North Harwich Reservoir Dam Reservoir Report
Last Updated: December 21, 2025
The North Harwich Reservoir Dam in Barnstable, Massachusetts, is a concrete buttress dam primarily used for irrigation purposes.
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Summary
With a height of 7.6 feet and a storage capacity of 216 acre-feet, it serves as a vital water resource for the local community. The dam is state-regulated by the Department of Conservation and Recreation, ensuring proper inspection, enforcement, and permitting processes are in place to maintain its structural integrity and safety.
Despite being classified as having a low hazard potential and a satisfactory condition assessment, the dam is subject to moderate risk (level 3) due to its location and potential impact on the surrounding area in case of a breach. The last inspection in 2009 revealed no significant issues, but regular inspections every 10 years are mandated to ensure continued safety. The presence of an uncontrolled spillway and the absence of outlet gates may pose challenges in managing water levels during periods of high discharge, highlighting the importance of ongoing risk management measures.
Overall, the North Harwich Reservoir Dam serves as a crucial infrastructure for water management in Harwich, Massachusetts. With its moderate risk level and state regulatory oversight, it underscores the importance of proactive maintenance and emergency preparedness to mitigate potential hazards and ensure the continued reliability of this essential water resource.
Dam Height |
7.6 |
Primary Dam Type |
Concrete |
Surface Area |
0.11 |
Hydraulic Height |
6.2 |
Drainage Area |
2.25 |
Nid Storage |
216 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
8 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
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.
North Harwich Reservoir Dam
Slough Road 159-265, Brewster