Graymont Sludge Lagoons

Graymont Sludge Lagoons is an earth dam located in Ottawa County, Ohio, built in 1981. It carries a Significant hazard potential classification and has a fair condition assessment.

About Graymont Sludge Lagoons

The primary purpose of Graymont Sludge Lagoons is tailings. Tailings dams contain waste material from mining operations — typically a slurry of finely ground rock left over after valuable minerals have been extracted. These structures require ongoing monitoring because tailings can contain heavy metals and other contaminants. The dam is owned by Graymont Dolime (oh) Inc. It impounds the Toussaint Creek near Genoa.

The dam stands 18 feet tall and stretches 7,083 feet across, creates a reservoir covering 53 acres, has a maximum storage capacity of 934 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1981, the structure is 45 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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 10/10/2024.

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Significant HazardFair ConditionEmergency Action Plan: Yes

Location

StateOhio
CountyOttawa
Nearest CityGenoa
River/StreamToussaint Creek
Coordinates41.51333, -83.34667

Physical Characteristics

Dam TypeEarth
NID Height18 ft
Dam Height18 ft
Dam Length7,083 ft
Year Completed1981 (45 years old)

Storage & Hydraulics

NID Storage934 acre-ft
Max Storage934 acre-ft
Normal Storage772 acre-ft
Surface Area53 acres
Drainage Area0 sq mi

Ownership & Safety

PurposeTailings
OwnerGraymont Dolime (OH) Inc
Owner TypeNot Listed
Hazard ClassificationSignificant
Condition AssessmentFair
Last Inspection10/10/2024
Emergency Action PlanYes

Identifiers

NID IDOH02980
Federal IDOH02980
More InfoState Dam Safety Program

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