Surface hydrological processes of rock glaciated basins in the San Juan Mountains, Colorado

ABSTRACT

Glaciers in the western USA contribute summer meltwater to regional hydrological systems. In the San Juan Mountains of Colorado, where glaciers do not exist, rock glaciers serve that function during the summer runoff period. Most rock glaciers in Colorado are located on northern slopes in mountainous areas; however, some rock glaciers in southwest Colorado have different aspects. In this study, we asked how slope aspect and rising air temperatures influence the hydrological processes of streams sourced from rock glaciers in the San Juan Mountains. We focused on three adjacent basins, Yankee Boy basin, Blue Lakes basin, and Mill Creek basin, which share a common peak, Gilpin Peak. Using HOBO® U20-001–04 water-level loggers, streamflow data were collected in each of these basins, below each rock glacier. Air temperature significantly influenced stream discharge below the rock glacier. Discharge and air temperature patterns indicate a possible air temperature threshold during late summer when rock glacier melt increases at a greater rate. The results also suggest that the aspect of rock glacier basins influences stream discharge, but that temperature and precipitation are likely larger components of melt regimes.

KEYWORDS:

• Rock glacier
• water resources
• climate change
• alpine hydrology
• Rocky Mountains

Acknowledgments

We are grateful for support from the Laurance Herold Fund of the Department of Geography and the Environment, University of Denver. We thank the US Forest Service for a special use permit for the summer of 2016 within Uncompahgre National Forest. We thank committee members Don Sullivan and Hillary Hamann and research assistants Vickie Otto, Corey Martz, Blaise Murphy, and Maddy Kelley. We would also like to thank the four anonymous reviewers who provided constructive comments to improve this paper.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the University of Denver Department of Geography and the Environment.