Iowa City Press-Citizen: Student Project Uses Sonar to Measure River Levels

Saturday, March 20, 2010

By Josh O'Leary
Iowa City Press-Citizen

A project spearheaded by a group of University of Iowa students has the potential to help hundreds of Iowa communities be better prepared in future years when floodwaters threaten.

The team of engineering students has developed a relatively low-cost, automated sonar sensor that, when fixed to the underside of bridges, can transmit up-to-the-minute data on river stages.

Electrical engineering major Nick Sitter, along with fellow engineering students Ben Peiffer and Matt Kemp, all undergraduates, and graduate student Jim Niemeier have been building and tweaking the sensors since last fall as part of their senior design project.

“I think this is probably the cheapest solution I’ve seen, and just the fact that someone doesn’t have to go out and collect the data is a big deal,” Sitter said. “You can have as many of these out in the field that you want, and they’re all sending the data back to the university so you don’t have to go out and collect data.”

This is far from a typical classroom project. Plans are in the works to manufacture 50 of the devices for the Iowa Department of Natural Resources, which will distribute them to communities around the state, said Larry Weber, the director of UI’s Hydraulic Research Laboratory, known as IIHR.

“Our vision is to have hundreds of these in the state,” Weber said. “We’re starting with 50, and we expect we could have a couple hundred in the next year or two.”

The solar-powered sensors, which are about the size of a picnic basket, bounce ultrasonic waves off the water surface, then measure the time it takes for them to return to determine the river’s height.

A GPS component is used to provide an accurate timestamp, and every 15 minutes a microcontroller activates the device and transmits the data via cell phone technology to a Web server.

The idea for the project and the funding was provided by the Iowa Flood Center, a UI-led program that was established by the Legislature last year and is housed within the Hydraulic Research Laboratory along the Iowa River.

The Flood Center will collect the data from the river sensors, and then maintain a Web site where municipal leaders and residents alike can access and monitor water levels. The system could include alarm notifications that would alert communities if levels rise beyond a certain threshold.

The sensors currently each cost about $3,000 to build, but designers have set $1,000 as a target price for future models.

Anton Kruger, a UI associate professor of electrical and computer engineering and a mentor for the students in the project, said had the devices been produced by a private business, the cost of each unit would be significantly higher because of development costs.

Kruger said the sensors could serve as a supplement to data currently collected by the river gages maintained by the United State Geological Survey. Because of their low cost, Kruger said the sensors could be more widely disbursed and would make it more affordable for smaller communities that do not lie on a major river to monitor water levels.

“There are not too many of (the gages), and they are on bigger rivers and are expensive to calibrate and maintain,” Kruger said.

Sitter said the sensors are a low-cost alternative to traditional means of measuring rivers.

“The only other way they have of measuring river stages right now is to basically build a building on the side of the river, and they have a well in there that rises to whatever the river height is,” Sitter said. “Those cost about $20,000.”

Sitter said they’ve been working with their prototype on the Iowa River and other local bodies of water. He was planning this past week to install a pair of sensors along the Cedar River near Palo, which is still recovering from the 2008 flooding.

Weber said last week the Flood Center was nearing a contract with the DNR for the purchase of the first batch of sensors, and fabrication of the devices could begin in the next month or two. He expected installation to begin later this summer, which would mean they wouldn’t be available to monitor this year’s flood season but would be ready for 2011.

The Department of Transportation has also expressed interest in the sensors, Kruger said.

For Sitter, who grew up in the Cedar Rapids area and like so many Iowans witnessed the ruinous effects of the 2008 flooding first-hand, it has been a meaningful project.

“It’s a really cool feeling to know we’ve made this much progress in the last year,” Sitter said. “Especially since it’s for a senior design class, where most people just get a working prototype. But we’ve already had one out in the field. We’re actually developing this for a reason, and not just to get a grade in school.”

Said Kruger: “Two of the students (Sitter and Peiffer) are from Cedar Rapids, which was so hard hit by the flood, and the other student (Kemp) is from Dubuque. So you have all of these Iowa kids come to the university and had this project, and they really did a nice job with it. It’s funded by Iowans, and Iowans will benefit from this.”