EXAMINING DAMS AND FLUVIAL PROCESSES IN THE THAMES RIVER WATERSHED, SOUTHERN NEW ENGLAND

There are currently 724 dams located on streams and major rivers in the Thames River Watershed. Of these 724 some are remnants of dams that have been breached while most are concrete or earthen dam mixes that retain moderate reservoirs. The age of some of these dams extend back to the late 1800’s, while many dams are more recent additions there are still many old mill dams on rivers in New England.

Here were present the preliminary results of our study to determine the affect these dams have had on fluvial processes in the watershed. Dams directly affect the upstream and downstream portions of these rivers and streams, trapping sediment and reducing or increasing its presence along the river profile. Using modern LiDar based Digital Elevation Models (DEMs), historical aerial imagery, and ground surveys in conjunction with a GIS platform, we quantify the degree to which sediment is deposited upstream of dams and where more is entrained below increasing the rate of erosion. Some current questions we address are whether the rate of erosion and sediment deposition is constant for certain types of dams on rivers and streams with similar slope and volume or if there is more variation. We hope to explore the causes of variation in deposition and erosion.