Trees around Gahanna's Giant Eagle could be removed to protect residents from flooding.

Trees around Gahanna's Giant Eagle could be removed to protect residents from flooding.

The Gahanna Planning Commission on Aug. 24 unanimously approved a variance to allow a detention basin to be expanded on dedicated parkland for Giant Eagle and the Shagbark subdivision. The favorable recommendation will be forwarded to Gahanna City Council.

Commission members said they hate to lose mature trees to expand the detention basin, but it's necessary to protect residents from flooding problems along McKenna Creek. Legislation passed in 2001 allowed the use of an existing natural basin on dedicated parkland from the Shagbark condominium project for stormwater detention for Giant Eagle, planning and zoning administrator Bonnie Gard said.

When the parkland dedication code was revised in 2009, the basin became nonconforming. The change necessitated a variance for the proposed basin expansion.

Commission member Dave Andrews said he regrets losing mature trees to expand the basin, but he has to consider being a good neighbor.

"I'm still mixed up on the emotions of it," he said.

Commission member David Thom doesn't believe stormwater solutions are high on Columbus' priority list.

"If we don't do anything, we'll experience erosion, and it will get worse," he said. "I do hate to see the loss of trees, but we have to see to the health and welfare of other citizens. The solution outweighs the loss of trees."

Sanctuary Place resident Tom Widney said he opposes the variance.

Affected residents have expressed a common desire to stop erosion along the creek, but the basin wouldn't help that problem, he said.

"The city has a land-use plan that says preservation of a wooded area is a priority," Widney said, adding that more effective alternatives are available at lower costs.

Louis Houser, treasurer of the 118-unit Woods at Shagbark Association, said he supports the variance. He also favored Gahanna parks and recreation director Tony Collins' recommendation for a small walking path along the edge of the basin, as well as wildflower or rain-garden plantings. The proposal would improve the health and safety of the neighborhood and reduce the water flow that has caused problems for residents, Houser said.

According to Academy Acres resident Windy McKenna, flooding issues began after the development of the Hamilton and Morse corridor.

"Most of us have had to take drastic measures," McKenna said. "My husband and I sandbagged to keep from losing more of our land. When the water comes though, it comes with such force that it takes everything in its path."

She pleaded with the commission to help her and others along the creek "before someone loses their basement walls and backyards."

City engineer Karl Wetherholt said the expanded basin is a dry one that would occupy about three-fourths of the city's 2.443-acre parcel, with the rim of the existing basin suitable for a walking path.

The basin would divert high flows from the creek into the basin, where water would be detained for several hours, he said.

"It's not an ideal solution, but it aids with flooding for downstream people," Wetherholt said. "It's something we can do immediately and get results."

Scott Sonnenberg, a civil engineer specializing in stormwater-management planning, has worked with some Shagbark residents concerning the flooding and erosion issues.

He agreed that the proposed basin would reduce peak flows and flooding downstream but warned that it likely would cause more erosion.

Sonnenberg offered six alternative projects to the basin, such as increasing stormwater storage volume at the Meijer basin and modifying storm drainage in the Kohl's parking lot. Most of those solutions, however, were in Columbus' corporation limits. Wetherholt said the ideal solution is to go upstream to address stormwater management, but Gahanna doesn't own those properties, and incentives would need to be offered.

Gahanna is committed to working with Columbus, he said, and with upstream property owners in devising additional solutions.