Comments:
Reach segmented and data updated in 2007 relying on 2002 Ph2 data, 2003 cross section, USGS Bridge Scour rpt for Route 7 bridge, and limited 2007 observations. Straightening inferred due to linear planform, proximity of bridge crossing, and adjacent agricultural fields; similar planform depicted on historic aerial photos from 1942, 1962, 1974, and 1995. Short, shallow berm of field stone along RB (edge corn field) upstream of the bridge. Route 7 and 3 Mile Bridge Rd encroach on the floodplain but not substantial enough to cause substantial change in average valley confinement (Very Broad). Minor degree of incision is inferred to be historic. Nearest upstream grade control at bedrock exposures in segment M08-A. It is expected that Incision would also be offset by aggradation in this location within 1.5 miles downstream of reduced valley slope (and reduced sediment transport capacity). Pebble count relies on June 1996 cross section conducted for USGS bridge scour study within 50 ft d/s of 2002 Ph2 cross section - supported by visual observations in 2003. Channel bed appears naturally armored (through winnowing of fines). Mature trees along both banks probably contributing to channel stability. Rt 7 bridge constructed 1964; has piers.