ANALYSING THE GEOMORPHIC FUNCTION OF FLUVIAL WOOD IN NEW ENGLAND STREAMS

In recent years, the importance of large woody debris in channels has been a focal point for researchers across the globe, but little is known about the geomorphic function of wood accumulation in New England rivers. The goal of this study was to first, determine the role of wood in streams in the New England area, and second, determine how wood function changes downstream of beaver dams versus anthropogenic dams. Throughout the summer of 2015, field studies were conducted at three rivers in Massachusetts and one in New Hampshire, with drainage areas ranging in size from 3.57 to 38.33 square kilometers. The GPS coordinates of in-channel wood, that met the basic qualifications of at least 1 m in length and 10 cm in diameter, were tagged using the GPS Tour iPhone app. The decay class, stability class, and accumulation category were also recorded for each individual piece of wood. Statistical analysis was completed in RStudio. Preliminary data suggest that wood tends to accumulate in individual pieces, rather than jams. Wood in the basins are commonly bare of bark, but not decayed. The majority of wood are pieces bridging the stream or ramped along the edges, indicating that the adjacent riparian zone is the dominant source. Across the four field sites, the mean length of wood was 5.01 meters and the mean diameter was 0.284 meters. Further analyses include determining the spatial distribution of wood load along the length of the channel using LiDAR data in ArcGIS, including an examination of how wood load changes are related both to geomorphology and land use.