Case
Case is an earth dam located in Johnson County, Wyoming, built in 1991. It carries a Low hazard potential classification and has a poor condition assessment.
About Case
The primary purpose of Case is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Robinson Canyon Ranch, Llc (private). It impounds the Seventy-six Draw near Arvada.
The dam stands 35 feet tall and stretches 880 feet across, creates a reservoir covering 29 acres, has a maximum storage capacity of 349 acre-feet, and collects water from a drainage area of 4,820 square miles. Completed in 1991, the structure is 35 years old.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. The most recent inspection on record was 06/21/2021.
At 35 feet, this dam is taller than 82% of dams nationwide.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Wyoming |
| County | Johnson |
| Nearest City | Arvada |
| River/Stream | Seventy-six Draw |
| Coordinates | 44.03460, -106.73450 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 35 ft |
| Dam Height | 30 ft |
| Dam Length | 880 ft |
| Year Completed | 1991 (35 years old) |
Storage & Hydraulics
| NID Storage | 349 acre-ft |
| Max Storage | 349 acre-ft |
| Normal Storage | 199 acre-ft |
| Surface Area | 29 acres |
| Drainage Area | 4,820 sq mi |
| Max Discharge | 17,640 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | ROBINSON CANYON RANCH, LLC |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Poor |
| Last Inspection | 06/21/2021 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | WY00786 |
| Federal ID | WY00786 |
| More Info | State Dam Safety Program |