Iowa City Parks

Waterworks Prairie Park

by Paul Schmitt

“We all contain water in about the same ratio as Earth does, and salt water in the same ratio that the oceans do. We are poems about the hyperobject Earth.”

– Timothy Morton, Hyperobjects

General History

Listen to the Audio Tour on General History

After more than a decade of deliberation and planning, Iowa City opened the water treatment plant at this site in March 2003, to replace a plant that had operated downtown since 1882 and was found ineffective in the late 1980s. The site here was chosen because of its capacity to use water both from aquifers deep in the ground and close to the surface, the latter of which draws in water from the Iowa River, naturally filtered through the earth. Choosing a site was a long process as the city sought a balance between water quality, efficient land use, and public opinion.

Because of the costs involved with the construction of a new treatment plant, water rates rose sharply in 1991, and again from 1995 through 2000. As a result, families and individuals (such as students at the University of Iowa) living on low incomes feared difficulty in paying more for water.

The project to construct a public park on the premises was approved by the city council in February 2002, drawing concern from members of the public as to whether the revenue from the increased water rates, which was meant to cover only the treatment plant, would be used in the park’s construction. Although the park was initially budgeted on general operation funds, water revenue funds were eventually used for some aspects of the park that intertwined with treatment plant functions, such as the paved wellhead access trails.


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Waterworks Prairie Park is built around five wells drilled to different depths. One reaches the Jordanian aquifer, 1600 feet underground. Two reach the Silurian aquifer at 400 feet, and two others are quite shallow, at only 40 feet deep.

These shallow wells, tapping into the “Alluvial aquifer,” carry the risk of being easily contaminated, due to their proximity to the ground surface. The soil is a type of Wisconsinon loess, which is particularly permeable and allows liquid to seep quickly through it. For this reason, vehicular traffic is prohibited in the park, to prevent accidental spills of gasoline, oil, or other contaminant fluids. Each wellhead has a protection zone of a 500 foot radius, within which no other wells can be drilled, and where use of chemicals is strictly prohibited to maintain water safety.

As an added precaution, a three acre pond with a constructed wetland was built in the southeast corner of the park to scrub possible automotive pollution from runoff from the I-80/Dubuque Street interchange before it reaches the wellhead protection zones.

Raw Pond Water

Listen to the Audio Tour about Raw Pond Water

This 18 acre pond used to be a gravel quarry pit, and now serves as an additional source of raw water for the treatment plant. The mechanism in the middle of the pond is called a SolarBee, and cycles water to prevent the growth of harmful cyanobacteria, also known as “blue-green algae,” which have the potential to produce neurotoxins if they bloom out of control.

The fishing pier also serves as the location of a Purple Martin colony recently established by local birdwatchers. A native songbird, Purple Martins are heavily reliant on human-made housing, such as the gourd-house here. In 2015, the first year of the project, three pairs of Purple Martins fledged eleven young.

Prairie Restoration

Although Iowa was once in the middle of 240 million acres of tall-grass prairie that spanned the United States, by 1896 the prairie had almost vanished as land was developed for agriculture and human settlement. One of the goals of the Waterworks Prairie Park was to restore the landscape to a prairie wetland from the quarry site and farmland it had been. Some of the plant species now present are coneflower, horsemint, prairie sage, rosinweed, white wild indigo, and goldenrods, among plenty others. Many of the plants can be used as seed sources for other prairie restoration projects.

Maintaining tall-grass prairie involves preventing invasive species from getting out of hand. This is typically done through controlled burns of sections of prairie grass, but doing so with I-80 to the south can often become a safety hazard to drivers because of the smoke, and therefore has only been carried out three times in the life of the park.

When the 2008 flood washed willow and cottonwood seeds into the low-lying Waterworks Prairie Park, many of the seeds ended up sprouting saplings in the tall-grass. In order to clear out some of the invasive trees that had begun to grow along the ponds, numerous volunteer groups organized about 25 events over the course of two years, cutting out the unwanted plants.

Sludge Lagoons

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A part of the water treatment process involves adding lime to the water clarifier, which raises the pH to 10, softening the water. This process creates the by-product of lime sludge, which is exported to one of two holding lagoons here in the park. Wash water from the filter cleaning process also is sent to the lagoons. Because of the lime in the lagoon water, the pH is considered alkaline and hazardous, and the lagoons are fenced off to keep visitors safe. As the waste material fills one of the lagoons, the liquid in the other lagoon evaporates off. Approximately every other year the lime is removed from the offline cell by truck and sent off as a heavy slurry to be used on area farm fields as a soil amenity. Because the site is low-lying, these sludge lagoons have been constructed at an elevation so they are not vulnerable to flooding.


Listen to the Wildlife Audio Tour

Because the park is a protected haven, a wide variety of organisms have been spotted here, including turkeys, deer, coyotes, fox, mink, beavers, and a multitude of turtles and fish.

Waterworks Prairie Park is a popular local birding spot. Though the park is frequented by many relatively common species, such as Starlings, Indigo Buntings, Blue birds, Goldfinches, geese, and ducks, there are also some oddities. In particular, male American Woodcocks can be spotted in the spring doing a special mating display around the park. American Woodcocks are plump little birds with long beaks. In the small pond below the sludge lagoons, Sora can be spotted in groups as large as six every spring. Even Blue Grosbeaks, which are uncommon to this area of Iowa, can be spotted in the spring.

In the temperate seasons, bird houses line the walking trails throughout the park. Black-capped Chickadees and Eastern Bluebirds commonly nest here, as well as Tree Swallows, which can be fun to watch as they eat thousands of insects every day.

One of the hopes in restoring the prairie wetland was that it would also help bring Trumpeter Swan populations back to the area. Though the species doesn’t frequent the park, a few individuals have been spotted by birders from time to time.

Listen to Bird Audio:
Indigo Bunting
Purple Martin

Aerial Photos

These aerial photos show how the Waterworks Prairie site has changed over the course of the twentieth century. Note, in particular, the growth of the quarry across the river from the park and the construction of I-80. The park is interesting as a natural preserve nestled among industrial developments and can bring to mind the close link between nature and industry. Though the quarry isn’t visible from the park through trees along the riverbank, visitors can likely hear the low hum of the interstate beyond the borders of the tallgrass prairie.

The invisible hazards are becoming visible. Damage to and destruction of nature no longer occur outside our personal experience in the sphere of chemical, physical or biological chains of effects; instead they strike more and more clearly our eyes, ears and noses.

– Ulrich Beck, Risk Society: Towards a New Modernity


  • University of Iowa Map Collection
  • Iowa City Press-Citizen
  • Carol Sweeting, Iowa City Water Division
  • Parks and Recreation Department Archives
  • U.S. Fish and Wildlife Service (bird audio, Public Domain)
  • Jim Walters and Linda Rudolph, local birdwatchers

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