Keeping water safe, preventing flooding: Updated state water plan to give suburbs new guidance

From making sure our water is safe to determining what to do when there's too much of it, managing water issues is a complex subject in the suburbs and around the state.

A newly updated Illinois State Water Plan aims to tackle the challenge.

The plan prioritizes 13 areas where we are facing the most significant water resource challenges in the state today, including water quality, Lake Michigan issues, flood damage mitigation and climate change. It provides a total of 144 recommendations for how to address them over the next decade.

Work on water issues overlaps the objectives of so many regional and state agencies, as well as outside stakeholders, so the plan serves to unite those efforts, said Wes Cattoor, the engineering studies chief with the Illinois Department of Natural Resources' Office of Water Resources.

“As we show in the report, you can't talk about flooding impacts without talking about climate change and water quality impacts. It's critical to have the state water plan to know that this is a multiagency, multifaceted issue that we're trying to address on a wide variety of topics,” Cattoor said. “It's essentially a vision for Illinois and the water resource we have available as we move in the future.”

The IDNR led the production of the plan, but other agencies involved in writing the extensive document include the Prairie Research Institute's Illinois State Water Survey, the Metropolitan Water Reclamation District of Greater Chicago and several environmental advocacy groups such as the Nature Conservancy.

The plan is also meant to act as a resource for local communities. The results of a survey conducted during the plan's development showed that 13% of respondents intended to “incorporate (it) into a local comprehensive plan,” while 17% planned to use it for “regional/watershed area planning.”

Cattoor said the plan will not impose regulations on local municipalities but will instead provide programs and data that communities could benefit from.

For example, a growing concern with designing stormwater infrastructure is that rainfall data is increasingly out of date due to the uncertainties of climate change. Several recommendations involve gathering more climate projections and making them more accessible to local planners.

Given that the local impacts of climate change can vary drastically, improving those projections to produce localized data is also a top priority, said David Kristovich, the plan's climate change committee chair and a professor of atmospheric sciences at the University of Illinois.

“On a global scale, you could talk about the generalities of what will happen — temperatures expected to continue to increase, the rainfall world average that's going to be increasing and so forth. But each community needs to deal with separate issues,” he said.

For instance, communities close to Lake Michigan may have to deal with coastal erosion issues, and communities that have a large wind power industry would be primarily concerned about how winds may change.

In another example, the plan notes several issues specific to urban areas and surrounding communities, such as vulnerability to changing storm frequencies and intensities, “potentially decreasing flood mitigation effectiveness.”

The recommendation for this issue is to provide localized information to the public on anticipated changes in storm intensity and frequency. According to the document, this is particularly important in communities with combined storm sewer drainage systems, which carry sewage and stormwater runoff in the same piping system.

In Des Plaines, planning is critical to mitigate and reduce floods from large rainstorms that result in the Des Plaines River overflowing its banks.

Floods in 2008 and 2013 caused widespread damage to the city's Big Bend Drive neighborhood, prompting the demolition of nearly 90 structures to permanently remove them from the floodplain. Most recently, a heavy rainstorm in 2020 left many of the city's streets underwater.

Jon Duddles, Des Plaines' assistant public works director, said in addition to having a stormwater master plan, the city conducts studies whenever there is a significant flood event.

While the city has to grapple with a future that includes more intense and frequent rains, Duddles said they rely on state data to account for the effects of climate change.

“We refer back to the State Water Survey and the state agencies to provide us with those projections,” he said. “We don't go and do our own, so we rely on the state to make those projections to update the rainfall bulletins.”

Duddles said the Metropolitan Water Reclamation District requires that municipalities use an Illinois State Water Survey document referred to as “Bulletin 75” as a source of precipitation frequency data for stormwater infrastructure projects such as detention ponds.

The bulletin, published in 2020, says the average amount of annual Illinois precipitation increased from 36 to 40 inches per year — or 11% — over the past century.

Similar to the recommendations in the state water plan, the document calls for more frequent assessments of precipitation that include both historical data and climate model-based projections.

The final draft of the state water plan is set to go before the state legislature in November after three years of development. First created in the 1960s, the plan hasn't been updated since 1994.

IDNR officials said that while the task force continued meeting quarterly to address water issues, efforts to update the plan “fell off the radar.”

“State water plans have become very common in the last 20 years, and Illinois was unfortunately one of those states that were probably at the bottom as far as how recent they've updated their plan,” Cattoor said. “We're looking to get back on track with this.”

Through Sept. 30, the team is continuing to accept feedback from the public on the draft, which can be found at tinyurl.com/ILWaterPlan.

• Jenny Whidden is a Report For America corps member covering climate change and the environment for the Daily Herald. To help support her work, click here to make a tax-deductible donation.