Removal of Invasive Species Protects
One of Kroon Hall's Key 'Green' Features

mars pond restoration wide
Photo by Matthew Garrett
Technicians from Dietters Water Gardens remove Phragmites from Mars Pond, located in Kroon Hall's south courtyard.
Since Kroon Hall was opened in 2009, a narrow human-made pond in the building’s south courtyard has provided one of the building’s key sustainability attributes. Stocked with aquatic plants, Mars Pond filters water from the building’s roof and grounds, which is then pumped into the building to be used as gray water for toilets.
phragmites mars pond 16
Photo courtesy of Sara Smiley Smith
Thriving Phragmites in Mars Pond in 2016.
But in recent years a common invasive has made itself at home in Mars Pond. Phragmites have overrun the system, threatening other plant species and disrupting the water filtration system.
Over the past two weeks, a team of technicians, from Dietters Water Gardens, has painstakingly removed the plants, ripping out a resilient network of roots that had become embedded beneath the stones at the bottom of the pond. They’ve also removed the planting rafts that had begun to deteriorate. This maintenance, School officials say, will assure the continued operation of the gray water system.
“The Phragmites removal created an opportunity for us to carefully consider the role of this gray water system in Kroon’s operations, and to brainstorm how best to provide stewardship of it moving forward,” said Sara Smiley Smith, chair of the F&ES Environmental Stewardship Committee (ESC), which is working with Yale Facilities to revitalize the pond.
Inside the pond now are a series of pots that will sit under the water line as the feature is refilled. These pots will hold a variety of local plant species, including irises, water lilies, and marigolds, and there will also be free-floating aquatic plants added to the system.
The project will be done in time for the May graduation ceremony, traditionally held on the southern courtyard.
mars pond restoration crew
Photo by Matthew Garrett
PUBLISHED: April 12, 2017
Note: Yale School of the Environment (YSE) was formerly known as the Yale School of Forestry & Environmental Studies (F&ES). News articles posted prior to July 1, 2020, refer to the School's name at that time.