Patterson Brixius Grey Watershed 1 Dam Reservoir Report

Last Updated: December 5, 2025

The Patterson Brixius Grey Watershed 1 Dam, also known as the Toronto Reservoir, is a vital structure in Endwell, New York, serving as a key player in flood risk reduction along the Patterson Creek.


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Summary

Built in 1966 by the USDA NRCS, this earth dam stands at 65 feet in height and spans 1300 feet in length, with a storage capacity of 1280 acre-feet. The dam's primary purpose is flood risk reduction, with a maximum discharge capability of 17,500 cubic feet per second.

Located in Broome County, this dam is regulated by the NYS DEC and undergoes regular inspections to ensure its operational integrity. With a high hazard potential, the dam is deemed to have a moderate risk level. While its condition assessment remains unrated, the dam has an emergency action plan in place to address any potential risks. The presence of an uncontrolled spillway with a width of 355 feet further highlights the importance of this structure in managing water flow and mitigating the impact of extreme weather events on the surrounding area. For water resource and climate enthusiasts, the Patterson Brixius Grey Watershed 1 Dam serves as a critical piece of infrastructure in safeguarding the community against flooding and ensuring the sustainable management of water resources in the region.

Year Completed

1966

Dam Length

1300

Dam Height

65

River Or Stream

PATTERSON CREEK

Primary Dam Type

Earth

Surface Area

24

Drainage Area

4.42

Nid Storage

1280

Hazard Potential

High

Nid Height

65
       
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.