Water Resources Professional Project Reports

Document Type

Report

Publication Date

Fall 2020

Abstract

Mountain snowpacks provide much of the water resources for the southwestern United States. Due to limited freshwater supply and mounting climate stressors, accurate water budget forecasts have become increasingly important. Many regions, such as the lower-elevation mountains found in central New Mexico, lack valuable snow data that could improve these forecasts. The purpose of this research project is to measure and analyze the variability of a moderate snowpack in this region to better understand the representativeness of snow depth distribution and more accurately estimate snow water equivalence (SWE). A survey site with a 1,200 square meter plot in the eastern Sandia Mountains has been established to perform this analysis and to improve the collection of snowpack data in this region. Depth measurements across a forest stand boundary have been compared for the 2019 and 2020 winter seasons to evaluate annual snowpack distribution as well as interannual variability. One snow pit in both the open and forest areas provided density measurements for SWE estimates as well as temperature profiles for energy budget calculations. During 2019, snow depth reached a maximum of 148 cm (mean 83 cm). Maximum depth reached 125 cm (mean 57 cm) in 2020. Snow depth coefficients of variation ranged from 0.2 to 2.6 for both years although depth variability was noticeably higher in 2020. A transition period has been identified as occurring between the accumulation and melt period, whereby snow depth is recorded as increasing and decreasing in different locations across the plot and snowpack temperatures show some variability as they become more isothermal. One transect per 100 m2 and about one depth point 20 per m2 was required to achieve a representative depth measurement into the melt period during both seasons. A better understanding of snowpack distribution in these water-stressed regions will improve spring runoff forecasts and assist in more proactive water management decisions.

Keywords

snowpack, snow depth, Sandia Mountains

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