U42A-01
Glacier loss and emerging hydrologic vulnerabilities in the Peruvian Andes
Thursday, 17 December 2015: 10:20
2022-2024 (Moscone West)
Bryan G Mark1,2, Jeffrey M McKenzie3, Michel Baraer4, Pablo Lagos5, Laura Lautz6, Mark Carey7, Jeff Bury8, Ryan Crumley9, Oliver Wigmore10 and Lauren Dorothy Somers3, (1)Ohio State University Main Campus, Columbus, OH, United States, (2)OSU-Byrd Polar Rsrch Ctr, Columbus, OH, United States, (3)McGill University, Montreal, QC, Canada, (4)Ecole de Technologie Superieur, Montreal, QC, Canada, (5)Instituto Geofísico del Perú, Lima, Peru, (6)Syracuse University, Syracuse, NY, United States, (7)University of Oregon, Eugene, OR, United States, (8)University of California Santa Cruz, Environmental Studies, Santa Cruz, CA, United States, (9)Oregon State University, Corvallis, OR, United States, (10)The Ohio State University, Columbus, OH, United States
Abstract:
Accelerating glacier recession in the tropical Andes is transforming downstream hydrology, while increasing demands for water by end-users (even beyond the watershed limits) is complicating the assessment of vulnerability. Future scenarios of hydro-climatic vulnerability require a better understanding of coupled hydrologic and human systems, involving both multiscale process studies and more robust models of glacier-climate interactions. We synthesize research in two proglacial valleys of glacierized mountain ranges in different regions of Peru that are both in proximity to growing water usage from urban sectors, agriculture, hydroelectric generation, and mining. In both the Santa River watershed draining the Cordillera Blanca and the Shullcas River watershed below Hyuatapallana Mountain in Junin, glaciers have receded over 25% since the 1980s. Historical runoff and glacier data, combined with glacier-climate modeling, show a long-term decrease in discharge resulting from a net loss of stored water. We find evidence that this altered hydrology is transforming proglacial wetland ecology and water quality, even while water resource use has intensified. Beyond glaciers, our results show that over 60% of the dry season base flow in each watershed is groundwater sourced from heterogeneous aquifers. Municipal water supply in Huancayo already relies on 18 groundwater wells. Perceptions of water availability and actual water use practices remain relatively divorced from the actual water resources provided from each mountain range. Critical changes in glacier volume and water supply are not perceived or acknowledged consistently amongst different water users, nor reflected in water management decisions. In order to identify, understand, model, and adapt to climate-glacier-water changes, it is vital to integrate the analysis of water availability and groundwater processes (the domain of hydrologists) with that of water use (the focus for social scientists). Attention must be drawn to evaluating risks and adaptation options with rigorous, data-based scenario evaluations of how management decisions impact all end users.
