Copley Township, Summit County, Ohio
- Summit County Engineer
- Key Services Provided:
- Site Assessment & Survey
- Watershed Delineation
- Hydrologic Modeling
- Hydraulic 1D/2D Modeling, Existing & Proposed Conditions
- Final Design
- Property Acquisition & Easements
- Opinion of Probable Construction Costs
- Permits & Regulatory Compliance
- Project Duration: 2022 to Present (expected completion 2026)
- Project Cost: $492,000
Hydrologic & Hydraulic 1D/2D Model Development for Copley Ditch Drainage Basin: (a) land use, (b) curve number, (c) HMS Model schematic, (d) HEC-RAS 1D/2D depth results for 100-year event.
EnviroScience, Inc. completed initial site assessment and developed preliminary ditch restoration and bankfull wetland concept designs on behalf of the Summit County Engineer’s Office (SCEO). The Copley Ditch and Black Pond Outlet project consists of a 1,500-acre drainage basin, 16,000 linear feet of petition ditches, and twelve major crossings. The topography and soil conditions of the region make this area prone to poor drainage and flooding, as the area was a large wetland historically. Development pressures from roads, small farms, homes, and infrastructure resulted in systematic stream ditching, causing significant disruption to the natural stream, floodplain, and wetland system. The SCEO tasked EnviroScience with applying a holistic approach to develop sustainable stormwater solutions by integrating all site elements to reduce flooding potential, achieve systemic recovery, and improve water quality.
EnviroScience devised a survey plan and coordinated with subcontractors to obtain high-resolution aerial maps through photogrammetry and traditional survey. EnviroScience processed all data to develop an existing conditions base model. EnviroScience then proposed preliminary improvement concepts to reduce flooding potential through floodplain expansion and hydraulically efficient design practices. To evaluate the concepts, EnviroScience performed rainfall-runoff analysis for the 1,500-acre drainage basin to calculate peak flows using HEC-HMS. HEC-RAS was used to develop water surface profiles for the 1- through 500-year flood events using 1D and 2D approaches. Inundation and depth mapping were performed for existing conditions to identify at-risk structures, choke points, flood hazards, and potential for roadway overtopping and undersized culverts. Proposed conditions were then modeled to evaluate the hydraulic feasibility of the designs and quantify floodplain improvements, including reductions in water surface elevations.
Immediate benefits identified by H&H modeling of the proposed improvements include additional stormwater capacity for lower-frequency storms, improved water quality through natural filtration and settling within the flood-prone and wetland areas, and improved stream function, meaning better sediment transport to help alleviate sediment buildup. The SCEO used the study results to successfully obtain funding for improvements through the American Rescue Plan Act.
Upon completion of the Copley Ditch and Black Pond Outlet Study, EnviroScience was selected by SCEO to evaluate the additional study area of Copley Meadows, then proceeded to final design for the Copley Ditch and Copley Meadows project areas. In addition to the H&H modeling and watershed study, the final design tasks included development of construction plans with specifications and details for two-stage ditch improvements, wetland creation, flood-prone bench expansions, reconnection to existing wetlands through levee removal, native plantings, and sediment and erosion control BMPs. EnviroScience also generated an opinion of probable construction cost, presented at public stakeholder meetings, and will assist SCEO with the bidding process. EnviroScience is currently coordinating with FEMA to obtain a CLOMR for the project and will also complete a LOMR upon construction completion.
