Low Impact Development (LID) Technologies at Providence
The retrofitted rooftop is an example of extensive green roof technology. Unlike roof top gardens, extensive green roofs are not designed for regular visitation by the public. They consist of a series of layers including a waterproof membrane, growth media and plants such as sedums, shallow rooted succulents that will withstand harsh exposed conditions. The plants filter out airborne pollutants and absorb rain and snowmelt that would otherwise travel down gutters and spouts to streets and storm drains.
Permeable Pavers - approximately 1,600 square feet
Unlike traditional asphalt or concrete pavement, permeable pavement is composed of many interlocking pavers that present a solid surface for traffic. Small spaces between the pavers allow water to percolate through to the soil surface or to a retention area where the water gradually is absorbed into the soil. Nine parking spaces at Merrifield Fire Station 30 were replaced with permeable pavers.
Rain Garden - 680 square feet
Rain gardens can be many sizes and shapes depending on the conditions at a site. They are designed to hold and filter water and release it slowly into the surrounding soil. In this way, rain gardens prevent oversaturation and flooding and improve water quality. Composed of several layers including layers of gravel, pea gravel, engineered soil and mulch, rain gardens are typically planted with native plants that can withstand fluctuating water levels and can be an attractive landscape component.