County approves plans to improve Ditch 12

Talk about it

WORTHINGTON — As part of their lengthy agenda of items to cover Tuesday, Nobles County Commissioners did approve plans for minor alterations to be made to Nobles County Ditch 12, which flows through the city of Worthington, crosses under Interstate 90, winds around the Travelodge and passes under U.S. 59, just south of 27th Street.

The nearly $5 million construction project, which is anticipated to take place by mid-summer, will result in the closure of U.S. 59 for an extended period of time, according to Worthington City Engineer Dwayne Haffield. Perhaps most affected are those who make frequent trips between the city and the Prairie Justice Center, as well as those who need to access businesses along U.S. 59, north of 27th Street, and travelers destined for the city.

“It’s not going to be a minor closure,” Haffield said. “It’s not going to be just a quick thing.”

He said traffic coming from the north will likely be detoured on County State Aid Highway 14, then east to Minnesota 60 and south into the city limits.

“We may have to work with Worthington Township for local traffic access into Worthington,” added Nobles County Public Works Director Stephen Schnieder.

With at least another month before the city begins advertising for bids on the estimated $3.3 million project, there is ample time to work out those details.

Bill Douglass, a water resources engineer from Bolton & Menk Inc., joined Haffield and Schnieder to present the proposed changes to County Ditch 12, which are hoped to alleviate some of the flooding issues within the city limits.

Plans are to widen the ditch to 50 feet wide on the north side of the Travelodge, which will create a linear pond for water storage. An existing concrete culvert under U.S. 59 will be replaced with an 8- by 8-foot primary culvert leading to a 6- by 4-foot secondary culvert.

“We will be putting in two dry detention basins,” Douglass explained. “We’d love to put in wet ones, but they’re too close to the airport.”

Wetlands in close proximity to the airport can cause too many problems because of the potential for geese to take up residence in the ponds and impact flights arriving or leaving the airport.

The dry detention ponds include a 4.3 acre pond on the north side of the ditch and a 4.6 acre pond on the south side. The south pond will slow water coming into the ditch to alleviate increased flows downstream, Douglass said.

“It’s the city’s intention to develop this in the industrial park, so these will be designed as retention ponds,” he added.

The dry ponds will be constructed with an underdrain system that will take water away slowly.

“We want to use it as a water quality treatment (method). The water has to filter through the ground and into the underground system,” said Douglass. “It will alleviate debris clogging up the culvert and settle out the sediment so it doesn’t go into Heron Lake.”

Douglass said the project won’t solve all of the flooding problems, adding that there will still be some issues upstream to be addressed.

“This does not harm you, but it won’t alleviate your current situation,” he added. “This is the first step — you need to start downstream and correct before you can move upstream.”

Haffield said this summer’s project is the first step in implementing a long-term plan that will hopefully reduce flooding in the city.

“We started out doing flood mitigation and flood reduction,” he said. “The city has been looking at Ditch 12 as a tough problem for a long time.”

The city has received a $3.3 million TED (Transportation for Economic Development) grant to put toward the project, which was estimated at nearly $5 million. Haffield said the remaining $1.7 million would have to be covered by the city of Worthington, but added that some changes are being made to the plan to further reduce the cost of the project.

While the board approved plans for the ditch modifications, Commissioner Marv Zylstra asked Douglass that they be “sensitive to those residents upstream and how, sometimes, they’re affected.”

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