C33A-0799
Isotopic Insights into Catchment Hydrology: Use of Tritium and Oxygen-18 to Interpret Age and Flow Paths of Waters in the Langtang River Basin, Nepal
Wednesday, 16 December 2015
Poster Hall (Moscone South)
Alana M Wilson, Organization Not Listed, Washington, DC, United States, Mark W Williams, Univ Colorado, Boulder, CO, United States, Rijan Bhakta Kayastha, Kathmandu University, Dhulikhel, Nepal and Holly Hughes, Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO, United States
Abstract:
Understanding the hydrology of glacierized catchments is an important step in assessing vulnerability of water resources to a changing climate. While there have been increased efforts recently to understand the dynamics of Asia’s cryosphere, glacier melt dynamics and the contribution of melting ice to river discharge is open question. Tritium samples collected from water and ice in the Langtang Valley, Nepal in 2013, 2014 and 2015 offer new insights into relative age and residence times of different water sources in the basin, and seasonal changes in river water composition. With tritium values below detection limits in terminal glacier ice, values between 1 and 5 Tritium Units (TU) in spring water, and greater than 3 TU but declining with elevation in the Langtang River, the role of glacier melt in river hydrology can be compared to that estimated using oxygen-18 values in two component mixing models. Tritium results suggest that oxygen-18 mixing model results over-estimate glacier ice contributions to river discharge.
