“Necessity is the mother of invention” certainly rings true in the case of Shawn French’s winning 2022 Innovation Award.
Shawn, a Project Manager in CEC Pittsburgh’s Ecological Services practice, devised a solution to a fish habitat mitigation challenge at the proposed riverfront site of Nucor Steel in Apple Grove, West Virginia.
Compensatory mitigation in the form of fish habitat enhancement or replacement was required by the U.S. Army Corps of Engineers for the permanent loss of riverbed below the Ohio River’s normal pool elevation. It was up to CEC to evaluate both on-site and off-site options to mitigate Nucor’s unavoidable impacts and loss of aquatic habitat.
Nucor’s proposed facilities will occupy almost the entire property’s riverfront. These include:
- Two barge docks, inbound and outbound
- Five barge fleeting areas
- Five stormwater discharges
- One water intake
- One wastewater discharge
- And a to-be-determined number of mooring cells.
While the Army Corps required a solution to this loss of fish habitat, it had none to offer. Requests to the agency for acceptable examples of mitigation for large rivers which could be used on-site went unanswered.
While rock dike structures, root wads, and woody debris bundles are often used for habitat mitigation on smaller tributaries, successful examples or studies showing their use on larger navigable rivers with higher flows were lacking. Placing these structures between barge fleeting areas and near intakes can alter river hydraulics, resulting in increased sediment deposition and more frequent maintenance dredging, or become potential hazards if these materials migrate during high-flow events.
That’s where Shawn’s outside-the-box thinking came into play to solve this problem.
“I knew people often fish around man-made structures in rivers and streams. So why not use the mooring cells needed to secure the barges as a key component of the required fish habitat mitigation?” Shawn says.
Since only the riverward face of a mooring cell is typically used to moor barges, the back or landward side of the cell could be used to securely affix fish habitat structures. The structures will provide cover and refuge for fingerlings and smaller fish species. The fixed location and longevity of these structures also makes it much easier to monitor the effectiveness of the solution. “These habitats will be around for the long haul,” he adds.
Each fish habitat structure will be attached to the mooring cells by commercial divers after the cells are installed in the Ohio River. They will be customized according to water depth at the Nucor site.
Shawn says the fish habitat structures can be retrofitted to existing mooring cells to offset impacts from facility expansions or modifications. “It’s a simple solution. Once the mooring cells are there, they are there. This could become a standard practice. Coming up with an idea to solve this problem was a neat, a-ha moment,” he says.
The fact the client was amenable to this idea and that it was approved by the Army Corps makes it that much sweeter.
He received the Innovation Award during the 2023 Annual Planning Meeting earlier this year.