PEGASUS: Producing EnerGy and preventing hAzards from SUrface water Storage in Peru

秘鲁安第斯山脉拥有世界上71%的热带冰川，它们提供的融化水是下游依赖它进行灌溉和卫生设施的人的基本资源。此外，由冰川融化水驱动的水电站提供了秘鲁40%以上的电力。然而，秘鲁的冰川正在迅速消退，威胁着这种供应，并向山谷地区释放沉积物，暴露出可能成为冰川径流天然水库的地形凹陷。这些正在融化的景观也非常活跃，可能会对下游人民和基础设施构成风险。Pegasus将评估快速演变的景观和自然资源将给秘鲁安第斯山脉三个冰川科迪莱拉-乌鲁班巴、维尔卡班巴和维尔卡诺塔的人民和企业带来的机会和威胁，并提出建议，最大限度地实现在持续环境变化中可能获得的潜在繁荣。对秘鲁等山区集水区的气候进行建模是复杂的，因为大范围天气系统与当地范围的风和极端起伏相互作用。气候模型的不确定性纳入了冰川变化预测，而冰川变化预测本身受到缺乏用于校准的以往冰川行为的数据和用于验证的下游河流流量的数据的限制。预测永久冻土(冰冻)高度也需要强有力的气候模型，这是控制冰层和基岩稳定性的关键因素，因此也是雪崩风险的关键。Pegasus将对气候做出新的、精细的预测，这将驱动尖端的冰川和永久冻土模型，从而对从现在到本世纪末五年一次的冰川和冰冻水平将如何变化做出可靠的预测。随着冰川的消退和山坡变得更加活跃，沉积物将被释放到山谷中，冰存在的地方将形成湖泊。一些沉积物将被困在这些冰川湖泊中，另一些将被河流流向下游。处于衰退高级状态的冰川释放沉积物的速度鲜为人知，湖泊在捕获沉积物方面的作用也没有得到很好的量化。Pegasus将进行实地测量和建模，以更好地了解冰川湖泊在清除、输送和储存冰川释放的沉积物方面所起的作用，并表征这将对下游水质和关键的水电基础设施产生的影响。通过对当前冰川的厚度进行建模，并确定将随着冰川消退而揭示的冰下凹陷，可以预测未来冰川湖泊的位置。使用这种无冰地形的数字高程模型(DEM)，可以对这些新湖泊以及现有的冰川湖泊如果发生灾难性决口对下游地区构成的危险进行定量评估。Pegasus将对乌鲁班巴-维卡班巴-维尔卡诺塔研究区域内最大的湖泊进行评估，然后进行额外的精细分辨率和基于物理的数值模拟，以强有力地量化洪水和泥石流对人、土地、下游河流动态和水电基础设施的影响。然后，PEGASUS将确定将这些湖泊用于蓄水和水电开发存在的障碍和机会。这项评估将整合与政府(CORECC)、一家大型水电公司(EGEMSA)以及生活在我们所分析的湖泊集水区的社区的协商。以下建议将提供关于现有和未来水电计划的可持续性、如何管理未来几十年的用水和制定反映所有利益攸关方需求的政策的信息，以及不稳定的山区环境在未来几年可能对生命和生计构成的潜在危险。

The Peruvian Andes is home to 71% of the world's tropical glaciers, and the meltwater they supply is an essential resource for people downstream who depend on it for irrigation and sanitation. Further, hydropower plants driven by glacial meltwater provide more than 40% of Peru's electricity. However, Peru's glaciers are receding rapidly, threatening this supply, as well as releasing sediment to valley areas and revealing topographic depressions that may become natural reservoirs for glacier runoff. These thawing landscapes are also very active and can pose risks to downstream people and infrastructure. PEGASUS will assess the opportunities and threats that rapidly evolving landscapes, and natural resources, will bring to the people and businesses of three glacierised Cordilleras of the Peruvian Andes - Urubamba, Vilcabamba and Vilcanota - and make recommendations that will maximise the potential prosperity that can be gained in the face of continued environmental change. Modelling the climate of mountain catchments such as those in Peru is complex because of the interaction of large-scale weather systems with local-scale winds and extreme relief. Uncertainties in modelling the climate feed into projections of glacier change, which themselves are limited by a lack of data on previous glacier behaviour for calibration, and downstream river flows for validation. Robust climate modelling is also required for predictions of permafrost (freezing) heights, which are a key control on ice and bedrock stability, and thus avalanche risk. PEGASUS will produce new and refined projections of climate that will drive cutting edge glacier and permafrost models, to yield firm predictions of how the glaciers and freezing levels will change on a 5-yearly interval from now until the end of the century.As the glaciers recede and hillslopes become more active, sediment will be released into the valleys, and lakes will develop where ice existed. Some of the sediment will be trapped within these glacial lakes, and some will be transferred downstream by river flows. The rate of sediment release by glaciers in advanced states of recession is poorly known, and the role of lakes in capturing the sediment is also poorly quantified. PEGASUS will perform field measurements and modelling to improve understanding of the role of glacial lakes in removing, conveying and storing sediment being released from the glaciers, and characterise the impact this will have on downstream water quality and critical hydropower infrastructure.The locations of future glacial lakes can be predicted by modelling the thickness of the current glaciers and identifying subglacial depressions that will be revealed as the ice recedes. Using a Digital Elevation Model (DEM) of this ice-free terrain, it is possible to make a quantitative assessment of the hazard that these new lakes, as well as existing glacial lakes, pose to downstream areas if they were to burst catastrophically. PEGASUS will carry out this assessment for the largest lakes in the Urubamba-Vicabamba-Vilcanota study area and then undertake additional fine-resolution and physically-based numerical modelling to robustly quantify the effects of flooding and debris flows on people, land, the downstream river dynamics, and hydropower infrastructure.PEGASUS will then identify the barriers and opportunities that exist to the use of these lakes for water storage and hydropower development. This assessment will integrate consultations with government (CORECC), a large hydropower company (EGEMSA) and, crucially, communities living in the catchments of the lakes we have analysed. The recommendations that follow will provide information on the sustainability of existing and future hydropower schemes, how to manage water use in future decades and formulate policies that reflect the needs of all stakeholders, and the potential hazards that unstable mountain environments may pose to lives and livelihoods in future years.