Growing Water Demand Research Articles

Assessment of water resources availability and demand in the Mara River Basin

A simple model was developed to assess space–time relationships of water resource availability and demand in data limited watersheds. The model used a defined index method to evaluate water resource status with respect to anticipated demands. Input data requirements and data processing steps and strategies were discussed. The model takes outputs from a hydrologic system model and demand estimates and compares supply–demand relationships on the basis of expected percentage of demand satisfaction for the basin of interest. Space–time matrices were used to display results of the model for ease of understanding and decision making. The model was customized and applied for the Mara River Basin (MRB) to assess water resource availability and demand. Assessment of water resources in blocks of water use using indicators of the growing water demand among competing sectors threatening the sustainability of communities and ecosystems in the basin. The spatial and temporal distribution of water resources and the corresponding demand were quantified. Twelve distinct sub-basins were defined in the basin and their water availability was assessed based on long term rainfall-runoff simulation using the Soil and Water Assessment Tool (SWAT). Water demands from six consumptive sectors were divided into three classes and compared with a corresponding three classes of monthly water availability. Results have shown significant variability of water availability and demand in the MRB. Further study on possible quantitative indicators to redistribute water among stakeholders may assist in improving water management.

A long-term forecast of water demand for a desalinated dependent city: case of Riyadh City in Saudi Arabia

The forecast of long-term water demand is important for the planning of future requirements for water supply, distribution, and wastewater systems. The forecast is particularly important for arid countries such as Saudi Arabia which rely on costly desalination plants to satisfy the growing water demand. This study develops a model for forecasting water demand for Riyadh city, the capital of the country. The development of a sound forecast model is complicated by the uncertainties associated with key factors, such as the population growth and the economic activity, which is largely dependent on fluctuating oil prices. The forecast is also made difficult by the inefficient management of unaccounted-for-water (UFW). All these factors limit the usefulness of any deterministic forecast model. This paper develops a probabilistic forecast model that incorporates explicitly the uncertainties associated with population growth, household size, household income as well as conservation measures, and UFW management. The methodology makes use of historic time series records of water consumption to forecast the future demand, and applies the Monte Carlo sampling to describe the associated uncertainties. Results show that future water demand in the city is governed equally by socioeconomic factors and weather conditions. The study also illustrates the importance of conservation measures and the need for reduction of UFW.

Quantitative and qualitative diagnosis of water resources in the Saf-Saf river basin (north east of Algeria)

Efficient and fair management of water resources is one of the most important challenges faced by the Saf-Saf river basin. The rapid economic growth of the city of Skikda and the intensive urbanization of the alluvial Saf-Saf valley have induced a fast growing water demand of urban and socio-economic sectors including agriculture and industry. Moreover, the quality of water resources are threatened by different pollutions types not only from petrochemical industries, but also, agricultural pollution resulting from some agricultural practices (fertilizers and pesticides). This study presents an optimization approach for the integrated and sustainable demand management of water resources, including quantitative and qualitative diagnosis of the water potentialities in the Saf-Saf basin.

Quality assessment of treated wastewater in Kuwait and possibility of reuse it to meet growing water demand

Kuwait’s water resources are insufficient and will become the limiting factor for sustainable development in the future. The need for water supplies in Kuwait is extremely high and expected to be growing due to increasing population growth. To face this challenge Kuwait has introduced a new element in water management system by considering and reusing treated wastewater. Currently, huge amounts of municipal wastewater are treated in four main treatment plants located at Regga, Jahra, Um Al-Haiman and Sulaibiya. In general overview on Kuwait’s water resource, water demand and wastewater treatment plants (WWTPs) is presented. In addition, data of treated effluent quality was collected from three main sources; namely; available publications and records within Kuwait, and the results of a wastewater-monitoring program involving survey, collection and analysis of samples from selected wastewater streams. Data reveal that the treatment plants at Jahra, Regga and Um Al-Haiman provide wastewater treatment up to a tertiary level with sand filters following the conventional activated sludge process. All three plants produce excellent effluent quality at a tertiary level of treatment. The advanced WWTP at Sulaibiya treats wastewater beyond tertiary level with advanced facilities of ultrafiltraion and, reverse osmosis producing super quality of effluent with insignificant traces of pollutants. The COD and TSS removals are above 90% for all the plants. Sulaibiya in particular achieved almost 100% COD and TSS removal. The utilization of Sulaibiya plant effluent for recharging ground-aquifers is a viable option to store treated effluent for future need.

Water transfer as a solution to water shortage: A fix that can Backfire

summary Zayandeh-Rud River Basin is one of the most important basins in central Iran, which has been continually challenged by water stress during the past 60 years. Traditionally, a supply-oriented management scheme has been prescribed as a reliable solution to water shortage problems in the basin, resulting in a number of water transfer projects that have more than doubled the natural flow of the river. The main objective of this study is to evaluate the reliability of inter-basin water transfer to meet the growing water demand in Zayandeh-Rud River Basin. A system dynamics model is developed to capture the interrelationships between different sub-systems of the river basin, namely the hydrologic, socioeconomic, and agricultural sub-systems. Results from simulating a range of possible policy options for resolving water shortage problems indicate that water is essentially the development engine of the system. Therefore, supplying more water to the basin without considering the dynamics of the interrelated problems will eventually lead to increased water demand. It is demonstrated that the Zayandeh-Rud River Basin management system has characteristics of the ‘‘Fixes that Backfire’’ system archetype, in which interbasin water transfer is an inadequate water management policy, causing significant unintended sideeffects. A comprehensive solution to the problem includes several policy options that simultaneously control the dynamics of the system, minimizing the risk of unintended consequences. In particular, policy makers should consider minimizing agricultural water demand through changing crop patterns as an effective policy solution for the basin’s water problems.

Long-term changes in the algal composition of the Vaal River, South Africa – did the Lesotho Highlands Water Project play a role?

The Vaal River has become so nutrient-enriched that algal blooms pose problems. A unique opportunity arose to determine if there were changes in the chemistry en algal composition of the Vaal River after oligomesotrophic Katse Dam (Lesotho) water was imported to augment supplies in the light of growing water demands in the Vaal River catchment area. Algal concentration and composition in the Vaal River during three periods (between 1992 and 1994, 1998 and 2000, as well as 2004 and 2006) were compared to those in the Katse Dam (1998–2006). Some algal species, initially absent from the Vaal River, appeared in the river during and after transfer. Mixed algal assemblages found in the Vaal River before transfer of Katse Dam water gradually changed after transfer to assemblages mainly composed of cyanobacteria. The total algal concentration in the Vaal River Barrage doubled from the period between 1992 and 1994 to that between 2004 and 2006, indicating that the transfer of clear, oligomesotrophic Katse Dam water did not dilute the eutrophic Vaal River water sufficiently in order to reduce algal concentrations. Results showed that continuous downstream pollution and eutrophication of the Vaal River system eliminated the diluting effect of Katse imports. This resulted in changes in algal composition and concentration in the Vaal, characteristic of those associated with increasing eutrophication.

Five centuries of Upper Indus River flow from tree rings

Water wars are a prospect in coming years as nations struggle with the effects of climate change, growing water demand, and declining resources. The Indus River supplies water to the world’s largest contiguous irrigation system generating 90% of the food production in Pakistan as well as 13 gigawatts of hydroelectricity. Because any gap between water supply and demand has major and far-reaching ramifications, an understanding of natural flow variability is vital – especially when only 47 years of instrumental record is available. A network of tree-ring sites from the Upper Indus Basin (UIB) was used to reconstruct river discharge levels covering the period AD 1452–2008. Novel methods tree-ring detrending based on the ‘signal free’ method and estimation of reconstruction uncertainty based on the ‘maximum entropy bootstrap’ are used. This 557-year record displays strong inter-decadal fluctuations that could not have been deduced from the short gauged record. Recent discharge levels are high but not statistically unprecedented and are likely to be associated with increased meltwater from unusually heavy prior winter snowfall. A period of prolonged below-average discharge is indicated during AD 1572–1683. This unprecedented low-flow period may have been a time of persistently below-average winter snowfall and provides a warning for future water resource planning. Our reconstruction thus helps fill the hydrological information vacuum for modeling the Hindu Kush–Karakoram–Himalayan region and is useful for planning future development of UIB water resources in an effort to close Pakistan’s “water gap”. Finally, the river discharge reconstruction provides the basis for comparing past, present, and future hydrologic changes, which will be crucial for detection and attribution of hydroclimate change in the Upper Indus Basin.

Brackish groundwater desalination by reverse osmosis in southeastern Spain. Presence of emerging contaminants and potential impacts on soil-aquifer media

ABSTRACT Desalinated brackish groundwater is becoming a new source of water supply to comply with growing water demands, especially in (semi-) arid countries. Recent publications show that some chemical compounds may persist in an unaltered form after the desalination processes and that there is an associated risk of mixing waters with different salinity for irrigation. At the university of Alicante campus (Spain), a mix of desalinated brackish groundwater and water from the existing aquifer is currently applied for landscape irrigation. The presence of 209 emerging compounds, surfactants, priority substances according to the 2008/105/EC Directive, 11 heavy metals and microbiological organisms in blended water and aquifer samples was investigated. Thirty-five compounds were detected (pesticides, pharmaceuticals and surfactants) among them two priority substances α-endosulfan and Ni were found above the permitted maximum concentration. Blended water used for landscape irrigation during the summer period is supersaturated with respect to carbonates, which may ultimately lead to mineral precipitation in the soil-aquifer media and changes in hydraulic parameters.

Design and start-up experiences of 19,000 m3/d Camp de Tarragona-Vilaseca Water Reclamation Plant

Within the current and future world’s water scarcity, the reuse of treated waste water for specific applications offers an appealing alternative to conventional fresh water sources that cannot meet the expectations, mostly in terms of quantity. Spain is no exception to this global situation, with a constantly increasing population, in combination with growing water demand for applications such as production industry, exportation oriented agriculture, tourism development, and booming construction, access to sufficient quantities of fresh water is currently a rising concern. Camp de Tarragona (ACA) Water Reclamation Project is a prime example how water scarcity can be solved regionally by reclaiming water that would otherwise be discharged to the sea. The new reclamation plant treats municipal secondary effluent from Tarragona and Salou/Vilaseca Wastewater Treatment Plants to supply process water for the petrochemical industry of Tarragona. The plant capacity is currently 19,000 m3/d (Phase I), and further expansions are planned for increases up to 29,000 m3/d (Phase II) and even to 55,000 m3/d (Phase III) in the coming years. This additional supply would replace the water currently taken from the Ebro River, thus releasing this volume for drinking water supply to the population. Utilizing such a process, the industrial growth in water scarce regions can be supported and industry sustainability is increased further. A pipeline connects the two different Wastewater Treatment Plants (WWTPs), 10 km apart from each other, and feeds secondary treated effluent to the reverse osmosis (RO) pretreatment process. The pretreatment consists of ballasted flocculation, followed by disc filtration, sand filtration, and multimedia filtration prior feeding it to the two pass RO system. Final permeate treatment is done by UV light and chlorine disinfection, prior releasing water to the distribution system. This paper will review the detailed design of the plant, as a scale-up of pilot plant results, as well as the RO membranes performance data obtained during the start-up of the installation. RO performance is evaluated in detail taking into account the performance differences when different combinations of raw water sources were used. This paper will also explain in detail the preservation of the installation by means of 5-Chloro-2-Methyl-2H-Isothiazol-3-one/2-Methyl-2HIsothiazol-3-one (CMIT/MIT), during a medium term stop of the plant.

Prediction of municipal water production in touristic Mecca City in Saudi Arabia using neural networks

Accurate forecast of municipal water production is critically important for arid and oil rich countries such as Saudi Arabia which depend on costly desalination plants to satisfy the growing water demand. Achieving the desired prediction accuracy is a challenging task since the forecast model should take into consideration a variety of factors such as economic development, climate conditions and population growth. The task is further complicated given that Mecca city is visited regularly by large numbers during specific months in the year due to religious reasons. This study develops a neural network model for forecasting the monthly and annual water demand for Mecca city, Saudi Arabia. The proposed model used historic records of water production and estimated visitors’ distribution to calibrate a neural network model for water demand forecast. The explanatory variables included annually-varying variables such as household income, persons per household, and city population, along with monthly-varying variables such as expected number of visitors each month and maximum monthly temperature. The NN prediction outperforms that of a regular econometric model. The latter is adjusted such that it can provide monthly and annual predictions.

Influence of climate change mitigation technology on global demands of water for electricity generation

Globally, electricity generation accounts for a large and potentially growing water demand, and as such is an important component to assessments of global and regional water scarcity. However, the current suite—as well as potential future suite—of thermoelectric generation technologies has a very wide range of water demand intensities, spanning two orders of magnitude. As such, the evolution of the generation mix is important for the future water demands of the sector. This study uses GCAM, an integrated assessment model, to analyze the global electric sector's water demands in three futures of climate change mitigation policy and two technology strategies. We find that despite five- to seven-fold expansion of the electric sector as a whole from 2005 to 2095, global electric sector water withdrawals remain relatively stable, due to the retirement of existing power plants with water-intensive once-through flow cooling systems. In the scenarios examined here, climate policies lead to the large-scale deployment of advanced, low-emissions technologies such as carbon dioxide capture and storage (CCS), concentrating solar power, and engineered geothermal systems. In particular, we find that the large-scale deployment of CCS technologies does not increase long-term water consumption from hydrocarbon-fueled power generation as compared with a no-policy scenario without CCS. Moreover, in sensitivity scenarios where low-emissions electricity technologies are required to use dry cooling systems, we find that the consequent additional costs and efficiency reductions do not limit the utility of these technologies in achieving cost-effective whole-system emissions mitigation.

Determinants of residential water demand in an arid and oil rich country: A case study of Riyadh city in Saudi Arabia

The accurate forecast of residential water demand is critically important for arid and oil rich countries such as Saudi Arabia which depend on costly desalination plants to satisfy the growing water demand. Achieving the desired prediction accuracy is a challenging task since the forecast model should take into consideration a variety of factors such as economic development, climate conditions and population growth. The task is further complicated given that the water sector in the country is characterized by high levels of unaccounted-for-water and heavy government subsidies, which lead to an artificially high water demand. This study presents a model for forecasting the long term water demand for Riyadh city, the capital of Saudi Arabia. The proposed model used historic records of water consumption to calibrate an econometric predictive model for per capita water use. The explanatory variables included household income, persons per household and maximum monthly temperature. Both the effects of unaccounted-for-water and conservation measures were also included. The calibration results indicate that socio-economic factors and weather temperature are equally important for water demand. The results also predict considerable savings if a comprehensive policy for water conservation and unaccounted-for-water management is implemented. Key words: Water demand forecast, predictive model, water demand management, Saudi Arabia.

Water resources management in theJordanRiverBasin

AbstractTheJordanRiverBasin is under great hydric stress. Increases in population and agricultural demand are contributing to the closure of the basin. This paper analyses the results of integrated water resources planning model (WEAP) by studying the vulnerability of water resources in the lowerJordanRiver under a changing climate pattern and growing water demands. Water balance models show that all aquifers supplying the city ofAmman will be depleted within the next few decades. Mitigation measures should include the introduction of additional water into the basin through theRedSea–DeadSea canal, in addition to demand management measures such as water conservation and increase in irrigation efficiency. The findings of this study would provide a useful guide to the co‐riparians for policy formulation, decision making and dispute resolution. Cooperation among the five riparian countries may be improved by building a Geographic Information System (GIS) database that provides access to accurate data for hydrological analysis.

Scenario analysis for sustainable development of Chongming Island: Water resources sustainability

With the socioeconomic and urban development of Chongming Island (the largest alluvial island in the world), water demand is rapidly growing. To make adjustments to the water utilization structure of each industry, allocate limited water resources, and increase local water use efficiency, this study performed a scenario analysis for the water sustainability of Chongming Island. Four different scenarios were performed to assess the water resource availability by 2020. The growth rate for water demand will be much higher than that of water supply under a serious situation prediction. The water supply growth volume will be 2.22×108m3 from 2010 to 2020 under Scenario I and Scenario II while the corresponding water demand growth volume will be 2.74×108m3 and 2.64×108m3, respectively. There will be a rapid growth in water use benefit under both high and low development modes. The water use benefit will be about 50CNY/m3 under Scenarios I and II in 2020. The production structure will need to be adjusted for sustainable utilization of water resources. Sewage drainage but not the forest and grass coverage rate will be a major obstacle to future development and environmental quality. According to a multi-level fuzzy comprehensive evaluation, Scenario II is finally deemed to be the most desirable plan, suggesting that the policy of rapid socioeconomic development and better environmental protection may achieve the most sustainable development of Chongming Island in the future.

Non-revenue water: financial model for optimal management in developing countries – application in Aqaba, Jordan

This paper presents the application of a financial model for optimal non-revenue water (NRW) to the Aqaba Water Company (AW), which serves approximately 130,000 residents of the Aqaba Governorate in Southern Jordan. It describes the water supply circumstances in Aqaba, summarizes previous NRW-reduction programs and their historical impacts, outlines the process of application for an NRW financial optimization model, and then presents the results, focusing on Aqaba City in particular. Currently, Aqaba Governorate's water is supplied from non-renewable groundwater drawn from the Disi Aquifer. With growing water demand, Aqaba will face a severe constraint – the limited capacity of wells and of the pipeline from Disi to Aqaba. As of 2010, the actual NRW was 361 L/customer/day, while the optimal amount was found to be about 89 L/customer/day. Sensitivity analysis shows that the reliability of the optimal NRW model result is plus or minus 10%. Depending on the effort expended, AW could reach optimal NRW by 2014–2017. Approximate projections show that NRW reduction can be a ‘source’ of water supply for the near future by delaying the date when Aqaba reaches full capacity of its current source of supply. However, a major new source of water will be needed for the long term. The paper concludes with a discussion of observations, conclusions and future work.

Principles to coordinate managed aquifer recharge with natural resource management policies in Australia

Managed aquifer recharge (MAR) is a tool available to water-resources managers that assists agencies to secure water supplies and protect aquifers and groundwater-dependent ecosystems in the face of climate change and growing water demand. Yet few natural-resources managers have access to a coordinated set of policies that enable the potential benefits of MAR to be fully realised in urban and rural areas. This paper reviews contemporary Australian water-resource policies and systematically applies a refined set of ‘robust separation of rights’ principles based on secure entitlements, annual allocations and end-use obligations to guide the coordination of policies specific to each of the four operational processes central to MAR schemes: source water harvesting, aquifer recharge, recovery of stored water and end use. Particular attention is given to the formulation of policies relating to the recovery of water, including the feasibility for market exchange of permanent and temporary rights to recover recharged water, as these have the potential to greatly expand the role of MAR. Aquifer characteristics, existing groundwater extractions and potential third party effects need to be taken into account in determining both recovery entitlements and annual allocations. A transitional pathway to implement novel MAR policies is suggested.

Seawater desalination for agriculture by integrated forward and reverse osmosis: Improved product water quality for potentially less energy

Seawater desalination for agricultural irrigation will be an important contributor to satisfying growing water demands in water scarce regions. Irrigated agriculture for food production drives global water demands, which are expected to increase while available supplies are further diminished. Implementation of reverse osmosis, the current leading technology for seawater desalination, has been limited in part because of high costs and energy consumption. Because of stringent boron and chloride standards for agricultural irrigation water, desalination for agriculture is more energy intensive than desalination for potable use, and additional post-treatment, such as a second pass reverse osmosis process, is required. In this perspective, we introduce the concept of an integrated forward osmosis and reverse osmosis process for seawater desalination. Process modeling results indicate that the integrated process can achieve boron and chloride water quality requirements for agricultural irrigation while consuming less energy than a conventional two-pass reverse osmosis process. The challenges to further development of an integrated forward and reverse osmosis desalination process and its potential benefits beyond energy savings are discussed.

Developing an Agricultural Planning Model in a Watershed Considering Climate Change Impacts

AbstractSocieties are facing major challenges in allocating water resources to growing water demands due to population growth and industrial and agricultural developments. With increasing water scarcity, the need to increase agricultural water productivity is receiving significant attention in developing countries. Among alternative options for meeting increasing water demand, improving productivity has received considerable attention. Therefore, planning of water systems to face future development conditions needs further studies on land, water use, and resources as well as consideration of objectives to maximize crop production to achieve the maximum net return. Because climate change is likely to have impact on the hydrological cycle and consequently on the available water resources and agricultural water demand, there are concerns about the effects of climate change on agricultural productivity. Considering climate change impacts, in order to optimize agricultural productivity, practical frameworks an...

Will climate change affect the electricity production sector? A European study

Climate change and increasing electricity production affect future freshwater requirements for thermoelectric power plants in Europe. This paper explores the reasons and shows ‘hot spots’ for further analysis. A scenario and simulation approach was selected to estimate water availability and water uses in Europe up to 2050. Depending on the scenario, water withdrawals in thermal electricity production would increase by 64% or decrease by 92% between 2005 and 2050. At the same time, average summer water availability is expected to decrease because of climate change in southern and south-eastern parts of Europe. In these regions in particular, hot spots were identified where water is scarce and where growing water demand is likely to exacerbate water stress which may cause economic losses. Hot spots identified in the Economy First scenario indicate increasing competition for freshwater resources for the thermal electricity production sector. Increasing efficiency and improved awareness as assumed in the Sustainability Eventually scenario can reduce these hot spots by 90%.

Modelling global water stress of the recent past: on the relative importance of trends in water demand and climate variability

Abstract. During the past decades, human water use has more than doubled, yet available freshwater resources are finite. As a result, water scarcity has been prevalent in various regions of the world. Here, we present the first global assessment of past development of water stress considering not only climate variability but also growing water demand, desalinated water use and non-renewable groundwater abstraction over the period 1960–2001 at a spatial resolution of 0.5°. Agricultural water demand is estimated based on past extents of irrigated areas and livestock densities. We approximate past economic development based on GDP, energy and household consumption and electricity production, which are subsequently used together with population numbers to estimate industrial and domestic water demand. Climate variability is expressed by simulated blue water availability defined by freshwater in rivers, lakes, wetlands and reservoirs by means of the global hydrological model PCR-GLOBWB. We thus define blue water stress by comparing blue water availability with corresponding net total blue water demand by means of the commonly used, Water Scarcity Index. The results show a drastic increase in the global population living under water-stressed conditions (i.e. moderate to high water stress) due to growing water demand, primarily for irrigation, which has more than doubled from 1708/818 to 3708/1832 km3 yr−1 (gross/net) over the period 1960–2000. We estimate that 800 million people or 27% of the global population were living under water-stressed conditions for 1960. This number is eventually increased to 2.6 billion or 43% for 2000. Our results indicate that increased water demand is a decisive factor for heightened water stress in various regions such as India and North China, enhancing the intensity of water stress up to 200%, while climate variability is often a main determinant of extreme events. However, our results also suggest that in several emerging and developing economies (e.g. India, Turkey, Romania and Cuba) some of past extreme events were anthropogenically driven due to increased water demand rather than being climate-induced.