The site is located on what is referred to in this PER as stream-major. Streambank erosion is occurring along both sides of the channel; however, the east side erosion adjacent to the residences along Stonemeade Drive appears to be of greater significance due to the proximity of adjacent structures and loss of actual property in terms of eroded square footage of land.
The stream at this project location has a bedrock bottom with silt and small cobbles in some bends. A narrow floodplain is generally along the west side of the channel, but shifts to the east side at approximately 400 feet upstream of the box culvert at Millbrook Drive. The project site begins at the upstream end of the existing 4’ x 8’ box culvert under Millbrook to approximately 620 feet upstream of the box. Visible signs of erosion, scour, and undercutting of existing trees and household debris in the channel indicate the presence of high velocity flows typically seen in urban and suburban streams.
The banks where erosion is occurring are generally vertical and range in height from 2 feet tall to over 6 feet. There appears to be several locations where the eroded banks are in proximity to the rear corners or rear property lines of the parcels that back up to the channel. Above the eroded vertical banks, some sloughing of overbank material was observed at several locations. A relatively small segmental block retaining wall was observed to have been constructed by a property owner. At one location along the channel, bank erosion was observed to be within approximately 10 feet of an existing privacy fence.