Columbia Marsh Unit #1 Dam Reservoir Report

Last Updated: December 14, 2025

Columbia Marsh Unit #1 Dam, located in Grant County, Washington, was completed in 1958 by the Bureau of Sport Fisheries and Wildlife.


°F

°F

mph

Wind

%

Humidity

Summary

This Federal-owned structure serves as a Fish and Wildlife Pond and stands at a height of 25 feet with a length of 2500 feet. With a capacity of 570 acre-feet for storage, the dam plays a crucial role in managing water resources for the surrounding area.

The dam is situated along Lower Crab Creek and is regulated by the Fish and Wildlife Service. Despite its low hazard potential, a 2012 inspection reported poor condition assessment, highlighting the need for maintenance and potential upgrades to ensure long-term functionality. The dam features outlet gates for controlled water release and emergency preparedness measures are currently under assessment to meet guidelines and mitigate risks associated with the structure.

Incorporating elements of Earth, Buttress, and Stone core types, Columbia Marsh Unit #1 Dam plays a vital role in water management within the region, supporting fish and wildlife conservation efforts. With its historical significance and ongoing maintenance needs, the dam serves as a key component in the broader ecosystem and climate resilience strategies in the area.

Years Modified

1997 - Other

Year Completed

1958

Dam Length

2500

Dam Height

20

River Or Stream

LOWER CRAB CREEK

Primary Dam Type

Earth

Surface Area

58

Hydraulic Height

20

Drainage Area

5.2

Nid Storage

570

Structural Height

25

Outlet Gates

Other Controlled, Slide (sluice gate)

Hazard Potential

Low

Foundations

Rock, Soil

Nid Height

25
       
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.