Water Resources Research Act Program

Details for Project ID 2020NM328B

Adding snow physics to PyRANA to understand the impacts of climate change on diffuse recharge in New Mexico headwaters

Institute: New Mexico
Year Established: 2020 Start Date: 2020-03-01 End Date: 2021-02-28
Total Federal Funds: $30,000 Total Non-Federal Funds: $60,000

Principal Investigators: Alex Rinehart

Abstract: We aim to answer the question: how will diffuse recharge in the headwaters of New Mexican rivers alter during climate change? The annual flows in New Mexico and in much of the Mountain West are dominated by snow-melt (Lehner et al., 2017). As climate warms and precipitation becomes less reliable, snow packs are expected to decrease in amount, melt earlier and for a longer though for a smaller overall volume, and be less consistent through time (Mote et al., 2005; Hamlet et al., 2005; Jones and Gutzler, 2016; Musselman et al., 2017). This means that previous estimates of recharge driving baseflow will no longer be reliable. At the same time, snow accumulation and ablation at the lower mid-latitudes (<35°N) and changing vegetation are more sensitive to sunlight-terrain interactions not commonly captured in snow models (Rinehart et al., 2008; Musselman et al., 2012). Similarly, simple degree-day and radiation-restricted degree-day models are not as reliable for thin snow packs (Hock, 2003) and their calibrations are not valid under many climate change scenarios (Melsen and Guse, 2019). During melt, estimating recharge is further complicated by the heterogeneity of mountain landscapes, both in static fields (soils, elevation) and for inputs (precipitation, air temperature and radiation; (Clark et al., 2015; Xu, 2018).To predict changing diffuse recharge under changing climate in New Mexico, we propose adding a multilayered energy balance snow model (pySNOBAL; Python Snow Energy and Mass Balance Model; Marks and Dozier, 1992; Marks et al., 1999; Marks and Winstral, 2001; Havens et al., 2018) to the potential recharge model, PyRANA, the Python Recharge Assessment for New Mexico Aquifers developed at New Mexico Tech under the NMWRRI funded NM SWB project (Ketchum, 2016; ReVelle, 2017; Xu, 2018). PyRANA couples terrain- corrected radiation budgets and potential evapotranspiration of the Gridded Atmospheric Data downscalinG and Evapotranspiration Tools (GADGET) and a detailed multilayer infiltration model to produce robust estimates of potential diffuse recharge at operational computational speeds, high spatial resolution (250 m), and daily time-steps for the entirety of New Mexico. The addition of an energy balance snow model to PyRANA will replace the calibrated lumped parameter model, which will struggle in climate change simulations (Melsen and Guse, 2019).