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The Providence stormwater retrofit project integrates
three emerging low impact development (LID) technologies: a
green roof, permeable pavers and a
rain garden.
- 240 square feet
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.
- 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.
- 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.
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