Rocky Gorge Upper

Rocky Gorge Upper is a concrete dam located in York County, Maine, built in 1900. It carries a Low hazard potential classification and has a satisfactory condition assessment.

About Rocky Gorge Upper

The primary purpose of Rocky Gorge Upper 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 Rocky Gorge Corporation (private). It impounds the Great Works River near South Berwick.

The dam stands 10 feet tall and stretches 140 feet across, creates a reservoir covering 43 acres, has a maximum storage capacity of 141 acre-feet, and collects water from a drainage area of 85 square miles. Completed in 1900, the structure is over a century old.

This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 07/30/2019.

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Low HazardSatisfactory ConditionEmergency Action Plan: Not Required

Location

StateMaine
CountyYork
Nearest CitySouth Berwick
River/StreamGreat Works River
Coordinates43.21900, -70.79690

Physical Characteristics

Dam TypeConcrete
NID Height10 ft
Dam Height10 ft
Dam Length140 ft
Year Completed1900 (126 years old)

Storage & Hydraulics

NID Storage141 acre-ft
Max Storage141 acre-ft
Normal Storage141 acre-ft
Surface Area43 acres
Drainage Area85 sq mi
Max Discharge6,600 cfs
Spillway TypeUncontrolled

Ownership & Safety

PurposeHydroelectric
OwnerRocky Gorge Corporation
Owner TypePrivate
Hazard ClassificationLow
Condition AssessmentSatisfactory
Last Inspection07/30/2019
Emergency Action PlanNot Required

Identifiers

NID IDME00391
Federal IDME00391
More InfoState Dam Safety Program

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