The City of Lima selected DLZ to provide the required professional services to conduct preliminary field reconnaissance and investigations. Then, based on the investigations, prepare a Preliminary Design Report for the rehabilitation of Schoonover Lake Dam in Allen County. The report identified deficiencies with the facility and contained alternatives, recommendations, cost estimates to repair or replace any imperfections noted.
Schoonover Lake is a public recreational lake. Construction of the lake, reportedly completed in 1890 after damming and cutting off a portion of the Ottawa River. The earthen dam had an embankment height and length of 16.5 feet and 1,562 feet, respectively, and a storage capacity of 214 acre-feet. The dam’s principal spillway outlet consisted of a concrete drop-box structure with a notched weir at the upstream end. The drop-box connects to another structure in the middle of the earthen dam. Inside this structure was a steel standpipe that discharges into the Ottawa River.
Based on previous observations and inspections, DLZ had noted several deficiencies with the Schoonover Lake Dam. These included the lack of an emergency spillway and means for controlled drainage of the lake, insufficient erosion protection on the upstream and downstream slopes, excessive vegetation along the slopes (including large diameter trees), seepage along the downstream slope, and disrepair of existing appurtenant structures.
DLZ Tasks for the Schoonover Lake Dam Rehabilitation Project
DLZ provided a wide range of disciplines to accomplish the project tasks. These disciplines included survey, geotechnical engineering, structural engineering, hydraulics and hydrology, and permitting.
The preliminary investigation results indicated that the dam was inadequate to seepage, slope stability, and erosion control. The final design needed to address these deficiencies and include the installation of an emergency spillway, replacement of the existing, deteriorated principal spillway and outlet pipe, installation of a device to permit controlled draining of the lake, and removal of several existing but no longer needed appurtenant structures.
DLZ completed the final designs, plans, specifications, and quantity and costs estimates in early 2019, and scheduled to complete the construction by mid-2020.