Tapps Lake Dike No 11 Reservoir Report

Last Updated: December 15, 2025

Tapps Lake Dike No 11, located in Auburn, Washington, was completed in 1911 and serves as a recreational area along with being a vital structure for water resource management.


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Summary

The dike is owned by a public utility and is regulated by the Washington Department of Ecology. It stands at a height of 23 feet and spans 1600 feet in length, with a storage capacity of 38,000 acre-feet and a surface area of 2570 acres.

The dam is primarily made of earth and stone materials, with a soil foundation, and diverts water from the White River. Despite its age, the structure is deemed to be in satisfactory condition during the last assessment in February 2018. However, it poses a high hazard potential, indicating the importance of regular inspections and maintenance. The dike is under the jurisdiction of Congressional District 08, represented by Kim Schrier, and falls under the oversight of the Seattle District of the US Army Corps of Engineers.

In the event of an emergency, the dike has an Emergency Action Plan (EAP) in place, last revised in March 2020. The structure is inspected every 5 years, with the last inspection conducted in February 2017. Tapps Lake Dike No 11 plays a crucial role in water management in the region, ensuring the safety of the surrounding community and providing recreational opportunities for visitors.

Year Completed

1911

Dam Length

1600

River Or Stream

Diversion from White River

Primary Dam Type

Earth

Surface Area

2570

Hydraulic Height

23

Drainage Area

9.69

Nid Storage

38000

Structural Height

23

Hazard Potential

High

Foundations

Soil

Nid Height

23
       
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.