|
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 |
|
