Nissenbaum Dam - VT00000-3552
Dam Name: Nissenbaum Dam
State: VT
Downstream Hazard Potential: L
Incident Type: Failure
Incident Date: 12/23/2022
Incident Driver: Seepage/Internal Erosion
Incident Mechanism 1: Excessive/Increased Seepage
Incident Mechanism 2
Incident Mechanism 3
Incident IDVT00000-3552
Incident DescriptionInternal 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 IncidentNo
Fatalities (Number)0
Number of People Evacuated0
Number of Habitable Structures Evacuated0
Number of Habitable Structures Flooded0
Other Infrastructure ImpactsOther
Economic Damages (in $)$1 to $100,000
ResponseState 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.
Volume released at failure (ac-ft)6.9
Additional Remarks or UpdatesDam 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
Owner TypeP
Dam TypeRE
Primary Purpose(s)R
EAPNR
Dam Height41 ft
Max Storage (ac-ft)6.90
Surface Area (acres)1.00
Year Completed2022
NID NumberVT00000
River NameTR-Little River/Winooski River
Latitude44.5248
Longitude-72.7329
Year Modified
Regulatory Agency(ies)
Incident Time
Incident Duration
Incident Report ProducedNo
Information SourcesVT Dam Safety
