Year Established: 2017 Start Date: 2017-03-01 End Date: 2018-02-28
Total Federal Funds: $10,000 Total Non-Federal Funds: $20,359
Principal Investigators: Thomas Meixner, Jennifer McIntosh, Ravindra Dwivedi, Paul Ferre
Abstract: Mountain systems are regionally and locally important areas of recharge for waters that ultimately end up in adjacent alluvial basins, which contain critical groundwater resources for arid and semi-arid regions such as Arizona. For example, in Arizona 66.5% of the state is classified as mountainous and these regions receive a significant amount of precipitation, both rain and snow, compared to nearby low land regions. Yet, little is known about natural recharge processes (e.g. recharge rates, flow paths and residence time) and critical zone services provided by montane regions or their connection to low land regions. Therefore, the main purpose of this study is to improve our current understanding of recharge processes and hydrologic functioning of mountain systems through observational (using multiple tracers) and numerical modeling (using multiple models) approaches. Specifically, our science questions are: (i) What proportion of groundwater discharges into high elevation streams versus infiltrates to subsequently become mountain-block recharge in mountainous catchments? And (ii) Can the optimal set of observations be identified using a multi-model approach to reduce model uncertainty to improve predictions related to total catchment water storage and the water quantity and quality of discharging water downstream? A successful assessment of our science questions will lead to an improved understanding of hydrologic functioning such as recharge processes and how catchments store water and discharge it with time, i.e., streamflow sustainability of high elevation catchments. Our results will further inform water management practices for the state of Arizona by improving our understanding of both groundwater replenishment rates and the susceptibility of these systems to climate change in low-land regions where the major source of groundwater is recharge from local or regional mountain systems. Finally, once successfully tested and applied to the state of Arizona, the findings from our work will be relevant to other fractured-bedrock aquifers in high elevation areas regionally and globally.