Rainbow Lake Dam Reservoir Report
Last Updated: December 6, 2025
Rainbow Lake Dam, located in East Otto, New York, is a private dam regulated by the NYS DEC.
°F
°F
mph
Wind
%
Humidity
Summary
Completed in 1964, this earth-type dam stands at 22 feet high and spans 1040 feet, with a storage capacity of 745 acre-feet. The dam serves purposes of recreation and other activities, with a spillway width of 36 feet and a maximum discharge of 343 cubic feet per second.
With a significant hazard potential and a moderate risk assessment, Rainbow Lake Dam has not been rated for its condition assessment. Although inspections are conducted every 4 years, the last recorded inspection was in July 2017. The dam is situated on TR-East Otto Creek and has a drainage area of 0.6 square miles, providing a surface area of 51 acres.
Water resource and climate enthusiasts will be intrigued by Rainbow Lake Dam's role in managing water resources and providing recreational opportunities in Cattaraugus County, New York. Its historical significance since the 1960s, combined with its regulatory oversight and potential risks, make Rainbow Lake Dam a focal point for ongoing monitoring and management efforts to ensure the safety and sustainability of its operations.
Year Completed |
1964 |
Dam Length |
1040 |
Dam Height |
22 |
River Or Stream |
TR-EAST OTTO CREEK |
Primary Dam Type |
Earth |
Surface Area |
51 |
Drainage Area |
0.6 |
Nid Storage |
745 |
Hazard Potential |
Significant |
Nid Height |
22 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Allegheny River At Salamanca Ny
|
1540cfs |
Cattaraugus Creek At Gowanda Ny
|
490cfs |
Chadakoin River At Falconer Ny
|
64cfs |
Allegheny River At Eldred
|
473cfs |
Cazenovia Creek At Ebenezer Ny
|
102cfs |
Buffalo Creek At Gardenville Ny
|
417cfs |
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.
Rainbow Lake Dam