Publication Date

2017

Comments

This report was made possible by USDA-NIFA Grant # 2013-51130-21488 for "Farms, Floods and Fluvial Geomorphology: Making the most of our natural resources" (UMass, PI: Christine Hatch) and funding from the Massachusetts Department of Transportation (Massachusetts Geological Survey, UMass).

Abstract

This geomorphic assessment of Deerfield River in western Massachusetts and southern Vermont has been prepared by Milone & MacBroom, Inc. (MMI) on behalf of the University of Massachusetts as part of its "Farms, Floods, and FGM" project, funded by the United States Department of Agriculture – National Institute of Food and Agriculture National Integrated Water Quality Program(USDA – NIFA NIWQP) program. This project is a broad-based geomorphic assessment of the Deerfield River and its adjacent riparian corridor to define its characteristics, processes, and management issues. The river channel is used extensively for hydroelectric power generation and recreation, with agricultural land uses on the floodplains.

This river assessment focuses upon temporal river processes and resulting features rather than the more common assessment of local cross section forms and characteristics that change after annual floods. The Deerfield River has been found to be remarkably stable with moderate specific stream power (SSP) except in highly contracted segments, and the few large floodplains are more prone to sediment deposition rather than dynamic migratory channels or avulsions. In contrast, several larger tributaries have steep gradients and narrow confined valleys that lead to high stream power and dramatic geomorphic changes during floods. Consequently, the anticipated hydrologic effects of climate change will be more acute along the tributaries than the main stem.

The second part of this project included developing a Geographic Information System (GIS)-based model to compute specific stream power and using the results to help predict culvert and bridge vulnerability of failure. This vulnerability screening tool uses remote sensing data and a regression equation to predict hydrology and channel reach slope and a prediction of channel and structure condition that is compared to a field inventory of culverts. The purpose of the vulnerability screen analysis is to help identify the potential for channel and structural risk at culverts due to erosion, sedimentation, debris, and flooding. Vulnerable structures can then be ranked by priority for subsequent on-site investigation.

River Assessment Methodology is based on a "hydro-morphology" approach and employs fluvial assessment of watershed valley and river channel characteristics, an analysis of the Active River Area, an assessment of the equilibrium state and adjustments, and culvert/ bridge vulnerability analyses throughout the Deerfield watershed in Vermont and Massachusetts (HUC 01080203).

Pages

125

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