Seaside City

Seaside City is an earth dam located in Clatsop County, Oregon, built in 1996. It carries a High hazard potential classification and has a satisfactory condition assessment.

About Seaside City

The primary purpose of Seaside City is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by City Of Seaside (local government). It impounds the Necanicum River near Seaside.

The dam stands 45 feet tall and stretches 150 feet across, creates a reservoir covering 12 acres, has a storage capacity of 170 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1996, the structure is 30 years old.

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 10/15/2020.

At 45 feet, this dam is taller than 91% of dams nationwide.

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 Oregon dam safety program can provide more specific information about emergency planning for this structure.

Search for dams near your address to see all dams in your area with hazard classifications and safety data.

High HazardSatisfactory ConditionEmergency Action Plan: Yes

Location

StateOregon
CountyClatsop
Nearest CitySeaside
River/StreamNecanicum River
Coordinates45.95233, -123.92079

Physical Characteristics

Dam TypeEarth
NID Height45 ft
Dam Height45 ft
Dam Length150 ft
Year Completed1996 (30 years old)

Storage & Hydraulics

NID Storage170 acre-ft
Normal Storage170 acre-ft
Surface Area12 acres
Drainage Area1 sq mi
Max Discharge68 cfs

Ownership & Safety

PurposeWater Supply
OwnerCITY OF SEASIDE
Owner TypeLocal Government
Hazard ClassificationHigh
Condition AssessmentSatisfactory
Last Inspection10/15/2020
Emergency Action PlanYes

Identifiers

NID IDOR01387
Federal IDOR01387
More InfoState Dam Safety Program