Modeling Streamflow Source Area Contributions in a Forested Watershed of the Colorado Rocky Mountains

Predicting streamflow source areas is important to understanding the quantity and quality of runoff generation. In forested watersheds, the spatial patterning of forest cover can influence the duration of hillslope hydrologic connectivity to the stream network and the chemical composition of water delivered to the stream. Across the western United States (US), forest cover change has been accelerating at a rapid pace due to wildfire, infestation, and timber harvest. As a first step toward understanding forest land cover controls on source area contributions, we utilize the Watershed ECOHydrology (WECOH, Nippgen et al., 2015) model to evaluate hillslope-to-stream hydrologic connectivity in the Fool Creek Watershed of the Fraser Experimental Forest, Colorado. WECOH was originally developed in the Tenderfoot Creek Experimental Forest (TCEF) of central Montana (Northern Rockies Ecoregion) and here we extend the use of WECOH to an Experimental Forest of the Southern Rockies Ecoregion. Next, we evaluate predictions of contributing areas derived from WECOH against empirical measurements from a network of groundwater wells. In this initial analysis we aim to enhance the prediction of streamflow source area contributions across forested watersheds which has become increasingly important in the face of accelerated forest land cover change across the western United States.