Integrated Hydrologic Model to Understand Snowmelt and Water Availability in the Upper Colorado River Basin, USA
Abstract
The growing population of the arid and semiarid Southwest relies on over-allocated surface-water resources and poorly-quantified groundwater resources, including those of the Upper Colorado River Basin (UCOL). These two sources of water must be assessed together to address water availability in the UCOL. Recent studies have found that, on average, about 50 percent of the surface water flow at U.S. Geological Survey (USGS) streamgages in the UCOL is derived from groundwater contributions as base flow. An integrated hydrologic model, which represents interactions of snow processes, land surface hydrology, and groundwater in the Upper Colorado River basin is being developed to improve understanding of the linkages between snowmelt, climate and water availability. The model is developed using GSFLOW, a coupled groundwater and surface-water flow model that integrates the Precipitation-Runoff Modeling System (PRMS) and the Modular Groundwater Flow Model (MODFLOW). PRMS simulates surface and near surface watershed hydrology, and MODFLOW simulates saturated groundwater hydrology. Model simulations will include 1) natural conditions pre-1980, 2) more recent (1980-2020) conditions, and 3) climate change scenarios exploring how water availability may change in the future. Python scripts leveraging the FloPy and PyEMU packages are used to build and run the model, perform very-high-dimensional parameter estimation and uncertainty analysis using PEST++, and process results. This coupled modeling system solves for snowmelt recharge to groundwater as well as runoff to streams while preserving the balance that is not easily achieved in independent models.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFM.H22O1003D