Lake Roslyn

Lake Roslyn is an earth dam located in Clackamas County, Oregon, built in 1959. It carries a Significant hazard potential classification.

About Lake Roslyn

The primary purpose of Lake Roslyn is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. The dam is owned by Pge (public utility). It impounds the Big And Little Sandy Rivers near Troutdale.

The dam stands 49 feet tall and stretches 8,000 feet across, creates a reservoir covering 152 acres, has a maximum storage capacity of 2,011 acre-feet, and collects water from a drainage area of 4 square miles. Completed in 1959, the structure is well into its service life at over 50 years old.

This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life.

At 49 feet, this dam is taller than 92% of dams nationwide.

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Significant HazardNot Rated ConditionEmergency Action Plan: Not Required

Location

StateOregon
CountyClackamas
Nearest CityTroutdale
River/StreamBig And Little Sandy Rivers
Coordinates45.42878, -122.24175

Physical Characteristics

Dam TypeEarth
NID Height49 ft
Dam Height45 ft
Dam Length8,000 ft
Year Completed1959 (67 years old)

Storage & Hydraulics

NID Storage2,011 acre-ft
Max Storage2,011 acre-ft
Normal Storage2,011 acre-ft
Surface Area152 acres
Drainage Area4 sq mi
Max Discharge800 cfs

Ownership & Safety

PurposeHydroelectric
OwnerPGE
Owner TypePublic Utility
Hazard ClassificationSignificant
Condition AssessmentNot Rated
Emergency Action PlanNot Required

Identifiers

NID IDOR00543
Federal IDOR00543
More InfoState Dam Safety Program

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