The basic shape of the rain garden is a shallow depression designed to increase stormwater infiltration by capturing runoff from the impervious surface of the parking lot adjacent to the Madeline F. Elder Greenhouse. Additional benefits accrue from the installation including replenished groundwater supplies, and the prevention of flooding, erosion of stream banks, and destruction of wildlife habitat.
Rain gardens are designed to improve water quality by mimicking natural cleansing processes in forests and meadows where rainfall is evaporated, taken up by plants, or drained into the soil within 24 to 48 hours. The garden traps sediment, fertilizers, and other non-point source pollutants (motor oil, metals, bacteria, etc.) found in stormwater runoff, preventing them from being carried untreated into rivers and streams.
Plants were chosen for their adaptability to varying soil moisture levels, made possible by vast root systems which channel water deeper into the soil profile. Once established, plants should not require extensive use of fertilizers and pesticides, nor irrigation except in periods of extreme drought. The inclusion of native plants will provide food and shelter for wildlife. The IMA focused on incorporating plants with contrasting scale, color, form, and texture for additional visual interest in an informal design.