By DENISE GRANT
New flood-control plans for the Blanchard River at Findlay look radically different than those proposed by the U.S. Army Corps of Engineers.
During a public meeting Wednesday attended by about 300 people, Stantec, the engineering firm hired by the Hancock County commissioners to evaluate the corps’ plan, said it did not recommend the corps’ proposed Eagle Creek diversion channel.
Instead, Stantec recommended improving the river channel as it flows through Findlay, and building dams upstream of Findlay to create large “dry storage” basins along the Blanchard River, along Eagle Creek, and along a tributary of the river known as Potato Run, just south of Mount Blanchard.
In all, the Stantec plan would cost an estimated $160 million, twice the cost of the Army Corps’ proposal.
Altogether, the changes could drop the Blanchard River’s level by 3.6 feet on Main Street during a 100-year flood, according to Stantec.
The commissioners contracted with Stantec, a Canadian-based engineering firm, to take charge of the flood-control study last July. The firm employs a workforce of about 300 in Ohio, with offices in Toledo, Columbus, Cincinnati and Cleveland.
Improving the river channel through Findlay would cost about $20 million, Stantec said.
The bulk of that expense, about $18.8 million, would be spent to cut “benches” into the river’s banks, and to widen the supports of the Norfolk Southern railroad bridge as it crosses the river.
The benches would widen the river and increase its capacity. The corps considered that option, too, but abandoned the idea due to the possibility of hazardous waste at the old Brandman Corp. tire dump off Cory Street.
Scott Peyton, project manager and senior principal engineer with Stantec, said Wednesday that contaminated waste at the Brandman site is minimal, and would need to be removed and disposed of properly.
The Army Corps also ruled out the idea of modifying the railroad bridge as too expensive.
However, Stantec said the railroad is interested in replacing the bridge, which is about 90 years old.
Peyton called the bridge a “pinch point” in the river.
It would cost an additional $1 million to remove four low dams from the river that were installed in the early 1900s, when the river was straightened. The dams were meant to pool water for aesthetics. The dam at Riverside Park would be spared.
Peyton said there are ways to design the channel to avoid having the Blanchard River reduced to a dry riverbed in the summer.
The channel improvements in Findlay would be enough to drop the floodwater level in the city by nearly a foot, matching the benefit of the corps’ proposed $80 million, 9.4-mile Eagle Creek diversion channel, according to Stantec.
In its review of the corps’ recommendation, which was made in August 2015, Peyton said Stantec found an error that reduced the benefit of the diversion channel drastically.
The corps claimed its plan would reduce the floodwater level in downtown Findlay by 4.6 feet during a 100-year flood. Based on Stantec’s findings, the diversion channel would have reduced flooding in downtown Findlay by less than 1 foot.
Asked about the discrepancy, Peyton said, the corps blamed the mistake on an error in its computer modeling.
Also, while the corps said the diversion channel would be built to accommodate flooding at a 100-year level, Stantec said the channel, as proposed, would only handle about 25 percent of that amount of water.
Stantec said the recommended work to improve the river channel through Findlay may be able to proceed very quickly.
The proposed water storage basins, however, would take longer. The basins would cost about $140 million to construct. It could take several years before that work could begin, officials said Wednesday.
Public hearings about the Stantec proposals will be held this spring.
A web page has been created to provide additional information about the project at www.hancockcountyflooding.com.
While Stantec is recommending modifications to the river channel and railroad bridge, along with the dry basins, it will be up to the Maumee Watershed Conservancy District in Defiance to wade through all the options and decide which projects to pursue.
Peyton said the Eagle Creek diversion channel is still considered an option, but said it should be about 100 feet wider. Stantec would also shorten the channel, and remove a culvert meant to carry water from Aurand Run over the channel. These modifications would increase the cost of the diversion channel to about $106 million.
Another way to provide more floodwater control would be to extend the diversion channel from Eagle Creek east to the Blanchard River, an option that will be delivered to the conservancy district. However, Peyton said, the extension would be very expensive: about $88 million. And, it would have to be coupled with the western diversion channel, for a total cost of about $194 million.
Another alternative would be to modify the river, and build only the Eagle Creek dry storage basin for a cost of about $90 million.
A 4-mile dam would contain floodwater from Eagle Creek in the basin during a flood.
During a high-water event, the basin would release a controlled amount of water down the creek and Aurand Run. During a 100-year flood, about 1,000 acres would be inundated with water.
The proposed Potato Run dry storage basin, and a separate Blanchard River dry storage basin, would both be south of Mount Blanchard.
Dams on the two waterways would cause water to back up during floods.
Backed-up water on Potato Run would be close to Riverdale School, according to maps provided by Stantec.
It still must be decided whether land for the basins would be bought, leased, or easements sought. During dry times, the land could still be farmed or used as parks or wildlife areas.
Peyton said it will be up to the community to decide the best options.
Data studied by Stantec shows that since the severe flood of August 2007, Findlay has endured greater and more frequent flooding that at any time since the last great flood in 1913, the worst on record. The 2007 flood was a very close second.
Since 2000, the city has flooded 14 times, and six of those floods were above the major flood stage of 13.5 feet. The floods of 1913 and 2007 were both measured at about 18.5 feet, with both being considered a little greater than a 100-year event. A 100-year flood has a 1 percent chance of occurring in any given year.
Peyton said climate change, plus changes in farming practices and land use, most likely all are contributing to the flooding. Whatever the cause, he said the trend toward greater flooding makes finding a solution more of an imperative.
Stantec’s focus was narrow: lower the level of a 100-year flood at Findlay’s Main Street and other major routes, to permit the passage of emergency response vehicles.
“Solving the flooding problem is not easy for this community, otherwise it would have been resolved a long time ago,” Peyton said.
Peyton said Stantec’s recommendation provides increased control of floodwater throughout the watershed, not just Eagle Creek. The creek accounts for only about 15 percent of the entire watershed, he said.
“If the rainfall doesn’t fall over Eagle Creek, then the diversion channel wouldn’t help at all,” he said.
Peyton said the flood of 2007 was most likely a 500-year, or even a 1,000-year flood for Eagle Creek.
He said the modifications to the Blanchard River at Findlay will help the city weather any flood event, no matter where the water comes from, or at what level.
The Hancock County commissioners voted in June to take local control of the flood plan and seek outside engineers, after learning that an Army Corps of Engineers internal review of its flood plan found problems.
Corps reviewers decided the estimated cost of the proposed diversion channel on Findlay’s west side, which had been set at $60.5 million, was too low, and increased the estimate to $80 million. The added expense reduced the benefit-to-cost ratio of the project to the point that the corps no longer considered the plan economically feasible.
The benefit-to-cost ratio of the diversion channel was less than $1.
Peyton said Stantec is confident that its recommendation will have a ratio above $1, as required for consideration by the Maumee Watershed Conservancy District.
In September, the commissioners and the conservancy district voted to approve an agreement that puts the conservancy district in charge of the day-to-day management of the flood plan.
The conservancy district, which represents 15 counties, is the second-largest in Ohio, according to the Ohio Department of Natural Resources. The district was established in 1949 and has primarily overseen flood-control measures and improved drainage for the Auglaize River basin.
Under the agreement, the commissioners keep control of the county’s $18 million flood fund.
The commissioners set aside about $2.5 million a year for flood mitigation from a half-percent, 10-year sales tax increase approved by city and county voters in 2009. Half of the tax is used for flood control, the other half for county operations.