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The impacts of climate change on the conjunctive use of surface water and groundwater resources of the Khorramabad basin were evaluated. Monthly temperature and rainfall modelled using HadCM3 and CGCM2 under greenhouse gas emissions scenarios (GHGESs) A2 and B2 were downscaled to baseline (1971–2000) and future periods (2040–2069 and 2070–2099). Simulations were performed for four climate change scenarios (CCSs) (A2-2040–2069, A2-2070–2099, B2-2040–2069 and B2-2070–2099). The projections indicated an increase in temperature and a decrease in rainfall. Future surface water resources were simulated using IHACRES. The results indicated that average annual runoff under GHGESs A2 and B2 would decrease by, respectively, 2.03% and 4.17% in 2040–2069 and by 6.64% and 8.94% in 2070–2099. Groundwater simulation was carried out using ModFlow. The results showed that under, the four CCSs, groundwater level would decline by 2.3, 3.0, 2.5 and 3.4%, respectively, relative to the baseline. Aquifer recharge under the four scenarios would decline by 1.43, 5.71, 2.86 and 7.14%, respectively. The results from IHACRES and ModFlow were employed to develop a conjunctive operation model with the Weap model. Several CCSs with various levels of future water demand were assessed using Weap. A 20% increase in water demand relative to the baseline, for instance, was projected to produce annual deficits in future agricultural water supply of 3.3, 5.08, 3.05 and 5.18 (× 106 m3), respectively, under the four CCSs.

Mountain headwater streams are important freshwater sources, but they are mostly intermittent and highly susceptible to climate change. This paper examines the sustainability of augmented freshwater availability in mountain headwater streams for water supply under baseline and future climate change scenarios using an integrated modeling approach. The climate change data in the 2040s (2030–2059), under Representative Concentration Pathway 4.5 and 8.5 scenarios, were downscaled for the impact assessment. In the region, climate change raises the average precipitation by 5–7% and the temperature by 13–15% in the 2040s. SWAT–MODFLOW model, integrating Soil and Water Assessment Tool (SWAT2012) and finite-difference Modular Groundwater Flow (MODFLOW) models in a single package, was used to assess the water balance. Results show that extracting a minimum of 16.2 m3/day from the sand storage and 30 m3/day from the aquifer was possible without affecting the groundwater table and water yield. The average annual catchment recharge was 6% of the precipitation under the baseline simulation. Climate change is projected to reduce the average water yield and groundwater recharge by 26% and 19%, respectively. However, the water supply-demand is significantly small compared to the exploitable rate of water in the area. This study was based on limited data, and therefore the findings need to be interpreted with caution, though the model output was validated using satellite products. Construction of a series of sand dams is suggested to maximize the benefit under the potential climate change and water supply-demand increase.

In this paper, bulk water abstractions and a purification process in terms of water pumped energy consumption, is modelled and simulated. The study proposes an optimal energy consumption-rate management system, using real-time data. The aim is to achieve the goal of obtaining potable water by scheduling the pumping process, to obtain the cheapest energy-rate at any given load demand. Considering the loss due to the effect of evaporation, the effect of precipitation (or rainfall) and seepage losses. As a baseline, an electronic timer switching system for the powering of electrical pumps, used to pump water from one level to another, is incorporated. An optimal control system is included that looks at the energy cost before scheduling the pumping sequence in such a way that pumping occurs during the more affordable energy costing period and ensures that the water demand from consumers matches the water pump level in the storage reservoir. The configuration involved the time of use (TOU) tariff; in the context of the South African electricity tariff. The optimal control output, compared to an electronic timer switching system, shows an end-of-day cost reduction of 1994 ZAR in water-pumped energy consumption from the grid. This reduction in energy consumption is therefore a direct reflection of the reduction in the cost of water supply to consumers.

The deteriorative processes occurring in the environment, the growth of population, the water demand of industry and agriculture, point out day after day the increasing role of water management. The economical use of drinking-water consumption as well as the cost reduction is becoming more and more important. In this research, the measure of a water supplier of Győr was examined in terms of implementing the purposes above.

Zebra mussels Dreissena polymorpha are tiny bivalve mollusca , invade water supply of cooling system unit in Al- Musayab power plant, 60 km south-west Baghdad and grow to dense clusters. Its ability to rapidly colonize intake structures, such as pipes and screens causing reduction in water pumping capabilities .Some biological aspects of zebra mussel Dreissena polymorpha have been studied and some physical & chemical parameters were examined as alimenting factors for the species Samples collecting was done monthly from two sites within the water system , the first was the traveling band screen (TBS ) and the other site was small canal collecting excess water passing from TBS .Biological studies revealed that the samples collected from the canal includes five size groups with average length of 5.7 ; 11.3 ; 16.7 ; 21.9 & 27.3 mm. In TBS , the individuals found all over the year with highest number of 135 individuals recorded in August . Individuals of a length of 11.3 & 16.7mm were the dominant.In general, from total number of 799 individuals collected from TBS, 388 individuals were of size of 11.3mm and 239 individual were of size 16.7mm while no large specimens of large size group of 27.3mm were recorded in TBS.To study the settlement rate of larvae, several concreat tiles of (25X25cm) were suspended at depths of 2,4& 6 m. in the sedimentation pond (12m depth). The number of juveniles were counted monthly . The result showed that there were two peaks of settlement , one in June and the other in September and October .Depth of 6m was the most suitable for settlement.The average length of settled juveniles ranged between 3.5-6.1mm. Water temperature in the site ranged between 11-32o C , Dissolved oxygen was 4.8-8.3ml/L . The highest value of turbidity was 49NTU.Ca++ was 68-136mg/l and Mg++ was 34- 72mg/l

The Tala water tank in Kolkata, India, is the largest water tank in the world with an active capacity of 41 Ml. The tank is an integral part of the first organised water supply system of the city since its commissioning in 1911. It was introduced to relieve the upstream supply pumps of stresses caused by fluctuating downstream demand. The tank structure is robust with an overall dimension of 97 m square and total 6 m height. The steel frame staging is supported on multiple types of trussed grouped columns with only one inlet-cum-delivery pipe. The tank was constructed in steel riveted joints and staged over 28 m from the ground level. The framed staging comprises 295 columns with a combined length of steel members measuring over 80 km. There are inclined rafters securing its walls by connecting to its floor. The bottom plate is made of flat steel riveted sheets of 6 m square panels. It has four compartments with an isolation facility. Kolkata Municipal Corporation has taken up a project to rehabilitate and retrofit this unique asset. This paper identifies the extremely technical and logistical challenges faced in the refurbishment and retrofitting of this engineering marvel.

Beijing is a city with severe water shortage, and the rapidly growing economy and population has led to an increasing water demand for households. Thus, water conservation has become the focus of urban water supply and demand management. This study analyzed the impact of water saving devices on urban residential water consumption and water supply security in Beijing. The results show that the popularization of water saving devices brings significant water conservation potential to households in Beijing, with 22% water saving efficiency in 2019. It is predicted that the per capita urban residential water demand of Beijing in 2030 will be 201 lpd (liters per capita per day), but the water consumption may decrease to 163 lpd, 148 lpd or 133 lpd, respectively, in three proposed water saving scenarios (S1 to S3). Compared with water demand, the water saving efficiency was calculated at 19%, 26% and 34%, respectively. Meanwhile, the total urban residential water consumption under the four scenarios in 2030 would be 1.372, 1.242 or 1.113 billion m3, respectively. However, the Comprehensive National Water Resources Plan proposes that urban residential water consumption in 2030 should be limited to 1.12 billion m3. Therefore, only in the enhanced water saving scenario (S3) can the total urban residential water consumption meet the household demand and achieve the goal of security controlling. In addition, this paper analyzes the cost-effectiveness of water saving devices promotion policy and proposes some further measures to ensure the water supply security and develop the water conservation potential in Beijing households.

This paper proposes the concept of “sub-wet bulb temperature” for the application of evaporative cooling technology, discusses the principle and implementation approach of the indirect-direct evaporative chiller for producing sub-wet bulb temperature cold water, and puts forward a way to describe the cooling performance of the pre-cooling section of indirect evaporative cooling through “sub-wet bulb efficiency”, using the “cooling efficiency of the water drenching filler on the air side and the water side” to show the cooling performance of the direct evaporative cooling section of the Water drenching filler, and utilizing the “unit's chilled water efficiency” to describe the cooling performance of the whole unit, and then explicit equation for predicting the unit's water supply temperature is derived out. The cooling performance of evaporative cooling chillers under different ambient air pre-cooling types was tested in Xinjiang region. The results showed that the chilled water efficiency of evaporative chillers reached a maximum value of 45.9 under the coil and vertical tube type of indirect evaporative pre-cooling form. At this time, the sub-wet bulb efficiency of the pre-cooling section of indirect evaporative cooling is 52.1%, the cooling efficiency of the water drenching filler on the air side has reached to 59.8%, and the water supply temperature of the unit is 13.7 °C, which is 2.3 °C lower than the wet bulb temperature of ambient air.

The global vegetation cover is increasing and is expected continue increasing till 2100, owing to CO2 fertilisation and afforestation. This greening phenomenon may create conflicting demands for water between ecosystems, atmosphere, and humans, and has aroused a series of controversies. For exploring the effects of greening phenomenon on terrestrial water availability, we estimated the balance between water supply (precipitation and snowmelt runoff) and water consumption (evaporation, human water use, transpiration, and interception losses) in the global vegetation land based on the outputs of 30 models from the Coupled Model Intercomparison Project Phase 6. Water consumption showed an increasing trend in most regions of global vegetation land for the period 1982–2016 as well as 2040–2100, mainly driven by the increased transpiration and interception losses for vegetation growth (contributing 85.4–90.5%). Although the greening phenomenon widely exacerbates water shortages, 94.3–98.8% of the global vegetation land was still found to be sustainable during 1982–2100, due to the water supply exceeding the total water consumption. More attention should be paid to the unsustainable regions where the total water consumption exceeded the total water supply. Such areas were continuously found to increase from 2.1–5.3% (1982–2016) to 5.4–5.7% (2040–2100) of the global vegetation land. We predict that Oceania, Northern India, the southern coastal regions of North America will be transformed from sustainable regions in 1982–2016 to unsustainable regions in 2040–2100.

In order to achieve automatic pressure regulating and promote the field application of negative pressure irrigation, an automatic negative pressure control device based on a single-chip microcomputer was developed for regulating and recording data automatically. The results of laboratory and field tests showed that the pressure adjustment precision was 0.45%, 1.79%, 1.99% and 0.84% respectively. In a field test, the water infiltration rates were decreased from 7.20–9.72 mm d−1 on the first day to 1.6–2.5 mm d−1 in the following 30 d, the soil moisture content was the largest around the emitter for 0.24–0.27 g g−1 and lowest in the margin for about 0.07–0.08 g g−1 at different negative pressure. Both laboratory and in-field measurements demonstrated that the device functioned well in signal acquisition, data conversion, processing, transmission, storage and control. The result showed the device could supply a low-rate water continuously and keep soil wetted. It needed more than 10 d obtain soil moisture conditions suitable for crop growth in the field, thus it is advised that a positive pressure should be applied in the initial to generate a stable water distribution, and then adopt a suitable negative pressure to meet crop water requirements. The study confirmed the potential of the device to be used for regulating pressure and recording data accurately in the laboratory and field experiment, and helped ensure future research of similar irrigation systems in the field.

Droughts increasingly threaten the world’s forests and their potential to mitigate climate change. In 2018–2019, Central European forests were hit by two consecutive hotter drought years, an unprecedented phenomenon that is likely to occur more frequently with climate change. Here, we examine tree growth and physiological stress responses (increase in carbon isotope composition; Δδ13C) to this consecutive drought based on tree-rings of dominant tree species in a Central European floodplain forest. Tree growth was not reduced for most species in 2018, indicating that water supply in floodplain forests can partly buffer meteorological water deficits. Drought stress responses in 2018 were comparable to former single drought years but the hotter drought in 2018 induced drought legacies in tree growth while former droughts did not. We observed strong decreases in tree growth and increases in Δδ13C across all tree species in 2019, which are likely driven by the cumulative stress both consecutive hotter droughts exerted. Our results show that consecutive hotter droughts pose a novel threat to forests under climate change, even in forest ecosystems with comparably high levels of water supply.

In this study, we develop a hydro-economic modelling framework for river-basin scales by integrating a water resources system model and an economic model. This framework allows for the representation of both local-scale features, such as reservoirs, diversions, and water licenses and priorities, and regional- and provincial-scale features, such as cross-sectoral and inter-regional connectedness and trade flows. This framework is able to: (a) represent nonlinearities and interactions that cannot be represented by either of typical water resources or economic models; (b) analyze the sensitivity of macro-scale economy to different local water management decisions (called ‘decision levers’ herein); and (c) identify water allocation strategies that are economically sound across sectors and regions. This integrated model is applied to the multi-jurisdictional Saskatchewan River Basin in Western Canada. Our findings reveal that an economically optimal water allocation strategy can mitigate the economic losses of water stress up to 80% compared to the existing water allocation strategy. We draw lessons from our analysis and discuss how integrated inter-regional hydro-economic modelling can benefit vulnerability assessment and robust decision making.

This paper presents the application of hydraulic modelling for the prediction of pipe bursts in a water distribution system (WDS). As a case study, more than 1430 km of pipelines within 29 water pressure zones (PZs) in Bendigo and Castlemaine WDSs, located in Victoria, Australia, were modelled and calibrated using an InfoWorks WS hydraulic model. A pressure index (PI) was defined to quantify the intensity of high pressures in the WDS pipes. The PIs for all the PZs were calculated using hydraulic model simulations. Ten years of actual pipe burst data (2007–2017) in the studied WDSs were used in the research. A burst index (BI) was used to measure the burst rate for the length of pipe network within the study area. A mathematical relationship between PI and BI was proposed based on the first eight years (2007–2015) of burst data and the results of the hydraulic modelling in the same period. The number of pipe bursts for the last two years (2016–2017) in each PZ was then predicted according to the proposed mathematical relationship. The predicted number of bursts fitted well with the actual recorded pipe burst data, with a coefficient of determination of 0.98.

Energy efficiency interventions in Water Supply Systems (WSSs) need a precise evaluation of the available water flow rates for energy recovery interventions; however, flow meters are generally too costly for being installed in all the gravity adduction pipelines of a WSS. This paper presents a methodology for predicting flow rates in gravity adduction pipelines based on the electricity bill consumption. In this study, the predicted average flow rate is 0.0300 m3∗s−1, being 1.64% lower than the real one. A Pelton turbine has been chosen as energy recovery unit for supplying electricity to a pumping station of a preloading tank where the water is treated to make it drinkable. An energy saving of 475.26 (MW∗h)∗year−1 is achieved, which can be also expressed as 88.87 saved Tonnes of Oil Equivalent (TOE) and 204.36 ktCO2 not released into the atmosphere. The gross economic saving due to the installation of the Pelton turbine is equal to 94.29 k€∗year−1 and it can be further increased up to 116.51 k€∗year−1 if the energy efficiency certificates issued by the Italian Authorities are considered. The Payback Period (PBP) of the intervention corresponds to 3 years, and a Net Present Value (NPV) after twenty years is approximately 1.4 M€.

Water crises in arid and semi-arid regions, particularly in desert areas, are considered a challenge owing to the fact that no functioning solutions have been introduced throughout history to change the whole map from yellow to green. Current desert regions are still deserts from millions of years ago, and all scenarios that have been introduced to occupy desert regions accounts for 1%–2% of the total area. Middle East and North Africa (MENA) countries that are located in such arid and semi-arid zones are disadvantaged by limited water supply because of high temperature, low precipitation, and limited water resources. We have found that, there is no consortium between different fields of interest in the hopes of eventually overcoming the global water crisis. This is practically the case when it comes to using desalination and wastewater treatment technologies and their application for agriculture. Water crises should not only be solved using desalination and wastewater treatment, but other items should be also taken into consideration such as soil, plant, and organic matter use, among others. In the present perspective, we are developing novel solutions to overcome the global water crisis via nonconventional water reuse with minimum constrains to ecosystems using the principles of the Sophisticated Desert Development Project (SDDP) or “Electro-agric technology”. Electro-agric is technique that uses electrical fields throughout agricultural practices. Electro-agric technology comprises five main sections, including water, soil, organic matter, and plants, among others, that may be achieved via the establishment of a consortium between different major establishments like the Faculties of Engineering, Agriculture, and Science. Traditional approaches for cultivating land in arid and semi-arid regions are inappropriate and electro-agric technologies may be considered as the only alternative solution for regions that are located between the latitudes 35°N to 35°S in which the arid and semi-arid weather prevails and in which in seven of the world's major deserts are located. We believe that the map of MENA countries produced will transform from yellow to green, indicating reclamation of this resource; however this can only be accomplished if we comply with electro-agric technologies. Moreover, national incomes will be increased, and new communities will be stabilized.

Groundwater is the world's central supply of fresh water. Water supply policies, particularly in dry seasons, thus need to be based on accurate modelling of groundwater level (GWL) fluctuations. In the work reported in this paper, a hybrid wavelet-transform-based extreme learning machine (ELM) model was investigated for predicting GWL. Two other popular models – a wavelet-transform based artificial neural network and a wavelet-transform-based adaptive neuro-fuzzy interference system – were used to evaluate the model. GWL data and mean temperatures of observation wells in an Iranian watershed between 1981 and 2017 were used in the study. The performance of the models was assessed be evaluating their root mean square error, correlation coefficient and mean absolute error. The wavelet-transform-based ELM model outperformed the other two models with a correlation coefficient of 0.983 during a 1 month period. The model was also superior to the others in terms of training and testing speeds.

The stochastic nature of water demand could lead to deficits in the case that flows from the reservoir and pressure in networks are not properly managed. Installation of pumping facilities has the potential to resolve this issue. However, the energy used by these facilities is a concern. In addition, utilisation of the grid also contributes towards the carbonisation of the atmosphere. This work proposes the utilisation of a PV-battery micro-grid to power the pumping station. The size of the micro-grid is determined by the power required to operate the pump to mitigate the supply deficit. A pressure-driven model is used to solve the water distribution network and to determine the deficit in supply. The results show that the proposed micro-grid can supply the pumping for 24 hours without interventions from the grid. The cost of energy is found to be 0.951 ZAR which is considerably lower than the reselling price of utilities standing at 1.16–1.28 ZAR in South Africa.

Groundwater is a precious source of fresh water and a major component of the entire water supply. Both water quality and quantity could be satisfied by evaluating the groundwater potential sites (GWPS). This paper analyzes the ground-water potentials in a semi-arid region of Khyber Pakhtunkhwa, Pakistan. It describes a standard methodology to identify and map GWPS using integrated Geographical Information System (GIS) and remote sensing (RS) methods. Eight parameters including elevation, slope, drainage density, lineaments density, soil, geology, land use/land cover and rainfall were integrated to explore areas with groundwater holding capability. GWPS were delineated through subjective weights assigned after coupling various thematic layers using Saaty’s Analytical Hierarchical Process (AHP). The modelled GWPS were cross-checked with tube wells data. The result indicates that the central part of the study area has good potential for groundwater reserves/exploitation, where the factors i.e. moderate to high drainage density, sedimentary sequence of alluvial plain, low elevation etc. discern the central portion of the study area as a suitable site for groundwater. This study suggests that the applied method proves to be very significant and reliable tool for timely assessment of quality assured evaluation of groundwater resources. This study could be a systematic guide for future investigations for water related explorations, especially in semi-arid environments.

The purpose of this study is to assess and compare the quality of groundwater (GW) and surface water (SW) used for domestic purposes in rural areas near crude oil exploration sites in order to determine which source is more susceptible to pollution. Surface water samples were obtained from three (3) distinct locations in the study area, from upstream and downstream of the watercourses, for physicochemical, bacteriological, and heavy metal analysis using conventional laboratory procedures. Similarly, groundwater samples were taken from three (3) separate boreholes in the region for the same analysis, as per American Standard for Testing Materials (ASTM) and American Public Health Association (APHA) procedures. The relative significance of fourteen (14) water quality indicators in defining the quality of water for human consumption was evaluated in this study. The pH of the two water sources was somewhat acidic, with values ranging from 5.19 to 6.24, according to the results of the laboratory analysis. Water quality indicators such as Fe, Pb, TDS, TPC, DO, BOD, F coli, and E coli, on the other hand, were found to be above the permissible tolerance in drinking water, according to the Nigerian Standard for Drinking Water Quality (NSDWQ) and the World Health Organisation (WHO). Pollutant concentrations in surface water were higher than in groundwater, which may be attributable to the presence of humans or animal excrements (from open grazing) as well as offshore activities.

The Middle Route (MR) of the South-to-North Water Diversion Project (SNWDP) of China is one of the world's largest inter-basin water diversion projects. As an important source of drinking water in North China, its water quality safety determines the success or failure of a sizable water supply. At present, there is a lack of in-depth and systematic understanding of the interaction between hydrodynamics and the water environment as well as water ecological processes in the main canal at the early stages of operation. It is not currently possible to accurately predict water quality and algae status at the early stage of canal ecosystem succession. Change trends and distribution characteristics of the main water ecological environment elements in the main canal at the early MR stage are analyzed in this study. The main factors influencing algae are investigated by principal component analysis (PCA) to characterize the water quality and algae transport distribution in the main MR canal under the complex multi-sluice joint dispatching conditions. The relationship between environmental factors, hydrodynamic, water quality, and algae in the coupled canal-sluice system in the SNWDP MR is determined. Algae distributions under different water transmission conditions in a typical canal section are predicted accordingly. CODMn and algal density in the main canal are shown to increase from south to north along the canal. DO decreases from south to north; other water quality indexes do not significantly differ from north to south. Algal density along the canal differs to the greatest extent in summer, followed by spring and autumn, and is the weakest in winter. The predicted algae densities in the main canal under different water conveying conditions show that single sluice control and strong water flow from Taocha Head Section increase the flow velocity after passing through the sluice with a fixed opening. Algal density decreases flow rate increases under single sluice regulation conditions. The maximum rate of algal density change reaches 22.13% and 29.55% under double sluice and four sluice scheduling. Algae control effects grow significantly as the number of control sluices increases. The results of this work may provide technical support for water quality forecasting and algae risk warning in the SNWDP MR as well as a workable reference for similar projects.

This article addresses the issue of environmental safety as well as the quality of drinking water and wastewater treatment. The problem of supplying clean water and sewage of settlements and cities of the Kyrgyz Republic is raised. Anthropogenic pollution of natural waters. Inadequate wastewater treatment and unsatisfactory condition of sewage treatment plants. This state of affairs in the water supply and sanitation system of the Kyrgyz Republic requires the development and implementation of new advanced technologies for the treatment of natural and waste waters.

Riverbank filtration (RBF) is an affordable technique to provide drinking water with adequate quality. The ultimate objective of this study is to facilitate the transferability and application of this sustainable technique in Egypt. In this work, a numerical model was constructed using Groundwater Modeling System (GMS) to study the effect of four design parameters on the RBF performance parameters (i.e., river filtrate portion and travel time) with the aid of MODPATH and ZONEBUDGET. The design parameters were: (1) the pumping rates of the RBF wells, (2) number of operating wells, (3) distance between wells and the river, and (4) the spacing between wells. This study was focused on the hydraulic aspects of the technique. The results demonstrated that: (1) the river filtrate portion exceeds 75% regardless of the design conditions, and (2) the hydraulic performance of the RBF technique is highly controlled by the production capacity of the wells and their positions relative to the surface water systems; the spacing between wells has a minimum effect. Two equations were developed to estimate the river filtrate portion and minimum travel time as functions of pumping rate and distance between the pumping well and the river.

The aim of the present study is to determine the impact of the disturbed irrigation regime on the yield and the chemical composition of Sudan grass, grown as a second crop. To accomplish this goal, a trial was conducted in the experimental field of the Agricultural Institute - Stara Zagora with Sudan grass on meadow-cinnamon soil under irrigated conditions. The following variants have been studied: 1 - without irrigation (control variant); variant 2 - optimal irrigation, 75-80% of field capacity (FC); variant 3 - irrigation as in variant 2, but with the removal of the first watering; variant 4 - irrigation as variant 2, but with the removal of the second irrigation; variant 5 - irrigation as variant 2, but with the removal of the third watering. It was found that when growing Sudan grass as a second crop with optimal irrigation and disturbed irrigation regime done by canceling successive watering, the highest yield of dry biomass is obtained with optimal irrigation including three irrigations. Its yield increased by 24.2% compared to the control treatment. Irrigation of Sudan grass with only the second and the third irrigation in a row, without the first irrigation provided, leads to the lowest yield of dry biomass - 11290 kg / ha. Among the chemical composition indicators, the most significant change is observed in the content of the crude fat, followed by that of the crude fiber and crude protein, depending on the method of growing Sudan grass (with or without irrigation).

Groundwater is a vital water supply available in Egypt. Hydrogeochemical processes are important in regulating groundwater quality, impacting human health. In this paper, the relationships between diverse groundwater quality parameters, potential sources of groundwater pollution, and overall health risk were assessed in the Assiut Province, Egypt. For this study, 108 groundwater samples were collected randomly from the study area and analyzed to evaluate their quality. The obtained data were compared to the limit values recommended by the World Health Organization and the Egyptian water standards. The combination of hydrogeochemical and statistical methods proved that the groundwater salinity ranged between fresh and slightly saline. Furthermore, the water–rock interactions, the return flow of the irrigation water, and agricultural fertilizers are the main factors controlling groundwater compositions. Based on human health consideration, 3.7%, 2.8%, 5.6%, 5.6%, and 17.6% of the groundwater samples are rated as poor water due to the elevated concentrations of EC, Ca2+, Mg2+, HCO3−, and SO42−, respectively. Ingesting this water presents a risk to human health and has a serious impact on the skin, hair, and eyes.

Water resources/reservoir management in developing countries attracts considerable attention due to growing human requirements and environmental concerns. The Seimare–Karkheh hydropower reservoir cascade, in the Karkheh River basin southwest of Iran, was studied. The impacts of changing reservoir operating water levels on hydropower generation and downstream environmental requirements were evaluated under different climate change conditions. For several years, the operating water level of Seimare reservoir was 704.5–720.0 metres above sea level (masl) (H1). Decision makers then adopted a different policy, with the operating range changed to 704.5–723.0 masl (H2). More recently, decision makers reduced the normal and minimum water levels so the reservoir now operates at 695.0–704.5 masl (H3). It was found that, for the period 2006–2050, based on H3, hydropower production would be reduced by 2.3–12.1% and 2.4–12.6% compared with policies H1 and H2, respectively. In 2051–2100, these reductions were found to be 5.8–11.2% and 7.7–11.3%, respectively. Furthermore, the results demonstrated that the current policy would substantially affect downstream hydrological alteration: 60–72% in Seimare River and 48–66% in Karkheh River for the period 2006–2050. The issue was found to be more pronounced in 2051–2100, with hydrological alteration of 68–73% in Seimare River and 59–66% in Karkheh River.

Rapid urbanization poses challenges to meet the increased water supply demands. Apart from the quantity, the distributed water quality often fails to meet the permissible level. This study aimed to conduct a citywide spatio-temporal variation of water quality parameters. Water sampling points were selected by applying the Analytical Hierarchical Process (AHP) technique using ArcGIS considering pipe leakage, source water quality, pipe age, and pipe materials. The Chattogram city comprises 397 km of pipes; pipe material distribution shows 71.28% PVC, 20.94% asbestos, 5.16% mild steel, 2.17% ductile, and 0.45% cast iron. The citywide pipe network was established in 1963; 20.87% of pipes aged over 30 years, 15.07% 20–30 years, 26.38% 10–20 years, and 37.68% pipelines are relatively new, i.e., within 0–10 years. Eight water quality parameters, i.e., pH, temperature, turbidity, biochemical oxygen demand after five days (BOD5), total coliform, fecal coliform, chloride, and residual chlorine, were collected from the secondary source cross-checked by field survey. Computation of the Water Quality Index (WQI) was interpolated using Inverse Distance Weighted (IDW) method to generate a WQI map. Thus, this study could be a basis to improve the treatment system and proper distribution network maintenance. HIGHLIGHTS Spatio-temporal variation of water quality parameters in the citywide distribution system.; Water sampling locations were identified using the Analytical Hierarchical Process (AHP).; Inverse Distance Weighted (IDW) method to generate a Water Quality Index (WQI) map.

The Dujiangyan Project, located at the junction of the upstream of the Minjiang River and Chengdu Plain, Sichuan Province, China, is an irrigation system project as important as the Great Wall in the history of China. Without dam structures, this project has been continuously playing its crucial role in diverting water for irrigation, separating sediments, and controlling flood for 2275 years. In this study, the predicaments of the Dujiangyan Project under the background of rapid urbanization and social economic development were summarized by conducting the field research and using the Indicators of Hydrological alteration (IHA) method: excessive diversion of water, disruption of hydrological pulses, erosion and deposition imbalance and conflicts between power generation and water supply. These contradictions have led to the weakening of the function of automatic water diversion and sand removal in the Dujiangyan Project. Considering the influence of climate change and strong human activities, we pointed out the challenges faced by the millennium ancient weir in balancing human and environmental water usage and project operation and management based on the simulation results of the hydrological model. The corresponding suggestions about strengthening agricultural water saving, generating artificial flood peak were provided to protect and continue to maintain the function of the Dujiangyan Project.

This study aims to investigate the effectiveness of the low impact development (LID) practices on sustainable urban flood storm water management. We applied three LID techniques, i.e. green roof, permeable pavements and bioretention cells, on a highly urbanized watershed in Istanbul, Turkey. The EPA-SWMM was used as a hydrologic-hydraulic model and the model calibration was performed by the well-known Parameter ESTimation (PEST) tool. The rainfall-runoff events occurred between 2012 and 2020. A sensitivity analysis on the parameter selection was applied to reduce the computational cost. The Nash-Sutcliffe efficiency coefficient (NSE) was used as the objective function and it was calculated as 0.809 in the model calibration. The simulations were conducted for six different return periods of a storm event, i.e. 2, 5, 10, 25, 50 and 100 years, in which the synthetic storm event hyetographs were produced by means of the alternating block method. The results revealed that the combination of green roof and permeable pavements have the major impact on both the peak flood reduction and runoff volume reduction compared to the single LIDs. The maximum runoff reduction percentage was obtained as 56.02% for a 10 years return period of a storm event in the combination scenario. HIGHLIGHTS The PEST software is used for the auto-calibration of US EPA-SWMM and the calibration results are statistically significant.; The green roof application has more impact on both the peak discharge reduction and the volume reduction than both the permeable pavements and bioretention cells in the highly urbanized Ayamama watershed.; The combination of green roof and permeable pavements has substantial effect on flood mitigation.

Water consumed is stored in several water bodies in and around us, out of which dams accommodate a major portion of water. The quantity and quality monitoring of water in dams is troublesome due to their large surface area and high depths. Although groundwater resources are the primary water source in India, dams plays a vital role in water distribution and storage network. The Central Water Commission in India has identified more than 5,000 dams of which a major portion is persistently consumed by the rural and urban populations for drinking and irrigation. The water quality of these reservoirs is of serious concern as it would not only affect the socio-economic status of the nation but the aquatic systems as well. Water quality control and management are vital for a delivering clean water supply to the general society. Because of their size, collecting, assessing, and managing a vast volume of water quality data are critical. Water quality data are primarily obtained through manual field sampling; however, real-time sensor monitoring is increasingly being used for more efficient data collection. The literature depicts that the methods involving remote sensing and image processing of water quality analysis consume time, and require sample collection at various depths, analysis of collected samples, and manual interpretations. The objective of this study was to propose a novel cost-effective method to monitor water quality devoid of considerable human intervention. Sensor-based online monitoring aids in assessing the sample with limited technology, at various depths of water in the dam to analyze turbidity which gives the major indication of pure water. The quality analysis of the dam water is suitable if the water is assessed at the distribution end before consumption. Hence, to enhance the water management system, other quality parameters like pH, conductivity, temperature are sensed and monitored in the distribution pipeline. An unstable pH can alter the chemical and microbiological aspects of water, resulting in a variation of other water quality parameters. Temperature variations affect the amount of dissolved oxygen in the water bodies and results in unstable quality parameters. The change in dissolved solvents and the ionic concentration alters the electrical conductivity of the water and the increased concentration of salts also results in turbidity. The data from all the sensors are processed by the microcontroller, transmitted, and displayed in a mobile application comprehensible to the layman. HIGHLIGHTS The quantity and quality monitoring of water in dams is troublesome due to their large surface area and high depths.; An effective quality analysis is the demand of the hour and the problem statement is identified in developing a system to check water quality at various depths in a dam.; An efficient pipeline with various sensors which monitor turbidity, pH, and conductivity is developed as a prototype low cost device.

In this article, extractor of atmospheric water has been described. Results of statistical study of experimental sample of atmospheric water extractor obtained in the course of field tests have been presented. The trends of physical properties of atmosphere have been analyzed and the relationship between climate parameters and volumes of extracted water has been studied. Results of the analysis of experimental and calculated data of studies of atmospheric water extractor have shown that the difference between calculated and experimental values does not exceed 2% to 4% which proves acceptable accuracy of the selected method of theoretical estimations. While calculating the correlation factor, it was found out that the direct dependence most clearly appears in the dependence of experimental values of extracted water volume on ambient air temperature. Use of nano-materials in the heat exchanger unit makes it possible to perform effective water extraction in conditions of low relative humidity from 5% and temperatures up to 20 °C.

The use of air vessels is an effective measure to control water hammers, and its volume selection has a certain blindness. This paper aims to reveal the surge wave characteristics and provide design guidelines for air vessels in long-distance water supply systems. First, the analytical formulas of water-level oscillations in the air vessel are derived based on the Krylov–Bogoliubov–Mitropolsky method. Then, an optimization model is constructed for selecting the optimal volume of the air vessels. Finally, the validation of the analytical formulas and the optimization of the model are conducted through two actual projects. The results show that the calculation error of the analytical formulas can be controlled within a very small range, and the process of selecting air vessel volume can be simplified with the provided model. In addition, increasing the air chamber height within its range can reduce the volume of air vessels with the same protection requirements. The optimization analysis results of the air vessel can provide guidance and reference for the design of actual projects. HIGHLIGHTS The analytical formulas for water-level oscillations considering pipe friction are derived.; The volume optimization model can preliminarily estimate the minimum volume of the air vessel.; Under the same protection requirements, the volume of air vessels decreases with the increase of air chamber height.

Membrane separation has enjoyed tremendous advances in relevant material and engineering sciences, making it the fastest growing technology in water treatment. Although membranes as a broad-spectrum physical barrier have great advantages over conventional treatment processes in a myriad of applications, the need for higher selectivity and specificity in membrane separation is rising as we move to target contaminants at trace concentrations and to recover valuable chemicals from wastewater with low energy consumption. In this review, we discuss the drivers, fundamental science, and potential enabling materials for high selectivity membranes, as well as their applications in different water treatment processes. Membrane materials and processes that show promise to achieve high selectivity for water, ions, and small molecules—as well as the mechanisms involved—are highlighted. We further identify practical needs, knowledge gaps, and technological barriers in both material development and process design for high selectivity membrane processes. Finally, we discuss research priorities in the context of existing and future water supply paradigms.

In majority cities of Pakistan, ground water is the main source of drinking water supply in the taps. Studies from different areas of Pakistan reported the presence of arsenic (As3/5+) and fluoride (F−) in drinking water supplies and can be envisaged as a deep-rooted cause of daily exposure of these in humans. The present study was planned with three way approach, i.e., to assess drinking water quality in Multan city, a highly populated and industrial activity area; synthesis of nano-adsorbent for simultaneous, effective and low-cost removal of fluoride and arsenic and manage waste by utilization of kitchen waste for synthesis of the nano-adsorbent. Out of 30 samples collected, 80% and 73% samples were found exceeding maximum residual limits (MRL) for F− and As3/5+, respectively, while 53% samples had both As3/5+ and F− concentrations greater than MRL. All these water samples were then treated with prepared nano-adsorbent, i.e., iron nanoparticles doped kitchen waste charcoal after evaluating the optimized experimental parameters and application of adsorption, kinetics and thermodynamic models. The nano-adsorbent showed high removal efficacy 81–100% for F− and 13–100% for As3+.

Reservoirs play an important role in water management and are key elements for water supply. Monitoring is needed in order to guarantee the quantity and quality of stored water. However, this task is sometimes not easy. The objective of this study was to develop a procedure for predicting volume of stored water with remote sensing in water bodies under Mediterranean climate conditions. To achieve this objective,multispectral Landsat 7 and 8 images (NASA) were analyzed for the following five reservoirs: La Serena,La Pedrera, Beniarrés, Cubillas and Negratín (Spain). Reservoirs water surface was computed with the spectral angle mapper (SAM) algorithm.After that, cross-validation regression models were computed in order to assess the capability of water surface estimations to predict stored water in each of the reservoirs. The statistical models were trained with Landsat 7 images and were validated by using Landsat 8 images. Our results suggest a good capability of water volume prediction from free satellite imagery derived from surface water estimations. Combining free remote sensing images and open source GIS algorithms can be a very useful tool for water management and an integrated and efficient way to control water storage,especially in low accessible sites.

Groups of spatially distributed wells interconnected by sections of pipelines (a common collector) supplying water to a clean water reservoir are used in water supply systems in order to provide drinking water to settlements. A group of wells together with a clean water reservoir is called a water intake facility of the water supply system. Further, water is supplied from the clean water reservoir to consumers in settlements by means of second stage pumping stations. In terms of each well the operating mode of the submersible pumping unit, i.e. the position of its operating point at a fixed moment in time, depends on the actual values ​​of many internal and external factors: dynamic water level in the well; the actual characteristics of the pumping unit; the position of the final control elements (drive speed, opening degree of the regulating valve); hydraulic resistances of pipeline sections of the water intake facility; the water level in the clean water reservoir; the number and operating modes of pumping units in other wells of the water intake facility. The paper describes a deterministic model of a water intake well. At the same time, the processes of water consumption are random processes, since they depend on many uncontrolled and unmanageable factors. The parameters of the technological equipment of the water intake facility are also random values, since they are estimated from experimental data of finite length. Therefore, a stochastic model of a water intake well is also proposed. A model of a quasi-stationary operation mode of a water intake facility, which is used to optimize the operation of a group of artesian wells operating on a common collector, is considered.

Recent climate change and vegetation greening have important implications for global terrestrial hydrological cycles and other ecosystem functions, raising concerns about the watershed water supply capacity for large water diversion projects. To address this emerging concern, we built a hybrid model based on the Coupled Carbon and Water (CCW) and Water Supply Stress Index (WaSSI) models and conducted a case study on the upper Han River basin (UHRB) in Central China that serves as the water source area to the middle route of the South-to-North Water Diversion Project (SNWDP). Significant vegetation greening occurred in the UHRB during 2001–2018, largely driven by the widespread afforestation in the region, with the normalized difference vegetation index increasing at a rate of 0.5±0.1 % yr−1 (p<0.05) but with no significant trends in climate during the same period (albeit with large interannual variability). Annual water yield greatly decreased, and vegetation greening alone induced a significant decrease in water yield of 3.2±1.0 mm yr−1 (p<0.05). Vegetation greening could potentially reduce the annual water supply by 7.3 km3 on average, accounting for 77 % of the intended annual water diversion volume of the SNWDP. Although vegetation greening can bring enormous ecosystem goods and services (e.g., carbon sequestration and water quality improvement), it could aggravate the severity of hydrological drought. Our analysis indicated that vegetation greening in the UHRB reduced about a quarter of water yield on average during drought periods. Given the future warming and drying climate is likely to continue to raise evaporative demand and exert stress on water availability, the potential water yield decline induced by vegetation greening revealed by our study needs to be taken into account in the water resources management over the UHRB while reaping other benefits of forest protection and ecological restoration.

Reliable and accurate streamflow simulation has a vital role in water resource development, mainly in agriculture, environment, domestic water supply, hydropower generation, flood control, and early warning systems. In this context, these days, deep learning algorithms have got enormous attention due to their high-performance simulation capacity. In this study, we compared multilayer perceptron (MLP), long short-term memory (LSTM), and gated recurrent unit (GRU) with the proposed new hybrid models, including CNN-LSTM and CNN-GRU. Hence, we can simulate one-step daily streamflow in different agroclimatic conditions, rolling time windows, and a range of variable input combinations. The analysis used daily multivariate and multisite time series data collected from Awash River Basin (Borkena watershed: Ethiopia) and Tiber River Basin (Upper Tiber River Basin: Italy) stations. The datasets were subjected to rigorous quality control processes. Consequently, it rolled to a different time lag to remove noise in the time series and further split into training and testing datasets using a ratio of 80 : 20, respectively. Finally, the results showed that integrating the GRU layer with the convolutional layer and using monthly rolled average daily input time series could substantially improve the simulation of streamflow time series.

Anthropogenic climate change is decreasing seasonal snowpacks globally, with potentially catastrophic consequences on water resources, given the long-held reliance on snowpack in water management. In this Review, we examine the changes and trickle-down impacts of snow loss in the western United States (WUS). Across the WUS, snow water equivalent declines of ~25% are expected by 2050, with losses comparable with contemporary historical trends. There is less consensus on the time horizon of snow disappearance, but model projections combined with a new low-to-no snow definition suggest ~35–60 years before low-to-no snow becomes persistent if greenhouse gas emissions continue unabated. Diminished and more ephemeral snowpacks that melt earlier will alter groundwater and streamflow dynamics. The direction of these changes are difficult to constrain given competing factors such as higher evapotranspiration, altered vegetation composition and changes in wildfire behaviour in a warmer world. These changes undermine conventional WUS water management practices, but through proactive implementation of soft and hard adaptation strategies, there is potential to build resilience to extreme, episodic and, eventually, persistent low-to-no snow conditions. Federal investments offer a timely opportunity to address these vulnerabilities, but they require a concerted portfolio of activities that cross historically siloed physical and disciplinary boundaries. Much of the western United States relies on seasonal snowpacks for water supply. This Review examines the projected changes and impacts of a declining western United States snowpack, and discusses the adaptation opportunities available to mitigate against such snow losses.

Inter-basin water transfer projects are powerful measures for resolving the uneven distribution of water resources, but their scale directly affects the associated investment and income. Therefore, determining the scale of an inter-basin water transfer project is essential. Based on the inter-basin agricultural water transfer project in the Sanjiang Plain, Northeast China, combined with the suitable development scale of the irrigation area with the joint allocation of existing water sources, this research proposes a technique to demonstrate the scale of an inter-basin water transfer project based on dynamic trial feedback under the condition of the optimization method of despiking of the groundwater allocation; the water transfer project scale is demonstrated for each section in reverse order. According to the water demand prediction results in the study area, the scale of water transfer project BC is demonstrated, and the scale of water transfer project AB is demonstrated on the basis of the BC scale. The final AB and BC water transfer scales decrease by 15% and 13%, respectively, compared with the conventional method under the premise that the water supply guarantee rate is 75%. When the water is transferred, the process is stable, and the utilization rate of the canal is high, thereby saving investment funds and facilitating project scheduling and management.

Background: Monitoring the quality of potable water is a challenging endeavor due to the significant sources of contaminants, the majority of which are human-induced. Limited access to drinking water owing to acceleration in industrialization, urbanization in consort with growing inhabitants, unprocessed sewage discharge, and toxic industrial effluents causes different life-threatening diseases. Manual water quality monitoring techniques vividly aggravate quality deterioration. Considering the significance of the automatic water quality monitoring system, we need an in-situ, real-time, continuous surveillance system to ascertain the quality of potable water. Wireless Sensor Network (WSN) motivated us for a practical water quality monitoring system due to their continuous, real-time, and adaptive infrastructure to provide an early alert in hazardous conditions. Objective: To design and implement an online potable water quality monitoring network for rural water supply schemes in Nagapattinam district, Tamilnadu, India, to sense physiochemical parameters of potable water such as pH, turbidity, conductivity and temperature. Methods: Online POTable water quality monitoring NETwork (POTNET) integrates the reimbursements of WSN and different information and communication technologies for data acquisition, data processing, and data visualization. The core hardware of POTNET contains off-the-shelf sensors (i.e., electrodes), a microcontroller, a data transmission system, a customized buoyage, and a sink node. It senses physiochemical parameters of potable water such as pH, turbidity, conductivity, and temperature in a pre-programmed time interval. Furthermore, it enables cloud storage for gathered information and generates an alert to the preregistered user via mobile phones when there is a deviation of quality measures from threshold values. Results: The system was implemented in three overhead tanks for seven days in order to validate the stability of the buoy and efficiency of energy source, storage, and data transmission. It senses physiochemical parameters of potable water such as pH, turbidity, conductivity, and temperature in its predefined interval of 30 minutes. To check the system accuracy, the measured data values from developed sensors were compared with the observed data values using a commercial multi-parameter water checker, the Horiba® probe. Measured data were sent through the transceivers to the base station for data logging in a suitable format for ease of data visualization and utilization. Conclusion: Extensive experimental results reveal that our POTNET can be employed for potable water quality surveillance to help consumers or concern authorities to make a sound decision by providing appropriate and real-time data.

The study examined the water supply situation in Abeokuta, with emphasis on the quality of water distributed by the Ogun State Water Corporation from the treatment plant of the Abeokuta Water Scheme. Water samples were collected from standpipes (taps) across the city randomly selected using the stratified random sampling method and was analysed for physical and chemical parameters: pH, total dissolved solids (TDS), electrical conductivity (EC), total alkalinity, total hardness, calcium, magnesium, potassium, sodium, nitrate, bicarbonate, sulphate and chloride. The result of the physical and chemical parameters was subjected to statistical analyses using the multivariate t-test. The result of the treated water was further compared with the result of the analyses of raw water obtained from the source of water used in the treatment plant.

Air adalah sumber daya yang penting bagi semua organisme hidup. Sumber daya air harus dikelola secara berkelanjutan untuk melindungi lingkungan dan kegunaannya bagi kehidupan manusia dan organisme lain. Air sungai merupakan salah satu sumber daya air bagi kehidupan manusia. Salah satu daerah yang memanfaatkan air sungai untuk sumber air adalah Surabaya. Sungai Surabaya dianggap sebagai sumber air utama yang dimanfaatkan oleh warga. Air Sungai Surabaya merupakan bahan baku air minum dan salah satu sumber suplai air PDAM Surabaya. Selain itu, Sungai tidak hanya dimanfaatkan sebagai sumber air bagi kehidupan masyarakat dan industri tetapi juga sebagai tempat pembuangan limbah industri. Meningkatnya perkembangan industri telah menimbulkan kekhawatiran tentang konsumsi air, sehingga perlu dilakukan pemantauan kualitas air Sungai Surabaya untuk mengetahui parameter kimia, fisik, dan biologi.

Background: Better water quality, improved sanitation and sound water resource management will improve public health and economic development in low-income countries. Water safety plan-based risk assessment and risk management from catchment to consumers are the modern and efficient approaches to safe drinking water supply established by World Health Organization. Thus, this paper aimed to assess risk from catchment level to consumers in the community of Brikama. Methods: This study report assessments of risk or hazards from catchment to consumers in Brikama Water Treatment Plant (BWTP), West Coast Region, The Gambia. The various means of data collection used include water quality monitoring, visual field inspection and questionnaire survey to explore data on where the water supply system goes wrong from catchment to consumers, so as to provide an improvement plan. Results: Overall, the day-to-day administration of services at BWTP was very impressive. The fencing of all the 17 boreholes at catchment sites has drastically reduced the risk of contamination including treatment systems and distribution lines. There are less risks observed and constant monitoring of the system was ensured. However, at the consumer end, there are some risks with poor practices associated with water handling, storage and hygiene measures at the household level. Some still use some unclean 20-liter containers to store water and indiscriminately kept drinking cups on the floor and unclean surfaces, and 50% lacked WASH knowledge related to water treatment, such as boiling and filtration at households. The overall perception of water storage, sanitation and hygiene practices could be rated moderately good. Conclusion: The overall findings of this study have shown tremendous achievement in the government's commitment to providing potable water to the people in Brikama Local Government Area. WASH education in the study area is recommended to avoid waterborne disease infections.

An air vessel, as an effective and reliable water hammer protective device, is widely used in long-distance water supply systems. However, the volume of the air vessel must be extra-large to guarantee security of the system, especially in a system with a high head and large flow. In this paper, to reduce the volume of the air vessel, a novel protective method combining an air vessel and over pressure relief valve was proposed and verified using a numerical simulation based on a practical project. In addition, the protection performance under the combined protective method was compared with the traditional method. The results show that the combined protective method can significantly reduce the volume of air vessel and exhibit a better protection performance. Furthermore, after analysis and optimization of the rule of opening and closing over the pressure relief valve, the valve should be opened in a short time to produce fast discharge so as to eliminate the large pressure rise rapidly. The duration of opening the over pressure relief valve has little effect on the maximum pressure. The closing time of the over pressure valve should be slow, as much as possible, to avoid producing large pressure wave. HIGHLIGHTS An optimized protective method by combining air vessel and over pressure relief valve is proposed to reduce the volume of the air vessel.; The sensitive analysis of operating valve and total cost anaysis are compared, which can make this combined method more effective and reliable.; The method was verified by comparing with the traditional protective method, and the results can provide a reference for similar situations.

Airborne LiDAR can support high resolution watershed-scale snow depth mapping that provides the spatial coverage necessary to inform water supply forecasts for mountainous headwaters. This research...

The presence of diverse pollutants in water has been threating human health and aquatic ecosystems on a global scale. For more than a century, chemical oxidation using strongly oxidizing species was one of the most effective technologies to destruct pollutants and to ensure a safe and clean water supply. However, the removal of increasing amount of pollutants with higher structural complexity, especially the emerging micropollutants with trace concentrations in the complicated water matrix, requires excessive dosage of oxidant and/or energy input, resulting in a low cost-effectiveness and possible secondary pollution. Consequently, it is of practical significance but scientifically challenging to achieve selective oxidation of pollutants of interest for water decontamination. Currently, there are a variety of examples concerning selective oxidation of pollutants in aqueous systems. However, a systematic understanding of the relationship between the origin of selectivity and its applicable water treatment scenarios, as well as the rational design of catalyst for selective catalytic oxidation, is still lacking. In this critical review, we summarize the state-of-the-art selective oxidation strategies in water decontamination and probe the origins of selectivity, that is, the selectivity resulting from the reactivity of either oxidants or target pollutants, the selectivity arising from the accessibility of pollutants to oxidants via adsorption and size exclusion, as well as the selectivity due to the interfacial electron transfer process and enzymatic oxidation. Finally, the challenges and perspectives are briefly outlined to stimulate future discussion and interest on selective oxidation for water decontamination, particularly toward application in real scenarios.