A valuable flow of groundwater information for Iowa

In 2014, the city of North Liberty realized it had a water problem.

The second-fastest-growing city in Iowa—its population had swelled more than 500% in nearly two decades—was struggling to provide enough water to its residents and new businesses. On top of that, state regulations changed that year governing how much water the city could pump out of the ground.

“We experienced quite a few years there where we had very, very rapid growth, and it became really challenging just to meet our peak day demands,” says Greg Metternich, North Liberty’s water superintendent.

That’s when Metternich turned to the Iowa Geological Survey (IGS) at the University of Iowa for help.

The IGS examined North Liberty’s water pumping rates, its groundwater sources, and its water infrastructure to create a comprehensive series of models that showed the city how it could expand its water supply and stay well within state water-use regulations—now and for the next 20 years.

“Without the modeling, it was an unknown,” Metternich says. “Are we going to sustain the growth that we’ve seen in the last decade? What type of industry are we going to allow to come in? With the information and data from the IGS, we were able to move forward. And I can sit here today and say that I think 20 years from now we’ll be sustainable.”

The IGS has produced sophisticated models to help communities and industries sustainably manage groundwater use, ensuring the continued steady supply of water in Iowa’s rich, underground reservoirs, known as aquifers.

A visualization of Iowa groundwater produced by IGS software. Photo by Matt Jansen.

“Water is essential for drinking, and it’s essential for jobs, agriculture, and other industries in Iowa,” says Mike Gannon, hydrologist with the IGS, part of the College of Engineering at Iowa. “Our role is to ensure Iowans have safe, abundant sources of water. We do that by developing tools that help manage water from a quantity and quality standpoint. We provide those tools to communities, to industry, to rural drinking water suppliers—really anyone in the state that needs it.”

Three out of four Iowans get their drinking water from groundwater sources. The state is blessed with as many as six aquifers—one of which is the Cambrian-Ordovician, or Jordan, the principal water source for numerous cities and industries statewide.

But even Iowa’s rich underground water reservoirs have limits. The aquifers, especially the Jordan, recharge slowly and can be over-pumped if there are too many wells located in one area or if a particular entity uses it heavily. Recognizing the threat, the state legislature began in 2009 to allocate $500,000 annually to the IGS to study and monitor Iowa’s groundwater supply.

The IGS began by mapping below-ground geology. The maps showed in great detail the location of the aquifers and how much water flowed in each aquifer at various points throughout the state. From those maps, and using information from major water users and the Iowa Department of Natural Resources, Gannon and his team have generated models that calculate the amount of water being used in a given region and forecast whether current use can be sustained without substantively depleting the aquifer.

“We need to be smarter about how we use water,” Gannon says. “We now have the tools available to us to quantify our water resources and also to provide information on how we can better protect our aquifers.”

The IGS has produced a model for Johnson and Linn counties, and worked directly with cities in the region on water management plans. The IGS also produced a groundwater-flow model for a four-county region in northern Iowa that included tailored plans for Fort Dodge and Mason City. The IGS is finalizing agreements to produce a model in central Iowa, and will consult directly with several cities in the Des Moines metropolitan area.

“We’re all for population growth, for jobs, and for businesses and industries to succeed,” Gannon says. “We just have to make sure there’s enough water to go around for everyone.”

The services provided by Gannon’s team are many. In Marion, located north of Cedar Rapids and the third-fastest-growing city in the state, the IGS helped water managers decide where to locate new wells to maximize the amount of water that can be pumped without overly straining supply. The IGS also helped Marion site additional wells to tap into a shallower aquifer, called the Silurian. The result: Marion has a sustainable water-use plan to meet its needs for the next two decades.

“Marion’s future is looking bright—looking wet, if you want to call it wet—because of the (IGS’s) expertise and technology,” says Todd Steigerwaldt, general manager for the Marion Water Department. “We are positively moving forth with confidence that we’ll have plenty of water to support industry and our growing population.”

IGS hydrologist Mike Gannon speaks at a Rotary meeting for the Marion-East Cedar Rapids chapter in Marion, Iowa. Photo by Matt Jansen.

In Mason City, leaders asked the IGS to provide the northern Iowa community with a 20-year projection of its groundwater supply. Gannon and his team found that Mason City can increase water use by 50% with its existing wells and still be within state limits.

That means Mason City, essentially, has water to sell.

“We’ve had businesses and developers looking at Mason City, but many times there is that question mark: Do we have the ability to support their water demand if they come to our city?” said Mark Rahm, city engineer in Mason City. “By going through this process and getting this report from the IGS, we now have the confidence that we can invite the big users and can assure them that we can meet their needs. That is a great level of comfort to myself and city leaders.” 

IGS’s current project is in the Des Moines metropolitan area, the fastest-growing region in Iowa and one in which several expanding municipalities are tapping into the same aquifer. In the next year, Gannon expects they will work on groundwater management plans with Altoona, Ankeny, West Des Moines, and Des Moines Waterworks, the water supplier for Des Moines. There may be more partnerships in the region too, potentially involving Grimes, Indianola, Knoxville, and Pella.

Gannon says his team will consult for any customer, large or small.

“Although our models focus primarily on the larger metropolitan areas, we also are here to protect the smaller communities and smaller users from private wells to very small communities,” he says. “We want to assure that that all Iowans have abundant drinking water.”