Perrywood (Manor House Drive) Reservoir Report

Last Updated: December 5, 2025

Perrywood (Manor House Drive) is a privately owned earth dam located in Largo, Maryland, along the Collington Branch - TR.


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Summary

Constructed in 1984 by Greenhorne & O'Mara, Inc., the dam stands at a height of 16.3 feet and has a storage capacity of 110.83 acre-feet. With a surface area of 2.8 acres and a drainage area of 0.15 square miles, Perrywood serves as a crucial water resource in Prince George's County.

Despite being regulated by the Maryland Dam Safety agency, Perrywood has been assessed to be in fair condition with a significant hazard potential. The dam's spillway type is uncontrolled, capable of a maximum discharge of 125.8 cubic feet per second. In the event of an emergency, the dam's Emergency Action Plan (EAP) status and risk assessment are currently unspecified. However, with routine inspections and a moderate risk rating, Perrywood remains a key structure for managing water resources in the region.

Water resource and climate enthusiasts will find Perrywood (Manor House Drive) to be a notable landmark in Maryland, showcasing the intersection of infrastructure and environmental stewardship. As a privately owned dam with state regulation, its vital role in water management and flood control highlights the importance of maintaining and monitoring such structures for the safety and sustainability of surrounding communities. With a rich history dating back to 1984, Perrywood stands as a testament to the ongoing efforts to balance water resource needs with environmental protection in the face of changing climate conditions in the region.

Year Completed

1984

Dam Length

300

Dam Height

16.3

River Or Stream

Collington Branch - TR

Primary Dam Type

Earth

Surface Area

2.8

Drainage Area

0.15

Nid Storage

110.83

Hazard Potential

Significant

Nid Height

16
       
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.