Lylah Marsh Dam is an earth dam located in Howard County, Iowa, built in 1960. It carries a Low hazard potential classification.
Dam profile
NID height · 11 ft11 ft tall and 932 ft long. 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 Lylah Marsh Dam
The primary purpose of Lylah Marsh Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Howard County Conservation Board (local government). It impounds the Little Wapsipinicon River near Elma.
The dam stands 11 feet tall and stretches 932 feet across, creates a reservoir covering 52 acres, has a maximum storage capacity of 358 acre-feet, and collects water from a drainage area of 21 square miles. Completed in 1960, the structure is well into its service life at over 50 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. The most recent inspection on record was 12/30/1965. That was over 60 years ago.
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Location
| State | Iowa |
| County | Howard |
| Nearest City | Elma |
| River/Stream | Little Wapsipinicon River |
| Coordinates | 43.28460, -92.47010 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 11 ft |
| Dam Height | 11 ft |
| Dam Length | 932 ft |
| Year Completed | 1960 (66 years old) |
Storage & Hydraulics
| NID Storage | 358 acre-ft |
| Max Storage | 358 acre-ft |
| Normal Storage | 158 acre-ft |
| Surface Area | 52 acres |
| Drainage Area | 21 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Howard County Conservation Board |
| Owner Type | Local Government |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 12/30/1965 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | IA00496 |
| Federal ID | IA00496 |
| More Info | State Dam Safety Program |