Conowingo Reservoir Report

Last Updated: December 8, 2025

Conowingo Dam, located on the Susquehanna River in Port Deposit, Maryland, is a significant hydroelectric facility with a rich history dating back to its completion in 1928 by Stone & Webster Engineering Corp.


°F

°F

mph

Wind

%

Humidity

Summary

The dam stands at a height of 94 feet and spans 4,648 feet, making it a vital structure for generating hydroelectric power and providing water supply and recreational opportunities in the area. With a storage capacity of 310,000 acre-feet and a drainage area of 27,077 square miles, Conowingo Dam plays a crucial role in managing water resources and flood control in the region.

The dam's controlled spillway, with a width of 3,036 feet, ensures the safe release of water during periods of high flow, while its 52 slide gates allow for efficient regulation of water levels. However, with a high hazard potential and very high risk assessment rating, Conowingo Dam faces challenges in maintaining its structural integrity and addressing potential safety concerns. Despite not being regulated by the state or subject to regular inspections, the Federal Energy Regulatory Commission oversees the dam's operations and inspections to ensure compliance with safety standards.

As a key player in the region's water management infrastructure, Conowingo Dam continues to be a focal point for water resource and climate enthusiasts. Its role in generating clean energy, providing recreational opportunities, and supporting water supply needs underscores the dam's importance in balancing environmental conservation with sustainable development. With its impressive engineering design and historical significance, Conowingo Dam remains a symbol of human ingenuity in harnessing the power of water for the benefit of the community and the environment.

Year Completed

1928

Dam Length

4648

Dam Height

94

River Or Stream

Susquehanna River

Surface Area

8563

Drainage Area

27077

Nid Storage

310000

Outlet Gates

Slide (sluice gate) - 52

Hazard Potential

High

Foundations

Rock

Nid Height

94
       
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.