Alpine

Alpine is a gravity dam located in Marin County, California, built in 1917. It carries a High hazard potential classification and has a satisfactory condition assessment.

About Alpine

Alpine is a dam in Marin, California. The dam is owned by Marin Municipal Water District (public utility). It impounds the Lagunitas Creek near Point Reyes Station.

The dam stands 143 feet tall and stretches 524 feet across, creates a reservoir covering 224 acres, has a maximum storage capacity of 8,892 acre-feet, and collects water from a drainage area of 10 square miles. Completed in 1917, the structure is over a century 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 09/17/2025.

At 143 feet, this dam is taller than 99% of all dams in the United States.

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 California 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

StateCalifornia
CountyMarin
Nearest CityPoint Reyes Station
River/StreamLagunitas Creek
Coordinates37.94080, -122.63870

Physical Characteristics

Dam TypeGravity
NID Height143 ft
Dam Height143 ft
Dam Length524 ft
Year Completed1917 (109 years old)

Storage & Hydraulics

NID Storage8,892 acre-ft
Max Storage8,892 acre-ft
Surface Area224 acres
Drainage Area10 sq mi

Ownership & Safety

PurposeOther
OwnerMarin Municipal Water District
Owner TypePublic Utility
Hazard ClassificationHigh
Condition AssessmentSatisfactory
Last Inspection09/17/2025
Emergency Action PlanYes

Identifiers

NID IDCA00204
Federal IDCA00204
More InfoState Dam Safety Program

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