St Marys Pond Reservoir Report
Nearby: Sisson Pond Lawton Valley Reservoir
Last Updated: December 17, 2025
St Marys Pond in Portsmouth, Rhode Island, is a vital water supply reservoir managed by local government authorities.
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Summary
The dam, completed in 1878, stands at 12 feet high and holds a maximum storage capacity of 1,220 acre-feet. The pond covers an area of 117 acres and is fed by Lawton Valley Brook, serving as a crucial source of water for the surrounding community.
Despite its historical significance, St Marys Pond faces challenges in terms of its condition assessment, which is rated as poor. With a high hazard potential, the dam requires regular inspections to ensure its structural integrity and the safety of the area. The last inspection was conducted in September 2013, with a frequency of every 2 years. It is essential for water resource and climate enthusiasts to monitor and advocate for the maintenance and improvement of this important water source to mitigate potential risks and safeguard the local ecosystem.
As a key water supply source in Newport, Rhode Island, St Marys Pond plays a critical role in providing clean water to the community. With its rockfill dam type and high hazard potential, there is a pressing need for ongoing risk management measures to address its poor condition assessment. By staying informed and actively engaging in the preservation of St Marys Pond, water resource and climate enthusiasts can contribute to the sustainable management of this essential water resource for future generations.
Year Completed |
1878 |
Dam Length |
2288 |
Dam Height |
12 |
River Or Stream |
LAWTON VALLEY BROOK |
Primary Dam Type |
Rockfill |
Surface Area |
117 |
Hydraulic Height |
10 |
Drainage Area |
1 |
Nid Storage |
1220 |
Structural Height |
12 |
Hazard Potential |
High |
Nid Height |
12 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
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.
St Marys Pond
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