BETA was approached by Thundermist Task Force, an organization that supports community projects which improve water quality in and around Woonsocket, to create a rain garden at the St. Charles Borromeo Church. The year-long project included team meetings, site visits, conceptual design, and procurement of materials, plants, contractors, and construction volunteers.
BETA assessed placement of the rain garden on the site from the standpoints of aesthetics, neighborhood appeal, existing plantings and utilities, and stormwater runoff from the expansive church roof and adjacent paving. The first step in designing such a rain garden is sizing it and locating it properly, using a specific formula that takes into account the soil type, amount of stormwater runoff expected, and temporary ponding depth of the planned rain garden. Rain gardens are designed according to state Stormwater Guidelines, including inclusion of a pre-filtration forebay, use of a custom soil mix, and use of suitable native plants.
After those elements are in place, the artistic elements that make the garden beautiful and appealing can be designed. The emblem of Saint Charles Borromeo is humility, which is signified by the color white. Hence, this is intentionally a white-flowering garden. Located at the rear of the historic church, it combines a beautiful contemplative spot with a functional accommodation for stormwater. Shaped like a bowl set in the earth, the garden sits quietly by the church walls under the protection of the two existing flowering shade trees. It provides a place for reading, study, observation, prayer, music, and many other activities. A planned interpretive sign about stormwater and the flora and fauna that inhabit rain gardens will add an educational element.
All rain gardens are designed to drain completely within 72 hours, so that standing water, which can breed mosquitos, will not be a problem. The stormwater is cleansed by the planting medium and infiltrates through the bottom of the rain garden into the natural aquifers below ground. Upkeep for a rain garden is similar to that of a regular garden bed.