A trench outside a high school parking lot in northeast Minneapolis has become an environmentally friendly hotspot for University of Minnesota researchers and high school students.
University professors have worked at Thomas Edison High School since early this year to document how well the trench gathers polluted rainwater. Meanwhile, the high school’s teachers recently began exploring new ways to use the trench to teach students about sustainability.
The school, with the help of the Mississippi Watershed Management Organization, recruited civil engineers and University of Minnesota professors to help high school juniors monitor the effectiveness of the trench in keeping polluted water out of the Mississippi River. The trench, which collects runoff rainwater from the school’s parking lot, could serve as a model for other area high schools to reduce their impact on the environment.
Bioproducts and biosystems engineering professor and project head Bruce Wilson said the trench aims to prevent water that collects pollutants on the parking lot from flowing straight into storm drains, which empty into the Mississippi River. The trench, originally installed in 2013, can hold the volume of water supplied by a four-inch rainstorm.
A system that monitors the trench’s water inflow was installed in March. Students began studying the trench in May.
Wilson, who monitors the amount of water in the trench, said the storm water it collects is sucked up by soil in the ground, where it is filtered before being dispelled into the river or taken up by trees in the trench.
The trench is preferable to storm drains because keeping storm water out of the river is cheaper and easier than removing pollutants from the river, said Doug Snyder, executive director of the Mississippi Watershed Management Organization.
Snyder said the trench could help educate the high school’s students and faculty members about environmentally friendly practices, such as using less salt to melt ice in the winter or keeping mowed grass off pavement where it might flow into the river.
The project serves as an example for repurposing storm water to save drinking water, Snyder said, adding that the water the ditch collects could be used to irrigate plants.
“The reason to do this demonstration is to have people start to view storm water as a resource rather than a waste product,” Snyder said.
John Gulliver, a University professor of civil, environmental and geo- engineering, said he thought the shade and aesthetic appeal created from trees planted on the trench were a plus, but he said a trench without trees would be more cost-effective.
Integrating the trench into the high school curriculum teaches students to appreciate environmental conservation, said Andrew Lyman-Buttler, a science teacher at Thomas Edison High School.
“From the pre- and the post-test that we have given [to students], we saw comments like they feel greater responsibility for environmental conservation [and] they have a greater awareness of water-quality issues,” Lyman-Buttler said.
The project could be incorporated into other science courses, Lyman-Buttler said. Surrounding high schools might also use the system in their classroom instruction.
Wilson said he will be collecting and analyzing data until December. However, he said he hopes the project will continue until next spring to give him a chance to monitor how snowfall could affect the success of the trench.
