To decrease potable water consumption on campus, Macalester has focused on improving efficiency. Nearly all buildings on campus have installed low-flow faucets and shower heads, and some have dual-flush toilets to minimize water consumption.
In 2011 Macalester instituted a ban on selling bottled water in vending machines, at athletic events, and at all retail sources, while simultaneously installing automatic bottle filling stations throughout campus. In addition to reducing waste, the effort also keeps water local to its source. Read more about the bottled water campaign in this Case Study by Clare Pillsbury ‘12.
As a result of climate change, Minnesota is experiencing more intense storms with large volumes of water falling in a shorter period of time. When this occurs, the ground is unable to absorb and filter the water effectively, resulting in an increase in water runoff into the stormwater system. This water flows directly into the Mississippi River, introducing pollutants and causing short-term flooding. To address this issue, the Macalester College Sustainability Plan set a goal of reducing the pollution, quantity, and speed at which water runs off the campus by infiltrating the first inch of precipitation on campus.
Permeable pavement walkways, such as the porous pavers which have been installed in front of Markim Hall and along the walkways leading from the Janet Wallace Fine Arts Center, allow a percent of precipitation to filter into the ground rather than run off. This reduces erosion, flooding, and the sweeping of chemicals into our waterways. As precipitation filters through the pavement into the ground, it passes through a series of minerals, such as rocks and sand, which remove pollutants from the water before it is deposited back into the earth.
Here’s a link to a video all about permeable pavers, made by Amber Wiedenhoeft in Dr. Kelly MacGregor’s Surface and Groundwater Hydrology class in spring 2021.
Landscaping and Turf
Macalester has replaced several turf areas with native plants, increasing both the amount of precipitation that can be absorbed as well as the biodiversity of the area. This choice also reduces the amount of water used and greenhouse gas emissions associated with maintaining the area. Also, plant basins were installed at the edges of some parking lots. Filled with a specially engineered sand that filters out harmful phosphorus from the rainwater, the water is then used by the plants and trees in the basin rather than running off into the stormwater system.
The Macalester Grounds Department has made some sustainable landscaping choices, such as maintaining sharp lawnmower blades and mowing at a higher height, which improves soil health and in turn allows the soil to absorb more precipitation. Also, in 2021, the department upgraded the irrigation controls to a new system that optimizes the amount of water used through a combination of soil moisture sensors and online weather data.
Leonard Center Pool
The pool in The Leonard Center, Macalester’s Athletic & Wellness Complex, uses sphagnum moss, placed in plastic bags in the contact chambers of the pool, to reduce organic contamination and naturally stabilize the pool’s pH. The moss addresses scale, staining, and corrosion while reducing maintenance and the need for chemicals, as well as water and energy use. The technique was introduced by Creative Water Solutions, a contractor on the building project.