Clark-Lawall Marsh Dam Reservoir Report
Nearby: Faun Lake Dam Henry Becker Dam
Last Updated: December 25, 2025
The Clark-Lawall Marsh Dam, also known as Beaver Lake, is an Earth-type dam located in Johnsonburg, New York.
°F
°F
mph
Wind
%
Humidity
Summary
Completed in 1953, this dam serves a primary purpose of recreation and has a normal storage capacity of 48 acre-feet. Situated on the East Fork Tonawanda Creek, the dam has a low hazard potential and is currently in a not rated condition assessment.
Although the dam does not have a spillway, it has a spillway width of 22 feet and a maximum discharge of 200 cubic feet per second. With a maximum storage capacity of 72 acre-feet and a surface area of 29 acres, the dam offers recreational opportunities for visitors while helping regulate water flow in the area. The risk assessment for the dam is considered high, indicating the importance of ongoing monitoring and maintenance to ensure its safety and effectiveness in managing water resources in Wyoming County, New York.
Year Completed |
1953 |
Dam Length |
75 |
Dam Height |
8 |
River Or Stream |
EAST FORK TONAWANDA CREEK |
Primary Dam Type |
Earth |
Surface Area |
29 |
Drainage Area |
0.6 |
Nid Storage |
72 |
Hazard Potential |
Low |
Nid Height |
8 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Oatka Creek At Warsaw Ny
|
53cfs |
Genesee River At Portageville Ny
|
1090cfs |
Tonawanda Creek At Attica Ny
|
102cfs |
Keshequa Cr @ Craig Colony @ Sonyea Ny
|
8cfs |
Genesee River Near Mount Morris Ny
|
1280cfs |
Cayuga Creek Nr Lancaster Ny
|
106cfs |
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.
Clark-Lawall Marsh Dam