Abstract Description: The Loecy Pond Dam is located along Industrial Parkway in Chardon, about 30 miles east of Cleveland in Geauga County, Ohio on property with multiple property owners along the dam structure. There is also a City street along the crest of the dam, an old railroad embankment along the downstream slope, and a bike trail at the toe of the dam. The Loecy Pond Dam is considered a Class I Dam by the Ohio Department of Natural Resources (ODNR), Division of Water Resources, Dam Safety. ODNR Dam Safety had identified several deficiencies as reported in their 2016 inspection report. The property owners worked together and decided to pursue investigations to confirm the classification of the dam, repair options, and identify all stakeholders. The dam owners set up an escrow account to deposit funds into for engineering support.
Verdantas performed a topographic survey, dam assessment, spillway integrity investigation, and hydrologic & hydraulic study with a downstream hazard analysis. The upstream drainage area and potential detention structures were also studied. Based on the results of the analyses, the dam remained a high hazard structure. The principal spillway consisted of a rectangular concrete riser with a 30” RCP connected to an old, stone viaduct beneath the original railroad right-of-way. The dam also could not safely pass the design storm without overtopping.
Verdantas performed an alternatives analysis with estimated costs comparisons. The alternative selected by the owners consisted of raising the dam, lowering the normal pool level, and replacing the spillway pipe. In order to minimize costs and impacts to the city street on top of the dam, the dam raising was accomplished by a vertical extension of the concrete curb along the upstream crest. New inlets were constructed in the sides of the spillway riser to control the pool level. Instead of a full spillway pipe replacement, which would have required open-cutting the embankment and roadway, a partial slip-lining was proposed. The spillway repair included removal of the top and sides of the stone viaduct, and slip-lining the RCP with a 24” diameter HDPE pipe. As part of the design and construction, the lake drain valve was also replaced and the dam embankment was re-graded.
We present the engineering approach used by the team for the study, alternatives analysis and design.
Learning Objectives:
Learn how to collaborate with multiple dam owners.
Demonstrate alternative methods for dam improvements to bring structures into compliance.
Learn about the effects of downstream developments on re-classifications of dams.
