Coastways

Tr Ano Nuevo Creek· San Mateo, California· Built 1951· Earth· 46 ft tall
High Hazard Water Supply Irrigation Private

Key Takeaway

Coastways is classified as high hazard in California. It was completed in 1951 and is 75 years old. Its primary use is water supply. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.

Physical Details

Dam Height 46 ft (taller than 55.4% in CA)
Dam Length1,000 ft
Dam TypeEarth
Max Storage100 acre-ft
Surface Area9 acres
Drainage Area0 sq mi
Year Completed1951 (75 years old)
NID IDCA01007

Safety Information

High Hazard

Loss of human life is likely if the dam fails.

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

Emergency Action Plan: Yes
Last Inspection: April 6, 2022
State Regulated: Yes
Regulatory Agency: DWR, Division of Safety of Dams

Ownership

Coastways Ranch

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Coastways?

Coastways is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Coastways?

Coastways is owned by Coastways Ranch (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Coastways built?

Coastways was completed in 1951, making it 75 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 Coastways?

Coastways serves the following purposes: Water Supply, Irrigation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Coastways?

Coastways has a dam height of 46 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 Coastways last inspected?

Coastways was last inspected on April 6, 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.