|
Incident ID |
AK00044-2651 |
|
Dam Name |
LONG LAKE DAM |
|
Downstream Hazard Potential |
L |
|
State |
AK |
|
Incident Date |
09/11/2015 |
|
Incident Type |
Non-failure |
|
Incident Driver |
Hydrologic/flooding |
|
Incident Mechanism 1 |
Gate/valve Failure |
|
Incident Mechanism 2 |
|
|
Incident Mechanism 3 |
|
|
Incident Description |
Heavy rain event (7.73 in 24 hrs & 2.8 in earlier in the week) resulted in a rainfall induced flood event during which a section of the wooden flashboards failed. |
|
Named Hydrologic Event |
|
|
EAP Enacted (Y/N) due to Incident |
|
|
Fatalities (Number) |
0 |
|
Number of People Evacuated |
0 |
|
Number of Habitable Structures Evacuated |
0 |
|
Number of Habitable Structures Flooded |
0 |
|
Other Infrastructure Impacts |
|
|
Economic Damages (in $) |
|
|
Volume released at failure (ac-ft) |
|
|
Response |
|
|
Additional Remarks or Updates |
“The flashboards include a 20ft.x1ft. notch, near the south end of the dam, that will pass a nominal flow of 75 cfs. All additional flows will overtop the flashboards along the length of the dam. Based on the 1999 stability analysis, the flashboards are expected to fail at flood flows above 4500 cfs. This is a storm with a return interval of 10 years.
The dam is located in a very remote area and
there is no development downstream of the dam. |
|
Incident Time |
|
|
Incident Duration |
|
|
Incident Report Produced |
Yes |
|
Information Sources |
AK DNR |
|
Owner Type |
U |
|
Dam Type |
CNPG |
|
Primary Purpose(s) |
H |
|
EAP |
NR |
|
Year Completed |
1973 |
|
Year Modified |
0 |
|
Dam Height |
30 ft |
|
Max Storage (ac-ft) |
147000 ac-ft |
|
Surface Area (acres) |
1375 acres |
|
River Name |
LONG RIVER |
|
Latitude |
58.1667 |
|
Longitude |
-133.733 |
|
Regulatory Agency(ies) |
AKDNR |
|
NID Number |
AK00044 |
|
Attachments |
Y |
