International - Translation of Environmental Flow Research in Cambodia (TEFRIC)

环境流量描述了维持具有经济、社会和生态重要性的生态系统服务所需的河流流量状况。已经建立了一系列评估环境流量要求的方法。变异范围法（RVA）使用水文变化指标（IHA），这是一种比较自然和变化的水流状态的统计技术。项目小组加强了RVA / IHA方法，以提供一种方法（水流变化引起的生态风险- ERFA），根据覆盖整个水流状况（包括对河流生态系统产生不同影响的低流量和高流量）的IHA数量超过规定阈值，确定变化风险。这项工作在湄公河流域进行了试验，目前正在印度和孟加拉国的集水区进一步开发，由NERC提供资金。由于水资源计划、快速发展和广泛的土地使用变化，柬埔寨的河流面临越来越大的压力。气候变化对区域的影响也不确定。由于许多柬埔寨人严重依赖河流和相关水生生态系统提供的生态系统服务，因此迫切需要引入环境流量评估的最佳做法，并进行案例研究，以展示其在柬埔寨的应用。这将使环境流量能够纳入水资源管理计划和政策的制定以及气候变化适应战略的制定。我们将加强现有的ERFA代码，使其从专家系统转变为非专家更容易使用的工具。这将包括改变分析中使用的IHA和相关阈值的选项，以及增强输出以帮助解释结果。产出将包括使用“交通灯”系统对变化风险的标题摘要，以及关于每个组成部分国际人道主义行动协定变化的更多细节。将对湄公河流域的水文/水力耦合模型中已经存在的广泛的情景（>50种）应用应急风险分析。一个由柬埔寨有关水/环境管理机构、大学学者和其他个人组成的专家组将利用研究结果调整环境流量方法中的备选方案，以便应急储备金分析得出的变化风险符合专家意见。柬埔寨的这一调整将被硬编码到ERFA代码中（用R语言开发），该代码将通过CEH环境信息数据中心免费分发。将选择全部或大部分限制在柬埔寨境内且已有水文模型的洞里萨河子流域，以代表该国河流系统内环境和资源使用特征的多样性。这些子集水区将为柬埔寨调整后的ERFA提供示范案例。我们将与专家组一起定义一系列适用于模拟的全流域和子流域特定情景。后者将反映每个分集水区的特点和目前/计划的水资源使用情况。这些变化可能包括自然植被被清除的程度增加和目前取水量的变化。全世界范围的情景将侧重于与气候变化有关的气象投入的修改。每个模型的基线（原始）和情景河流排放量将应用于经调整的ERFA。一个主要的传播会议将启动经调整的ERFA。与会者将包括柬埔寨的科学家、环境工作者和决策者。为了增加在湄公河流域更广泛应用ERFA的潜力，还将邀请其他沿岸国家的国家湄公河委员会。利益相关者的参与将包括使用示范子流域和湄公河流域模型的结果进行实地示范。

Environmental flows describe the flow regime of a river required to maintain economically, socially and ecologically important ecosystem services. A range of methods for assessing environmental flow requirements has been established. The Range of Variability Approach (RVA) uses Indicators of Hydrological Alteration (IHA), a statistical technique to compare natural and altered flow regimes. The project team have enhanced RVA / IHA approaches to provide a method (Ecological Risk due to Flow Alteration - ERFA) that assigns risk of change based on the number of IHAs covering the entire flow regime (including low and high flows which exert different influences upon riverine ecosystems) exceeding specified thresholds. This work was trialled on the Mekong River Basin and is being further developed for catchments in India and Bangladesh with NERC funding.Cambodia's rivers are under increasing pressure due to water resource schemes, rapid development and extensive land use change. Regional impacts of climate change have also been shown to be uncertain. Since many Cambodians rely heavily on ecosystem services provided by rivers and associated aquatic ecosystem there is a pressing need to introduce best practice for environmental flow assessments and to establish case studies to demonstrate their application within Cambodia. This will permit the inclusion of environmental flows in developing water resource management plans and policies as well as in the formulation of climate change adaptation strategies.We will enhance the existing ERFA code to translate it from the expert system to a tool that can be much more easily used by non-experts. This will include options for varying the IHAs and associated thresholds used in the analysis as well as enhancing outputs to aid the interpretation of results. Outputs will include a headline summary of risk of change using a "traffic light" system as well as more detail on changes in each component IHAs. ERFA will be applied to a wide range of scenarios (>50) already available from coupled hydrological / hydraulic modelling of the Mekong Basin. An Expert Group drawn from relevant water / environmental management agencies, university academics and other individuals within Cambodia will use results to tune the options within the environmental flow methodology so that ERFA derived risks of change match expert opinion. This Cambodian tuning will be hard-coded into the ERFA code (developed in R) that will be freely distributed via the CEH Environmental Information Date Centre.Sub-catchments of the Tonle Sap that are wholly or largely constrained within Cambodia's borders and for which hydrological models are already available will be selected to represent the diversity of environmental and resource use characteristics within the nation's river systems. These sub-catchments will provide demonstration cases for the Cambodian tuned ERFA. With the Expert Group we will define a series of Cambodian-wide and sub-catchment specific scenarios for simulation. The latter will reflect the characteristics of each sub-catchment and current / planned water resource uses. They could include increases in the extent of natural vegetation removal and changes to current water abstractions. Cambodian-wide scenarios will focus on climate change-related modifications to meteorological inputs. Baseline (original) and scenario river discharges from these scenarios for each model will be applied to the Cambodian-tuned ERFA.A major dissemination meeting will launch the Cambodian-tuned ERFA. Participants will include scientists, environmental practitioners and decision / policy makers in Cambodia. In order to increase the potential for wider application of ERFA within the Mekong Basin, National Mekong Committees of other riparian states will also be invited. Stakeholder engagement will include hand-on demonstrations of ERFA using results from the demonstration sub-catchments and Mekong-wide models.