Natural Storm Water Treatment
Landscape Architecture, Inc has been involved with the design and hands-on construction of several rain gardens (sometimes called rain water gardens), throughout the metro area.
Our latest endeavor involved a small commercial building in St. Paul who's tenants decided they wanted to do more to conserve natural resources while beautifying their space.
The project involved analysis of the storm water volume generated in an average rain fall event, then sizing the garden space to accommodate the correct volume of water.
A graphic plan and section were drawn to illustrate the proposed appearance of the garden. This was approved by the tenants then sent to the local Watershed District (Capitol Region) for approval.
Construction began by outlining the bed area and saw-cutting the existing bituminous pavement. Once the pavement was removed, the underlying rock was also removed to expose the native soil sub-grade.
Test holes were dug and flooded with water to determine the permeability (or the ability of the soil to infiltrate water). The soil passed the infiltration test and was ready to be planted.
The Serviceberry (Amelanchier sp.) trees were selected for their compact growing form and tolerance to heat and drought stress. Iris (Iris sibirica) and Catmint (Nepeta x faasenii 'Walker's Low') were added under the trees for color, fragrance and contrast.
In addition to reducing the amount of storm water run-off generated during a rain event, the garden also serves as a habitat for urban wildlife including birds, frogs, and butterflies.
The platings also provide shade to the rear of the building and parking areas as well as greatly enhancing the aesthetics and appearance of the building.