Trossachs Detention Pond Pc-3 Reservoir Report

Last Updated: December 15, 2025

Trossachs Detention Pond Pc-3 is a crucial water management structure located in King County, Washington, designed by Entranco to reduce flood risks effectively.


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Summary

Completed in 1999, this earth dam has a hydraulic height of 15 feet and a structural height of 15 feet, with a storage capacity of 18 acre-feet. The pond covers a surface area of 2.07 acres and serves the primary purpose of flood risk reduction in the region.

Managed by the Washington Department of Ecology, Trossachs Detention Pond Pc-3 is inspected every five years to ensure its fair condition and high hazard potential are adequately addressed. Situated offstream, the pond has a drainage area of 0.05 square miles and a maximum discharge capacity of 57 cubic feet per second. Despite its critical role in mitigating flooding in the area, the dam's spillway type, width, and other specifications are not explicitly mentioned in the data provided.

With its strategic location and efficient design, Trossachs Detention Pond Pc-3 stands as a vital infrastructure for water resource and climate enthusiasts in King County, Washington. As climate change continues to impact the region, this detention pond plays a crucial role in safeguarding the community against potential flooding events. Its regular inspections and state-regulated status ensure that it remains a reliable asset for flood risk reduction in the area.

Year Completed

1999

Dam Length

600

River Or Stream

Offstream

Primary Dam Type

Earth

Surface Area

2.07

Hydraulic Height

15

Drainage Area

0.05

Nid Storage

18

Structural Height

15

Hazard Potential

High

Nid Height

15
       
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.