Johnston Dam is an earth dam located in Jasper County, Iowa, built in 2005. It carries a Significant hazard potential classification.
Dam profile
NID height · 30 ft30 ft tall and 527 ft long, taller than 68% of U.S. dams with a recorded height. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Johnston Dam
The primary purpose of Johnston Dam is fire protection, stock, or small fish pond. The dam maintains a small impoundment used for fire suppression, livestock watering, or as a fish pond. The dam is owned by James E Johnston (private). It impounds the Tr-turner Creek near Lynnville.
The dam stands 30 feet tall and stretches 527 feet across, creates a reservoir covering 10 acres, has a maximum storage capacity of 193 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 2005, the structure is relatively new.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life.
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Location
| State | Iowa |
| County | Jasper |
| Nearest City | Lynnville |
| River/Stream | Tr-turner Creek |
| Coordinates | 41.69620, -92.80280 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 30 ft |
| Dam Height | 30 ft |
| Dam Length | 527 ft |
| Year Completed | 2005 (21 years old) |
Storage & Hydraulics
| NID Storage | 193 acre-ft |
| Max Storage | 193 acre-ft |
| Normal Storage | 81 acre-ft |
| Surface Area | 10 acres |
| Drainage Area | 0 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Fire Protection, Stock, Or Small Fish Pond |
| Owner | James E Johnston |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | IA03692 |
| Federal ID | IA03692 |
| More Info | State Dam Safety Program |