Guard Lock & Gates Reservoir Report
Nearby: Pawtucket Dam Great River Wall (Grw)
Last Updated: December 17, 2025
Guard Lock & Gates, also known as Francis Gate Dam, is a privately owned structure located in Lowell, Massachusetts.
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Summary
Completed in 1848, this masonry dam stands at a height of 27.6 feet and serves primarily for hydroelectric purposes. With a storage capacity of 4,500 acre-feet and covering a surface area of 720 acres, it plays a crucial role in flood risk reduction and water supply management in the region.
The dam is associated with 15 other structures and is regulated by the Federal Energy Regulatory Commission. It features a unique design with buttress core types and rock foundations. The outlet gates include Other Controlled and Vertical Lift types, demonstrating its versatility in water flow control. Despite being classified as a high hazard potential structure, its condition assessment is currently not available, highlighting the need for continuous monitoring and emergency preparedness.
For water resource and climate enthusiasts, Guard Lock & Gates offers a fascinating glimpse into the intersection of historic infrastructure and modern water management practices. Its strategic location along the Pawtucket Canal and extensive storage capacity make it a vital asset for both energy generation and environmental protection. As discussions around water security and climate resilience continue to evolve, this dam serves as a tangible example of how human ingenuity and natural resources can be harnessed for sustainable development.
Year Completed |
1848 |
Dam Length |
160 |
Dam Height |
27.6 |
River Or Stream |
Pawtucket Canal |
Primary Dam Type |
Masonry |
Surface Area |
720 |
Hydraulic Height |
10 |
Drainage Area |
3979 |
Nid Storage |
4500 |
Structural Height |
27.6 |
Outlet Gates |
Other Controlled - 2, Vertical Lift - 5 |
Hazard Potential |
High |
Foundations |
Rock |
Nid Height |
28 |
Seasonal Comparison
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Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Guard Lock & Gates
Pawtucket Boulevard 936-970, Lowell