Black Lake Dam Reservoir Report

Last Updated: December 14, 2025

Black Lake Dam, located in Adams County, Washington, is a privately-owned structure regulated by the Washington Department of Ecology.


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Summary

Completed in 1938, this gravity dam on Crab Creek serves primarily for recreational purposes, offering a surface area of 28 acres and a maximum storage capacity of 250 acre-feet. Standing at a hydraulic height of 7 feet and a structural height of 6 feet, Black Lake Dam boasts a low hazard potential and has not been rated for its condition.

This multi-arch dam with a rock foundation spans 70 feet in length and has a drainage area of only 0.01 square miles. Despite its small size, the dam is equipped to handle a maximum discharge of 225 cubic feet per second. With no spillway type specified and no outlet gates, the dam's risk assessment, emergency action plan, and inundation maps have not been prepared or updated. While it may not be a prominent feature on the water resource or climate preservation radar, Black Lake Dam serves as a reminder of the diverse range of dam structures across the United States and their varying levels of regulatory oversight and maintenance.

Year Completed

1938

Dam Length

70

River Or Stream

Crab Creek

Primary Dam Type

Gravity

Surface Area

28

Hydraulic Height

7

Drainage Area

0.01

Nid Storage

250

Structural Height

6

Hazard Potential

Low

Foundations

Rock

Nid Height

7
       
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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.