Removal of the Ponderosa Lake Dam
The division used its emergency authority to protect public safety from a failing dam by lowering the dam at Ponderosa Park Resort, located 5 miles southeast of Canfield in Mahoning County. Division officials informed Ponderosa Park Resort’s owners, on many occasions, of deficiencies at the 21-foot-high earthen dam, but the owners chose not to comply with the inspection report requirements, warnings, and orders, which resulted in the emergency action.
An inspection of the dam in April 2010 revealed that the dam had significant erosion and slippage, in addition to seepage and potential stability problems with the deteriorated masonry spillway. State Route 45 is below the dam and a catastrophic failure of the dam could have significantly damaged the roadway, putting motorists at risk. Ohio EPA also shared concerns that polluted sediment had accumulated behind the dam and failure could send a significant amount of the sediment into Meander Creek, harming aquatic life in and along the creek.
Dam Safety developed an engineering plan to breach the dam then hired a contractor to lower the masonry spillway to the point where less than 3 feet of water would be impounded, but most of the sediment will remain behind the dam. In addition to removing the hazard of the dam, the work resulted in the creation of a wetland, which benefits the watershed.
The project took about two weeks to complete. Some of the project costs were covered by a Surface Water Improvement Fund grant from Ohio EPA. ODNR is in the process of seeking restitution for all state funds expended from the owners of Ponderosa Park Resort.
Several Mahoning County agencies assisted the division in responding to this emergency situation, including the county’s Emergency Management Agency, Health Department, and Soil and Water Conservation District.
Breaching Proccess and Dam Condition
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1. Overview of the dam and the masonry spillway. Note the overgrown condition of the earthen dam in background.
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2. The masonry spillway and slide adjacent to the left end of the principal spillway on the downstream slope.
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3. Close-up view of the slide adjacent to the left end of the principal spillway. Seepage is exiting the embankment in the slide.
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4. Construction of the controlled breach by removing a portion of the masonry spillway.
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5. Further breach construction.
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6. Construction of a check dam in the former lakebed.
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7. Completed breach section.
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8. Former lakebed looking downstream
toward the breached spillway following completion of construction.
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9. Former lakebed looking upstream.
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