Johnson No. 1

HANCOCK DRAW· Niobrara, Wyoming· Built 1916· Earth· 30 ft tall
Low Hazard Irrigation Private

Key Takeaway

Johnson No. 1 is classified as low hazard in Wyoming. It was completed in 1916 and is 110 years old. Its primary use is irrigation.

Physical Details

Dam Height 30 ft (taller than 63.1% in WY)
Dam Length460 ft
Dam TypeEarth
Max Storage333 acre-ft
Normal Storage239 acre-ft
Surface Area40 acres
Drainage Area0 sq mi
Max Discharge0 cfs
Year Completed1916 (110 years old)
NID IDWY00933

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: August 29, 2022
State Regulated: Yes
Regulatory Agency: SEO

Ownership

CROSS A RANCH LLC

Private

Nearby Dams

Paddy No. 1

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Paddy No. 2

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Low Hazard 25 ft

East No. 1 Beardsley

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Low Hazard 29 ft

Beardsley No. 1

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Low Hazard 27 ft

Walker

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Low Hazard 21 ft

Johnson #3

Niobrara, WY

Low Hazard 22 ft

Dogie No. 3

Niobrara, WY

Low Hazard 21 ft

Brenner

Niobrara, WY

Low Hazard 27 ft

Frequently Asked Questions

What is the hazard classification of Johnson No. 1?

Johnson No. 1 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 Johnson No. 1?

Johnson No. 1 is owned by CROSS A RANCH LLC (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Johnson No. 1 built?

Johnson No. 1 was completed in 1916, making it 110 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 Johnson No. 1?

Johnson No. 1 serves the following purposes: Irrigation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Johnson No. 1?

Johnson No. 1 has a dam height of 30 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 Johnson No. 1 last inspected?

Johnson No. 1 was last inspected on August 29, 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.