Marina Lagoon

Belmount Slough· San Mateo, California· Built 1953· Earth· 17 ft tall
Low Hazard Flood Risk Reduction Recreation Local Government

Key Takeaway

Marina Lagoon is classified as low hazard in California. It was completed in 1953 and is 73 years old. Its primary use is flood risk reduction.

Physical Details

Dam Height 17 ft (taller than 11.1% in CA)
Dam Length350 ft
Dam TypeEarth
Max Storage1.6K acre-ft
Surface Area200 acres
Drainage Area9 sq mi
Year Completed1953 (73 years old)
NID IDCA01429

Safety Information

Low Hazard

No probable loss of human life and low economic/environmental losses expected.

Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?

Emergency Action Plan: No
Last Inspection: June 22, 2022
State Regulated: Yes
Regulatory Agency: DWR, Division of Safety of Dams

Ownership

City of San Mateo

Local Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Marina Lagoon?

Marina Lagoon is classified as Low Hazard. No probable loss of human life and low economic/environmental losses expected. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Marina Lagoon?

Marina Lagoon is owned by City of San Mateo (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Marina Lagoon built?

Marina Lagoon was completed in 1953, making it 73 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.

What is the primary purpose of Marina Lagoon?

Marina Lagoon serves the following purposes: Flood Risk Reduction, Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Marina Lagoon?

Marina Lagoon has a dam height of 17 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.

When was Marina Lagoon last inspected?

Marina Lagoon was last inspected on June 22, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.