Diamond Lake Dam (poweshiek Co) is an earth dam located in Poweshiek County, Iowa, built in 1952. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 40 ft40 ft tall and 900 ft long, taller than 86% 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 Diamond Lake Dam (poweshiek Co)
The primary purpose of Diamond Lake Dam (poweshiek Co) is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by Montezuma Water Works (local government). It impounds the Tr-moon Creek near Spring Valley.
The dam stands 40 feet tall and stretches 900 feet across, creates a reservoir covering 93 acres, has a maximum storage capacity of 1,100 acre-feet, and collects water from a drainage area of 4 square miles. Completed in 1952, the structure is well into its service life at over 50 years old.
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. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 08/23/2022.
At 40 feet, this dam is taller than 86% of dams nationwide.
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Location
| State | Iowa |
| County | Poweshiek |
| Nearest City | Spring Valley |
| River/Stream | Tr-moon Creek |
| Coordinates | 41.58340, -92.55780 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 40 ft |
| Dam Height | 40 ft |
| Dam Length | 900 ft |
| Year Completed | 1952 (74 years old) |
Storage & Hydraulics
| NID Storage | 1,100 acre-ft |
| Max Storage | 1,100 acre-ft |
| Normal Storage | 780 acre-ft |
| Surface Area | 93 acres |
| Drainage Area | 4 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Montezuma Water Works |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 08/23/2022 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | IA01368 |
| Federal ID | IA01368 |
| More Info | State Dam Safety Program |