Abstract
This presentation will explore land cover change impacts on hydrology,
starting by posing the question: What makes a watershed sensitive to
forest disturbance? Despite a long appreciation of the significance of
forested watersheds to water supplies—supplying water to more than 180
million people in the U.S.—watershed sensitivity to forest
disturbances remains difficult to predict. Individual studies have often
contradicted long-standing understanding that forest disturbance leads
to increases in total water yield. This research seeks to address the
above question by linking a national-scale watershed database with
high-resolution forest disturbance imagery. Results indicate that
disturbance can caused significant changes (both increases and
decreases) in water yield and streamflow timing. Watersheds exhibiting
post-disturbance increases or decreases in water yield were found to be
distinct from each other (p<0.05) and regional patterns of
sensitivity are explored in the context of observable climatic and
physiographic variables. The last part of the presentation will explore
the development of a multi-algorithm sediment modeling system motivated
towards understanding the impacts of changing climate and land cover on
sediment yield. Sediment loading driven by current and future
hydrological extremes challenges drinking water utilities’ ability to
treat water to meet regulatory and public health protection goals. This
framework is tested over medium sized (~1000 sq. km)
watersheds, with the aim of a larger-scale analysis over the western
U.S.