Rawson Hill Brook Dam Reservoir Report
Last Updated: December 15, 2025
Rawson Hill Brook Dam, also known as the A-4a Site, is a state-owned structure located in Northborough, Massachusetts.
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Summary
Designed by the USDA NRCS and completed in 1963, this earth dam stands at a height of 16.3 feet and serves the primary purpose of flood risk reduction. The dam has a storage capacity of 480 acre-feet and is regulated by the Department of Conservation and Recreation, with state permitting, inspection, and enforcement in place.
Situated on Rawson Hill Brook, this dam plays a vital role in protecting the surrounding area from potential flooding events. With a significant hazard potential but a satisfactory condition assessment, the dam is closely monitored and inspected every five years to ensure its safety and functionality. Despite its moderate risk level, the dam's risk management measures and emergency action plan status are not clearly defined, highlighting the importance of continued monitoring and maintenance to mitigate potential threats.
In addition to flood risk reduction, the Rawson Hill Brook Dam also serves purposes such as fish and wildlife habitat creation and recreation. With its uncontrolled spillway and outlet gates, this dam plays a multifaceted role in the local ecosystem while safeguarding the community from the impacts of extreme weather events. As a key piece of infrastructure in Worcester County, Massachusetts, this dam stands as a testament to the importance of water resource management and climate resilience in the region.
Year Completed |
1963 |
Dam Length |
252 |
Dam Height |
16.3 |
River Or Stream |
RAWSON HILL BROOK |
Primary Dam Type |
Earth |
Hydraulic Height |
13.3 |
Drainage Area |
1.4 |
Nid Storage |
480 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Significant |
Foundations |
Unlisted/Unknown |
Nid Height |
16 |
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.
Rawson Hill Brook Dam
Sewell Drive Shrewsbury