Nissenbaum Dam - VT00000-3552


Incident ID VT00000-3552
Dam Name Nissenbaum Dam
Downstream Hazard Potential L
State VT
Incident Date 12/23/2022
Incident Type Failure
Incident Driver Seepage/internal Erosion
Incident Mechanism 1 Excessive/increased Seepage
Incident Mechanism 2
Incident Mechanism 3
Incident Description Internal erosion along the approximate alignment of the principal spillway outlet barrel that opened up to a sizable pipe and held an intact roof until the pond had been drained.
Named Hydrologic Event
EAP Enacted (Y/N) due to Incident No
Fatalities (Number) 0
Number of People Evacuated 0
Number of Habitable Structures Evacuated 0
Number of Habitable Structures Flooded 0
Other Infrastructure Impacts Other
Economic Damages (in $) $1 to $100,000
Volume released at failure (ac-ft) 6.9 ac-ft
Response State DSP required an engineered breach be constructed through the embankment and armored until appropriate engineering investigations, design, and permitting could be completed prior to repair construction.
Additional Remarks or Updates Dam constructed of non-plastic silt and placed and compacted with no engineering oversight or testing. It was reported that during construction, there was a slope failure of the downstream slope that had to be repaired. Overtopping and damages to downstream driveways and a private pond. Large sediment release caused environmental damages in streams downsream and caused sedimentation issues in two downstream ponds. Sub-500,000 CF dam not on a perennial stream. VT Dam Safety Program has limited authorities
Incident Time
Incident Duration
Incident Report Produced No
Information Sources VT Dam Safety
Owner Type P
Dam Type RE
Primary Purpose(s) R
EAP NR
Year Completed 2022
Year Modified 0
Dam Height 41 ft
Max Storage (ac-ft) 6 ac-ft
Surface Area (acres) 1 acres
River Name TR-Little River/Winooski River
Latitude 44.5248
Longitude -72.7329
Regulatory Agency(ies)
NID Number VT00000
Attachments