Human Modifications and Watershed Hydrologic Processes in a Postglacial Landscape
Brett Gerard1,2, Sean MC Smith
1,3, Alexander Sivitskis
4, Andrew S Reeve
1,2 and Brian Mathys Van Dam Jr
1,2, (1)University of Maine, School of Earth and Climate Sciences, Orono, ME, United States, (2)Sen. George J. Mitchell Center, Orono, ME, United States, (3)Sen. George J. Mitchell Center for Sustainability Solutions, Orono, ME, United States, (4)Johns Hopkins University, Baltimore, MD, United States
Contact First Author: Brett Gerard; brett.gerard@maine.edu
Previously Published Material: Some of this work (the hydrologic modeling component) was part of a poster presentation for the 2013 AGU conference in San Fransisco. However, that work was in an earlier stage and additional work (the geomorphic assessment) has been added to this abstract.
English Abstract:
The rates and magnitudes of watershed hydrologic processes in northern New England are influenced by the post-glacial terrain and landscape modifications made by humans following European colonization of the area in the early 1600s. The extent to which glaciation and human activities control the surface hydrologic conditions and geomorphology of the region is the focus of this research. We examine: 1) How channel geomorphic conditions vary relative to watershed characteristics; and 2) How human modifications influence stream flow regimes in the region. This research is conducted in the Sebago Lake watershed of southern Maine. Despite extensive human interventions in the watershed over the past three centuries, the region remains predominantly rural and forested. However, projections indicate a change to more extensive development in future decades, which could have hydrologic, geomorphic, and water quality implications for Sebago Lake and its tributary network.
The geomorphic assessment component of our investigation examines fluvial conditions in our study area relative to sub-basin attributes and calculated hydrologic estimates using statistical techniques. Changes to surface flows influencing stream conditions are evaluated based on simulations with a distributed watershed hydrology model using predicted scenarios for land cover, hydraulic controls, and drainage network expansion in a sub-basin of the Sebago Lake watershed. These scenarios represent a range of watershed and drainage network modifications commonly associated with human development in the region. All scenarios result in alterations to flow conditions and the sub-basin water budget. Future work seeks to link surface flow regimes derived from varied climate and land cover scenarios with stream bed dynamics and the hydraulic conditions of the hyporheic zone.
