Riverdale Dam Reservoir Report
Nearby: Daniels Lake Dam Hadley Falls
Last Updated: December 19, 2025
Riverdale Dam, located in Weare, New Hampshire, is a concrete buttress dam on the Piscataquog River that serves the primary purpose of flood risk reduction.
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Summary
Owned by the federal government, the dam is regulated by the NHDES Dam Bureau and is subject to state permitting, inspection, and enforcement. With a height of 10 feet and a length of 90 feet, the dam has a storage capacity of 153 acre-feet and covers a surface area of 33.1 acres, contributing to the overall flood management efforts in the area.
Despite its low hazard potential, Riverdale Dam is classified as having a moderate risk level, indicating the need for ongoing monitoring and risk management measures. The dam has not been rated for its condition assessment, and the last inspection was conducted in October 2011, with a scheduled inspection frequency of every 6 years. While the dam does not have an Emergency Action Plan (EAP) in place, it is important for stakeholders and authorities to ensure that proper emergency contacts, inundation maps, and risk assessment guidelines are prepared and updated to mitigate any potential risks associated with the dam.
Overall, Riverdale Dam plays a crucial role in mitigating flood risks along the Piscataquog River in New Hampshire. As water resource and climate enthusiasts, it is essential to monitor and support the ongoing maintenance and management of the dam to ensure its continued effectiveness in protecting the surrounding communities and environment from potential flooding events.
Dam Length |
90 |
Dam Height |
10 |
River Or Stream |
PISCATAQUOG RIVER |
Primary Dam Type |
Concrete |
Surface Area |
33.1 |
Drainage Area |
47 |
Nid Storage |
153 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
10 |
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.
Riverdale Dam
Gorham Pond boat launch