Case

SEVENTY-SIX DRAW· Johnson, Wyoming· Built 1991· Earth· 30 ft tall
Low Hazard Irrigation Private

Key Takeaway

Case is classified as low hazard in Wyoming. It was completed in 1991 and is 35 years old. Its primary use is irrigation.

Physical Details

Dam Height 30 ft (taller than 63.1% in WY)
Dam Length880 ft
Dam TypeEarth
Max Storage349 acre-ft
Normal Storage199 acre-ft
Surface Area29 acres
Drainage Area4,820 sq mi
Max Discharge17,640 cfs
Year Completed1991 (35 years old)
Year Modified1991
NID IDWY00786

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 21, 2021
State Regulated: Yes
Regulatory Agency: SEO

Ownership

ROBINSON CANYON RANCH, LLC

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Case?

Case 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 Case?

Case is owned by ROBINSON CANYON RANCH, LLC (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Case built?

Case was completed in 1991, making it 35 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 Case?

Case 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 Case?

Case 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 Case last inspected?

Case was last inspected on June 21, 2021. 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.