogeological studies of Al Kufrah basin; these values were repeatedly adjusted for the three layers during the calibration of the first period until satisfactorily calibrated hydraulic heads were reached. A value of about 10% of the total applied water was assigned to layer 1 as a surface recharge. Analysis of the residual statistics and spatial distribution of residuals as well as the visual comparison between simulated and observed hydrographs and potentiometric surfaces were used to analyze the ability of the calibrated model to simulate aquifer conditions within acceptable error. The root of mean square errors ranges from 0.8 m to 2.34 m for the 33 observation wells. Calibrated model output includes a 43-year estimate of the water budget by the end of each stress period at the shallow and deep layers. The historical calibration of this transient-state model indicated a very close matching between the calculated and the observed drawdown values that have exceeded 40 m during some periods.

Groundwater serves as the main source of water for drinking and other domestic purposes, and often it is over exploited. Nowadays, it is facing threats due to anthropogenic activities. In this study, a total of 20 groundwater samples from boreholes used for drinking, and other domestic purposes were collected from Hadejia town northeastern Jigawa State, Nigeria, and analyzed for their physicochemical characteristics and trace metal levels using standard methods aimed at assessing the groundwater quality. The well-founded techniques of principal component analysis (PCA) and cluster analysis (CA) were jointly used. PCA was used to investigate the origin of each water quality parameters and yielded five varimax factors/components with 78.69% total variance in the groundwater quality data. First two factors reveal that 47.69% of the total variance dominated by total hardness, TDS, Cl⁻, NO₃⁻, Cu, EC, Fe, and Cr indicating the major variations are related to anthropogenic activities and natural processes. Cluster analysis results grouped the 15 parameters and 20 sampling sites into two and four statistically significant clusters, respectively, based on their similarities. The results showed that concentrations of Mn, Cr, and Pb are slightly higher above the maximum permissible limit of Nigerian standard for drinking water quality (NSDWQ, Nigerian Industrial Standard. NIS 554, Nigerian Standard for Drinking Water Quality (NSDWQ). (2007). Nigerian Industrial Standard (NIS) 554:2007 ICs 13.060.20.) and hence the need for the replacement of the affected wells.

To investigate the present of the two most common analytical tools; heterogeneity and homogeneity over a mutual cooperative in an irrigation system, we considered both of these in an attempt to find an existing mutual cooperative over aflaj (singular falaj) in Oman. In an aflaj community defined-boundary shareholders group, we expect some sort of equal size distribution by which all members interested in cooperative mutual collective action with regard to system maintenance, extra water renting right, and water flow reliability. We provided the necessary demonstration of the existing institutional arrangement to further prove the theory. Although fast body of literatures discussed these rules and cooperative with the different types of the common-pool resources, this study focus over the cooperative collective action, in particular investigate the presence of cooperative collective action within the Omani ancient-aflaj system (singular falaj). In Oman, aflaj water allocation and its institutional arrangement showed relatively resilient against recent regional development. Today, in many aflaj communities, common administrative as well as allocative water delivery processes were found over almost identical structural social hierarchy. While the documented Omani measuring unit, known as ather, (based on time) indicated the first condition of the present of cooperative collective action, another associated water auctioning which used to generate income, (known as rub’ah (quarter)) has been found.

Maintaining clean drinking water is a key factor in maintaining sustainable development and a healthy environment. In addition to monitoring water quality at water tanks, it is important to monitor water distribution network (WDN) and pipes where water is being transported. Intrusion in WDN can be triggered by transient low-pressure events. This intrusion may result in the contamination of drinking water supplied to consumers, which may have major health impacts. This experimental study was performed to monitor and count E. coli bacterial intrusion into WDN. Two experiments were performed to investigate (1) the effect of low and negative pressure in WDN on bacterial intrusion; (2) the propagation and growth of bulk bacterial intrusion in WDN; (3) premeditated bacterial contamination of water sources (tanks). It was found that the rate at which bacteria reaches customers is very comparable however, higher risks are found with premeditated bacterial intrusion. It was also found that there is a small chance for E. coli bacteria to be intruded into the system after sudden low/negative pressure events. The experiment shows that high pressure within water networks pumps out water of the system then the mixture (water and contaminants) is sucked back into the network. It was observed that contaminants were not able to be significantly intruded into the system if water pumps were shut down for a short period of time. The minimum time required for contaminant to be intruded into the system was found to depend on the water pressure prior water pumps which were turned off.

Mosquitoes are the major vectors of many diseases such as the malaria, filariasis, dengue, and Japanese encephalitis. Mosquitoes propagate quite successfully in a variety of aquatic habitats such as drinking water system, manmade water bodies, and sewage contaminated aquatic system. Since, water is essential for all life, without it, life won’t progress and at the same time, the quality of the water also important. With the unique structural features present in chitosan bio-polymer helps to bind effectively with fine suspended particles, pollutants, bacteria, heavy metals etc. The biocompatible and biodegradable nature of chitosan makes it a potential candidate for mosquito breeding water purification purposes. In this regard, chitosan has been extracted from freshwater crab shells Scylla serrata and reduced for silver nanoparticle synthesis. It has been utilized as a potent tool in control of young instars of Aedes aegypti and its breeding water purification. Bio-synthesized chitosan-reduced silver nanoparticles were characterized by UV–Vis spectrum, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (E-DAX), and X-ray diffraction (XRD). In laboratory condition, the chitosan silver nanocomplex was found to possess toxicity against young instars (I, II, III, and IV) of Aedes aegypti at the concentrations of 2, 4, 6, 8, and 10 ppm followed by chitosan treatment alone. The surface stagnant water from dengue vector breeding site checked the water purification parameters, such as water temperature (WT), pH, salinity, dissolved oxygen (DO), total dissolved solids (TDS), and electrical conductivity (EC) by using “μP Based Water & Soil Analysis Kit” (Model 1160). Further, from the results it is clearly postulated that the biomolecules present in the chitosan not only showed biopesticidal activity against mosquito larvae and pupae but also nullified the contaminants in the water and made human usage.

Sulphate ion is a naturally occurring substance present in various mineral salts that are found in soil and various water supplies. Sulphate ions are generally considered to be non-toxic and therefore not strictly regulated, however, the consumption of drinking water containing high amounts of magnesium or sodium sulphates may result in intestinal discomfort, diarrhoea and consequently dehydration. Although there are numerous traditional adsorbents for sulphate ions removal, it is imperative to develop a cheap, easily accessible, and ecological-friendly adsorbents for the treatment of sulphates in water. This research investigated sulphate ions removal by the synthesized modified bentonite (MB) and acid-digested bentonite (ADB) as an alternative for traditional adsorbents. The modified bentonite was prepared through microwave acid digestion of raw bentonite (RB) and was subsequently coated with cationic polyelectrolytes polydiallyl dimethyl ammonium chloride (poly-DADMAC). The RB, ADB and MB were characterized using scanning electron microscopy/energy dispersive X-ray (SEM/EDX), X-ray diffraction spectroscopy (XRD) and Fourier transform infrared ray (FTIR) spectrometer. The effects of solution pH, contact time, agitation speed, the dosage of the adsorbents and initial concentration of sulphate ions on the removal from synthesized wastewater were investigated in batch adsorption studies. The characterization results showed successful impregnation of poly-DADMAC and changes in the chemical composition of the synthesized adsorbents. Results of the study showed that as high as 65% of 10 ppm sulphates were removed using 20 g/L MB dosage at pH 6, agitation speed 50 rpm within 30 min of treatment time. However, only 16% of sulphates were removed with ADB under the same conditions. The results also showed that the sulphates removal by modified bentonite followed pseudo-first-order kinetics. It can be concluded that the Poly-DADMAC-modified bentonite has a very good removal capacity for sulphate ions in aqueous solution.

In the last decade, Syria has witnessed a dramatic change in rainfall patterns. These changes have badly affected vegetation cover and agricultural production. Thus, the aim of this research is to track agricultural drought changes over Syria and to highlight the most vulnerable zones to them. To achieve the study aim, monthly precipitation data observed at 36 metrological stations uniformly distributed over Syria were collected. After that, dataset was checked for homogeneity. The Standardized Precipitation Index (SPI) was then applied to detect agricultural drought. In the final steps, the results were driven to GIS and interpolated using the ‘Kriging’ method. The results showed that rainfall had decreased across Syria from 1990 to 2010. However, the years between 2006 and 2010 were the worst of the studied periods. Similarly, the Mann–Kendall test showed a negative trend for agricultural drought in almost all of the studied stations. All in all, this research emphasizes the negative trends of rainfall in Syria and the positive trend of agricultural drought.

The western part of the Rajasthan state is the desert area of India with low and erratic rainfall and sandy soils. The real problem related to water in desert is from its inter-annual variability in rainfall. The aim of this paper, therefore, is to study the basic characteristics of rainwater resources of India’s desert area in the west Rajasthan in relation to the variability of rainfall, the frequency of droughts and floods and the occurrence of maximum point and areal rain water on the basis of their latest rainfall data of 22 stations for the period from 1957 to 2012. It has been found that the annual variability in rainwater is quite large leading to a deficit in water supplies during low rainfall. When rainfall is only 186 mm or less drought conditions occur, which occurs about once in every four years, floods are rare due to low rainfall in the region but sometimes high rainfall results in flash floods as seen in the region of Barmer district in 1973. In such cases, there is a potential to utilize this flood water wisely for public consumption. The desert of West Rajasthan and other deserts of the world provide considerable hydrometeorological contrast.

Citrus is a major fruit crop produced (on 120,000 ha) and exported from Morocco, consuming 10,000 m³ of irrigation water per ha annually. Currently, irrigation water is becoming very scarce, and drip irrigation is the water supply system used in plantings because of its high water use efficiency and productivity. Recent research indicates that additional water saving and higher efficiency can be obtained via adoption of deficit irrigation strategies such as sustained deficit irrigation (SDI), regulated deficit irrigation (RDI), and partial root zone drying (PRD). These irrigation strategies were applied on citrus clementine (Citrus reticulata) plantings for two years at different tree phonological stages. Four cultivars were included: ‘Sidi Aissa’ and ‘Orogrande’ in 2017 and ‘Bruno’, and ‘Esbal’ in 2018. Results indicate that water saving was in the range of 6 to 31% compared to control fully irrigated plantings depending on the strategy. However, deficit irrigation reduced fruit size, yield, and vegetative growth but enhanced fruit quality with PRD treatments having more significant effect than SDI or RDI. The negative effect of water deficit stress was more pronounced on total yield than on fruit size, particularly in high vapor pressure deficit (VPD) years and for PRD strategy. Under years of mild VPD, this negative effect was significant but equal for fruit size and yield. Water productivity decreased with water amounts applied. However, since clementine fruit is destined to fresh market which demands fruit of large size, it can be safe to recommend use of RDI and avoid PRD under semi-arid conditions.

In our research, the magnetic nanocomposite adsorbent Zn Fe₃O₄/SiO₂ MCM-48 was prepared, and the ability of this nanocomposite to remove phosphate and nitrate ions from synthetic wastewater was investigated. Various batch adsorption conditions, including different pH, temperature, contact time, initial phosphate concentration and adsorbent dosage conditions, were considered. Phosphate and nitrate adsorption kinetics were well fitted by the pseudo-second-order kinetic model for all studied adsorbents. The adsorption process was represented by Langmuir isotherms. The thermodynamic parameters ∆G, ∆H and ∆S, which were determined using the Van't Hoff equation, indicated that the phosphate adsorption reactions on the Zn Fe₃O₄/SiO₂ MCM-48 nanocomposite were spontaneous and endothermic in nature. The optimal conditions for the adsorption of phosphate and nitrate ions onto Zn Fe₃O₄/SiO₂ MCM-48 were a pH of 2.0, temperature of 340 K and contact time of 66 min. The results presented here support the potential of using the Zn Fe₃O₄/SiO₂ MCM-48magnetic nanocomposite as a material for the treatment of phosphate and nitrate ions in wastewater.

The limited availability of freshwater and succession of drought years and climate change have put the pressor to look for alternative water resources including treated wastewater, in order to meet the demands of agriculture in the Souss-Massa, Morocco. This study focuses on the use of treated wastewater for growing sweet corn under different systems and doses of irrigation. An open field experiment was carried out in the Agadir region using two sweet corn varieties: Prime-plus and SF681 and two irrigation systems subsurface drippers (SSD) and surface drippers (SD) also two irrigation doses regime 100 and 120% of the ETM determined using Lysimeters. The growth and yield components of sweet corn were improved by irrigation under surface dripper, using high dose of irrigation. However, the high accumulation of salts in the root zone under subsurface drip irrigation reduced the growth and yield of corn. Adding a leaching fraction of 20% of ETM, improve growth and yield of both sweet corn varieties. The highest yield was achieved by SF681 variety with 20 T/ha, under (SD) irrigated with 120% of ETM. Reducing water application by 20% decreases yield production up to 24.4% under (SD) and gave the same yield for both 100 and 120% of ETM under (SSD). Despite that (SSD) saves water, it increased soil salinity, even in sandy soil, due to the accumulation of salts in the root zone. Under treated wastewater irrigation, the sweet corn water consumption was 186 mm, allowing a saving of conventional water. Furthermore, it generated an economic gain in terms of fertilizers: 240 kg/ha of N and 60 kg/ha of CaO in addition to 10.38 kg/ha of P₂O₅ and 65.12 kg/ha of K₂O in the case of 100% ETM and 12.45 kg/ha of P₂O₅ and 78.14 kg/ha of K₂O in the case of 120% ETM.

Catalase (CAT) is an important enzyme in the antioxidant defense system in marine bivalves. This present work consists first of all in studying the effect, of an acute exposure (bioassays) of the mussels Mytilus galloprovincialis to three types of real effluents [industrial wastewater (IW), desalination station effluent (DSE) and harbor effluents (HE)], on the enzymatic activities CAT. In situ, the transplantation of mussels into natural environments was carried out in the same context. The medium size class of the Mytilus mussel has proven to be the most resistant to contamination by the IW. Notwithstanding, this same size class showed hypersensitivity to contamination by the SDE, thus translating the high toxicity of the latter which led to very high CAT inductions whatever the concentration tested. Furthermore, under controlled laboratory conditions, the HE demonstrated a certain toxicity by inducing the CAT enzyme. On the other hand, the Mytilus mussels transplanted to the khemesti port site are found all dead after ten days of immersion. The deoxygenation of the medium probably had an additional and aggressive effect on our specimens of mussels. This study makes it possible to qualify catalase as a relevant, sensitive, rapid and effective defense biomarker in the evaluation of the health state of the surrounding environment. However, more studies must be made on metabolic activities and energy reserves while adopting the multibiomarker approach.

The preparation of activated carbon derived from aerobic biological treatment of the activated sludge (SSAC) is a promising way to dispose of sewage sludge as well as to produce a low-cost adsorbent for pollutant removal methylene blue (MB). In this work, the activated carbon was developed from aerobic biological treatment of the activated sludge using KOH as a chemical activation reagent. The SSAC was characterized by scanning electron microscope (SEM) and Fourier transforms infrared spectroscopy (FTIR) analysis. The SEM study showed that the activated carbon was not large and uniform porous. The main functional groups present in the prepared activated carbon were quinone and aromatic rings. The highest removal of methylene blue dye obtained at prepared SSAC optimum conditions (Temp. 500 °C, time 180 min, KOH 30 g) was 99.92%. It is concluded that the activated carbon from sewage sludge is promising for pollutant removal from wastewater using adsorption process.

Groundwater is the second biggest source of freshwater of our planet, and it is the only resource that can be access to face the problem of stopping water supply during war and disaster periods. However, there are several challenges facing water quality, particularly in arid and semi-arid regions where climate conditions, type of reservoir rock, geological setting and anthropogenic activities have a significant impact on the groundwater quality. In this work, 13 groundwater samples were taken to evaluate the water quality and investigate its suitability for various uses, such as drinking water, irrigation and household water supply at the left side of Mosul City. These samples were collected from the wells that were dug during the time of liberation the city from ISIS fighters. Attention was given on the examination of EC, TDS, pH, Ca⁺², Mg⁺², Na⁺, K⁺, SO ₄ ⁻² , Cl⁻, NO₃⁻ and other water quality parameters, such as sodium adsorption ratio, sodium percentage and magnesium adsorption ratio, as well as heterotrophic bacteria and coliform bacteria. The results of factor analysis proved that the geochemical composition of groundwater is mainly controlled by chemical weathering of carbonate–sulfate minerals and the contamination by municipal activities in the city. The results of the assessment of groundwater proprieties for drinking and irrigation purposes will give for both decision makers and people good insights for managing the groundwater during crises at this part of Mosul City.

Human management and social communication networks play an important role in water resources management, especially in arid and semi-arid regions. Active actors and a coherent network of individuals are very useful in establishing an appropriate collaborative governance to face the current constraints of water management, conservation, control, and optimal management. In this study, special attention pay to the human role of local actors in the context of a water management social network in central part of Iran with severe water restrictions and under the effects of repeated droughts. Due to the challenges in water distribution as well as local conflicts, it is evaluated based on social network analysis method. The relationships of actors were tested based on indices of density, reciprocity, and focus on local active networks throughout Yazd province during the year 2018–2019. The results show that lack of individuals as mediators between two or more close groups makes it difficult to transfer different information (social, environmental, and economic) between different groups. The lack of inter-group collaboration relationships has created structural holes (empty space) throughout the network that is reduced the direct contact between the actors. The absence of these people with appropriate distribution, who are able to get different ideas from different sources and share innovative ideas with others, has reduced creativity and innovation necessary in dealing with environmental problems especially drought. This study has provided to achieve ideal governance plan by introducing vital actors and presenting weaknesses at the macro level of the human relations network.

This paper is aimed to study the technical and economical supply of minimum potable water in the southern regions of Iran (isolated areas with lack of access to national water and electricity networks), especially on Hormuz Island. In this regard, the technical-economic analysis of solar membrane distillation and membrane distillation is carried out as a package (mobile desalination). The cost of thermal energy in each of these systems is zero. At present, the minimum required potable water on Hormuz Island is 30 m³/d. The cost of water generated from the solar membrane distillation is 6 $/m³, and the cost of water produced in the mobile desalination is 1 $/m³. Furthermore, the problems of the potable water transfer in a mobile desalination are also met.

The sources of groundwater pollution in Behbahan plain, southwest of Iran, as an urban aquifer in arid climate, were determined using hydrogeochemistry. Groundwater samples were collected from 40 water wells in both wet and dry periods, June 2017 and April 2018. The water samples were analyzed for determination of major ions, nitrate, fluoride, and bromide. The quality of groundwater pollution in the Behbahan plain was affected by natural groundwater recharge (R) and discharge (D) areas, Marun (M) and Bonehbasht (B) irrigation and drainage networks, contact with gypsum bedrock (G) of the Gachsaran formation, and wastewater of Behbahan City (T). The spatial variation of electrical conductivity, chloride, ionic ratios, and nitrate concentrations was investigated to determine anomalous groundwater zones associated with urban sources of groundwater pollution. Cluster analysis (CA) was also employed to evaluate the recharge sources, where it was observed that both natural and anthropogenic factors were affecting the groundwater quality. Two major water types Ca-SO₄ and Ca(Na)-SO₄(Cl) were present in the Behbahan groundwater plain. The high concentrations of sulfate, calcium, and magnesium were reflected in moderate-to-high TDS (about 3000 mg/l). The dominant hydrogeochemical processes in the aquifer were dissolution of gypsum and somewhat halite, dedolomitization, scant normal and reverse cation exchange, and mixing. The main sources of the nitrate pollution of groundwater were leaching of organic manure applied on cultivated areas as well as wastewater of Behbahan City. The minimum and maximum concentrations of nitrate in groundwater of the Behbahan plain were 5–105 mg/L and 5–150 mg/L in dry and wet periods, respectively. About one third of groundwater samples in the Behbahan plain had nitrate concentrations above drinking water standard (45 mg/L).

The economic expansion of Niger Delta region depends on groundwater resource for various uses. Therefore, there is need for an understanding of the hydrogeological and hydrochemical characteristics as an integral for management of the resource. Hence, this study was aimed at delineating areas of saltwater intrusion in the area. Geological and hydrogeological data were used to delineate two aquifers: alluvial aquifer (upper designated as A and lower designated as B) and a coastal plain aquifer (designated as C). Groundwater in the area was classified as fresh (<1500 μS/cm), brackish (1500–3000 μS/cm), and saline (>3000 μS/cm). Among the groundwater samples (n = 105), 95% from A, B, and C were classified as fresh, while 2 and 3% of the samples from A were classified as brackish and saline, respectively. The main groundwater facies were Na–Cl, Mg–Cl, and Na–HCO₃ respectively, for A, B, and C aquifers. The enrichment of Na⁺ and Cl⁻, freshwater–seawater mixing ratio, cross plots, and classifications by means of different schemes indicated that seawater intrusion was occurring in the A aquifer. In terms of drinking and irrigation use, the A aquifer water is of poor quality relative to the groundwater from B and C aquifers. The study highlights the potential danger of contaminated groundwater in the coastal areas occupied by low income dwellers. Hence, seawater intrusion should be continuously monitored for sustainable development and management of groundwater in coastal areas.

Results obtained from the interpretation of vertical electrical sounding (VES) were combined with geological data to determine the groundwater potential of the study area. The dominant lithology in the area is the shales of the Asu River group of Albian age. The tectonic activities that took place in Santonian times resulted in folding, uplift, and intense fracturing of the shales of the study area. The challenge lies on how to map the fracture zones in the shales in order to optimally exploit the groundwater resources in the area. Ten (10) vertical electrical soundings (VESs) with maximum current electrode (AB) spread of 300 m were acquired using the Schlumberger configuration. Four (4) of the soundings were carried out near existing boreholes for comparative purposes between the geological and geoelectric sections. Layer parameters (aquifer thickness, depth to water, transverse resistance, etc.) were obtained after data processing with the IP12 Win™ software. The derived layer parameters were combined with borehole logs and pumping test data from existing boreholes to estimate aquifer hydraulic parameters in other locations without boreholes. Results show that the depth to the fractured shale aquifer ranges from 22.1 to 54.9 m at Ekpelu (VES 9) and Ndufu Alike II (VES 2), respectively, while aquifer thicknesses vary from 19 m at Ndufu Alike I and II (VES 1 and VES 2) to 56.4 m at Amainyima (VES 10). Hydraulic conductivity varies between 0.0047 m/day at Ndufu Alike I (VES I) and 0.300 m/day at Onyikwa playground (VES 5), while transmissivity varies between 0.0893 m²/day at Ndufu Alike I (VES I) and 9.780 m²/day at Onyikwa Playground (VES 5).