Oyster Reservoir Dam Reservoir Report

Last Updated: December 16, 2025

Oyster Reservoir Dam, located in Durham, New Hampshire, is a concrete buttress dam completed in 1934 primarily for water supply purposes.


°F

°F

mph

Wind

%

Humidity

Summary

With a height of 21 feet and a length of 180 feet, the dam holds a maximum storage capacity of 208 acre-feet and a normal storage of 172 acre-feet. The dam's reservoir covers a surface area of 6.9 acres and drains a 16.8 square mile watershed, with a maximum discharge capacity of 4997 cubic feet per second.

Managed by the NHDES Dam Bureau, Oyster Reservoir Dam is regulated, permitted, inspected, and enforced by the State of New Hampshire. The dam has a significant hazard potential, assessed as fair in condition, with the last inspection conducted in July 2018. The dam's spillway, classified as uncontrolled, has a width of 100 feet, and there are no associated locks for navigation. The risk assessment for the dam is moderate, with measures in place for risk management.

For water resource and climate enthusiasts, Oyster Reservoir Dam presents a fascinating case study in dam construction and management. Its strategic location on the Oyster River ensures a reliable water supply for the region while also posing challenges in terms of hazard potential and risk assessment. As a key piece of infrastructure in New Hampshire, the dam highlights the importance of effective regulation, inspection, and emergency preparedness to ensure the safety and sustainability of water resources in the face of changing climate conditions.

Year Completed

1934

Dam Length

180

Dam Height

21

River Or Stream

OYSTER RIVER

Primary Dam Type

Concrete

Surface Area

6.9

Drainage Area

16.8

Nid Storage

208

Hazard Potential

Significant

Foundations

Unlisted/Unknown

Nid Height

21
       
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.