Desalination and water security in the US–Mexico border region: assessing the social,environmental and political impacts

In the western US–Mexico border region, both countries’ authorities look to desalination as a means to meet increased demands for dwindling supplies. In addition to several existing or planned desalination plants, plans exist to develop projects along Mexico’s coasts to convert seawater into freshwater primarily for conveyance and consumption in the United States. Even though desalination systems have the potential to increase water supply in the region, there are associated consequences, costs and constraints. To understand the impacts of such binational desalination systems, this paper assesses, through a water-security framework, the case of a proposed desalination plant on the Upper Gulf of California. The analysis suggests that for binational desalination systems, there are several key areas of impact against which the benefits of increased water supply must be weighed.     

Reasons for the Fast Growing Seawater Desalination Capacity in Algeria

Seawater/brackish water desalination has been widely adopted by the Algerian Government in the last few years to supply potable water to municipality for various purposes mainly for domestic and industrial uses especially in areas where demand is high due to shortage of fresh water resources, rapid population growth and development of industry and tourism. Ten years ago, desalination was confined to the industrial use only especially in oil and gas industry as the country was relying on rain water and other available sources to supply fresh water to municipalities. Due to chronic drought conditions, the Ministry of Water Resources reviewed the national water strategy and a strong option for desalination was adopted where an ambitious program was thus put into action. Sixteen mega-plants, with capacities ranging from 100,000 to 500,000 m³ per day, primarily based on Reverse Osmosis technology, were launched in the last few years making the Algerian desalination program one of the world’s fastest growing markets. Five desalination plants, including the Africa’s largest seawater reverse osmosis project with a total capacity of 200,000 m³ per day, are already in operation and the remaining projects are either under construction or in commissioning. An integrated water resources management was also adopted as additional option to cuter the increasing water demand as there is also a great potential for water reuse and conventional water treatment. An additional benefit of this would be reducing the volume of treated wastewater disposed into the environment.     

Ecosystem Service Impacts of Urban Water Supply and Demand Management

Utilities face the challenge of enhancing long-term water security while minimising undesirable economic, social and environmental impacts of supply and demand management options. This paper provides an example of how the ecosystem services concept can be used to enumerate and organise broad impacts of water supply options. A case study of Adelaide, South Australia, is used to examine costs and benefits associated with different sources of water and source-water mix scenarios. Ecosystem service impacts are estimated using estimates from the literature. Seven water supply and demand management options are considered for Adelaide: 1) the River Murray, 2) Mt. Lofty Ranges catchments, 3) wastewater reuse, 4) desalination, 5) stormwater harvesting, 6) groundwater and 7) water conservation. The largest costs are associated with sourcing water from conservation measures such as water restrictions on outdoor watering estimated at $1.87/kL. Salinity damage costs associated with residential uses are estimated at up to $1.54/kL. Salinity damage costs of wastewater reuse were estimated at $1.16/kL. The largest benefit is coastal amenity services associated with stormwater harvesting and treatment estimated at $1.03/kL. Results show that there is a trade-off between financial costs and ecosystem services impacts with source-water mix scenarios with the highest ecosystem services cost having the lowest financial O&M cost and vice versa. This highlights the importance of taking ecosystem services into account when evaluating water supply options.     

The Virtual Water Metaphor Enhances Policy Discussions Regarding Scarce Resources

Abstract

In a recent issue of Water International, three authors discuss their views of the virtual water metaphor that is used to describe the water embedded in crops that are traded in international markets. The term ‘virtual water’ was created originally to gain the attention of public officials responsible for choosing policies that influence water use in arid regions. Over time, both the terminology and the scope of the virtual water metaphor have been extended beyond the original purpose. This paper supports the view that the virtual water metaphor is helpful in encouraging public officials to consider the scarcity value (opportunity cost) of water when designing policies that influence water use. The paper proposes, also, that the policy relevance of the virtual water metaphor is found primarily in its application to issues regarding the supply of agricultural products, rather than demand. The distinction between supply and demand issues and the potential value of the virtual water metaphor in policy discussions regarding supply are demonstrated using three examples of water allocation decisions, described within the framework of economic optimization. The examples include wheat production in Saudi Arabia and the production of sudangrass and ethanol in the United States.     

Global Water Demand and Supply Projections

Abstract

This paper presents a modeling approach for projections of water demand and supply for domestic, industrial, livestock, and irrigation at the basin or country level in a global scope. Particular emphasis is put on simulating water availability for crops taking into account total renewable water, non-irrigation water demand, water supply infrastructure, and economic and environmental policies at the basin or country level. This paper focuses on concepts and methodology involved in the modeling exercise. Data assessment and results are presented in a companion paper (Rosegrant and Cai, 2002).     

The Role of Desalination in Meeting Water Supply Demands in Western Asia

Abstract

The increasing gap between the supply and demand for water in the Economic and Social Commission of Western Asia (ESCWA) member countries: Bahrain, Egypt, Iraq, Jordan, Kuwait, Lebanon, Oman, Palestine, Qatar, Saudi Arabia, United Arab Emirates, and Yemen) can be attributed to the limited availability of surface water, mining of fossil groundwater sources, and water pollution mainly of shallow aquifers, deficient institutional structure, poor management processes, and inapt allocation of financial resources. The non-sustainable use of natural water resources to meet the escalating water demand has also contributed to the depletion and deterioration of water quality and quantity. To meet water supply shortages in the domestic sector, water desalination has been entrenched as a viable option for the Gulf Cooperation Council (GCC), which includes the following countries: Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and United Arab Emirates. The objective of the paper is to investigate the role of water desalination in meeting the water demands in the ESCWA member countries. The significant role of desalination is highlighted with emphasis in evaluating not only its production trends, processes, and costs, but also its capacity in the provision of water demands. Water desalination has become a major and staunch water source for a number of large urban centers. For such countries such as Bahrain, Kuwait, and Qatar and the coastal zone areas of Oman, United Arab Emirates (UAE), and Saudi Arabia, desalination represents one of the most feasible and strategic alternative options for their current and future domestic water supply requirement. Given the high consumption rate from this source and its high production cost, fundamental efforts must be integrated and invested in both research and development programs to implement comprehensive conservation measures that would lead to a reduction in the consumption rates. Parallel to these achievements, efforts should be directed within the context of integrated management of water resources, to identify alternative potential water resources, to meet future water challenges.     

Performance Risk Analysis for Fukuoka Water Supply System

In this study, simulation is used to evaluate the performance of the municipal water system in Fukuoka city. In combination with daily simulation model, a kind of risk model incorporating water demand prediction is presented. This model applies five risk indices: reliability, resiliency, vulnerability, drought risk index (DRI) and drought damage index (DDI). They aid in the identification of operation policies for the municipal water system, and the planning and operational policies obtained are aimed at achieving minimum risk for a given scenario of operation. In this paper, the performance risk of the municipal water system is investigated under three alternatives: (1) the existing system operation when available supply from the Chikugo river is decreased; (2) water restrictions for different percentages of reduction are implemented; and (3) available water supply increases when desalination of sea water is implemented. The results obtained show that savings of between 5 and 12% of water consumption from May 1, or increasing of daily desalination of sea water about 30 000 m³ or more, may efficiently decrease the performance risk of the Fukuoka water supply system. Potentials also exist for further increase of reservoir storage by more rational operation. The measure that more attention should be paid to increasing the water supply from stable sources is recommended as well.     

THE INTERBASIN TRANSFER OF WATER: AN ISSUE OF EFFICIENCY AND EQUITY

ABSTRACT

Interbasin water transfers provide the option of redirecting water supplies to areas of high demand. Yet, water transfers may involve environmental damage or the loss of economic opportunity within the donor basin. It is essential, therefore, that a means for assessing potential impacts associated with proposed transfers and for accommodating damages be instituted to assure that water resources are being put to their highest and best use.

The following paper reviews recent experience in the United States with regard to interbasin transfers. It then presents a conceptual framework for assessing potential benefits and costs associated with water transfers and offers an approach for resolving conflicts that may allow for mutual benefit on the part of the affected parties.     

Submarine Groundwater: A New Concept for the Supply of Drinking Water

Submarine groundwater is water stored under the sea-bed. It might exist in large quantities and can have much lower salinity than the ambient sea-water. Therefore, it may be considered as a potential source of raw water for drinking water supply. This article assesses the feasibility of practical use of these resources. The hydro-geological potential and economical factors are discussed, and a technical concept for the withdrawal, transport and treatment of the water is presented. Based on these factors, we propose that submarine groundwater can be a potential substitute for desalination of sea water, in terms of comparable or lower cost potential. Furthermore, we expect energy efficiency gains and thus also higher environmental performance in terms of reduced CO₂-emissions, compared to desalination of sea water based on fossil fuel. We foresee no major environmental, social or political barrier in utilising submarine groundwater as a new source of raw water.     

Developing a Model for Decision-Makers in Dynamic Modeling of Urban Water System Management

Water managers may modify many components of urban water systems to minimize water shortage. Since each modification activity has its own positive and negative effects, it is necessary to define an appropriate procedure to predict the consequences of each action. As the parameters of urban water supply and demand system have internal relationships in the time domain, a dynamic model is needed to forecast the result of changes and select the best modification activity. Here the Vensim® is applied as a modeling tool to choose the most effective water management activities in Tehran province. It has been found that the annual increase rate of water tariff by 16.4% and assigning 4.5% of revenue on reducing non-revenue water may be the most effective demand management activity to reduce water shortage in Tehran province. It has also been revealed that, even by implementing the most effective demand management activities in Tehran, the amount of required water in the next 10 years is more than the sustainable capacity of its resources and activities like seawater desalination are inevitable to prevent unsustainable use of water sources.

     

Conjunctive use of Inter-Basin Transferred and Desalinated Water in a Multi-Source Water Supply System Based on Cost-Benefit Analysis

Water shortage has forced coastal cities to seek multi-source water supply with a focus on inter-basin water and desalinated seawater. The differences of water supply costs pose a challenge in the optimal use of multiple water resources. This paper aims to understand the impact of desalinated seawater’s variable costs on multi-source water supply through a cost-benefit analysis method based on a multi-objective optimization model, considering different combination scenarios of desalination yield, streamflow condition, seawater desalting plant (SDP) scheme, water shortage index and utilization ratio of the SDP. The application in the coastal city Tianjin, China shows that the desalination yield has an impact on the tradeoff between the water shortage index and the total water supply cost and an optimal desalination yield can be determined at a turning point. And where the turning point appears is influenced by the utilization ratio of the SDP and streamflow conditions of inter-basin water. Moreover, a single centralized SDP is found to have an overall lower water supply cost than several decentralized small-sized SDPs. Lower water shortage index leads to higher cost, and the unit decrease of shortage index will need more added cost when the shortage index is very low. This method is proven to be effective in identifying the best conjunctive use of inter-basin water and desalinated seawater, which can contribute to relieve urban water shortage.     

Hazard identification framework for water utilities with application to the city of Xalapa,Mexico

Abstract:

There is a growing need for a comprehensive approach for assessing drinking water systems that enables managers and engineers to quickly address critical hazards that impact their water supply systems and plan for system improvements. A hazard identification framework for water utilities is developed and applied to the municipal water supply system at Xalapa, Veracruz, Mexico, operated by the Comisión Municipal de Agua Potable y Saneamiento de Xalapa (CMAS Xalapa). The framework is designed to aid in the analysis of a water supply system from catchment to tap and consists of four components: system characterization, identification of hazards, assessment of the impacts of the major hazards, and determination of priority recommendations for system improvements. When the framework is applied to the CMAS Xalapa system, a number of significant hazardous events are identified including elevated turbidity events and high pressure surcharges. Recommendations for system improvements include increased data collection and analysis and enhanced management of control measures for mitigating the impacts of the hazards.     

An Optimization Approach for Multi-Sectoral Water Supply Management in the Greater Beirut Area

This paper presents a model that was developed and applied to serve as a water supply multi-sectoral decision support system for water resources management taking economic and socio-environmental factors into consideration. The applicability of the model was tested in the Greater Beirut Area by examining future supply-demand management alternatives and quantifying the cost-benefit of viable policies. The effect of eliminating a particular source to account for resources depletion and public acceptability, as well as increased returns from water use were proven to affect greatly the water allocation scheme. The model can also be a useful tool to assess the effect of decreasing unit costs from water supply options (desalination) and the resulting breakeven point, and the effect of increased water demand due to unplanned growth (tourism).     

Urban Water Management in Developing Arid Countries

Urbanization, industrialization and rapid population growth in developing countries of the Arabian Peninsula are putting increasing pressure on local water authorities and water planners to satisfy the growing urban water and sanitation demands. In the Arabian Peninsula, water resources are limited, average rainfall is low and the seawater and brackish water desalination in addition to limited groundwater resources are the major water supply sources. The population increased from about 17.688 million in 1970 to 38.52 million in 1995 and is expected to reach 81.25 million in 2025. The urban population is expected to rise from 60% in 1995 to more than 80% in 2025. The domestic water demand is expected to rise from 2863 million cubic metres (MCM) in 1990 to about 4264 MCM in 2000 and 10580 MCM in 2025. In Saudi Arabia, the population increased by 143.6% between 1970 and 1995; and it is expected to reach about 40.426 million in 2025, with about 80% urban population. The domestic water demand in the Kingdom is expected to be about 2350 MCM in 2000 and 6450 MCM in 2025. Specialized agencies have been established for water production and distribution, and for wastewater collection, treatment and reuse. Special legislation has been introduced to manage water demands and to protect the interests of the community and its natural resources. Fifty-seven costly desalination plants have been constructed in the Peninsula on the Gulf and Red Sea coasts, as well as water transmission lines to transport the desalinated water to coastal and inland major cities. The seawater desalination unit cost is about US$0.70/m 3 for a large desalination plant with energy priced at world prices. More than $30 billion has been invested on water and sanitation projects. Present desalination production is about 46% of the total domestic demand, and the rest is pumped from deep and shallow aquifers. In general, fragmented legislation and institutional arrangements and low water charges have indirectly resulted in over-usage of domestic water, production of excessive quantities of wastewater, significant leakage, and enhancement of shallow water-table formation and rise in some cities. Facing the challenges of satisfying the growing urban water demands requires several essential measures such as: (a) introduction of new technologies to reduce water demands, and losses, and to enhance wastewater recycling and water conservation; (b) the updating of legislation to coordinate both responsibilities and actions among different water agencies; (c) the introduction of a strong and transparent regulatory framework to adopt different forms of water supply privatization, to reduce the costs of building, operation and maintenance of water and sanitation facilities, and to improve the level of services and billing, leakage and wastewater collection and treatment; (d) an increase in water tariffs to reflect the actual value of the water, and to enhance the awareness of public as to the value of water; and (e) development of short-term and long-term national water plans based on realistic water demand forecasting.     

Analysis of the Water Resources Status in Kuwait

The acute lack of natural water resources in Kuwait is indisputable. The country essentially has one limited natural water resource that is groundwater, while the majority of the country's demands are met by seawater desalination. Notwithstanding this scarcity calls for careful foresighted utilization of the water resources, no clear plans is being followed. Attempting to initiate the planning process, this paper gives an assessment of the current status of water resources availability, production, future demand and expected increases in production, in Kuwait. While the desalination and wastewater reuse are only bounded by economical considerations, considerable efforts have already been made in assessing the baseline of the groundwater resources in Kuwait; nonetheless, no estimation is available of the aquifer system potential for sustainable development or even mining. The total water budget in 2001 is estimated at 655 Million m³, with desalination, groundwater production, and wastewater reuse constituting 59%, 32% and 9% respectively. The projected water demand for 2010 is 1020 Million m³. The plans of the Ministry of Electricity and Water and the Ministry of Public Works indicated that groundwater would cover 52% of the planned additional production, while desalination and wastewater reuse would cover 44% and 4% respectively. While the proposed increase in groundwater production would inevitably consume the only natural water resource of the country, only 40% of the generated wastewater is to be utilized. The absence of integrated planning is also manifested in the total planned production that surpasses the projected demands by more than 17%.     

The application of economic-engineering optimisation for water management in Ensenada, Baja California, Mexico.

Mathematical optimisation is used to integrate and economically evaluate wastewater reuse, desalination and other water management options for water supply in Ensenada, Baja California Mexico with future levels of population and water demand. The optimisation model (CALVIN) is used to explore and integrate water management alternatives such as water markets, reuse and seawater desalination, within physical capacity constraints and the region's water availability, minimising the sum of economic costs of water scarcity and operating costs within a region. The modelling approach integrates economic inputs from agricultural and urban water demand models with infrastructure and hydrological information, to identify an economically optimal water allocation between water users in Ensenada. Estimates of agricultural and urban economic water demands for year 2020 were used. The optimisation results indicate that wastewater reclamation and reuse for the city of Ensenada is the most economically promising alternative option to meet future water needs and make water imports less attractive. Seawater desalination and other options are not economically viable alone, but may have some utility if combined with other options for the Ensenada region.     

Integrated water and food analysis at the global and basin level. An application of WATERSIM

Several recent studies warn that under ‘Business-as-Usual’ a water crisis is impending, suggesting that appropriate actions need to be taken on the water supply and demand side. While many measures to alleviate water scarcity are within the water sector, it is increasingly recognized that many drivers, policies and institutions outside the water sector have large and real implications on how water is being allocated and used. Important drivers for water use include population and income growth, urbanization, trade and other macroeconomic policies, environmental regulations and climate policy. While some of these processes and trends, especially those at global level, may prove difficult to influence directly, it is important to understand their linkages with water issues to analyze the relative impact of various policies in the agricultural and water sectors on water and food security. The strong linkages between economic trends, agricultural policies and water use call for an integrated and multidisciplinary modelling approach. The WATERSIM model, developed by the International Water Management Institute (IWMI) is a suitable tool to explore the impacts of water and food related policies on global and regional water demand and supply, food production and the environment. This paper introduces the WATERSIM model and, using some preliminary results, illustrates the importance of global economic trends on food and water outcomes.     

A review of the current status of small-scale seawater reverse osmosis desalination

The current status of small-scale desalination (produced water capacity 100 m³/day or less) is reviewed to provide an overview of the market segment. The use of energy-recovery devices in this market segment is also reviewed. We find that the Middle East accounts for the largest market share worldwide at present, and reverse osmosis is overwhelmingly dominant among the desalination technologies adopted. Implementation of energy-recovery devices at small scale is rare, which leads to relatively high energy consumption for small-scale seawater reverse osmosis desalination systems.     

To desalinate or divert? A comparative supply cost analysis for north coastal China

Seawater desalination is largely presented as a last resort to address water scarcity in closed basins. The question of whether seawater desalination can substitute for other costly measures, specifically large-scale diversion, has not been adequately assessed. To this end the full unit cost of supplying water to Beijing from the South-to-North Water Diversion Project, the largest in the world, is compared to desalination. Desalination appears to be much more cost-efficient than diversion, even when the diversion’s environmental externalities are excluded. By implementing desalination and water management options, China could substantially reduce water costs; this suggests that desalination should not be viewed only as a last resort.     

Colonizing rural waters: the politics of hydro-territorial transformation in the Guadalhorce Valley,Málaga,Spain

ABSTRACT

This paper explores how, historically, the utopian thinking built into Spain’s water policies has legitimized profound transformations of the Guadalhorce Valley’s hydro-social territory (in Málaga), also justifying water transfers from rural to urban areas. It analyzes how the ‘regenerationist hydraulic utopia’ has been materialized through different ‘governmentality strategies’. This intensified during Francisco Franco’s dictatorship, decaying gradually into dystopias that, to this day, express profound socio-environmental impacts: dispossession, displacement, uprooting and breaking up local water governance institutions and practices. Meanwhile, the urban and tourism industries in Málaga have been strengthened by giving them priority for water supply.