Pittsford Mill Dam Reservoir Report
Last Updated: December 5, 2025
Pittsford Mill Dam, also known as Ross Dam, is a privately owned structure located in Hillsdale, Michigan, along the East Branch St Joseph River.
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Summary
Completed in 1872, this earth dam stands at 14 feet tall and spans 200 feet in length, serving a primary purpose of recreation. Despite its age, the dam's hazard potential is rated as low, with a very high risk assessment score of 1, likely due to its controlled spillway and overall structural integrity.
While the dam has not been rated for its condition assessment, it is regularly inspected by the state regulatory agency, Michigan DEGLE. The last inspection was conducted in December 1988, with a scheduled inspection frequency of every 5 years. With a maximum storage capacity of 75 acre-feet and a normal storage of 45 acre-feet, the dam covers a surface area of 8 acres and has a maximum discharge rate of 1400 cubic feet per second. Despite being privately owned, the dam falls under state jurisdiction and permitting, ensuring its compliance with safety regulations and enforcement measures.
Overall, Pittsford Mill Dam is a historic structure that continues to provide recreational benefits while being closely monitored for safety and compliance with state regulations. Its location in Pioneer, Ohio, and its association with the Detroit District of the US Army Corps of Engineers highlight its importance within the local water resource management framework. Enthusiasts of water resources and climate can appreciate the unique characteristics and risk management measures in place for this intriguing dam on the East Branch St Joseph River.
Year Completed |
1872 |
Dam Length |
200 |
Dam Height |
14 |
River Or Stream |
East Branch St Joseph River |
Primary Dam Type |
Earth |
Surface Area |
8 |
Hydraulic Height |
14 |
Nid Storage |
75 |
Structural Height |
14 |
Hazard Potential |
Low |
Nid Height |
14 |
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.
Pittsford Mill Dam