Johnson Dam
Johnson Dam is an earth dam located in Montgomery County, Iowa, built in 2024. It carries a Low hazard potential classification.
About Johnson Dam
The primary purpose of Johnson Dam is grade stabilization. Grade stabilization dams prevent erosion by reducing the slope and velocity of water flowing through a channel. They're commonly used to stop gullies from deepening and to protect downstream land and infrastructure. The dam is owned by Carl Tim & Richard Johnson (private). It impounds the Unnamed Trib To Tarkio River near Coin.
The dam stands 31 feet tall and stretches 420 feet across, creates a reservoir covering 3 acres, has a maximum storage capacity of 59 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 2024, the structure is relatively new.
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.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Iowa |
| County | Montgomery |
| Nearest City | Coin |
| River/Stream | Unnamed Trib To Tarkio River |
| Coordinates | 40.93290, -95.13820 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 31 ft |
| Dam Height | 31 ft |
| Dam Length | 420 ft |
| Year Completed | 2024 (2 years old) |
Storage & Hydraulics
| NID Storage | 59 acre-ft |
| Max Storage | 59 acre-ft |
| Normal Storage | 16 acre-ft |
| Surface Area | 3 acres |
| Drainage Area | 0 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Grade Stabilization |
| Owner | Carl Tim & Richard Johnson |
| Owner Type | Private |
| Hazard Classification | Low |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | IA04459 |
| Federal ID | IA04459 |
| More Info | State Dam Safety Program |