SHELBY – After a large amount of feedback, the Muskingum Watershed Conservancy District has introduced a flooding mitigation model for Shelby that takes dry dams off the table.
The exclusion of dry dams, officially known as regional detention basins, is only one of four scenarios being considered by Muskingum. Elected officials across Richland County will officially decide on a scenario moving forward later this year.
But the introduction of a fourth scenario with no dry dams is a small victory for property owners who have opposed the idea of the dams since the beginning – particularly members of the “Stop the Shelby Dams” Facebook group created in April 2017. It also includes those who support the grassroots Black Fork Clean-Up Project, which to-date has raised $214,645 towards its efforts.
The scenario was explained by Boris Slogar, chief engineer of the Muskingum Watershed Conservancy District (MWCD), at Monday’s meeting of Shelby City Council. Officials were forced to open the doors to council chambers to encompass the large crowd filling every seat and spilling into the hallway.
“Based on public input we’ve received so far and input from public officials, we are reviving a scenario we did look at previously, and we’ll be doing a lot more work to look at its effectiveness,” Slogar said.
The basis of the fourth scenario is a “hydraulics-only” solutions model, where “hydraulics” means the flow of water, Slogar explained. The scenario would include two means of flood mitigation – replacing and widening certain bridges to increase their capacity to handle larger flood events, and remove log jams and other debris to improve the water-carrying capacity of the river.
“We understand there is a lot of interest in clearing of the Black Fork,” Slogar said. “We also know that in certain parts of the Black Fork, particularly south of Shelby, there is a certain unwillingness to entertain detention basins. We hear that, so we are going to focus in on a hydraulics-only approach and essentially set the detention basins aside.”
However, there is a catch. If the Black Fork Subdistrict decides to adopt a hydraulics-only scenario, it would be on a “wait-and-see” matter, according to Slogar.
“There is a trigger,” Slogar said. “If a devastating flood were to occur after the hydraulic solutions were put in place, detention basins would then be resurrected and included in the plan.”
The parameters of that trigger are still under consideration, as the fourth scenario is not yet fully developed. It lies somewhere between “impossible to attain” and “too easily reached” – as Councilman Charlie Roub pointed out, the Black Fork will inevitably flood again.
The concern of Slogar is exactly that inevitability.
“We’re saying we’ve heard you and we’ll institute a plan where we’ll do all these hydraulic improvements, and if you’re right, Shelby is not going to flood,” Slogar said. “However, I still believe detention has to be part of a solution.
“There has to be some trigger where if – and our modeling indicates it will – it reaches a point where once again Shelby’s got millions of dollars in flood damage, then we’ve proven that detention basins are necessary.”
Slogar explained that detention basins installed upstream of Shelby would act as a “speed bump” to flood waters making their way downtown. Their purpose is intercepting flood waters and decreasing the flow of water downstream, and would require earthen embankments, which would in turn require the acquisition of property and/or easements.
“Under normal conditions the water flows through these earthen embankments and you’d never know they were there,” Slogar explained. “When you get a large flood event, they fill up a little bit before it throttles back slowly. That lowers the amount of water coming down through the Black Fork and helps us to achieve that goal of keeping Shelby from going under.”
The need to acquire property and/or easements in order to implement detention basins is the concern of most property owners.
“It’s not right to dam the river, and it’s not right to take away homes, property and farmland that are not yours,” said property owner Robin Bovie during council on Dec. 18 – an opinion echoed many times since. “Think of the consequences to the river, to the homeowners and the farmers.”
The involvement of the Muskingum Watershed Conservancy District dates back to 2011, when representatives from Shelby, Richland County and the Shelby Floodplain Management Commission asked the MWCD to reactive the Black Fork Subdistrict and to develop a multi-jurisdictional flood damage reduction plan.
MWCD enlisted the United States Geological Survey (USGS) to install gauges on the Black Fork River to measure how it reacts during rainfall, allowing USGS to create a model to predict how various flood reduction plans might decrease the potential for flood damage.
Since then, local officials along with community leaders, the MWCD and engineering experts have been analyzing these findings and creating scenarios to reduce flooding in the Black Fork Subdistrict.
“We are to a point where our work at the conceptual level is reaching a conclusion, and we will be asking the city later this year to render a recommendation on whether to proceed with the project,” Slogar said.
The original three scenarios developed by MWCD would create various numbers of detention basins, incorporate floodplain benching and log jam removal, and replace various numbers of bridges and culverts.
According to Slogar, depending on which of the currently four scenarios is chosen, final project costs would total anywhere from $15 to $40 million. Currently MWCD is performing an economic analysis of all four scenarios; in order for the project to proceed, the costs cannot outweigh the benefits.
Slogar also noted that estimated assessment costs, which would be used to pay for construction and ongoing maintenance of whichever flood reduction scenario is put in place, are currently being developed and would be shared with the public in the summer – the current target date is in June.
“This summer we will come back with final information on scenarios and costs, including assessment costs, and then I will be looking to you and the mayor and other elected leadership in the Black Fork Subdistrict for a decision in terms of what you’d like to do,” Slogar said.
“Keep in mind we’re here at your request; my job is to provide you with facts and data and scenarios that will meet the goal you asked us to meet,” he continued. “We will have that ready to go, and then we will await your response.”
