Collaborative Research: Groundwater-surface water interactions in tropical alpine catchments and their influence on sources and stability of water supply during glacial recession

高山流域及其包含的冰雪是世界上最重要的淡水资源之一，以冰川为主的山区对气候变化尤为敏感。目前，半干旱热带地区的冰川融化为年径流量提供了很大一部分，并缓冲了高度季节性降水制度，但预计持续的冰川消退将使高山径流量减少，时间变化更大，从而对水资源造成压力。以往的研究表明，前冰川流域的地下水含水层在旱季是一个重要的蓄水库，并可能在未来非冰川条件下的水流生成中发挥主导作用。尽管它们很重要，但人们对控制前冰川集水区地表水和地下水相互作用的基本水文地质过程知之甚少。该基金的研究人员将研究秘鲁安第斯山脉前冰期草甸地形地表水和地下水水库之间的相互作用，估计其储存量，并量化对河流流量的贡献。该研究计划将实地方法创造性地结合起来，直接量化偏远、数据贫乏的冰川流域地下水-地表水相互作用（GWSWI），并描述地下水储存和冰川融化的相对水文影响。拟建项目的目标是：(1)测量河道河段之间的水的得失，以及在湿季和旱季储存在前冰期草甸、冰碛、土坡和冲积扇中的地下水；(2)测量和绘制草甸含水层的地下结构、性质和含水量，估算库容；(3)确定GWSWI对地表水化学和用于估算冰川融化的水化学混合模型的影响。本文提出的研究解决了前冰川流域水文学的未知方面，其结果将扩大目前对热带冰川流域和高山流域地下水储存及其与地表水资源相互作用的认识。该研究的结论可以改变通常忽略或简化地下水储存的高寒水文模型。拟议的研究结果将广泛适用于水文学家、冰川学家、自然地理学家和人文地理学家，以及水资源管理人员、发展规划者、农业工程师、市政当局和地方政府、土著社区和工业部门（水电和采矿）。热带冰川山脉正在经历快速的环境和人口变化，特别容易受到气候变化和水资源压力的影响，该项目将有助于了解和预测对人类生计至关重要的水资源。教育和推广项目将加强与当地社区团体、地方政府和秘鲁研究人员的长期联系，这一努力将继续与安第斯山脉更广泛的用水社区建立联系。该项目由水文科学和国际科学与工程项目共同资助。

Alpine watersheds and the ice and snow they contain are one of the most important sources of fresh water in the world, and mountain regions that are dominated by glaciers are especially sensitive to climate change. Melting glaciers in the semi-arid tropics currently provide a large component of annual runoff and buffer highly seasonal precipitation regimes, but ongoing glacier recession is predicted to make alpine runoff smaller in volume and more temporally variable, stressing water resources. Previous research suggests that groundwater aquifers in proglacial catchments are an important storage reservoir during dry seasons, and will likely play a dominant role in streamflow generation under future non-glacierized conditions. Despite their importance, little is known about fundamental hydrogeologic processes governing the interaction of surface water and groundwater in proglacial catchments. The investigators on this grant will study the interactions between surface water and groundwater reservoirs in proglacial meadow landforms in the Andes of Peru, estimate their storage volumes, and quantify contributions to streamflow. The research plan integrates a creative combination of field methods to directly quantify groundwater-surface water interactions (GWSWI) in remote, data-poor glacierized catchments and describe the relative hydrologic influence of groundwater storage and melting glaciers. The objectives of the proposed project are to: (1) measure gains and losses of water between stream channel reaches and groundwater stored in proglacial meadows, moraines, talus slopes, and alluvial fans in wet and dry seasons; (2) measure and map subsurface structures, properties, and water content of meadow aquifers and estimate storage volumes; and (3) determine the impact of GWSWI on surface water chemistry and on hydrochemical mixing models used to estimate glacial melt.The proposed research addresses unknown aspects of proglacial watershed hydrology, and the results will expand the current state of knowledge about groundwater storage and its interaction with surface water resources in tropical glacierized catchments and alpine watersheds. Conclusions from this study could transform alpine hydrologic modeling, which typically ignores or simplifies groundwater storage. The results of the proposed research will be broadly relevant to hydrologists, glaciologists, and physical and human geographers, as well as to water resource managers, development planners, agricultural engineers, municipalities and local governments, indigenous communities, and industrial sectors (hydroelectric and mining). Tropical glacierized mountain ranges are undergoing rapid environmental and demographic shifts and are especially susceptible to climate change and water stress, and this project will contribute to the understanding and prediction of water resources vital to human livelihoods. Education and outreach programs will enhance long-term connections with local community groups, local governments, and Peruvian researchers, and this effort will continue to engage the broader community of water users in the Andes.This project is co-funded by the Hydrologic Sciences and the International Science and Engineering Programs.