As Iowans across the state turn their gaze toward the quality of Iowa’s waterways, student and faculty researchers at Iowa State University have developed prototype equipment to measure the nitrate levels of hard-to-reach watersheds with drones as the vehicle.
What started as a senior design project has grown into a multi-year, federally funded effort to turn the team’s proof of concept into multiple working drone lab systems that could potentially provide water quality monitoring support to government organizations and other groups.
“It’s really custom,” said Jonathan Claussen, ISU mechanical engineering professor and project lead. “It hasn’t been done before — trying to bring up water from the stream, put it into a test vial that could have enough fluid in there so the sensors could be placed inside to take measurements, and then to flush out that water afterwards.”
In its current form, the “lab-on-a-drone platform” as described in a paper published by the research team includes a pump and hose that bring water up from the source. The water reaches sensors that measure nitrate concentrations in the sample with a membrane developed by the researchers. Data is stored on an SD card in the system for users to access after taking samples.
Supported by the National Science Foundation and ISU’s Digital and Precision Agriculture Applications program, the research team in January also received a three-year, $590,000 grant from the U.S. Department of Agriculture National Institute of Food and Agriculture.
Traditional testing for water quality often can’t provide results quickly, said ISU electrical and computer engineering professor and researcher Nathan Neihart. That’s because the samples need to be taken from the water source then brought back to a lab for analysis.
“What we’re trying to do is have a much simpler, much lower-cost version of those sensors on board that maybe aren’t quite as flexible as what you see in a laboratory grade benchtop piece of equipment, but are tailored for the specific readings that we’re taking, and so can do it as accurately as the benchtop lab equipment,” Neihart said.
Michelle Soupir, agriculture and biosystems engineering professor and associate dean of the ISU graduate college, added that many of Iowa’s waterways are not easy to access, let alone allow for set-up of a stationary sensor system. Having the sample collection and testing on a mobile unit allows testers to bypass marshy areas where humans would have a hard time getting through and check out nitrate levels in areas where there may be agricultural runoff from nearby farms or other practices impacting the water.
Field testing of the drone sensor systems showed where some tweaks needed to occur, Claussen said. For example, researchers realized a filter was needed to stop the water collection from bringing sediment or other debris in the water into the testing chamber. The team is also working on a way to spool up the line that collects water, as right now it dangles and could potentially get caught on something.
Once the three-year grant period is complete, Claussen said he hopes to have multiple drones outfitted with sensor systems taking measurements in the field to the point where entire watersheds could be mapped out.
Graduate students involved in the project are pursuing licenses to pilot the drones. Meanwhile, Neihart said he is working on integrating the currently separate electronics into one piece while trying to add additional sensors to measure water temperature, pesticides and herbicides like glyphosate and dissolved oxygen.
In the days since ISU publicized the team’s work and results, Claussen said “a variety of different organizations” have reached out to share their interest in the project. Collaboration with Iowa’s neighboring states could also occur in the future, he said, through a National Science Foundation project having researchers look at nutrients in soil and water.
Water quality has been on the minds of state officials during the recently completed legislative session as well. Iowa Gov. Kim Reynolds on May 1 announced a “farm to faucet” water quality package that invests state funds in water quality monitoring and infrastructure.
There are sensor systems already in place across the state, Soupir said, including the Iowa Water Quality Information System operated by the University of Iowa IIHR Hydroscience and Engineering department and water quality monitoring through the Department of Natural Resources. However, those sensors are stationary and not every waterway in Iowa has one set up.
Having the drone water testing system available could mean better response to events like spills or other contamination of waterways, Soupir said, or giving farmers the chance to see if the cover crops or other conservation efforts they’ve implemented are actually having an impact on nearby streams.
“The timing is just really exciting, as far as being able to contribute to the conversations and to be part of a topic that really everyone across the state cares about,” Soupir said.
