Capitol Lake Dam

HILGERS GULCH· Hughes, South Dakota· Built 1921· Earth· 27 ft tall
High Hazard Recreation State Government

Key Takeaway

Capitol Lake Dam is classified as high hazard in South Dakota. It was completed in 1921 and is 105 years old. Its primary use is recreation. 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 27 ft (taller than 71.8% in SD)
Dam Length600 ft
Dam TypeEarth
Max Storage127 acre-ft
Normal Storage65 acre-ft
Surface Area6 acres
Drainage Area6 sq mi
Max Discharge2,200 cfs
Year Completed1921 (105 years old)
NID IDSD02209

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: July 27, 2022
State Regulated: Yes
Regulatory Agency: DANR

Ownership

S&PL

State Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Capitol Lake Dam?

Capitol 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 Capitol Lake Dam?

Capitol Lake Dam is owned by S&PL (State Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Capitol Lake Dam built?

Capitol Lake Dam was completed in 1921, making it 105 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 Capitol Lake Dam?

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

How tall is Capitol Lake Dam?

Capitol Lake Dam has a dam height of 27 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 Capitol Lake Dam last inspected?

Capitol Lake Dam was last inspected on July 27, 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.