Catchment response to bark beetle outbreak and dust-on-snow in the Colorado Rocky Mountains

摘要: Summary Since 2002, the headwaters of Colorado River and nearby basins have experienced extensive changes in land cover at sub-annual timescales. Widespread tree mortality from bark beetle infestation has taken place across a range forest types, elevation, latitude. Extent severity structure alteration been observed through combination aerial survey, satellite remote-sensing, situ measurements. Additional perturbations resulted deposition dust regional dry-land sources on mountain snowpacks that strongly alter snow surface albedo, driving earlier faster snowmelt runoff. One challenge facing past studies these forms disturbance is relatively small magnitude signals within larger climatic signal. The combined impacts dust-on-snow are explored hydrologic modeling framework. We drive Distributed Hydrology Soil Vegetation Model (DHSVM) with meteorological data, time-varying maps leaf area index properties to emulate impacts, parameterizations albedo based observations forcing. Results beetle-killed canopy suggest slightly greater accumulation as result less interception reduced sublimation evapotranspiration, contributing overall increases annual water yield between 8% 13%. However, understory regeneration roughly halves yield. A purely observation-based estimate runoff coefficient change cumulative shows comparable sensitivities simulated results; however, positive not statistically significant ( p  ⩽ 0.05). primary impact forcing an increased rate associated more extreme deposition, producing peak streamflow rates order 1–3 weeks. Simulations produced little compounding effects, due exclusive nature their impacts. Potential timing important implications for management decisions.