2010 Kirk Bryan Fieldtrip: Inferring the Historical Range of Variability in Rocky Mountain National Park

Kramer, Natalie; McLaughlin, Paul; Polvi, Lina; Rathburn, Sara; Rubin, Zan; Wohl, Ellen

The concept of historical range of variability (HRV) has been used to characterize the natural or background variability in geomorphic systems in the absence of intensive human impacts. The relevance of this approach has recently been called into question, given the extent and intensity of human impacts to landscapes and climates and the difficulty of returning to natural or reference conditions. During this fieldtrip, we will visit and sites in Rocky Mountain National Park where we are using diverse techniques to infer HRV and discuss the implications of this knowledge for resource management. We will visit Beaver Meadows, where the National Park Service seeks to reestablish beaver populations, and a site overlooking the Lawn Lake alluvial fan, where a dam failure flood in 1982 altered valley-bottom processes and forms. We will also discuss research being conducted in other portions of the park (the Upper Colorado River valley following the 2003 failure of a portion of the Grand Ditch, and the upper North St. Vrain Creek drainage south of Long’s Peak) in connection with HRV and restoration. Our intent is to facilitate discussions concerning (i) when the concepts of HRV and reference conditions are useful, (ii) the limitations on this usefulness, and (iii) how geomorphologists and Quaternary geologists can contribute to restoration efforts based on their knowledge of HRV.