Photos from our March 2013 Meeting:
Notes related to video clip meant to be shown during Larry Day's presentation on Post-Flood
Emergency Stream Intervention Concepts during the NY Wetlands Forum Spring 2013 annual meeting in
Using a stream demonstration table, this 30-second video shows how uncontrolled stream
dredging (which occurs just downstream and below the field of view) can create a "headcut"
that migrates up a stream channel. This subtle but important type of erosion progressively
lowers stream bed elevations to adjust to the dredged elevation, lowering water table
elevations adjacent to the stream and potentially drying up adjacent wetlands, as represented
by the circular wet spot visible pre-headcut.
Especially common after flood events, the practice of dredging or "removing excess gravel" from
streams can cause wide-ranging and off-site detrimental impacts if uncontrolled. Impacts can
occur upstream, as the stream becomes incised and separated from its floodplain; downstream,
due to excessive sediment deposition; and adjacent to the stream as water tables are lowered
and stream banks are destabilized.
Training in Emergency Stream Intervention was developed by the Delaware County Soil and
Water Conservation District and partner agencies, and is expanding across NY and PA. The NYS
DEC's website gives a schedule of upcoming training events in this subject: