Trees keep Evansville beautiful and storm water out of sewers

Part of the solution is as simple as planting trees, lots of them.

That's why the Evansville Sewer and Water Utility has partnered with the city's Tree Advisory Board to plant hundreds of trees in areas along the Lloyd Expressway and on the city's south side where sewer work is being done.

"It is a really important natural component to it," said Mike Labitzke, deputy director for engineering at the utility.

Trees naturally intercept rain, helping prevent storm water from deluging the city's combined storm and sanitary sewers.

In 2016 the city and federal government reached an agreement on a $729 million, 24-year plan to address unfiltered sewage that can spill into the Ohio River from the city's combined sanitary and storm sewers during times of heavy rain.

While it involves multiple complicated projects, planting trees is an important part of the effort too.

"A tree will catch and significantly reduce a lot of gallons of rain water," Labitzke said. "Most people don't realize the hundreds of gallons of rain water that can sit on a tree."

In fact, according to the conservation organization American Forests, on average, a mature tree can absorb 36 percent of the rainfall it comes in contact with. One large tree can capture and filter up to 36,500 gallons of water per year.

Instead of hitting the ground and running into sewers — carrying with it pollutants from pavement and ground — the water is slowly absorbed and filtered by the trees or evaporated back into the atmosphere. 

More than 200 new trees, including oaks, elms, lindens and others, were planted in areas along Expressway frontage roads Downtown, said Joe Ballard, chairman of the Evansville Tree Advisory Board.

"There were maybe only a dozen there before," said City Arborist Shawn Dickerson.

The board was created in 2000 along with the city's Department of Urban Forestry to oversee implementation of a tree ordinance aimed at improving the health of Evansville's urban tree canopy — which had long suffered from haphazard management and pruning.

Since then, at least 5,525 trees have been planted in the city compared to the removal, for various reasons, of 1,910 trees, Dickerson said. That is a nearly three-to-one ratio.

Evansville's urban canopy has been inventoried at 13,000 trees so far, Dickerson said, with several hundred more cataloged and waiting to be added to the database.

It's a relatively inexpensive proposition that relies largely on coordinated partnerships with local organizations, businesses and agencies, Dickerson said. About half are planted as part of other improvement projects.

Dickerson said the city encourages two trees to be planted for every one removed. The city also requires commercial developers to plant trees with parking lots of 30 spaces or larger.

The city maintains a nursery, stocked with trees donated by Vectren and others.

"Those are free. The only thing we have to do is grow, maintain and plant them," Dickerson said.

Tree plantings have affects beyond just ecology.

"It's a quality of life issue," said Mike McGarrah, who coordinates horticulture programs for Keep Evansville Beautiful.

Not only do trees create a positive aesthetic for city neighborhoods, McGarrah said, but planting them along entryways to the city such as First Avenue, U.S. 41, the Lloyd Expressway and Fulton Avenue also create a welcoming first impression.

"We are trying to have a positive impact on people coming into the city," McGarrah said.

Other recent examples of local tree plantings include Locust Hill Cemetery, Akin Park, the cloverleaf interchange at U.S. 41 and the Lloyd Expressway.

This spring, the city is planning on planting more trees on city streets such as Sunburst Boulevard, a relatively tree desolate stretch on the south side, as well as other locations, Dickerson said. 

"Not only do trees benefit taxpayers but they make neighborhoods more healthy and less stressful," he said. "They just make our community more pleasant."