Issaquah Highlands Falls Pond Dam

About Issaquah Highlands Falls Pond Dam

The primary purpose of Issaquah Highlands Falls Pond Dam is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Issaquah City (local government). It impounds the Offstream - E Fork Issaquah Cr near Issaquah.

The dam stands 22 feet tall and stretches 600 feet across, has a maximum storage capacity of 53 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 2008, the structure is relatively new.

This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 04/26/2018. That was 7 years ago, which is on the longer end for a high-hazard structure.

Living Downstream

If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Washington dam safety program can provide more specific information about emergency planning for this structure.

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