Calvert Gateway Reservoir Report

Last Updated: December 5, 2025

Calvert Gateway, also known as Penwick Village, is a privately owned dam located in Calvert County, Maryland.


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Summary

Completed in 2000, this earth-type dam stands 16 feet tall and spans 200 feet in length, with a storage capacity of 4.05 acre-feet and a surface area of 0.9 acres. The primary purpose of this structure is for recreation, offering opportunities for outdoor activities in the surrounding area.

Managed by the Maryland Dam Safety regulatory agency, Calvert Gateway has a significant hazard potential and is classified as being in fair condition as of the last assessment in April 2021. The dam is equipped with an uncontrolled spillway, measuring 40 feet in width, and has a maximum discharge capacity of 367 cubic feet per second. With a moderate risk assessment rating and a regular inspection frequency, this structure plays a crucial role in managing water resources and ensuring public safety in the region.

Situated near Hall Creek in the Apple Green Business Park, Calvert Gateway serves as a vital infrastructure for the local community. With its strategic location and functional design, this dam not only provides recreational opportunities but also contributes to water resource management efforts in Maryland. Climate and water resource enthusiasts can appreciate the importance of structures like Calvert Gateway in safeguarding the environment and enhancing the resilience of the region against potential hazards.

Year Completed

2000

Dam Length

200

Dam Height

16

River Or Stream

Hall Creek-TR

Primary Dam Type

Earth

Surface Area

0.9

Drainage Area

0.04

Nid Storage

4.05

Outlet Gates

Needle - 0

Hazard Potential

Significant

Foundations

Unlisted/Unknown

Nid Height

16
       
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.