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

秘鲁的安第斯山脉拥有世界上71%的热带冰川，它们提供的融水是下游人民灌溉和卫生的重要资源。此外，由冰川融水驱动的水力发电厂提供了秘鲁40%以上的电力。然而，秘鲁的冰川正在迅速消退，威胁到这一供应，并向山谷地区释放沉积物，露出地形凹陷，可能成为冰川径流的天然水库。这些解冻景观也非常活跃，可能对下游的人民和基础设施构成风险。PEGASUS将评估快速变化的景观和自然资源将给秘鲁安第斯山脉三条冰川山脉-乌鲁班巴、比尔卡班巴和比尔卡诺塔-的人民和企业带来的机遇和威胁，并提出建议，最大限度地提高面临持续环境变化时可能获得的潜在繁荣。由于大规模天气系统与当地风和极端地形的相互作用，对诸如秘鲁等山区集水区的气候建模是复杂的。在气候建模中，冰川变化的预测是不受限制的，因为缺乏关于以前冰川行为的数据进行校准，以及下游河流流量进行验证。预测永久冻土（冻结）高度也需要可靠的气候模型，这是控制冰和基岩稳定性的关键，因此也是雪崩风险的关键。PEGASUS将产生新的和完善的气候预测，将推动尖端的冰川和永久冻土模型，产生坚定的预测冰川和冻结水平将如何变化，从现在到世纪结束的5年间隔。随着冰川消退和山坡变得更加活跃，沉积物将释放到山谷中，湖泊将在冰存在的地方发展。一些沉积物将被困在这些冰川湖泊中，一些沉积物将被河流转移到下游。人们对冰川在衰退晚期释放沉积物的速度知之甚少，对湖泊在捕获沉积物方面的作用也知之甚少。PEGASUS将进行实地测量和建模，以更好地了解冰川湖在清除、输送和储存冰川释放的沉积物方面的作用，通过对当前冰川的厚度进行建模，并识别出将在未来几个月内出现的冰下洼地，冰退了。使用这个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灾难性地破裂对下游地区造成的危害进行定量评估。PEGASUS将对Urubamba-Vicabamba-Vilcanota研究区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，以有力地量化洪水和泥石流对人，土地，下游河流动态，然后，PEGASUS将确定利用这些湖泊进行蓄水和水力发电的障碍和机会发展这项评估将与政府（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进行协商。以下建议将提供以下方面的信息：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，以及不稳定的山区环境在未来几年可能对生命和生计造成的潜在危害。

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.