Grant would boost Edible Arboretum access, demonstrate rainwater management methods

By Bob Steenson, bsteenson@charlescitypress.com

A plan to increase access to the Clark Street Edible Arboretum would also show several examples of ways to control stormwater, reduce runoff and improve water quality — ideas that could be adopted by local homeowners and businesses.

The Charles City Council approved applying for a grant to pay for almost half of the $220,000 project, at its regular meeting this week.

The water quality initiative grant application, for $100,000, is to the Iowa Department of Agriculture and Land Stewardship (IDALS). Another $90,000 would be paid by the city through sponsored dollars from the water resource and recovery facility (WRRF) project grant.

About $10,000 or so would come from local groups such as the Izaak Walton League and Charles City Rotary Club through funds or in-kind work.

And the final $20,000 would come directly from the city, for sidewalk replacement around the park that is not eligible for grants.

Doug Johnson, the Charles City Watershed Project coordinator, discussed the project in depth at a recent Rotary Club meeting.

The project would show several ways of improving the amount of rain that is absorbed by the ground or held to evaporate, instead of running off land into the storm sewer system to eventually be discharged into a body of water.

That runoff contains soil erosion, lawn fertilizers, pesticides, waste and other contaminants that are discharged without a chance for any kind of filtering or biological degradation into something less harmful, Johnson said.

There are a lot of ways to reduce that, by managing the landscape to reduce runoff, he said.

Modern residential or commercial developments often have poor water penetration into the soil because the soil is heavily compacted during construction and development then only a thin layer of black dirt is spread on top to support the growth of turf grass.

“You end up with a soil that isn’t very good at infiltrating water. A lot of times that can be evident where you see a small rainfall and yet you still have runoff into the street,” he said.

Soil quality restoration involves aerating that soil, mixing in compost then reseeding — ideally with more native prairie species instead of the usual turf grasses, Johnson said.

About 30,000 square feet of the Edible Arboretum will have soil quality restoration.

The project would install a number of paths through the arboretum using permeable pavers, gravel surfaces and grass pavers that all allow water to go through them into the ground.

There would also be a rain garden, pollinator habitat, a bioretention cell and native turfgrass in parts of the arboretum, he said.

The Edible Arboretum is directly east of Immaculate Conception Elementary School, along Clark Street. It is in an area that was part of the federal flood management buyout.

Everything planted in the arboretum produces something edible, such as a nut or a berry or a fruit.

The committee that developed the arboretum had an idea for walkways through the area so the public could get in and immerse themselves in what’s going on there, but walkways are expensive, Johnson said.

“I saw this idea for a grant from the state and contacted my cousin, Wendy (Johnson), who was instrumental in getting a lot of the garden corridor projects started, and said, hey, this might be an opportunity to get some walkways established in there, as well as some other practices in order to meet the requirements of the grant program,” Doug Johnson said.

“We’re incorporating what we hope are a number of different kinds of urban practices that residential owners, commercial owners, industrial owners could see and experience and consider in their plans when retrofitting their existing facilities,” he said.

The project would also include signage throughout the arboretum to explain the different plant species and urban conservation practices.

City Administrator Steve Diers said the city made it through the first round of the grant and received favorable reviews, so they are hopeful it will be awarded.

Johnson said if the grant is approved, the timeline for the project would be soil restoration and new plantings next fall, then the majority of the rest of the work in the spring and summer of 2023.

Johnson said the Charles City Watershed Project, in addition to working with agricultural producers to manage runoff, is committed to doing some urban stormwater infiltration and water quality improvement practices.

“The earth is a big sponge and water quality is managed by the soil and the soil profile and the bacteria and fungi and other living organisms in the soil. So we want to try and mimic that as much as possible,” Johnson said

“We can do that with infiltration-based stormwater management practices that also have water quality benefits,” he said. “The name for this that sounds sort of cool is rainscaping. We’re going to manage the landscape to manage rainfall runoff.”

Johnson said a big part of rainscaping is using native plantings.

“They take less management. They usually don’t require hardly any pesticide or nutrient application, and you have biodiversity there, providing pollinator habitat and habitat for everything from insects to mammals,” he said.