Hydrochemistry, residence time and nutrient cycling of groundwater in two, climatesensitive, high-elevation catchments, Colorado Front Range

Groundwater is recognized as an important component of the hydrologic cycle of high-elevation catchments because it contributes significant proportions to surface water flows, exerting important controls on biogeochemical fluxes and reactions at the hillslope to catchment scale. The impacts of climate change are already causing earlier onset of snowmelt and changes to stream discharge quantity and quality in these catchments along the Colorado Front Range. Questions still remain as to how these changes will impact groundwater recharge, residence time and linked biogeochemical cycling. Using six years of hydrometric, hydrochemical and isotopic measurements from 14 piezometers in two adjacent headwater catchments in the alpine tundra of the Colorado Front Range, I explore the answers to these questions