Square Lake Dam

Prospect Creek· Chelan, Washington· Built 1938· Rockfill·
High Hazard Irrigation Recreation Public Utility

Key Takeaway

Square Lake Dam is classified as high hazard in Washington. It was completed in 1938 and is 88 years old. Its primary use is irrigation. 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 Length104 ft
Dam TypeRockfill
Max Storage913 acre-ft
Normal Storage674 acre-ft
Surface Area500 acres
Drainage Area1 sq mi
Max Discharge0 cfs
Year Completed1938 (88 years old)
NID IDWA00224

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: November 3, 2022
State Regulated: Yes
Regulatory Agency: Washington Dept of Ecology

Ownership

Icicle & Peshastin Irrigation District

Public Utility

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Square Lake Dam?

Square Lake Dam 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 Square Lake Dam?

Square Lake Dam is owned by Icicle & Peshastin Irrigation District (Public Utility). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Square Lake Dam built?

Square Lake Dam was completed in 1938, making it 88 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 Square Lake Dam?

Square Lake Dam serves the following purposes: Irrigation, Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

When was Square Lake Dam last inspected?

Square Lake Dam was last inspected on November 3, 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.