Rattlewood Golf Course Reservoir Report

Last Updated: December 5, 2025

Rattlewood Golf Course, also known as Frall Pond, is a picturesque irrigation and recreation facility located in Montgomery County, Maryland.


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Summary

Owned and managed by the local government, this Earth-type dam was completed in 1975 and stands at a height of 30.5 feet, with a storage capacity of 50 acre-feet. The dam serves primarily for irrigation purposes, supporting the lush greenery of the golf course while also providing recreational opportunities for visitors.

Managed by the Maryland Dam Safety regulatory agency, the Rattlewood Golf Course dam has a significant hazard potential but is currently assessed as being in satisfactory condition. Regular inspections are conducted to ensure its safety, with the latest inspection carried out in June 2021. The dam underwent structural upgrades in 2009, enhancing its resilience and functionality. With a moderate risk assessment rating, the dam is equipped with an uncontrolled spillway and measures in place to manage potential risks effectively.

Situated near the Patuxent River in the city of Mt Airy, Rattlewood Golf Course dam covers a surface area of 3 acres and drains a 0.2 square-mile watershed. The facility boasts a spillway width of 20 feet and a maximum discharge capacity of 10 cubic feet per second. As a crucial water resource for irrigation and recreation, Rattlewood Golf Course dam stands as a testament to sustainable water management practices and the harmonious integration of human activities with natural ecosystems.

Years Modified

2009 - Structural

Year Completed

1975

Dam Length

400

Dam Height

30.5

River Or Stream

Patuxent River-TR

Primary Dam Type

Earth

Surface Area

3

Drainage Area

0.2

Nid Storage

50

Hazard Potential

Significant

Foundations

Rock, Soil

Nid Height

31
       
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.