Pywr-WREW, a Water Resources model for England and Wales built in Python water resources simulation system

由于人口增长、气候变化的影响，以及需要确保自然生态系统有足够的水，人们越来越担心英格兰供水的弹性。由于这些压力，2014年的《水法》引入了一项义务，以确保供水系统的长期弹性。2020年，环境规划署的《满足我们未来的水需求：国家水资源框架》提出了供水压力日益增大的新证据，并从大规模系统的角度提出了建立新的水资源管理框架的理由。这反映了英国水务行业迈出的重要一步，自私有化以来，该行业一直专注于个别水务公司的层面。然而，考虑到未来水资源面临的挑战，仅仅在公司规模上管理水资源不再站得住脚。应对这些挑战将需要大规模的基础设施和政策干预。考虑到这一点，牛津大学、环境局和水务办公室发起了国家系统模拟建模(NSSM)项目，以在全国范围内审查潜在的供水解决方案和其他政策决策在不同未来气候变化和需求下的弹性和效益。在NSSM项目中，我们开发了第一个全国尺度的英格兰和威尔士水资源模型(WREW)。这种新的水资源系统仿真模型将公共供水与农业、发电等行业的用水结合在一起。我们的水资源模型已被用来探索未来干旱的不同情景，并评估现在和未来缺水的频率、持续时间和严重程度。我们还探讨了风险的不同方面与英格兰和威尔士水务公司目前正在考虑的替代供水解决方案的成本之间的权衡。我们关于水资源供应压力日益增大的证据有助于为水资源管理建立一个新的国家框架，采取大规模的系统观点，而不是公司规模的方法。WREW模型是评估国家规模基础设施和政策干预的宝贵工具，目前EA和Ofwat正在使用该模型来评估英格兰和威尔士的战略水资源基础设施。然而，WREW使用商业许可的软件，因此不能在EA内部或之外轻松和公开地与水务行业或学术界的利益相关者共享。我们建议利用达夫尼弹性基础设施分析卓越中心Stream One的资金，使用开源通用动态蟒蛇库Pywr重新构建英格兰和威尔士的国家水资源模型。这将使该模型得到研究人员和实践者的广泛应用。新模型将被命名为PYWR-WREW。作为NSSM项目的一部分，PYWR-WREW的开发将基于牛津大学最近和正在进行的研究。在Dafni平台上托管PYWR-WREW模拟模型将使我们能够更轻松地与我们的合作伙伴(例如，EA和水务行业利益相关者)合作，共同进行模型运行和探索结果。此外，Dafni最先进的计算基础设施将显著提高我们的模型和分析的效率。

There is increasing concern about the resilience of England's water supplies, because of the effects of population growth, climate change and the need to ensure enough water for natural ecosystems. Due to these pressures, the 2014 Water Act introduced a duty "to secure the long-term resilience of water supply systems". In 2020, the Environment Agency's "Meeting our Future Water Needs: A National Framework for Water Resources" presented new evidence of the increasing pressures on water supplies, and made the case for a new framework for management of water resources, taking a large-scale systems perspective. This reflected a major step for the water industry in England, which since privatization has focussed at the level of individual water companies. However, given the challenges facing future water resources it is no longer tenable to just manage water resources at a company scale. Responding to these challenges will require large-scale infrastructure and policy interventions. With this in mind, the University of Oxford, the Environment Agency and Ofwat initiated the National System Simulation Modelling (NSSM) project to examine, at a national scale, the resilience and benefits of potential water supply solutions and other policy decisions under different futures of climate change and demand. In the NSSM project, we developed the first national scale Water Resource model for England and Wales (WREW). This new water resource system simulation model integrates public water supplies with use of water in agriculture, power generation and other industries. Our water resource model has been used to explore different future scenarios of drought and assess the frequency, duration and severity of water shortages now and in the future. We have also explored trade-offs between different aspects of risk and the cost of alternative water supply solutions presently being considered by water companies in England and Wales. Our evidence on the increasing pressures on water supplies has helped to make the case for a new national framework for management of water resources, taking a large-scale systems perspective rather than a company-scale approach. The WREW model is an invaluable tool for evaluating national-scale infrastructure and policy interventions, and is currently being used by the EA and Ofwat to assess strategic water resource infrastructure in England and Wales. However, WREW uses commercially licensed software and so cannot be easily and openly shared within the EA, or beyond to stakeholders in the water industry or academia. We propose to use funding from Stream One of the Centre of Excellence for Resilient Infrastructure Analysis on DAFNI to re-build the national Water Resources model for England and Wales using the open-source generic dynamic python library Pywr. This will enable the model to be widely used by researchers and practitioners. The new model will be termed Pywr-WREW.Development of Pywr-WREW will build on recent and ongoing research by the University of Oxford as part of the NSSM project. Hosting the Pywr-WREW simulation model on the DAFNI Platform would allow us to collaborate with our partners (e.g., the EA and water industry stakeholders) much more easily to conduct model runs and explore results together. In addition, DAFNI's state of the art computational infrastructure would improve the efficiency of our model and analysis considerably.