Comments:
Topographic contours suggest alluvial fan type of feature; at least there is a significant decrease in gradient as compared to upstream segments. Old Mill Rd in RB corridor and Pleasant St in LB corridor are slightly elevated above the surrounding floodplain, and therefore resulted in a slight human-caused change in valley width (St 1.5) - enough to change the valley type (from Very Broad to Narrow), but not sufficient to change the confinement type (unconfined). Floodplain along both sides of the channel is developed with residential buildings (village of East Arlington). Development is historic dating back to the mid- to late-1700s (Child, 1880) and once included planing mill, black smith shop, and Judson & Billings factory (Walling, 1856; Beers, 1869). Channel margins have likely been graded and reworked during historical development and during recovery from past flood events. Streambanks have been heavily armored with rip-rap. Channel is partly incised below the floodplain (IRraf = 1.4). Berms are present along both banks (with an occasional break along the RB berm) - which has increased the degree of channel entrenchment (IRhef = 2.0, ER = 1.47) to cause a stream type departure (C to F). Vertical concrete wall at the downstream end of the segment protects Old Mill Rd and encroaches on the channel. Three stormwater pipes were observed penetrating the wall and directing drainage to the channel. Concrete wall has significant cracking/ spalling and is scoured near the interface with the channel bed. East Arlington Rd bridge crosses the channel at the downstream end of the segment; bridge has a bankfull-constricting span, with minor aggradation noted at the inlet. Channelization and dredging are inferred due to somewhat linear planform and extensive berming / armoring. Age of trees along berm would be consistent with berming after 1973 flood.