Year Established: 2014 Start Date: 2014-03-01 End Date: 2015-02-28
Total Federal Funds: $18,987 Total Non-Federal Funds: $5,538
Principal Investigators: Anna Liljedahl, Tom Trainor
Abstract: Alaska’s rivers are strongly influenced by snow and glacier melt, but rarely is the importance of this component to surface flow quantitatively defined. The uncertainty in what contributes to surface water resources ultimately impacts the ability of managers and communities to plan and adapt to short- or long-term changes in flood (or drought) forecasts. For example, anticipated climate warming will likely impact the release of water that is stored as snow or ice, which can play a major role in maintaining runoff during low summer precipitation periods. Conversely warming may also result in rapid releasing of extensive amounts of water during short time periods (snowmelt or mid- to late summer rain storms combined with high glacier melt). Effective forecasts and projections depend not only upon realistic total runoff amounts, but also the type of water that is contributing to streamflow. The proposed effort, complemented by runoff measurements, will provide perhaps the first hydrograph partitioning analysis for a glacial Alaskan river. The approach includes a combination of field measurements, laboratory analysis and modeling efforts. Field samples will be analyzed for major ions (Ca2+, Mg,2+ Na+, K+, NH4+, Cl-, F-, SO42, PO42-, NO3-) and δD and δ18O values. Samples include end-of-winter snow pack cores, snowmelt water, rain, surface water, melt water on top of the glacier, runoff at the glacier terminus, winter baseflow and groundwater from a variety of locations in the Jarvis Creek watershed (634 km2). The geochemical composition of diurnal low (early morning) and maximum (late afternoon) flows will be measured during the thawed season (late-April through mid-October). The water samples will be processed and analyzed using ion chromatograph and stable isotope spectrometry (Picarro isotope analyzer). Our end-member volumetric mixing models will be forced by stable isotope data and dissolved ion concentrations. This will allow us to gain fundamental knowledge about the regional hydrologic system by defining the role of the individual contributing sources and dominating flow pathways. Combined, the field measurements, laboratory and modeling analysis will equip us to address our two main objectives: a) Assess the hydrologic pathways of glacier wastage within a watershed underlain by discontinuous permafrost b) Quantify the contribution of glacier melt, snow melt and rainfall to stream runoff. The proposed effort will strongly integrate with and complement a recently funded National Science Foundation project. The funds from this proposal will support a M.Sc. student’s fall and spring semester salary and tuition, which are not covered by the existing National Science Foundation award. The proposed effort would allow the M.Sc. student to fully focus upon her course work and thesis research during her first year and ultimately speed-up the delivery of a quality product to benefit communities and mangers in their water resources decisions.