GREEN STORMWATER
INFRASTRUCTURE (GSI)
What is Green Stormwater
Infrastructure (GSI) and how will it
help Nashua accomplish its goals?
GSI is a set of tools and practices that
mimic natural methods of storing,
infiltration and/or filtering stormwater.
As more development occurs across
the City of Nashua, continued
integration of these practices into new
and redeveloped areas will mitigate
flooding, contribute to adaptation to
increased rainfall, and where plants
are present, will help filter urban
stormwater before returning it back to
groundwater reservoirs.
Where should it be employed?
How does each of these methods
work?
Enhanced Tree Wells : filters water
through a tree pit with well-drained,
amended planting soil
Vegetated Filters : turf or planted
surfaces used to slow runoff and trap
sediments between paved area and
GSI
Bioswale : moves and filters water
through a linear soft or hard-edged
channel with amended soils. In
streetscapes, streetscapes employ
underdrains
Pavement Reduction: restores and
infiltrates water through the reduction
of impervious cover to a permeable
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Permeable Surfaces : opens voids in
Comprehensive Master Plan
the surface and subbase allow water
to drain while still providing a rigid
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Underground Chambers : stores
and infiltrates stormwater volumes
underground while maximizing
useable surface space
Raingarden: Shallow depressions
that temporarily hold and filter water
through existing or amended soils
Infiltration Basin : landscape space
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water through a side slope or hard-
edged depression with amended sols,
pipes, and structures
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