Green Infrastructure

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Rainwater flows quickly over impermeable pavement, like concrete. If that water can be slowed down, held, or absorbed, less flooding will happen. Simple projects like installing a rain garden or rain barrel in your yard can help reduce the risk of flooding on your property.

Community Organizations

A community of non-profit organizations in New Orleans is here to help with green infrastructure education and installation.

Project types

Listed below are some green infrastructure projects that you can install on your property to hold rainwater. Maintenance, rainwater capacity, and cost are noted for each type of project. This guide was developed by the New Orleans Redevelopment Authority.

Remember, call 811 before you dig to avoid hitting underground utility lines.

Rain Garden

Labor

Rainwater capacity

Cost

A rain garden is a shallow basin with native plants that have deep roots and are water-tolerant. Rain gardens reduce rain runoff by allowing stormwater to soak directly into the ground, instead of flowing into storm drains. This decreases flooding, pollution, and subsidence. Rain gardens are better for larger areas. A typical rain garden is 100 square feet or more.

During its first year, a rain garden needs to be watered often enough to keep plants from suffering "transplant shock." As the rain garden becomes established, it will need less watering and maintenance. Additionally, invasive species and debris must be removed. Pipes and outlets should be inspected for blockages annually or when there is standing water for more than 48 hours.

Maintenance activities	Schedule
Debris removal Watering & weeding during establishment Visual inspection of inlets & outlets	Weekly
Weeding	Monthly
Mulching Regrade eroded areas Pipe and outlet inspection and clean out Replacing plants as needed	Annually

Detention Basin

Labor

Rainwater capacity

Cost

A DETENTION BASIN (or dry pond) captures a large amount of rainwater and releases it slowly into the ground and the drainage system. This helps reduce flooding on neighboring properties and roadways. Detention basins also help clean and filter rainwater before it enters the ground.

Maintenance of a detention basin will vary based on its planting design. If it has grass, shrubs, or trees, watering during the first year is important to keep plants from suffering "transplant shock." As the shrubs and trees become established, it will need less watering and maintenance. If it has grass, then mowing will be required.

Detention basins will need regular removal of invasive species and debris. Pipes and outlets should be inspected for blockages annually or when there is standing water for more than 48 hours.

See a video of this detention basin during a rainstorm.

Maintenance activities	Schedule
Debris removal Watering & weeding during establishment (if trees & shrubs are present) Mowing turf grass Visual inspection of inlets	Weekly
Weeding	Monthly
Mulching (if trees & shrubs are present) Regrading eroded areas Reseeding turf grass as needed Replacing plants as needed (if trees & shrubs are present) Pipe inspection and clean out	Annually

Stormwater Planter Box

Labor

Rainwater capacity

Cost

A STORMWATER PLANTER BOX captures water from the downspout of a building or canopy. Water is filtered through layers of mulch, soil, rock, and plants before it soaks into the ground. Stormwater planters can connect to an existing downspout and do not need a large amount of space. Planters can include native grasses, flowers, shrubbery, or trees.

During its first year, a planter box needs to be watered often enough to keep plants from suffering "transplant shock." As the plants become established, they will need less watering and maintenance. Additionally, invasive species and debris must be removed. Pipes and outlets should be inspected for blockages annually or when there is standing water for more than 48 hours.

Maintenance activities	Schedule
Debris removal Watering & weeding during establishment Visual inspection of inlets & outlets	Weekly
Weeding	Monthly
Mulching Regrading eroded areas Pipe and outlet inspection and clean out Replacing plants as needed	Annually

Infiltration Trench

Labor

Rainwater capacity

Cost

AN INFILTRATION TRENCH is a long, shallow trench filled with draining rock or crushed stone. The trench directs stormwater along a path, usually away from a building. It also cleans and filters the water while allowing it to soak into the ground.

During the first year, it is important to monitor drainage to be sure the trench is working properly. Over time, the top layer of rock or stone might need to be removed and washed to prevent clogging.

Maintenance activities	Schedule
Debris removal Weeding Visual inspection of inlets & outlets	Monthly
Regrade eroded areas Pipe and outlet inspection and cleanout	Annually
Washing of the top layer of aggregate	As needed

Pervious Pavers

Labor

Rainwater capacity

Cost

PERVIOUS PAVERS are solid interlocking paving units made of fired clay or concrete. They allow water to flow through the joints between the individual pavers. The joints are filled with small rocks or stones that still provide space for stormwater to flow.

They can be used instead of concrete, for walking paths, patios, or driveways. If pavers are near plants or trees, debris will need to be cleared during the growing season.

It's important to prevent trash and debris from collecting on the pavers to keep the system from clogging. This is especially important during the first year after the installation of project.

Maintenance activities	Schedule
Debris removal Visual inspection of inlets & outlets	Every other week
Spot pressure washing	Every other month
Replace joint fill material	Annually

Rain Barrel

Labor

Rainwater capacity

Cost

RAIN BARRELS collect rain runoff from the roof of a building through a downspout. Water can be stored for later use or held and released slowly back into the ground. Water stored in rain barrels can be used for many things, including to water gardens or wash cars.

Rain barrels will require regular removal of debris. Outlets, downspouts, and barrel screens should be inspected regularly. Additionally it is critical that rain barrels are drained within 24 hours of a rainstorm.

Maintenance activities	Schedule
Empty rain barrel within (24) hours of rainstorm	As needed
Debris removal Visual inspection of inlets & outlets	Weekly
Inspect barrel screen for signs of wear or deterioriation and repair / replace as needed Check that gutters and downspouts are secured to building	Twice a year
Clean and disinfect cisterns / rain barrels	Annually

Plant Trees

Labor

Rainwater capacity

Cost

PLANTING TREES helps to reduce rain runoff by absorbing water. A single mature bald cypress tree can absorb over 500 gallons of water per day.

During the first year of growth, water bags should be filled weekly. Weeding around the base of the tree should occur monthly. Additionally re-mulching around the tree base and pruning should be done annually.

Maintenance activities	Schedule
Fill water bags	Weekly (for first year)
Weeding	Monthly
Mulching Elevate lower limbs and remove dead, rubbing, or crossing limbs	Annually

Green Infrastructure

Community Organizations

​Project types

Rain Garden

Detention Basin

Stormwater Planter Box

Infiltration Trench

Pervious Pavers

Rain Barrel

Plant Trees

Project types