Using Information-Gap Decision Theory for Water Resources Planning Under Severe Uncertainty

Water resource managers are required to develop comprehensive water resources plans based on severely uncertain information of the effects of climate change on local hydrology and future socio-economic changes on localised demand. In England and Wales, current water resources planning methodologies include a headroom estimation process separate from water resource simulation modelling. This process quantifies uncertainty based on only one point of an assumed range of deviations from the expected climate and projected demand 25 years into the future. This paper utilises an integrated method based on Information-Gap decision theory to quantitatively assess the robustness of various supply side and demand side management options over a broad range of plausible futures. Findings show that beyond the uncertainty range explored with the headroom method, a preference reversal can occur, i.e. some management options that underperform at lower uncertainties, outperform at higher levels of uncertainty. This study also shows that when 50 % or more of the population adopts demand side management, efficiency related measures and innovative options such as rainwater collection can perform equally well or better than some supply side options The additional use of Multi-Criteria Decision Analysis shifts the focus away from reservoir expansion options, that perform best in regards to water availability, to combined strategies that include innovative demand side management actions of rainwater collection and greywater reuse as well efficiency measures and additional regional transfers. This paper illustrates how an Information-Gap based approach can offer a comprehensive picture of potential supply/demand futures and a rich variety of information to support adaptive management of water systems under severe uncertainty.     

Least Economic Cost Regional Water Supply Planning – Optimising Infrastructure Investments and Demand Management for South East England’s 17.6 Million People

This paper presents a deterministic capacity expansion optimisation model designed for large regional or national water supply systems. The annual model selects, sizes and schedules new options to meet predicted demands at minimum cost over a multi-year time horizon. Options include: supply-side schemes, demand management (water conservation) measures and bulk transfers. The problem is formulated as a mixed integer linear programming (MILP) optimisation model. Capital, operating, carbon, social and environmental costs of proposed discrete schemes are considered. User-defined annual water saving profiles for demand management schemes are allowed. Multiple water demand scenarios are considered simultaneously to ensure the supply–demand balance is preserved across high demand conditions and that variable costs are accurately assessed. A wide range of supplementary constraints are formulated to consider the interdependencies between schemes (pre-requisite, mutual exclusivity, etc.). A two-step optimisation scheme is introduced to prevent the infeasibilities that inevitably appear in real applications. The model was developed for and used by the ‘Water Resources in the South East’ stakeholder group to select which of the 316 available supply schemes (including imports) and 511 demand management options (considering 272 interdependencies) are to be activated to serve the inhabitants of South East of England. Selected schemes are scheduled and sized over a 25 year planning horizon. The model shows demand management options can play a significant role in the region’s water supply and should be considered alongside new supplies and regional transfers. Considering demand management schemes reduced overall total discounted economic costs by 10 % and removed two large reservoirs from the least-cost plan. This case-study optimisation model was built using a generalised data management software platform and solved using a mixed integer linear programme.     

Selecting Portfolios of Water Supply and Demand Management Strategies Under Uncertainty—Contrasting Economic Optimisation and ‘Robust Decision Making’ Approaches

Planning appropriate portfolios of new water supplies and demand management measures requires considering a wide array of options and their interactions over a largely unknown future. Various modelling-assisted approaches are available to help this planning process. This paper applies two such frameworks to the UK’s Thames water resource system and compares their methods and outputs: how they consider uncertainty, how they represent supply and demand management options, and what plans each recommends. The first method is the current England and Wales industry standard: annual least-cost capacity expansion optimisation over a 25 to 30 year time horizon considering capital, operating (fixed and variable), social and environmental costs. The second approach uses stochastic simulation and regret analysis to select a preferred alternative, then statistical cluster analysis to identify causes of system failure enabling further plan improvement. When applied iteratively with system planners this second approach is referred to as Robust Decision Making (RDM). The economic optimisation approach considers all plausible combinations of supply and conservation schemes and recommends the least-cost schedule of their implementation. Our RDM application considers a smaller number of options but makes a more detailed assessment of the effect of uncertainty (supply, demand and energy price uncertainty were considered) on multiple criteria of system performance. The simulation-based approach also enables more realistic interaction amongst supply and demand management schemes. Both approaches recommended different plans which we explain by discussing the benefits and limitations of each. Joint application is recommended to produce least-cost plans that are robust considering multiple criteria of performance across a wide range of futures.     

水网连通下山东蓝色半岛经济区水资源优化调配研究

对山东半岛蓝色经济区进行水资源优化配置,利于解决区内水资源短缺,促进经济区发展及规划实现。以山东现代水网建设为依托,针对山东蓝色地区水系连通的水资源可持续开发利用的功能需求以及河库连通的二元水网特征,构建水资源优化调配模型。模型基于最严格水资源管理制度需求,通过对现状及规划水平年水资源供需预测分析,开展山东半岛蓝色经济区水系连通下的分层水资源优化配置研究。研究结果为优化区域水资源配置方案,实现地区水资源与社会经济协调发展提供理论支撑。     

Major Trends in Groundwater Development: Opportunities for Public-Private Partnership?

Provision of sufficient water of good quality under growing water demands and increasing climate variability will be one of the main concerns for water managers in the coming decades. It is generally accepted that an integrated approach is required in which resource development options and demand management go hand in hand to provide a management structure with balances between immediate demand from different user groups and the short- and long-term environmental functions of our global water resources. Groundwater plays an important role in achieving this goal provided that its interaction with surface water is fully recognized and its function is fully integrated in land and water planning. The success of integrated water resources management will also benefit from a broader partnership in planning, development and management of our water resources. The focal role of central government is gradually complemented with a growing responsibility of lower levels in the public sector and broader partnerships with the private sector. This paper describes the comparative characteristics of groundwater and its functions in integrated water resources management. Some major trends are discussed in the use of aquifers for enhancing the role of groundwater to cope with increasing water demands and changes in climate variability: the use of brackish groundwater; and the enhancement of recharge and subsurface storage and the ability of aquifers to ameliorate water quality. These potential developments offer good opportunities to enhance the role of the private sector under the regulatory control of the government. These options are particularly important for the Middle East and North Africa region as coping strategies to alleviate the present water scarcity.     

Real Options for Increasing Value in Industrial Water Infrastructure

This paper presents a flexible approach that is real options to increase expected value in water infrastructure systems. Real options make an adaptable ability to respond the systems more effective to good opportunity and withdrawn unproductive situations from loss of investments in the future. The result of this approach is compared with traditional net present value in cases of with and without uncertainty to show expected values of investment of industrial water demand and supply schemes. It shows that real options in system can increase expected value of investment by reducing negative risks and increasing opportunities. An example of water infrastructure investment to support increasing industrial water demand demonstrates the use and results of this approach.     

Strategien und Potenziale zur Energieoptimierung bei der Wasserwiederverwendung

The energy and materials derived from treating sewage are becoming increasingly important worldwide and are thus progressively considered resources rather than a disposal problem. This is also apparent in the growing interest in recycling water from municipal wastewater for both non-potable and potable purposes, supplementing the drinking water supply in the latter case. However, the energy consumption of about 0.9–1.8 kWh/m³, required to recycle drinking water, is not insignificant. Due to the lack of national as well as international standardized regulatory specifications for recycled water quality, very different technical solutions for potable water reuse have been deployed worldwide. Therefore, energy-saving measures often can only be applied to internal operational optimizations and the achievable savings are rather limited. Strategies for integrated energy recovery, the increased use of anaerobic biological processes and combined heat and power (CHP) for water recycling are hence very promising. These provide opportunities for internal power provision and therefore options to reduce the specific energy requirements for potable water reuse to well below 1 kWh/m³, despite the necessary treatment processes. However, the greatest potential for energy-efficient water recycling is at the regional planning level. Recycling water is only attractive where local freshwater resources are insufficient or there is a dependency on imported water, and it is the significantly more cost-effective option than the treatment of brackish or sea water.     

A flexible modelling environment for integrated urban water harvesting and re-use

The steady increase of urban population and the possible effects of climate change that may adversely affect the amount of water available in current water supply systems, makes the study of stormwater and rainwater harvesting and wastewater recycling a high priority. The basic proposition is that any system of water supply that can reduce the amount of water drawn from main reservoirs will be of benefit to the whole supply region especially in terms of drought security. This paper describes a versatile modelling framework which can simulate a wide variety of combinations of centralised and decentralised Integrated Urban Water Management schemes from the allotment to the whole suburb scale. The framework combines two modelling approaches. The first, called urbanCycle, simulates water supply and demand, stormwater and wastewater using allotments as the basic building block. Although urbanCycle can simulate processes in great detail, it assumes that the network forms a directed acyclic graph. This simplifies the connectivity logic but precludes investigation of systems with decentralised storage, feedbacks and multiple supply paths. To overcome this, a second model, called urbanNet, based on network linear programming, is embedded in the urbanCycle framework to enable the modelling of recycling and harvesting options, as well as on-the-fly supply and demand decision making, based on objectives rather than pre-set operating rules.     

Multi-criteria Decision Making for Integrated Urban Water Management

The city of Zahedan, in South-eastern Iran, has high population growth, limited local freshwater resources and inadequate water distribution system resulting in water supply failures in recent years. This paper will investigate integration of several demand management measures such as leakage detection on water distribution network, water metering and low volume water fixtures as well as the conjunctive use of surface and groundwater resources of this city. For integration of water management criteria, compromise programming will be used as a multi-objective decision making method. The criteria include minimizing the cost, maximizing water supply and minimizing the social hazards due to the water supply operations. This model will derive optimum long-term plans for implementation of water resources. The results will show that demand management can delay a water transfer project for Zahedan city up to 10 years. Compromise programming is as an efficient tool for integrated water resources management in urban areas and the method is capable to being used by decision-makers in other cases.     

中山市水资源系统动态模拟与敏感性分析EI北大核心CSCD

为满足区域水资源可持续开发与高效利用条件下中山市未来的社会经济发展需求,构建了系统动力学模型,模拟中山市经济社会、水资源供需及水环境的变化趋势,采用了熵权TOPSIS模型进行参数敏感性分析,综合评价不同参数变化对2030年和2040年水质、水量以及经济社会的影响。结果表明:常规发展模式下,中山市水资源供需矛盾逐渐凸显,水环境恶化愈发严重;控制用水量的方案对促进区域可持续发展的作用较为明显,且万元工业(不含火电)增加值用水量的减少产生效果最为显著;不同参数调整方案对水资源系统近期及远期的影响不尽相同,为使水资源管理政策更加适合长远的发展,应重视远期作用明显的参数调整方案。     

三亚河流域水资源供需方案组合比较

针对三亚河流域水资源开发利用现状,以2010年为现状水平年,2020年、2030年为规划水平年,分析比较三亚河流域水资源配置方案。设置不同组合的需水方案和供水方案并进行分析比较。最终选定的需水方案是考虑节水及供需平衡反馈形成的修订方案,供水方案是在现状工程的基础上,规划水平年考虑增加工程措施,蓄水工程主要考虑增加小(Ⅰ)型以上水库的方案。结果表明,此水资源配置方案可解决各水平年P=90%保证率条件下各分区的缺水状况,使水资源供需达到基本平衡。     

Application of Water Balance Models to Different Climatic Regions in China for Water Resources Assessment

Uneven precipitation in space and time together with mismanagement and lack of knowledge about existing water resources, have caused water shortage problems for water supply to large cities and irrigation in many regions of China. There is an urgent need for the efficient use and regional planning of water resources. For these purposes, the monthly variation of discharges should be made available. In this paper, a simple water balance modelling approach was applied to seven catchments (385–2000²) for water resources assessment. Six catchments were chosen from the humid region in southern China and one catchment from the semi-arid and semi-humid region in northern China. The results are satisfactory. It is suggested that the proposed modelling approach provides a valuable tool in the hands of planners and designers of water resources.     

Sustainable Water Supply and Demand Management in Semi-arid Regions: Optimizing Water Resources Allocation Based on RCPs Scenarios

Climate as one of the key factors in water resources management affects the amount of water in the hydrological cycle, which subsequently impacts the level of water availability. Considering the challenges that the South Alborz Region, Iran is currently facing in supplying water for various consumers; in this study, the climate change adaptation scenarios are investigated for sustainable water supply and demand. This study uses a procedure in which five different adaptation approaches, under RCPs scenarios, were established using the WEAP model to assess the impacts of various adaptation strategies on increasing the balance between water supply and demand over current and 2020s accounts. The findings suggest an imbalance between supply and demand in the current situation with the greatest imbalance in domestic use while the minimum in the industrial sector. The results of assessing adaptive scenarios show that various scenarios have different effects on balancing the water supply and demand by different consumers; on the other hand, the scenarios that directly affect domestic water demand have the greatest effect on minimizing the gap between supply and demand in the region; therefore, the options for decreasing the population demand along with diminishing the losses in the domestic water distribution network are the most effective alternatives for balancing supply and demand under all of the climate scenarios. The findings of this research indicate that adaptive management with the focus on restricting demand helps actively management of water resources in the regions with scarce water resources.

     

基于生态优先的渝西地区水资源配置研究

重庆市渝西地区自产水资源短缺,河流生态脆弱,水资源和水环境承载能力不足以支撑区域经济社会可持续发展,水资源配置格局亟需优化。因此,基于MIKE BASIN软件平台建立了渝西水资源配置模型,模拟对象包括区内主要水源工程、用水户和河流;然后从生态基流需水、水生生物需水、基本自净功能需水3个方面分析了河流控制断面生态环境需水量。在此基础上提出了在退还现状生产生活挤占的生态用水和区内水资源优先满足生态环境需水的前提下,以提水利用嘉陵江、长江过境水为主要解决生产生活缺水并补充河流生态环境用水的水资源配置方案。     

环渤海地区水资源科学开发利用及管理探讨

随着经济高速发展和人口的不断增长,环渤海地区的水资源供需矛盾日益突出。在分析区域水资源开发利用管理存在问题的基础上,提出应采用节水、调水、海水利用、产业结构调整、水资源需求管理等措施,加强对水资源的科学合理开发利用,切实保障环渤海地区的水资源安全,促进区域经济社会和生态环境的可持续发展。     

Integrated modelling of nitrate loads to coastal waters and land rent applied to catchment-scale water management.

The EU Water Framework Directive (WFD) requires an integrated approach to river basin management in order to meet environmental and ecological objectives. This paper presents concepts and full-scale application of an integrated modelling framework. The Ringkoebing Fjord basin is characterized by intensive agricultural production and leakage of nitrate constitute a major pollution problem with respect groundwater aquifers (drinking water), fresh surface water systems (water quality of lakes) and coastal receiving waters (eutrophication). The case study presented illustrates an advanced modelling approach applied in river basin management. Point sources (e.g. sewage treatment plant discharges) and distributed diffuse sources (nitrate leakage) are included to provide a modelling tool capable of simulating pollution transport from source to recipient to analyse the effects of specific, localized basin water management plans. The paper also includes a land rent modelling approach which can be used to choose the most cost-effective measures and the location of these measures. As a forerunner to the use of basin-scale models in WFD basin water management plans this project demonstrates the potential and limitations of comprehensive, integrated modelling tools.     

徒骇马颊河流域水资源承载力研究

为实现以有限的水资源支撑和保障经济社会的可持续发展,水资源承载力的研究已经成为当前的现实问题。本文结合徒骇马颊河流域水资源综合规划工作,以水资源及其开发利用现状为基础,进行区域内供需平衡分析,研究水资源的承载能力,为区域内水资源的可持续利用,产业结构的调整等诸多方面提供参考。     

Transforming Inundated Rice Cultivation

Almost 90% of global rice is produced under inundated conditions, i.e. in fields with a standing water layer of 5 to 15 cm during the major part of the growing season. Recently, inundated rice cultivation has come under pressure due to declining availability of water and labour, increasing demand for rice and other food items, increasing claims on limited land resources, and increasing concern for environmental pollution. These changes in ecological, social and economic conditions call for a transformation in rice cultivation to comply with current and future developments. This paper focuses on management practices at the field scale affecting water productivity and other system characteristics and illustrates the consequences of some of these practices at the farm level based on case studies, while the promise of reduced water input in rice cultivation for options of regional allocation of water is demonstrated for a basin that supplies the metropolitan region of Jakarta. The paper discusses future options and opportunities for transforming inundated rice cultivation to comply with changing conditions.     

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.