Crossing At Lisbon Detention Dam Reservoir Report
Last Updated: December 5, 2025
The Crossing At Lisbon Detention Dam, located in Griswold, Connecticut, is a vital structure designed for flood risk reduction along the I-395 Drainage Quinebaug River.
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Summary
Completed in 2008, this privately owned earth dam stands at a height of 16 feet and spans 290 feet in length, with a controlled spillway width of 15 feet. The dam's primary purpose is to mitigate flood risks in the area, making it a crucial component of water resource management in New London County.
Managed by the Connecticut Department of Energy and Environmental Protection (DEEP), the Crossing At Lisbon Detention Dam has a significant hazard potential and is subject to regular inspections to ensure its structural integrity. Despite its satisfactory condition assessment as of April 2016, the dam's risk assessment categorizes it as very high (1), highlighting the importance of ongoing risk management measures. With a history of state regulation, permitting, and enforcement, this dam plays a crucial role in protecting the surrounding community from potential flooding events, emphasizing the intersection of water resource management and climate resilience in the region.
As a key component of the New England District's flood risk reduction infrastructure, the Crossing At Lisbon Detention Dam serves as a model for effective water resource management and emergency preparedness. With a robust emergency action plan in place and a commitment to meeting regulatory guidelines, this earth dam represents a proactive approach to mitigating the impacts of climate change on local water systems. Its strategic location in Lisbon, Connecticut, and close oversight by state agencies ensure that it continues to safeguard the community and surrounding areas from the threat of flooding, making it a critical asset in the region's water resource and climate resilience efforts.
Year Completed |
2008 |
Dam Length |
290 |
Dam Height |
16 |
River Or Stream |
I-395 DRAINAGE QUINEBAUG |
Primary Dam Type |
Earth |
Outlet Gates |
Other Controlled |
Hazard Potential |
Significant |
Foundations |
Rock, Soil |
Nid Height |
16 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Quinebaug River At Jewett City
|
1380cfs |
Shetucket River At Taftville
|
885cfs |
Little River Near Hanover
|
44cfs |
Yantic River At Yantic
|
147cfs |
Pendleton Hill Brook Near Clarks Falls
|
8cfs |
Shetucket River Near Willimantic
|
777cfs |
Dam Data Reference
Condition Assessment
SatisfactoryNo existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.
Hazard Potential Classification
HighDams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
Crossing At Lisbon Detention Dam
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