Merwin Dam Quick Facts
Merwin Dam Map
Merwin Dam Information
Merwin Dam is an arch concrete gravity dam located about 11 miles from Woodland, Wa, Cowlitz, Washington.
The dam, which is on the Lewis River, was primarily built for Hydroelectric purposes, but also serves for Fish and Wildlife Pond and Recreation benefits.
The dam was designed by and commissioned in 1931 and is currently owned by PacifiCorp.
Merwin Dam Structure
The Merwin Dam is approximately 1,250 feet (381 m) long, 313 feet (95 m) high and has a structural volume of cubic yards (0 cubic metres).
Merwin Dam Storage Capacity & Surface Area
The reservoir has a normal storage capacity of 422,000 acre-ft (520,529 Ml) and maximum capacity of 422,000 acre-ft (520,529 Ml).
The surface area of the reservoir is 3,921 acres (1,587 ha) and the total catchment area is 726 square miles (1,880 square kilometres).
Merwin Dam Spillway
The dam spillway has a maximum discharge capacity of 120000 cubic feet per second (3398 cubic metres per second).
Merwin Dam Compared to Five Famous American Dams
Merwin Dam Weather
Current Conditions at Merwin Dam
Failed to fetch current weather data.7-Day Forecast for Merwin Dam
Failed to fetch weather forecast data.Merwin Dam Frequently Asked Questions
Merwin Dam is in Washington.
Merwin Dam is in Cowlitz County.
Merwin Dam is 313 feet high.
Merwin Dam is 1,250 feet long.
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Condition Assessment Classification
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.
Source: National Inventory of Dams