Marlton South Swm Dam Reservoir Report

Last Updated: December 5, 2025

Marlton South Swm Dam, also known as Grandhaven Avenue Dam, is a local government-owned earth dam located in South Marlton, Maryland.


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Summary

Completed in 2000, this dam serves primarily for recreation purposes along the Southwest Branch of the river. With a height of 24 feet and a length of 500 feet, it has a storage capacity of 51 acre-feet and a surface area of 1.6 acres.

Managed by Maryland Dam Safety, Marlton South Swm Dam has a low hazard potential and is currently assessed to be in fair condition as of September 2014. Despite its moderate risk rating, the dam has undergone regular inspections, with the last one conducted in October 2020. The dam features an uncontrolled spillway with a width of 3 feet, capable of handling a maximum discharge of 150 cubic feet per second.

This dam plays a crucial role in the local community for recreational activities while also serving as a significant water resource management infrastructure. With its strategic location and design, Marlton South Swm Dam continues to be a vital asset in ensuring water safety and conservation in Prince George's County, Maryland.

Year Completed

2000

Dam Length

500

Dam Height

24

River Or Stream

Southwest Branch

Primary Dam Type

Earth

Surface Area

1.6

Drainage Area

0.63

Nid Storage

51

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

24
       
Seasonal Comparison

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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.