SILVER LAKE DAM - MIDDLETOWN - DE00051-3531
Dam Name: SILVER LAKE DAM - MIDDLETOWN
State: DE
Downstream Hazard Potential: H
Incident Type: Non-Failure
Incident Date: 07/27/2022
Incident Driver: Seepage/Internal Erosion
Incident Mechanism 1: Piping
Incident Mechanism 2Sinkhole
Incident Mechanism 3Excessive/Increased Seepage
Incident IDDE00051-3531
Incident DescriptionOn 7/27/2022 a sinkhole was discovered on the upstream slope adjacent to the right winwall of 1 of the bridge/spillway structures (this dam has two bridges with gates on the upstream side and a smaller culvert with boards on the upstream side) with an active boil on the downstream side of the dam. The piping/voids were under the bridge slab. The road was closed, the pond level was lowered and immeadiate measures including a liner and large sand sacks were placed on the upstream seepage entry point to prevent progression. Permanent repairs included flowable fill to fill the sinkhole and holes were drilled thru the slab to inject flowable fill in the voids under the bridge slab. All trees were clearded along the upstream slope and a sheet pile cutoff and riprap were installed.
Named Hydrologic Event
EAP Enacted (Y/N) due to IncidentYes
Fatalities (Number)
Number of People Evacuated0
Number of Habitable Structures Evacuated0
Number of Habitable Structures Flooded0
Other Infrastructure ImpactsBridges
Economic Damages (in $)$1 million to $5 million
Response
Volume released at failure (ac-ft)
Additional Remarks or Updates
Owner TypeS
Dam TypePGRE
Primary Purpose(s)R
EAPY
Dam Height18 ft
Max Storage (ac-ft)591.00
Surface Area (acres)39.00
Year Completed1945
NID NumberDE00051
River NameDEEP CREEK
Latitude39.438
Longitude-75.6934
Year Modified
Regulatory Agency(ies)DNREC
Incident Time
Incident Duration
Incident Report ProducedNo
Information SourcesDE Dam Safety
