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.     

A Method for Predicting Long-Term Municipal Water Demands Under Climate Change

Water Resources Management - The accurate forecast of water demand is challenging for water utilities, specifically when considering the implications of climate change. As such, this is the first...     

Water Resource Availability in Three Catchments of Swaziland under Expected Climate Change

Abstract

The greenhouse gases (CO₂, CH₄, N₂O, HFCs, PFCs, and SF₆) concentrations in the atmosphere have increased very much since the industrial revolution. The greenhouse gas effect has been projected to cause a global average temperature increase on the order of 1.4 to 5.8°C over the period of 1990 to 2100. The global average annual precipitation is projected to increase during the 21^st century due to the greenhouse effect. The impact of climate change on hydrology and water resources in the three catchments of Swaziland (Komati, Mbuluzi and Ngwavuma) has been evaluated using General Circulation Model results (rainfall, potential evapotranspiration, air temperature etc.) as inputs to a rainfall runoff model. Three General Circulation Models (GCMs) namely: Canadian Climate Change Equilibrium (CCC-EQ); Geophysical Fluid Dynamics Laboratory (GFDL) and United Kingdom Transient Resilient (UKTR) were found appropriate for use to project the temperature and precipitation changes for Swaziland for year 2075. This information was used to generate the temperature, precipitation and potential evapotranspiration values for the three catchments for year 2075 which was input into a calibrated WatBall rainfall runoff model. Simulation results without taking into consideration of water use projections show that there will be high flows during the summer months but low flows during the winter months. Simulation results after taking into consideration of water use projections show a water deficit from June to September in both the Komati, and Ngwavuma catchments and a water deficit from May to September in the Mbuluzi catchment. This means that the environmental water needs and Swaziland's water release obligation in the three catchments to South Africa and Mozambique will not be met during the winter months under expected climate change conditions.     

中国东部季风区水资源脆弱性评价

以中国东部季风区的八大流域为例,从水资源供需安全的角度,对2000年水资源状况和未来气候变化情景下的水资源脆弱性进行了评价。结果表明:海河流域是中国水资源的严重脆弱区,黄河和淮河均处于高度脆弱状态,辽河流域、松花江流域、长江流域、东南诸河和珠江流域绝大部分地区处于中度脆弱状态;未来气候变化使得中国东部季风区八大流域的水资源脆弱性均明显加重,黄淮海流域均上升到严重脆弱状态,对气候变化极度敏感,必须采取相应措施来积极应对气候变化对流域水资源的不利影响。     

Climate Change Impacts on Water Resources and Lake Regulation in the Vuoksi Watershed in Finland

The impacts of climate change on hydrology and water resources in the Vuoksi watershed in eastern Finland were studied in order to assess the possibilities to adapt lake regulation to the projected changes. A conceptual watershed model and several climate scenarios were used to estimate the effects of climate change on three lakes in the Vuoksi watershed for 2010–2039, 2040–2069 and 2070–2099. The adaptation possibilities were studied by using alternative regulation strategies. In Lake Pielinen the impacts of these water level changes on social, economic and ecological indicators were assessed with two different outflow strategies. According to the results, climate change will alter snow accumulation and melt and therefore cause large seasonal changes in runoff and water levels. Runoff and water levels will decrease during late spring and summer and increase during late autumn and winter. In some lakes current calendar-based regulation practices and limits, which have been developed based on past hydrology, may not be appropriate in the future. Modifying the regulation practices and limits is a necessary and effective way to adapt to climate change.     

气候变化下水资源适应性对策的定量评估方法

论述了气候变化背景下水资源管理所面临的主要问题和适应性管理的基本内涵,介绍了应对气候变化影响的水资源适应性管理的国内外研究进展,梳理归纳了目前分析评价适应性管理对策的几种不同方法,认为定量分析适应性对策的经济效益至为关键,成本效益分析的步骤主要包括:①点绘实物量基线曲线;②点绘经济量基线曲线;③点绘过去适应性管理变化曲线;④分析气候变化引发的变化;⑤适应性管理获得的效益变化。     

Water Resources Under Climate Change in Himalayan Basins

Water Resources Management - Climate change has significant implications for glaciers and water resources in the Himalayan region. There is an urgent need to improve our current knowledge and...     

The Impacts of Climate Variability and Future Climate Change in the Nile Basin on Water Resources in Egypt

This paper describes the application of hydrologic models of the Blue Nile and Lake Victoria sub-basins to assess the magnitude of potential impacts of climate change on Main Nile discharge. The models are calibrated to simulate historical observed runoff and then driven with the temperature and precipitation changes from three general circulation model (GCM) climate scenarios. The differences in the resulting magnitude and direction of changes in runoff highlight the inter-model differences in future climate change scenarios. A 'wet' case, 'dry' case and composite case produced +15 (+12), -9 (-9) and + 1(+7) per cent changes in mean annual Blue Nile (Lake Victoria) runoff for 2025, respectively. These figures are used to estimate changes in the availability of Nile water in Egypt by making assumptions about the runoff response in the other Nile sub-basins and the continued use of the Nile Waters Agreement. Comparison of these availability scenarios with demand projections for Egypt show a slight surplus of water in 2025 with and without climate change. If, however, water demand for desert reclamation is taken into account then water deficits occur for the present-day situation and also 2025 with ('dry' case GCM only) and without climate change. A revision of Egypt's allocation of Nile water based on the recent low-flow decade-mean flows of the Nile (1981-90) shows that during this period Egypt's water use actually exceeded availability. The magnitude of 'natural' fluctuations in discharge therefore has very important consequences for water resource management regardless of future climate change.     

气候变化对大型水利工程的影响

气候变化将导致流域降雨径流关系、水文极端事件的大小和频率发生改变，影响大型水利工程的建设标准、规模和运行规程。以三峡工程和南水北调工程为例，介绍了气候变化对大型水利工程设计、运行等方面的可能影响。     

Water Conflict Management between Agriculture and Wetland under Climate Change: Application of Economic-Hydrological-Behavioral Modelling

Water Resources Management - Water resources at the basin level are affected by climate change in the form of available water scarcity and multiple droughts leading to conflicts among different...     

Quantifying the Urban Water Supply Impacts of Climate Change

The difference in timing between water supply and urban water demand necessitates water storage. Existing reservoirs were designed based upon hydrologic data from a given historical period, and, given recent evidence for climatic change, may be insufficient to meet demand under future climate change scenarios. The focus of this study is to present a generally applicable methodology to assess the ability of existing storage to meet urban water demand under present and projected future climatic scenarios, and to determine the effectiveness of storage capacity expansions. Uncertainties in climatic forcing and projected demand scenarios are considered explicitly by the models. The reservoir system in San Diego, California is used as a case study. We find that the climate change scenarios will be more costly to the city than scenarios using historical hydrologic parameters. The magnitude of the expected costs and the optimal investment policy are sensitive to projected population growth and the accuracy to which our model can predict spills.     

Climate Change Impacts on the Water Supply of Thessaloniki

This paper examines the assessment of the impacts of climate change on water resources in the Aliakmon river basin, Northern Greece, and on some critical water management issues, such as reservoir storage and water supply of the city of Thessaloniki. A monthly conceptual water balance model was calibrated using historical hydrometeorological data. This model was applied to estimate runoffs in the entrance of the Polyfyto reservoir under two different equilibrium scenarios (UKHI, CCC) referring to 2050. Reduction of the mean annual runoff, mean winter runoff and summer runoff would occur. By using these scenarios, the sensitivity of the risk associated with the water supply for the city of Thessaloniki was evaluated under conditions of altered runoff. Increases of the risks associated with the annual quantities of water supply were observed, particularly under the UKHI scenario.     

气候变化下水资源动态承载力概念及计算方法讨论

水资源是生命之源、生产之要、生态之基,人多水少、水资源时空分布不均是我国的基本水情;气候变化是目前国际社会公认的最主要的全球性环境问题之一,未来的气候变化将有可能进一步加剧我国水资源的供需矛盾。国内外关于水资源承载能力的研究已有大量文献,对于水资源承载能力的定义可以归纳为两种观点:一种观点是水资源开发容量论或水资源开发规模论,另一种观点是水资源支持可持续发展能力论。在实际应用中,水资源承载能力计算一般基于未来水平年不同保证率水资源可利用量。不同保证率水资源可利用量是基于历史降水资料通过概率统计方法计算得到,不能真实反映未来年份水资源可利用量的大小。水资源动态承载力是相对于传统的水资源承载能力计算来说的,传统的水资源承载能力计算一般基于未来水平年不同保证率水资源可利用量。而水资源动态承载能力计算的前提是首先通过气候模型、水文模型模拟得到未来年份水资源可利用量。因此,可以把"水资源动态承载能力"概括为:"一个流域或地区的水资源动态承载能力,是指在可以预见的时期内,水资源系统在气候变化的影响下能够维系生态系统良性循环,支撑社会经济发展的最大规模"。本文在回顾和总结水资源承载力研究的基础上,系统地阐述了气候变化下水资源动态承载力的概念与内涵。提出了气候变化下水资源动态承载力的计算框架和主要技术方法,分析了气候变化下水资源动态承载力的优点和应用范围,旨在为进一步深入研究气候变化下流域和区域水资源动态承载力提供参考。     

On the Barriers to Adaption to Less Water under Climate Change: Policy Choices in Mediterranean Countries

Barriers and constraints to adapting water resources management to climate change in the Mediterranean region are analysed in this paper. First, we analysed the risks to the water resources sector derived from climate change. We then identified the main objective of water adaptation measures: ensuring there is enough water for food, for people, and for ecosystems. This implies visions about availability - being sufficient water -, accessibility - both physical and economic access -, and adequacy - being safe for ecosystems and human consumption. A portfolio of local and collective actions to adapt water management for agriculture to climate change in Mediterranean countries is presented. Adaptation strategies included improved efficiency, optimisation of governance, enhancement of participation, development of risk-based choices, and economic instruments. Finally, the paper categorised the constraints to implement the measures, give specific examples about these issues and also quantify their impact. When considering constraints and opportunities to implement these water management practices, any environmental policy regulating their adoption should be based on recommending the use of extension and training to local actors on the application of the practices.     

气候变化条件下山东省未来水资源情势预估

利用山东省实测降水资料、政府水资源公报数据,采用小波分析、数理统计等方法,预估了山东省未来水资源情势。结果表明:从目前到2030年左右,山东省降水将处于相对枯水期,受降水量减少和极端降水强度增大的影响,当地水资源量将减少、水资源开发利用难度将增大;黄河水和长江水等客水资源受到干流上游来水量减少、脆弱性增强、调蓄工程不完善、水价成本高等因素限制,未来情势不容乐观;目前山东省非常规水资源利用潜力较大,应在增大非常规水资源利用力度的同时,做好建设节水型社会、完善现代水网工程、提高水利工程调蓄能力等工作。     

Water Structures and Climate Change Impact: a Review

Climate change impact started to play significant role since the last three decades almost in every aspects of life especially on meteorological and climatological events and their impacts on water resources, which are managed by engineering structures. Its effects on hydro-meteorological data are assessed by means of available methodologies, but the climate change impact of engineering water structures (dams, culverts, channels, wells, highways and their side drainages, levees, etc.) are not treated equally. This paper provides the review of the necessary adaptation, combat and mitigation activities against the climate change for protection, construction or augmentation of the engineering water structures design capacity. Additionally, land use practices and geomorphological changes also trigger the climate changes on the engineering water structures. The main aim of this paper is to present the impact of such changes on the engineering water structure capacity, operation and maintenance.

     

Impact of Climate Change on Salinization of Coastal Water Resources

Water Resources Management - A density-dependent numerical model was set up to quantify the actual and future (2050) salinization of a coastal aquifer in the Po Delta (Italy). SEAWAT 4.0 was used...     

Collaborative Planning in Adaptive Flood Risk Management under Climate Change

Flood risk management (FRM) is moving towards more proactive and collaborative direction to enable adaptation to changing conditions. We present a case study on collaborative planning process, which contributed to the development of adaptive FRM in one of the largest river basins in Finland. The focus was on the possibility and acceptability of using large regulated lakes as storage for flood water in an extreme flood event to decrease flood damage at the downstream riverside towns. We defined an extreme flood event that would cause dramatic flood damage and developed tools for simulating the event with alternative regulation strategies using Watershed Simulation and Forecasting System (WSFS). We organized a stakeholder event to demonstrate the alternative lake regulation strategies, their socio-economic consequences, and to discuss their acceptability. We found that storing flood water in the lakes above the regulation limits and preparing for winter floods in advance by lowering the lakes in the autumn can minimize the total damage in the target area. The majority of stakeholders considered these actions acceptable in an extreme flood event, regardless of deliberately induced flooding of areas where no floods have occurred for over 50 years. However, lowering the lakes in the autumn on annual basis gained less support. We emphasize the importance of deliberations on the FRM procedures and responsibilities in extreme flood events with the stakeholders in advance to increase adaptive capacity and legitimacy of decisions.     

Assessment of Water Resources Vulnerability and Adaptation to Climate Change

This paper provides an overview of the 'standard' methodology developed for the United States Country Studies Program on the Assessment of Water Resources Vulnerability and Adaptation to Clim ate Change. The methodology is described in more detail in accompanying articles in this issue. A standard methodology was developed for two reasons. First, for countries with little or no experience in hydrologic and water resources modelling, it provided a simple, yet appropriate set of modelling tools that could be quickly learned and applied with a limited data set. Second, it provided a consistent methodology for synthesizing results for regional and global assessments as well as cross-country and cross-regional comparisons.     

Assessment of Water Resources Development Projects under Conditions of Climate Change Using Efficiency Indexes (EIs)

The purpose of this study is to evaluate Gharanghu multi-purpose reservoir system (East Azerbaijan, Iran) using efficiency indexes (EIs) affected by climate change. At first, the effects of climate change on inflow to the reservoir, as well as changes in the demand volume over a time interval of 30 years (2040–2069) are reviewed. Simulation results show that inflow to the reservoir is decreased in climate change interval compared to the baseline interval (1971–2000), so that comparison of long-term average monthly inflow to the reservoir in climate change interval is reduced about 25% compared to the baseline. Also, water demand in climate change interval will increase, namely volume of water demand for agricultural, drinking and industrial, and environmental in climate change interval is expected to increase by 20%. The simulation results of the water evaluation and planning (WEAP) model is used to determine EIs of multi-purpose reservoir system. Next, three scenarios of water supply for climate change interval are introduced to WEAP model, keeping variable of parameter related to water demand volume (based on different percentages of supply) and keeping constant of the parameter related to the volume of inflow to the reservoir. Results show that system EIs in climate change interval will have a disadvantage compared to the baseline. So that, reliability, vulnerability, resiliency and flexibility indexes in climate change interval based on 100% of water supply compared to the baseline will decrease 18%, increase 150%, decrease 33%, and decrease 47%, respectively. These indexes based on 85% of supply compared to the baseline will decrease 12%, increase 75%, decrease 30%, and decrease 39%, respectively. Also, those based on 70% of supply compared to the baseline will decrease 1%, will be without change, decrease 18%, and decrease 18%, respectively. Changes in indexes in future interval indicate the need to manage water resource development projects in the basin.