Sliver by the River
Sliver by the River
Sliver by the River
What is Green Infrastructure (GI)?
Green infrastructure is a set of strategies that use nature and natural processes to address environmental problems, reducing the negative impact of issues like water pollution, rising temperatures in cities, and rising sea levels. It primarily does so by mimicking what nature would do without human interventions like asphalt parking lots, concrete sidewalks, the introduction of invasive plants, and the destruction of natural landscapes.
Why Put Green Infrastructure at the Sliver Site?
Sliver by the River sits on the bank of the Pequonnock River, and rising tides cause routine flooding that gets worse during storms. The asphalt on the Sliver contributes to flooding since the extra water pools on the hard surfaces and can’t soak into the ground, and this water picks up and carries pollutants into the Pequonnock River. Installing green infrastructure would help the ground absorb more water and filter it before it enters the river, improving water quality and protecting wildlife. Dark surfaces like asphalt also absorb sunlight and make the city hotter, so replacing it with plants would help to create a cool refuge for locals in downtown Bridgeport.
Types of GI Interventions
Re-planting Native Plants:
Replacing asphalt with native plants makes public parks much more enjoyable spaces. Native plants cool the air when it’s hot, prevent soil from washing away, soak up extra rainwater and pollutants, and provide a home and food for native animals and pollinators. Different kinds of plants have different needs and serve different ecological functions, so certain plants need to be put in specific places to survive.
1. Shoreline
Planting native plants along the shoreline prevents the edges of the shore from washing away and filters water before it flows into the river. It would also provide more places for animals like mussels and fish to live, which would make it a better fishing spot.
2. Tidal zone
Introducing plants that thrive in marshes filters the water that runs off of hard surfaces in the city. This area is meant to flood and drain as tides change. It is also an important place for shorebirds and fish to live. Marshes prevent dirt on the shoreline from washing away and soak up flood water like a sponge. Since it has standing water so often, a marsh cannot be used recreationally, but boardwalks can be installed over the marsh as a walking trail.
Image: Hoan Luong / CC BY-NC-ND 2.0
3. Wet meadow:
To restore a wet meadow, grasses and flowers would be planted where the existing asphalt is. Plants like blue flag and great bulrush provide a home and food for native birds and pollinators and filter pollutants out of water.
Image: Peter O’Connor aka anemoneprojectors
4. Riparian forest:
Planting trees and plants in the highest parts of the site to make a dense forest would prevent dirt from washing away and filter rainwater. Trees like chokecherry and plants like common juniper and southern arrowwood create a home and food for animals. A riparian forest would be a great place to put benches, walking trails, or picnic areas for people to enjoy.
Image: David Smith / CC BY-SA 2.0
Protecting the Shoreline with Rocks and Concrete
Using the rocks and concrete that are already on the shoreline of the site prevents soil from washing away. Although there aren’t currently any plants there, native plants could be put in between the cracks, or the rocks could be rearranged to provide more room for plantings.
Floating Wetland
Floating wetlands are floating platforms that are anchored to the ground or another stable object and have wetland plants growing in mesh on top. Plants like cordgrass, black rush, or other salt marsh plants can thrive in floating wetlands. The plants absorb extra nutrients that are unhealthy for the river. They also provide a home and food for birds on top of the floating platform, and aquatic animals below it.
Image: Adam Lindquist / CC BY-NC 2.0
Green Bulkhead
A green bulkhead is one of the strongest ways to structurally reinforce the shoreline and prevent dirt from washing away. It requires removing the rocks and concrete that already border the shoreline and replacing them with a wall of metal, wood, or other hard material. It would provide fewer opportunities to plant native plants along the shoreline than other methods, but it can better prevent the upland parts of the site from flooding.
Image: U. S. Fish and Wildlife Service - Northeast Region
Tidal Swale
Tidal swales are gardens of marsh plants that are sunken lower than the surrounding ground. The swales soak up flood water and the plants and soil filter it, but are much smaller and have less of an impact than restoring the plants in a whole area.
Image: ChesapeakeBayFound / CC BY-NC-ND 2.0
Wetland
To create a water treatment wetland, parts of the ground are sunken lower than the surrounding dirt. These sunken areas catch extra rainwater, and special soil helps them absorb and hold onto the water. Trees like swamp white oak and plants like switchgrass help filter water, and a relatively small wetland can make a big impact.
Image: Kenneth Allen / CC BY-SA 2.0
Bioretention
Bioretention areas are gardens that are sunken slightly lower than the surrounding ground and are placed near hard surfaces like roads where a lot of water runs off. These gardens catch extra rainwater and use plants and soil to absorb some water and filter out pollutants. Then, the filtered water is deposited into the river. Planting species like cardinal flower and New England aster gives a home and food to pollinators and birds while beautifying the city.
Image: Dan Reed! / CC BY-NC 2.0
Permeable Pavement
In places where hard surfaces like concrete paths or parking lots may be wanted, they can be replaced with permeable pavements. Permeable pavements have gaps in them between stones or pavers to allow rainwater to soak into the ground.
Image: Center for Neighborhood Technology / CC BY-SA 2.0