AMES, Iowa – A new monitoring effort of the Black Hawk Lake watershed by Iowa State University researchers will answer some lingering questions regarding the long-term impact of land management practices on water quality.
Michelle Lynn Soupir, an associate professor of agricultural and biosystems engineering, said the five-year duration of the study will allow the research team to take a longer look at the watershed than typical studies that last between one and three years. The longer-term approach will paint a more complete picture of the impact of land management practices on surrounding farmland, which sometimes take years to significantly affect water quality.
The wealth of long-term data to be collected during the study could have ramifications for impaired watersheds across the state, Soupir said.
“There’s a lag time between when you implement land use practices and when you start to see water quality improvement,” she said. “We need a better understanding of that lag time, and five years of data will help fill in some of those gaps.”
The research is funded by a grant totaling $461,661 awarded in July by the Iowa Department of Natural Resources. The funds originally came from the Environmental Protection Agency under Section 319 of the Clean Water Act.
Black Hawk Lake covers around 957 acres near the city of Lake View in Sac County. The Iowa DNR has declared the lake an impaired waterway due in large part to sediment from nearby farmland washing into the watershed. The lake also suffers from algae and turbidity problems.
The Iowa DNR has undertaken efforts to rehabilitate the lake in recent years, and the ISU study will aid in the process, Soupir said.
The research team has chosen three sites in the 13,156-acre watershed where automated monitors will be installed next week to collect water samples and measure the flow of water through the area. The monitoring sites are located on land showcasing a range of land use practices that affect water quality, such as drainage tiles, terraces and grass waterways.
“Although the lake is an impaired body, the community has a history of farmers and landowners implementing land management practices to improve the health of the lake,” said Soupir, who teaches a course in watershed monitoring every other academic year. “That’ll make this a particularly interesting case study.”
The samplers will use modems that trigger the cell phones of the researchers to let them know when runoff has occurred and it’s time to collect the water samples. The samples will be brought back to campus where they’ll be tested in a laboratory for the presence of nitrogen, phosphorous and suspended solids, Soupir said.
The effort will tap the expertise of several faculty members in the ISU Agricultural and Biosystems Engineering Department. Matthew Helmers, a professor in the department, will oversee aspects of the research involving nutrients and nitrates in the water samples. He’ll also provide expertise on the impact of drainage tiles, which affect an extensive portion of the watershed.
Amy Kaleita, an associate professor of agricultural and biosystems engineering, will handle much of the statistical analysis and design of the water monitoring while Leigh Ann Long, a research associate in the department, will oversee sample collection and analysis, quality assurance, quality control and data management. And Carl Pederson, an agricultural specialist, designed the field installations where the samplers will be placed.
