In a global context of rapidly changing water availability, information that allows communities to better predict and manage their water resources will become ever more critical to socioeconomic sustainability. This project bridges traditional disciplinary boundaries in Earth and water sciences to generate new knowledge about the storage and flow of water through mountain watersheds. Mountainous regions of the world receive extensive precipitation and serve as crucial year-round sources of freshwater for human populations and natural ecosystems. Standard methods for estimating the total amount of water stored within mountain watersheds involve single-point measurements with limited spatial coverage or large-scale averages over hundreds of kilometers with limited resolution. Recent advances in geophysics, including the development and expansion of global navigation satellite systems (GNSS) that measure subtle changes in the shape of the Earth caused by the weight of groundwater and surface water, have transformed the ability to study Earth’s water cycle, especially at space and time scales that are relevant to complex mountain watersheds. By precisely observing and modeling the centimeter-scale deformation of Earth due to fluctuations in mountain snow and water storage, this project aims to place new constraints on hydrologic models at the watershed scale, create enhanced operational tools for water-resource management, and develop a prototype hydrologic early-warning system that can alert downstream communities to flood risk or flash droughts. Furthermore, demonstrating the capability to make estimates of water storage at individual watersheds using a few inexpensive GNSS sensors could change the way that freshwater resources are typically measured and managed.
This project combines fieldwork, data analysis, and modeling to investigate three hydrologically distinct mountain watersheds in the western USA. High-resolution (in space and time) observations of crustal displacement, streamflow, snow depth, precipitation, and atmospheric conditions will be collected in all three watersheds. Research products will include: (1) empirical calibrations that relate GNSS-inferred surface displacements to hydrologic parameters such as streamflow and aquifer recharge; (2) numerical tools for forward modeling of three-dimensional surface displacements due to heterogeneous loads on a heterogeneous Earth and for inverse modeling to calculate variations in water storage within the watershed; (3) coupled geodetic and hydrologic models that incorporate critical feedbacks between solid-Earth deformation, water storage, surface runoff, and groundwater flow; and (4) a pilot operational product for hydrologic forecasting.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
