SPONSOR: World Wildlife Fund
PROJECT DURATION: 1 September 2011 to 30 April 2014
PRINCIPAL INVESTIGATORS: Trent Biggs
GRADUATE STUDENTS: Raymond Lee, M.S. Student; Alex Messina, Ph.D. Student
PROJECT SUMMARY: Lakes play important roles in the hydrology and ecology of mountainous regions. Lakes can either increase dry season streamflow by recharging local or regional groundwater, or decrease dry season streamflow by increasing evaporation. Significant uncertainty remains about the influence of high elevation lakes on monthly and annual streamflow. The hydrology of lakes in closed basins, which have no surface outlet, can be particularly difficult to determine since the main outflow is through recharge to groundwater. Lakes in closed basins may impact regional hydrology through subsurface flow, which is difficult to quantify, and is usually calculated as a residual in the water balance. Given the likelihood of significant changes in the hydrology of the Himalaya due to climate change, it is imperative to understand the role that high elevation lakes play in the seasonal and annual water balance of Himalayan river systems. There is currently very little information on the role of evaporation and subsurface flow in the annual hydrologic budget of Himalayan lakes in closed basins. An interannual water balance on one of the largest lakes in the Tibetan Plateau (Nam Co) suggests that more than half of the inflow to the lake is lost through groundwater seepage, with important implications for the water balance of the Tibetan Plateau and receiving water bodies.
Biggs, T. W., C.-T. Lai, P. Chandan, R. M. Lee, A. Messina, R. S. Lesher, and N. Khatoon. (2015) Evaporative fractions and elevation effects on stable isotopes of high elevation lakes and streams in arid western Himalaya. Journal of Hydrology 522: 239–249. [link][pdf]