LAKE HANSON - SD00691-3410
Dam Name: LAKE HANSON
State: SD
Downstream Hazard Potential: L
Incident Type: Failure
Incident Date: 09/12/2019
Incident Driver: Hydrologic/Flooding
Incident Mechanism 1: Spillway Erosion/Head Cutting
Incident Mechanism 2
Incident Mechanism 3
Incident IDSD00691-3410
Incident DescriptionWide spread rainfall on saturated ground ranging from 5 to 10 inches between September 11-12, 2019 caused operation of the earthen secondary spillway which eroded back to the reservoir.
Named Hydrologic Event
EAP Enacted (Y/N) due to IncidentNo
Fatalities (Number)0
Number of People Evacuatedunknown
Number of Habitable Structures Evacuatedunknown
Number of Habitable Structures Floodedunknown
Other Infrastructure ImpactsRoads
Economic Damages (in $)
ResponseState dam safety staff did a site visit on Sept. 17, 2019 to document.
Volume released at failure (ac-ft)
Additional Remarks or UpdatesSame issue occurred in 2007. Repair to secondary from 2007 event was of limited scope.
Owner TypeS
Dam TypeRE
Primary Purpose(s)R
EAPNR
Dam Height24 ft
Max Storage (ac-ft)340.00
Surface Area (acres)0.00
Year Completed1932
NID NumberSD00691
River NameTR-JAMES
Latitude43.625
Longitude-97.805
Year Modified
1996
Regulatory Agency(ies)DENR
Incident Time
Incident Duration
Incident Report Produced
Information SourcesSD Dam Safety
