Exeter Sewage Lagoon Dam Reservoir Report

Last Updated: December 15, 2025

The Exeter Sewage Lagoon Dam in New Hampshire is a significant structure owned by the local government and regulated by the NHDES Dam Bureau.


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Summary

Completed in 1989, this Earth-type dam stands at a height of 12 feet and has a length of 1270 feet, with a storage capacity of 55 acre-feet. It serves a primary purpose that is classified as 'Other', and its hazard potential is deemed 'Significant' with a satisfactory condition assessment as of December 2016.

Located in Rockingham County, the Exeter Sewage Lagoon Dam plays a crucial role in managing water resources and protecting the surrounding area from potential flooding. Despite being a buttress-type dam with no spillway, it has a maximum discharge capacity of 30 cubic feet per second. The dam's risk assessment is categorized as 'High (2)', highlighting the importance of implementing effective risk management measures to ensure the safety of the structure and the community.

With its last inspection conducted in September 2020 and an inspection frequency of 4 times a year, the Exeter Sewage Lagoon Dam remains an essential infrastructure that requires careful monitoring and maintenance to mitigate any potential risks associated with its operation. Climate and water resource enthusiasts will find this dam a fascinating case study in infrastructure management and the intersection of environmental conservation with public health and safety.

Year Completed

1989

Dam Length

1270

Dam Height

12

River Or Stream

NA

Primary Dam Type

Earth

Surface Area

8.53

Nid Storage

55

Hazard Potential

Significant

Foundations

Unlisted/Unknown

Nid Height

12
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.