HomeMy Public PortalAboutLafayette-Square-Plaza-Rain-Gardens_FINALLafayette Square Plaza Rain G ardens
Lafayette Square Plaza’s rain garden project, completed in 2015, directs and stores stormwater in
multiple ways. A 50-foot bioswale collects runoff and directs it to bioretention cells, while traditional
pavers slope toward a 380-foot area of pervious pavers in one of the plaza’s corners. The rain garden
also includes two pervious concrete paths. The design for all these elements was proposed to prevent
nearly 404,500 gallons per year from entering the city’s sewer system.
Native plants not only aid in the rainwater retention effort, but they also beautify the square. “We
wanted to transform the pavement into an area people would want to visit,” said Linda Pallmann, a
former Lafayette Square Restoration Committee (LSRC) board member. “Since this project was
completed, we’ve been holding social events there – people are happy to gather on the plaza because
the green space is so refreshing,” she adds.
Rainscaping type: Bioretention and pervious pavement
Challenges: Getting rainwater to flow from one place to another to prevent pooling and overflow from
heavy storms presented unique design challenges. In addition, Lafayette Square is lauded for its beauty,
so it was particularly important that this rain garden balance aesthetics with rainwater runoff reduction.
The LSRC had a particular vision in mind for the area, requiring a high level of collaboration between the
community, the designer, the engineer, and MSD.
Solution: The project’s design engineer coordinated with the MSD Planning and Development Review
team to optimize volume reduction while achieving the aesthetic requirements of the LSRC. Pervious
concrete replaced non-pervious pedestrian walkways, and a permeable paver gathering area replaced a
non-functional bandstand – these upgrades allow stormwater to penetrate the surface and access a
below-ground stone infiltration reservoir, explained Brian Hartwig, a project manager for TRC, the
project’s designer. Bioretention basins along new traffic bump-outs help manage stormwater runoff by
temporarily storing it. Within 48 hours, engineered soil – assisted by deep-rooted native plants – purifies
the water before slowly releasing it to the sewer system.
What makes this project unique: The community was heavily involved in the design process, ensuring
that the rain garden will be enjoyed by Lafayette Square residents for years to come. In addition,
brochures and educational signs placed within the plaza make this rain garden an important tool for
educating the public about the benefits of rainwater retention. “The signs help people understand the
importance of the Mississippi watershed,” said Matt Negri, also a former LSRC board member. “We’re in
a brick and concrete jungle, and this adds some natural retention and prevents everything from running
into the storm drains.”
About MSD’s Rainscaping Large-Scale Grant Program: This rainscaping grant program (previously called
the Early Action Program) seeks to engage partners to identify joint opportunities to incorporate green
infrastructure into ongoing programs and future redevelopment projects. Each grant awarded allows
MSD to create a public-private partnership that contributes to the environmental, social, and economic
health of the St. Louis region. For more information or to learn how to apply for your organization, visit
projectclearstl.org.
See photos below