Marlu Lake Dam Reservoir Report

Last Updated: December 8, 2025

Marlu Lake Dam, located in Middletown, New Jersey, is a vital local government-owned structure designed for irrigation purposes.


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Summary

Completed in 1965, this earth dam stands at a height of 29 feet with a length of 424 feet, creating a storage capacity of 82 acre-feet for water from the Branch of Hop Brook. With a surface area of 20 acres and a drainage area of 1.4 square miles, Marlu Lake Dam plays a crucial role in water resource management in the area.

Managed by the New Jersey Department of Environmental Protection, Marlu Lake Dam has a low hazard potential and has been assessed to be in fair condition as of the last inspection in October 2019. The dam has a maximum discharge capacity of 866 cubic feet per second, ensuring effective flood control measures for the surrounding region. With its primary purpose being irrigation, Marlu Lake Dam serves as a key infrastructure for supporting agricultural activities and ensuring water availability for the local community.

The dam's location in Holmdel Township within Monmouth County, New Jersey, highlights its significance in the region's water resource and climate management efforts. With regular inspections and state regulatory oversight in place, Marlu Lake Dam continues to play a pivotal role in maintaining water security and environmental sustainability in the area. Its historical significance and ongoing operational importance make it a crucial asset for water resource and climate enthusiasts alike.

Year Completed

1965

Dam Length

424

Dam Height

29

River Or Stream

Branch of Hop Brook

Primary Dam Type

Earth

Surface Area

20

Drainage Area

1.4

Nid Storage

82

Hazard Potential

Low

Nid Height

29
       
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.