Rain, rain…go away (slowly)

Heavy equipment completely reshapes the Nature Center parking lot into a bowl shape
The City brought in the heavy equipment to change the Nature Center’s parking lot from a slant into a bowl shape

If you’ve visited the Nature Center anytime since last fall, you know we’ve been in the process of revamping our parking lot. What you may NOT know is that it was a project designed to help reduce the amount of rainwater and snowmelt (and everything it carries) that runs off into Indian Creek.

A deep trench was dug down the center of the lot for the bioswale
A deep trench was dug down the center of the lot for the bioswale

The City of Cedar Rapids has worked with us to redesign the entire layout of the lot and to add a bioswale in the center.

A layer of gravel is laid into the trench
The trench gets a layer of gravel which will allow runoff water to be absorbed slowly into the ground. Notice how deep the trench is! The workers are already standing on a thick layer of gravel.

What everyone thought would be a couple-of-weeks job turned into many months (with an interruption for winter), but at long last…we’re done!

Well, mostly.  The City is going to monitor the lot to make sure we don’t have any odd settlings or ruts develop and that the water does, indeed, run into and get absorbed by the bioswale rather than running off into the creek.  Just this past weekend, a big group of volunteers joined our Land and Facilities Steward, Jean Wiedenheft, to plant the bioswale.  Jean tells us how the bioswale finally came together…

Volunteers of all ages came to help plant the bioswale
Volunteers of all ages came for the final stage – planting the bioswale

Saturday, June 18, 11:30 in the morning. Thirty one volunteers gathered in the parking lot to create one of the more intriguing human-nature interfaces: the bioswale. Bioswales use native plants to decrease rainwater runoff from hard surfaces. Sediment and other pollutants are trapped in the swale. The water, instead of eroding the parking lot surface and racing into Indian Creek, has a chance to filter downward and gradually recharge the groundwater. The thick, deep roots that native prairie plants are known for create underground stability with a solid, tangled mass of roots, to accompany the engineering of the parking lot. The surface has to slope gently toward the swale. The swale has to be deep enough and have enough air pockets to hold the rain from the entire parking lot surface.

Nature Center Land and Facilities Steward, Jean Wiedenheft, works with volunteers to plant the bioswale
Nature Center Land and Facilities Steward, Jean Wiedenheft, works with volunteers to plant the bioswale with native plants

Above ground, the 800 plants the volunteers troweled into the ground will create a natural-looking refuge. From the ruby-throated hummingbirds that will visit the penstemons to the monarch butterflies that will visit the asclepias, the natural grace and beauty of the bioswale will be the first thing that greets human visitors when they come. The parking lot, shared by the Cedar Rapids Parks Department and the Indian Creek Nature Center, is an example of how natural systems can be a key component of engineered solutions. By incorporating bioswales when hard surfaces are necessary, individuals and corporations can greatly reduce their negative impact on the watershed. This project was done in partnership with ADM Cedar Rapids Corn Processing, the Cedar Rapids Parks Department, and the Greater Cedar Rapids Community Foundation.

This was a big project that required a lot of volunteers
There was lots of work to be done to get 800+ plants into the bioswale. Photo by Roger Heidt

The Nature Center seeded annual rye throughout the swale as a cover crop, to hold the soil while the native plants establish themselves. The cover crop will gradually disappear from the site over the next few years. Plants were spaced approximately 1 foot apart, with 50 percent grasses and 50 percent forbs. Forbs include: blue flag iris, blue wild indigo, butterfly weed, Canada milkvetch, cardinal flower, compass plant, cream gentian, large-flowered beardtongue, monkeyflower, obedient plant, Ohio spiderwort, pale purple coneflower, prairie coreopsis, prairie smoke, rough blazing star, smooth blue aster, swamp milkweed, turtlehead, and white wild indigo.


Volunteers hard at work planting the bioswale
Thanks to volunteers from ADM Cedar Rapids Corn Processing and other community volunteers, our bioswale should contribute to a healthier Indian Creek.



Grasses include: big bluestem, cordgrass, little bluestem, northern sea oats, side oats grama, and switchgrass. This fall, volunteers will be interseeding blazingstar, butterfly weed, Canada wild rye, grey-headed coneflower, Indian tobacco, rattlesnake master, and slender mountain mint, many of which will be collected from established Nature Center prairies.

Visit our Facebook page (just click on the Facebook “f” at the top of this page) to see more photos of the parking lot and bioswale construction.  We encourage other businesses and individuals to take a look at their properties and see if there are ways in which they can help minimize runoff into our rivers and streams.  We’ll keep you updated on how it looks…and how it works!

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