Wilson, Alana M.听1听;听Williams, Mark W.听2听;听Racoviteanu, Adina听3听;听Pellicciotti, Francesca听4听;听Juszak, Inge听5听;听Kayastha, Rijan B.听6
1听Department of Geography and Institute of Arctic and Alpine Research, 麻豆官网
2听Department of Geography and Institute of Arctic and Alpine Research, 麻豆官网
3听Laboratoire de Glaciologie et G茅ophysique de l鈥橢nvironnement (LGGE), France
4听Swiss Federal Institute of Technology (ETH) Z眉rich, Switzerland
5听University of Z眉rich (UZH), Switzerland
6听Kathmandu University, Nepal
Mountains play an invaluable role in regulating hydrologic resources that downstream communities depend on. As our climate changes, it is essential to evaluate the vulnerability of the high-elevation water cycle. An improved understanding of where the water in our rivers comes from is required before we can anticipate changes and devise adaptation measures. In the context of climate change, hydrograph separation methods may provide ways to determine how much streamflow comes from snow and glacier melt versus groundwater and direct precipitation in poorly sampled glacierized catchments in the Himalaya. Understanding hydrograph separation in high-elevation catchments provides insight into how the timing and volume of discharge may change over time.
This work , part of the USAID funded Contribution to High Asia Runoff from Ice and Snow (CHARIS) project, uses geochemical and isotopic data from surface water and precipitation samples collected in the Langtang Valley of Nepal to estimate contributions of meltwater to discharge. Results presented include a comparison of chemistry data from unique end member sources that contribute to streamflow. Additionally a suite of multiple-component (3+) End Member Mixing Analyses (EMMA) using the hydrochemistry data were conducted to test the plausibility of results. Variability in results depending on input suggests that the accuracy of different mixing model methods must be more closely examined before confidently comparing them to results from other types of models. We thus provide an evaluation of different hydrochemistry approaches to hydrograph separation in the Langtang River Basin.