Work to cut down on flooding near the intersection of Seventh Street and Illinois Avenue in Joplin has begun.

A regional detention pond is being built along Murphy Boulevard south of 15th Street. It is one of the stormwater drainage projects tied to voter approval in 2011 of renewal of the quarter-cent parks and stormwater sales tax, but city officials say they now have another option to pay for the work.

Crews will install a drainage system that will ease the accumulation of rainwater in the parkway area and help reduce flooding in the area of Seventh Street and Illinois Avenue, said Dan Johnson, a civil engineer for the Public Works Department.

While it will reduce the impact of flooding, it will not completely eliminate the threat, Johnson said.

The pond will hold water only during wet weather and not year-round, Johnson said.

“That is Joplin Creek that flows through the park, and it will continue unimpeded,” he said. “In heavy rain, water backed up in that area. What we have done is to improve on that existing condition and make it work for us as a regional detention pond.”

Johnson said the city staff considered making the pond a water feature for the area but added, “There were a lot of challenges and concerns.”

The added weight from the water could potentially have cracked the underlying rock, which Johnson said could have been rendered unstable because there are mining caverns beneath the area.

“In the end, we felt like our safest, most efficient solution was using it as in our original plan,” he said.

While there are deed restrictions that do not permit the city to develop the land, Johnson said the covenants do allow the city to do stormwater, sewer line and other types of necessary projects on the property.

Because the site is within the damage zone of the 2011 tornado, the project was made part of the city’s tornado recovery plan, and funding for it is to come from the state’s $14 million special allocation to aid Joplin in repairing and replacing infrastructure in the tornado zone. That will free up city sales tax revenue for other work.

A number of trees in the area that were weakened or damaged by the 2011 tornado have been cut down. Johnson said the city staff was told by an arborist that even though the trees had some leaves, they likely would have died soon from storm damage that left them weak and susceptible to disease and pests.

“The excavation and dirt work will be completed in the summer, with a temporary hot weather grass being planted to control erosion,” Johnson said. “In the fall, the contractor will return to the site and plant groups of trees to replace those damaged by the tornado and by the construction. Also, the hot weather grass will be replaced with a mixture of native grasses with wildflowers.”

Project cost

SNYDER CONSTRUCTION CO. won the contract to do the flood control project along Murphy Boulevard south of 15th Street. The bid was $804,605. Engineering, design and related costs will add about $100,000 to the cost.