Modeling Snowmelt Runoff Response to Climate Change in the Animas River Basin,Colorado

C Andrew Day

doi:10.4172/2329-6755.1000110

Abstract

Snowmelt runoff is a significant water resource in the western United States. However this resource is extremely sensitive to changes in the local or regional climate. In this paper the potential changes in snowmelt runoff volume in response to changes in the local climate for the Animas River basin, Colorado were studied. A set of statistically downscaled general circulation model scenarios encompassing generally warmer and drier future climates were used to drive the Snowmelt Runoff Model (SRM) to investigate how snowmelt season basinwide runoff would respond to these conditions. Results suggest a shift in the timing and size of the snowmelt relative to historical measurements, with increases in April-May runoff volume offset by decreases in June-July runoff. The success of the SRM in modeling these climate change impacts could provide valuable data for water resource planners of similar snowmelt dominated river basins across the western United States.

Highlights

The process of snowmelt is crucial in controlling the streamflow response of any mountain watershed dominated by snowfall in the winter months
The modeled snowmelt runoff volume registered an R2 fit of 0.93 and a volume difference of -5.8% to mirror the rise in runoff volume responding to the depletion of the snowpack as air temperatures increased into the snowmelt season
Using the snowmelt runoff model, Snowmelt Runoff Model (SRM), it may be concluded that projected climate changes have the potential to drastically alter the timing and volume of basinwide snowmelt runoff over the course of the century

Summary

Introduction

The process of snowmelt is crucial in controlling the streamflow response of any mountain watershed dominated by snowfall in the winter months. As much as 75-80% of annual streamflow across the western United States (US) originates from this snowmelt source [1,2,3]. Historical studies across this region have recorded multiple instances of warming air temperatures and declines in the ratio of snow-to-rain precipitation during the winter snowpack or spring snowmelt months for these watersheds leading to earlier snowmelt runoff in the snowmelt season [2,4,5,6,7]. The Snowmelt Runoff Model (SRM), in particular, has been used in over 100 river basin studies where snowmelt is a major factor in runoff [14]. This semi-distributed model uses the degree-day or temperature index method to calculate and calibrate daily snowmelt runoff volume, and includes a total of six parameters:

Methods

Results

Conclusion