Lower Rock Lake

Lower Rock Lake is an earth dam located in Nevada County, California, built in 1855. It carries a Low hazard potential classification and has a satisfactory condition assessment.

About Lower Rock Lake

The primary purpose of Lower Rock Lake 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 Pacific Gas And Electric Company (private). It impounds the Texas Creek.

The dam stands 11 feet tall and stretches 110 feet across, creates a reservoir covering 8 acres, has a maximum storage capacity of 48 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1855, the structure is one of the older dams in the region, with over a century and a half of service.

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 08/12/2019.

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Low HazardSatisfactory ConditionEmergency Action Plan: Not Required

Location

StateCalifornia
CountyNevada
Nearest CityNone
River/StreamTexas Creek
Coordinates39.42850, -120.62280

Physical Characteristics

Dam TypeEarth
NID Height11 ft
Dam Height10 ft
Dam Length110 ft
Year Completed1855 (171 years old)

Storage & Hydraulics

NID Storage50 acre-ft
Max Storage48 acre-ft
Normal Storage50 acre-ft
Surface Area8 acres
Drainage Area0 sq mi
Max Discharge33 cfs
Spillway TypeUncontrolled

Ownership & Safety

PurposeHydroelectric
OwnerPacific Gas and Electric Company
Owner TypePrivate
Hazard ClassificationLow
Condition AssessmentSatisfactory
Last Inspection08/12/2019
Emergency Action PlanNot Required

Identifiers

NID IDCA10428
Federal IDCA10428
More InfoState Dam Safety Program

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