Dead River Dam 1 Reservoir Report

Last Updated: December 16, 2025

Dead River Dam 1, also known as Jericho Lake Dam, is a state-owned structure located in Coos County, New Hampshire.


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Summary

Built in 1970 by the USDA NRCS, this earth dam serves the primary purpose of flood risk reduction along Jericho Brook. Standing at a height of 46.5 feet and stretching 3035 feet in length, the dam has a storage capacity of 4720 acre-feet, with a normal storage level of 1240 acre-feet.

Managed by the NHDES Dam Bureau, Dead River Dam 1 is subject to state regulation, permitting, inspection, and enforcement to ensure its safety and compliance with standards. The dam has a high hazard potential and was last assessed to be in fair condition in August 2017. With a moderate risk rating of 3, the structure is regularly monitored and inspected to mitigate any potential risks and ensure the safety of the surrounding area.

Water resource and climate enthusiasts will be fascinated by the engineering and management aspects of Dead River Dam 1, as well as its critical role in flood risk reduction in the region. The dam's design, construction, and operation reflect a commitment to safeguarding communities and natural resources from the impacts of extreme weather events. As a key component of the local water infrastructure, this dam exemplifies the importance of proactive risk management and regulatory oversight in ensuring the resilience of our water resource systems.

Year Completed

1970

Dam Length

3035

Dam Height

46.5

River Or Stream

JERICHO BROOK

Primary Dam Type

Earth

Surface Area

132

Drainage Area

6.48

Nid Storage

4720

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

47
       
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.