Asymmetry and Equity in Water Resources Management; Critical Institutional Issues for Southern Africa

Water users wish to achieve the highest benefits from water resources. Rules limit the manner in which water users may utilise the water resources occurring within their constituencies or territories. However an asymmetrical situation exists whereby downstream users may not affect upstream users but upstream users do cause downstream impacts. Because of this asymmetry the equitable sharing of water resources between upstream and downstream users will always imply that upstream users have to forego some potential water benefits. The general question that this paper addresses is: which institutional arrangements can be devised to (re-)establish an equilibrium between up- and downstream entities within a catchment area or river basin? The paper addresses this question by first focusing on some local and national water allocation arrangements. After briefly reviewing the different management regimes, customary and colonial, that co-evolved in Southern Africa, it assesses the water management principles that are currently being espoused. The focus then turns to the principles in international water law that deal with the allocation of water in transboundary river basins. It is concluded that it often proves difficult to reach agreement over how to share the scarce resource. The paper then discusses the current trend to look beyond water and beyond the river basin when seeking peaceful means to share a common water resource. The concept of “hydrosolidarity” emerges as a normative value that may help to recreate a balance between the various (asymmetrical) interests that exist within a river basin. The paper concludes that water resources can only be governed wisely is there is capacity to understand and monitor the water fluxes within a river basin. If such capacity is wanting, priority should be given to strengthen it.     

Assessment of impact of water diversion projects on ecological water uses in arid region

In arid regions, large-scale water diversion from rivers leads to significant changes in river flow regimes, which may have large impacts on ecological water uses of river-dependent ecosystems, such as river, lake, wetland, and riparian ecosystems. To assess the integrated impact of water diversion on ecological water uses, we proposed a hierarchy evaluation model composed of four layers representing the evaluation goal, sub-areas of the influenced region, evaluation criteria, and water diversion schemes, respectively. The evaluation criteria for different types of ecological water uses were proposed, and the analytical hierarchy process was used for the integrated assessment. For a river ecosystem, the percentage of mean annual flow was used to define the grade of environmental flow. For a lake ecosystem, water recharge to the lake to compensate the lake water losses was used to assess the ecological water use of a lake. The flooding level of the wetland and the groundwater level in the riparian plain were used to assess the wetland and riparian ecological water uses, respectively. The proposed model was applied to a basin in northern Xinjiang in northwest China, where both water diversion and inter-basin water transfer projects were planned to be carried out. Based on assessment results for the whole study area and two sub-areas, an appropriate scheme was recommended from four planning schemes. With the recommended scheme, ecological water uses of the influenced ecosystems can be maintained at an acceptable level. Meanwhile, economical water requirements can be met to a great extent.     

Integrated modelling for river basin management: the influence of temporal and spatial scale in economic models of water allocation.

The increasing use of integrated optimization or simulation models to guide river basin management has placed greater attention on the roles that the temporal and spatial scale of each model play in determining a model's suitability and effectiveness. This is especially the case in "economic" models that incorporate monetary incentives and the optimizing behaviour of economic agents to address decisions about the sources and levels of consumptive and non-consumptive water usage within the basin. With respect to spatial scale, models that aggregate behaviour over entire river basins may prove useful for examining inter-sectoral allocations of water, but are unlikely to provide useful information about how these water allocations influence-and are influenced by-choices of crops or of technologies in irrigation, for example. With respect to temporal scale, very short-run models can illustrate options for water management within an irrigation season should unforeseen water surpluses or deficits arise. Conversely, long-run models can allow adjustment time for investments in machinery, infrastructure and changes in land uses and cropping patterns. The basin management alternatives and choices generated by models on each scale are likely to vary considerably. The paper provides specific illustrative examples from recent models of Alberta's Bow River Basin.     

Hydrological Impacts of Flood Storage and Management on Irrigation Water Abstraction in Upper Ewaso Ng’iro River Basin, Kenya

The upper Ewaso Ng’iro basin, which starts from the central highlands of Kenya and stretches northwards transcending different climatic zones, has experienced decreasing river flows for the last two decades. The Naro Moru sub-basin is used to demonstrate the looming water crisis in this water scarce river basin. The objective of the study was to show the extent of dry seasons’ irrigation water abstractions on river flows, and to assess the hydrological impact of flood storage on temporal water distribution and irrigation water management. Decreasing river flows are attributed to over-abstraction mainly for irrigating horticultural crops. The number of abstractors has increased four times over a period of 10 years. The amount of water abstracted has also increased by 64% over the last 5 years. Moreover, the proportion of unauthorized abstractions has been increasing over the years, currently at about 80% and 95% during high and low flows respectively. This has resulted in alarming conflicts among various water users. The situation is aggravated by low irrigation efficiency (25–40%) and inadequate flood storage facilities. The paper analyzes over 40 years’ observed river flow data and 5-year interval water abstraction monitoring records for 15 years. It assesses whether flood storage and management, can reduce dry seasons’ irrigation water abstractions without significantly reducing river flows to affect the sustenance of natural ecosystems downstream. The results demonstrate that flood storage and management can reduce water abstraction and increase river flows during the dry seasons, without significantly reducing high flows to affect the downstream water users. However, socio-economic, hydrological and environmental implications should be considered if a sustainable river basin water resources management strategy is to be developed and implemented. The case study of Naro Moru sub-basin is representative of the situation in the other sub-basins, and hence can be taken as a pilot basin for developing an integrated water resources management strategy that will foster socio-economic development with minimal negative hydrological impacts in the water scarce upper Ewaso Ng’iro river basin.     

流域层面农业灌溉定额编制方法研究--以松辽流域为例

以松辽流域为例探讨流域层面灌溉定额的编制方法，提出为客观反映地带性差异导致的地区间灌溉定额的差异、科学评判各地用水效率，应采用净灌溉定额和灌溉水利用系数两类指标作为流域层面的基础指标。     

Water Use and Climate Stressors in a Multiuser River Basin Setting: Who Benefits from Adaptation?

Adapting to new climate conditions will require an intricate mix of knowledge, planning, coordination, and foresight. There is increasing sectoral evidence on the implementation of successful adaptation actions. However, the success of these actions when we consider the interdependencies among sectors remains debatable. This paper aims to assess who benefits from implementing adaptation options in a multiuser river basin to both climate-induced and demographic stress on water use. Our analysis relies on a hydro-economic model that considers two sets of water users: agriculture and urban households. We innovate in our modelling approach by analyzing and explicitly integrating the household-level economic behavior through its water demand. We assess the cross-user consequences of autonomous and planned adaptation actions. We provide insights into the different trade-offs at the basin level, demonstrating the compatibilities and divergences between agriculture and household-level water demand. We found different consequences of implementing either autonomous or planned adaptation measures. For instance, a decentralized scheme would drive negative implications for the entire basin, although the less water-intensive sector will be better off. On the other hand, different policy interventions would drive positive consequences for the entire basin, with the most water-intensive sector benefiting the most. These results highlight the distributional consequences across users of different adaptation measures.

     

A Coupled Water Quantity–Quality Model for Water Allocation Analysis

As the demand for water continuously increases with population growth and economic development, the gap between water supply and demand in China has become increasingly wide. In recent years worsening water pollution has caused this gap to become much more serious. Conventional allocation pattern, which mainly considers water quantity as the key factor, is no longer satisfying the water allocation need. A coupled water quantity–quality model in a river basin is presented in this paper to provide a tool for water allocation schemes analysis. The pollutants transport and hydrological cycling processes in a river basin are involved in the model. A river network is divided into different reaches. According to the division of river network, the areas out of the river are divided into a series of tanks. In each tank, hydrologic processes, pollutant loading production, water demand of users and water supply are calculated. In river network, hydrodynamics processes and water quality are simulated. Water quantity and quality exchanges between each tank and river are also considered. The time step of water quality calculation is 24 h, the same with that of water quantity calculation. In each time step period, the connections of river reaches and tanks are realized through the exchange of water quantity and quality between rivers and tanks: pollutants discharge from tanks to rivers and water intake from rivers to satisfy water demand in tanks. The water use in each tank includes three types: domestic, industrial and agricultural water use. Water allocation schemes are one of the input conditions of the model. Using the proposed model, in each tank, water demand and deficit of different uses, in both water quantity and quality, can be obtained under different water allocation schemes. According to the water deficit, water allocation schemes are analyzed to make proper allocation schemes. In this aspect, the proposed model can also be thought as a water allocation model. The model is tested and applied to the Jiaojiang River basin, Zhejiang Province, China, to analyze the different water resource allocation schemes.     

Development of Data and Information Centre System to Improve Water Resources Management in Indonesia

Most provinces in Indonesia will be facing water scarcity problems in the next decades due to increasing water demands resulting from population growth, urbanization and economic and industrial developments. As a consequence, they will also be facing a number of problems with regards water resource management, such as a lack of data and information needed to evaluate the real status of water resources, the unsystematic development of relevant infrastructure and economic instruments, inadequate human resources for the operation and maintenance of water resources, and a lack of interest in improving research and development activities. This paper examines the application of data and information management for improved water resources management in Indonesia through “one door data service system” linked among the related institutions from different sectors and levels both at the central and regional government agencies. One of the key solutions to help solve water resource problems would therefore be to obtain supporting data and information by developing an information system and water resources data centre (WRDC). Rapid developments in information and communication technology (ICT) could be used to support data communication and management requests in order to build capacity of the water resources sector, and as a prerequisite for an integrated water resources management program. Improved efficiency and effectiveness could be achieved by making relevant data and information available, as well by establishing a communication system among related institutions. Further, provinces should also prioritize developing human and social capital through education, service delivery and career development, as well as training for water resources development and management. Data and information such as the hydrological and water quality data, information of water resources potential, irrigation areas, population and economic growth as well as the others related data need to store in both the tabular and spatial formats. The water resources data management and warehouse system is a web-enabled application that permits spatial data to be stored with tabular data in a standard database management system. This system permits a dynamic generation of output from the tabular and spatial data and enables users to generate answers to their queries online, rather than simply presenting static maps and tables from the database. The WRDC applications were developed and chosen by gathering the ideas suggested by users at the ministerial, provincial and river basin levels. Within the resulting inventory system, information was grouped into irrigation scheme system; water resources potential; natural disaster; hydrological data and station networks; and other information. For the users at the ministerial level access the system by using local area network (LAN) connections and other users at the provincial and river basin levels or elsewhere in the world can use the internet for connections and regular browser software for system operation.     

水账户方法及其在流域水分生产率分析中的应用

引入水账户理论和方法,以研究流域水资源的利用状况。介绍了水账户的概念体系、基本数学表述、尺度和平衡要素。该方法根据水平衡原理,对流域内不同用途的水进行分类。通过分析水资源在生态经济系统中的流向、流量和存量等的变化过程,完整地呈现研究区内的所有用户,以便分析提高可用水量的途径及节水的可能性。应用该方法对黑河流域中游张掖市水资源利用情况的分析表明,研究时间内田间尺度所有可用水均被损耗殆尽,导致土壤水储量减少,减少水分的无效损耗量是提高灌区水资源利用率的重要措施。从流域尺度上看总入境水量中92.6%被损耗利用,该市的水资源利用处于不可持续的极限状态。最后讨论了不同尺度水分生产率转化、农业节水措施选择、流域生态健康与水利用效率的关系等,指出仅提高渠系利用率和渠道衬砌率等措施不能从根本上提高水分生产率,水利用效率的提高应以全流域水利用效率为指标。     

Capturing the complexity of water uses and water users within a multi-agent framework

Due to the hydrological and socio-economic complexity of water use within river basins and even sub-basins, it is a considerable challenge to manage water resources in an efficient, equitable and sustainable way. This paper shows that multi-agent simulation (MAS) is a promising approach to better understand the complexity of water uses and water users within sub-basins. This approach is especially suitable to take the collective action into account when simulating the outcome of technical innovation and policy change. A case study from Chile is used as an example to demonstrate the potential of the MAS framework. Chile has played a pioneering role in water policy reform by privatizing water rights and promoting trade in such rights, devolving irrigation management authority to user groups, and privatizing the provision of irrigation infrastructure. The paper describes the different components of a MAS model developed for four micro-watersheds in the Maule river basin. Preliminary results of simulation experiments are presented, which show the impacts of technical change and of informal rental markets on household income and water use efficiency. The paper also discusses how the collective action problems in water markets and in small-scale and large-scale infrastructure provision can be captured by the MAS model. To promote the use of the MAS approach for planning purposes, a collaborative research and learning framework has been established, with a recently created multi-stakeholder platform at the regional level (Comisión Regional de Recursos Hidricos) as the major partner. Finally, the paper discusses the potentials of using MAS models for water resources management, such as increasing transparency as an aspect of good governance. The challenges, for example the need to build trust in the model, are discussed as well.     

Water Resource Assessment for the Zambezi River Basin

The Zambezi river drains eight riparian countries: Angola, Namibia, Zambia, Botswana, Zimbabwe, Malawi, Tanzania, and Mozambique. The Zambezi river is, therefore, an international river basin. It drains an area of about 1,800,000 square km (Okavango-Chobe system included). The surface water resources of the Zambezi river have been assessed on the basis of average, typical dry, and wet year flow conditions. An overview of the water resources of the Zambezi river (surface water only) during the driest, average, and wettest year flow conditions are presented. It is anticipated that this information will form the backbone for the integrated water resource planning and management of the Zambezi river basin. According to the Helsinki Rules on the uses of the waters on international rivers, Article Four states that “Each basin state is entitled, within its territory, to a reasonable and equitable share of the beneficial uses of the waters of an international drainage basin.” Therefore, this information is also going to be useful in the negotiations between riparian countries/states for the equitable sharing of the water resources of the Zambezi river basin.     

平原地区城市河网水环境改善的补水调度策略研究——以天津市中心城区河网为例

针对平原地区城市河网中存在的补水效果差、水质不达标等水环境问题,采取问题解析-方法优化的思路开展河网水环境改善的补水调度策略研究,提出了融合现状模拟和成因分析、补水调度策略验证、补水调度实施方案的研究思路。以天津市中心城区环城河网进行实例应用,基于现状问题解析揭示了河网水质不达标原因,按照保持现有工程措施及增设工程措施的顺序提出了适用的推荐补水调度策略,并基于推荐补水调度策略提出了年度整体实施方案及实际实施方案,其中年度整体实施方案对应的年度补水调度总需水量为3.19亿m3。研究表明本文提出的补水调度策略研究方法可利用有限的补水资源有效地改善水环境,可在其他平原地区城市河网中进行推广。     

Examining Two Different Approaches to Modelling Management and Operation Rules in a Single River System Model

Different water agencies use different modeling tools for water resources planning and management. For example, different jurisdictions in Australia use a variety of river system models and these models vary considerably in approach and assumptions, including different time steps (monthly and daily), flow routing (different types of routing and no routing), ordering solution (optimization and heuristic) and representation of management and operational rules. These fundamental differences in approach make it difficult to integrate existing models of connected river systems at a basin scale. A collaborative joint venture (the eWater CRC) between research, industry and government partners has recently developed an integrated river system modelling tool called “eWater Source” to improve on the existing river system models in Australia. One of the major advances in Source is the implementation of two decision algorithms, heuristic and NetLP approaches, for water distribution modelling in the same modelling platform. This paper describes the implementation of heuristic and NetLP approaches for water delivery under management and operations rules in Source, and compares the performance of the two approaches through a case study in the Goulburn-Broken-Campaspe-Loddon (GBCL) river system in south-eastern Australia. The key performance measures used to compare the approaches include the efficiency and equity of water delivery to water users, impacts on the reliability of supply, agreement with storage operating targets, and model application run time. The results demonstrate that the heuristic approach implemented in Source can replicate the performance of the NetLP approach for a model of reasonable complexity. This is important because the run times of models with heuristic approaches are shorter than models with NetLP approaches, so this will allow more complexity to be represented than was previously practical in equivalent NetLP applications. Agreement between jurisdictions to move to the single river system modelling platform will contribute to overcoming the problems faced by river managers in Australia in transboundary river basins.     

A Shared Vision on the Transboundary Water Management Challenges of the Tagus River Basin

The Tagus River basin faces a growing water management challenge, as water demand and river regulation by large multi-purpose reservoirs lead to situations of water scarcity and mediocre conditions in some water bodies. The current situation and the impacts of increasing water demands are evaluated by a detailed river basin model which covers the whole river basin and includes the main hydraulic infrastructures and water uses of Spain and Portugal. Several indicators are computed from the model results to assess water demand satisfaction and the alteration of the hydrological regime, offering a better understanding of current hydro-climatic conditions in the basin. Results show that current water management practices have significantly altered the natural river flow conditions in the entire Tagus River basin. Water managers struggle to satisfy existing waters uses and increasing water demands will further accentuate these problems. The enforcement of new and planned environmental flow requirements may alleviate the conditions of some water bodies but will decrease the level of satisfaction of non-priority water demands. As additional measures are needed to improve water bodies status, water management and allocation policies must be revised at the river basin scale to improve the balance between water consumptive uses and environmental needs. A shared knowledge base and a common vision on the basin challenges will be required to achieve these goals and the datasets and tools applied in this study contribute to this needed transboundary cooperation.

     

叶尔羌河流域综合治理中存在的困难及不确定性因素

针对叶尔羌河流域灌区的特点,分析流域近期综合治理规划方案实施中潜在的困难和不确定性,并初步提出了各种困难和不确定性的解决途径,对于流域实施灌区节水改造、实现向塔里木河干流下泄水量目标、乃至改善塔河干流生态环境具有重要意义。     

基于开源和节流的乌伦古河流域水库群生态调度

针对乌伦古河流域水资源短缺、灌溉挤占生态用水等问题,以生活、工业、灌溉、河道生态基流、河谷林草及补湖生态用水为调度目标,设置开源、节流方案集,建立了以生态缺水量和社会经济缺水量最小为目标的水库群生态调度模型,采用人机对话模拟优化算法求解模型。结果表明：各节流方案的河谷林草和补湖供水保证率能够满足设计要求,缓解了灌溉用水与生态用水间的矛盾,但2017现状水平年和2025远景水平年需水方案的灌溉保证率未满足设计要求;当开源+节流方案调水量超过1.0亿m³时,满足农业灌溉、河谷林草和补湖的供水保证率要求,消除了灌溉用水与生态用水间的矛盾;随着调水量超过1.0亿m³且持续增加,对河谷林草、补湖缺水量、破坏深度等影响不大,推荐1.0亿m³为最佳调水量。     

Lake Turkana,major Omo River developments,associated hydrological cycle change and consequent lake physical and ecological change

This study aimed to explore Lake Turkana's ecological reliance on hydrology and to determine the hydrological changes and consequences arising from the major hydropower and irrigation developments in the lake's basin. The major developments on Ethiopia's Omo River are especially significant as this river provides over 80% of the lake's annual freshwater influx and associated nutrients. The cascade of hydropower dams permanently dampens the natural hydrological cycles and lake level variability. The driving force of the flood influx to the lake is curtailed and the pattern of lake currents will adjust. Ultimately 80% of the river inflow to the lake will be regulated. Large volumes of water are required to initially fill the hydropower dam reservoirs. During 2015–16 when the huge Gibe III reservoir was filled, Lake Turkana's water level declined 2?m.The study has shown that large-scale irrigation schemes in the Lower Omo can potentially abstract 50% of the Omo River water, and that this would cause the lake level to shrink permanently to the detriment of the lake ecology. Possible lake level drops of over 15?m are demonstrated. The basin's natural capital is being replaced by large-scale plantation developments. The hydrological changes are drastic and the ecological consequences on Lake Turkana have not been fully understood. Without serious mitigation measures, Lake Turkana is a potential African Aral Sea disaster in the making, emulating what has happened to other great lakes such as Lake Chad.     

喀什噶尔河流域英吾斯坦乡灌区节水研究

喀什噶尔河流域土地、日照资源相当丰富，但水资源十分有限，且在时间和空间上分布很不均匀。本文以该流域疏附县的英吾斯坦乡灌区为例，探讨了节水灌溉在喀什噶尔河流域的可行性和实用性，结果表明节水灌溉技术与农业结构调整相结合，能取得较好的节水和增加农民收入的效果，推动节水灌溉技术在喀什噶尔河流域的推广。     

Modelling river basin management: an institutional perspective

Implementation of a water availability modelling system for the 23 river basins of Texas illustrates key institutional aspects of this type of effort. Water supply capabilities depend upon institutional considerations such as water rights, contractual arrangements and reservoir project ownership, as well as river basin hydrology. A water management community must work together to develop decision support tools to help manage water resources shared by numerous water users. The Water Rights Analysis Package model adopted by the state of Texas and the lessons learned in its application are applicable to river basin management world-wide.     

A Method for comprehensively Assessing Economic Trade-Offs of New Irrigation Developments

To meet the anticipated increase in global demand for food and fibre products, large areas of land around the world are being cleared and infrastructure constructed to enable irrigation, referred to herein as ‘greenfield irrigation’. One of the challenges in assessing the profitability of a greenfield irrigation development is understanding the impact of variability in climate and water availability and the trade-offs with scheme size, cost and the sensitivity of crop yield to water stress. For example, is it more profitable to irrigate a small area of land most years or a large area once every few years? And, is it more profitable to partially or fully water the crop? This paper presents a new method for efficiently linking a river system model and an agricultural production model to explore the financial trade-offs of different management choices, thereby enabling the optimal scheme area and most appropriate level of farmer risk to be identified. The method is demonstrated for a hypothetical but plausible greenfield irrigation development based around a large dam in the Flinders catchment, northern Australia. It was found that a dam and irrigation development paid for and operated by the same entity is not, under the conditions examined in this analysis, economically sustainable. The method could also be used to explore the impact of different management strategies on the agricultural production and profitability of existing irrigation schemes within a whole of river system context.