Frequently Asked Questions

What is green infrastructure?
Why should I consider using green infrastructure on my project?
Does green infrastructure require more maintenance?
Don’t rain gardens look weedy and overgrown?
Since it collects water, doesn’t green infrastructure also breed mosquitoes?
How well does pervious pavement work? Is it durable?
Will a green roof work in winter?
Will road salt kill the plants in green infrastructure practices?
Will a green roof cost more because of its structure?
My clients don’t want a rain garden. Is that their only option?
Does green infrastructure cost more?
Will using green infrastructure on my projects increase my costs to meet building codes?
Does green infrastructure qualify me for any tax abatements or tax savings?
Where can I learn more about green infrastructure options to consider for my next project?
Are there green infrastructure consultants?


What is green infrastructure?
Green infrastructure is an approach to managing stormwater that is modeled on natural processes and systems. Unlike conventional “gray” infrastructure, which carries rainwater away from where it falls through gutters, drains and pipes, green infrastructure keeps most stormwater on-site through infiltration and beneficial reuse. In urban and suburban areas, this helps restore the natural water cycle and provides many environmental benefits. Rain gardens, green roofs, pervious pavements, and other types of green infrastructure practices can save money, help satisfy permitting requirements, and increase public acceptance of your development project.

Green infrastructure practices have been installed successfully throughout New Jersey. While these practices may not prevent flooding in extreme rain events, they have proven to be as effective as gray infrastructure at managing stormwater in many settings. They offer a cost-effective way for developers to help meet regulatory requirements, provide aesthetic enhancements for communities, attract customers to retail centers, and reduce long-term energy costs.


Why should I consider using green infrastructure on my project?
Green infrastructure can be a valuable tool for meeting the requirements of the state’s Stormwater Rule. It can offer the same stormwater management benefits as traditional gray infrastructure while providing a suite of other financial, and community engagement benefits to your development project at the same or lower cost. See the Green Infrastructure Benefits section of this Guide for further detail on how and why green infrastructure can serve your project. For specific examples of how some developers have leveraged green infrastructure for multiple benefits, refer to the Case Studies section of this Guide. For a side-by-side comparison of how green stacks up to gray infrastructure for a sample development scenario, refer to the Side-by-Side Comparisons.

In addition, green infrastructure can also help the local and state economy. It generates jobs for engineers, environmental scientists, and landscape architects who have technical knowledge of appropriate, site-specific practices. The installation of systems creates jobs for construction workers. The need to maintain system after construction also helps to create jobs, especially for entry level workers. These entry level jobs can lead to higher paying jobs as workers gain experience and knowledge.


Does green infrastructure require more maintenance?
No. A common misconception about green infrastructure is that it requires significantly more maintenance than traditional gray infrastructure or traditional landscaping. This is not the case. Maintenance tasks are usually very simple (such as occasional weeding, cleanup, etc.) and can be done by the property owner or the routine landscaping crew.

Maintenance varies depending on the type of green infrastructure practice. For example, recommended maintenance for pervious asphalt pavement involves biannual vacuuming to remove fine sediments. Less maintenance is required compared to regular asphalt due to superior snow melting characteristics.

(http://www.sandiegocounty.gov/reusable_components/images/dgs/
Documents/Grants_Prop40_AppendIII_.pdf)

Landscape practices need regular maintenance to remove debris, replace mulch in some cases, and maintain vegetation. Inspections (e.g., for erosion and sediment accumulation, or pH testing) can be performed occasionally as needed. (http://www.bluewaterbaltimore.org/wp-content/uploads/ RainGardenRoutineMaintenance1.pdf)


Don’t rain gardens look weedy and overgrown?
Rain gardens can be planted to look naturalistic, like a meadow, or they can be maintained with a more formal garden appearance. The plants and landscape design that are chosen will determine the appearance. If you think your customers would prefer a garden-like aesthetic over a meadow, simply communicate this need to the landscape designer or engineer. Like any garden, regular maintenance will ensure that it does not become weedy and overgrown.


Since it collects water, doesn’t green infrastructure also breed mosquitoes?
Mosquitoes are one of the most common concerns that citizens tend to raise about green infrastructure, but this concern is addressed by standard design requirements. Green infrastructure practices are designed to drain within 72 hours or less, which will prevent colonization of mosquitoes since they take about 72 hours to develop into their adult stage. Rain barrels, which may contain standing water for longer, should be covered with a mosquito net or screen to prevent mosquitoes from laying their eggs. Owners of rain barrels may also use Bti granules or “dunks”, an organic and highly effective way to prevent mosquitoes from multiplying.


How well does pervious pavement work? Is it durable?
The key difference between conventional concrete and asphalt pavements and pervious pavements is that the smallest stone particles, or fines, are left out of the pervious pavement mixture. This leaves small voids that allow water to infiltrate through the pavement. However, these pore spaces do slightly reduce the durability of the pavement in comparison with conventional pavements. Therefore, pervious pavements should be used strategically in areas with low vehicular traffic like parking stalls in parking lots or pedestrian and bicycle pathways. With proper design, construction and maintenance, pervious pavement works well for many years, including in winter weather. Black ice does not form on pervious asphalt, as any thawed water infiltrates; thus, pervious asphalt can help prevent slip and fall accidents.


Will a green roof work in winter?
Green roofs are still able to perform in cold weather, although not necessarily at the same level of effectiveness as during warm seasons. The soil in green roofs is porous, and therefore pervious, to some extent when frozen. Therefore, rainfall as well as snow that melts during freeze-thaw cycles can still be stored, although it will not be used by dormant plants.
(https://www.epa.gov/green-infrastructure/winter-weather-om-green-infrastructure)


Will road salt kill the plants in green infrastructure practices?
Green infrastructure practices, especially those located next to streets or sidewalks, should be designed with plants that are salt tolerant. They are also designed with well-drained soil that helps flush salt through the soil more rapidly and reduce high concentrations that negatively affect plants. Thus, road salt rarely kills the plants, although it can cause stress and damage if used in large quantities. To reduce the potential for any damage, you can choose eco-friendly salt such as calcium chloride, which is safe for plants and pets, or you can reduce the amount of salt spread.
(http://plant-pest-advisory.rutgers.edu/impact-of-road-salt-on-adjacent-vegetation/)
(http://www.deeproot.com/blog/blog-entries/minimizing-the-effects-of-salting-on-urban-trees)


Will a green roof cost more because of its structure?
Green roof cost will depend on the type of roof and the amount of weight you are loading onto the rooftop. A new building can be designed to support this additional weight. For existing buildings, a structural engineer should be consulted to ensure the rooftop is able to support the additional load. In many cases, the lightweight materials used for green roof construction allow for a retrofit on an existing building.


My clients don’t want a rain garden. Is that their only option?
There are many different types of green infrastructure that can be chosen to meet the specific needs of your client or project. For example, porous pavements and rain barrels can offer great alternatives in cases where a landscape practice is not the right choice for your project. Driveways and walkways can be repaved with porous pavement to infiltrate runoff from those surfaces, and downspouts can even be redirected into them to catch rooftop runoff as well. Rain barrels can be used to catch runoff from rooftops for reuse in watering plants or washing cars.

Although some homeowners have been discouraged from installing rain gardens due to misconceptions about them, many others in New Jersey have realized the functionality of green infrastructure and the benefits that rain gardens can bring to their home and community. For example, rain gardens can add to the aesthetics of a home, lower landscape maintenance costs, and can even increase property value!


Does green infrastructure cost more?
Green infrastructure practices often are more cost-effective than traditional gray infrastructure. Integrating green infrastructure into development projects can reduce costs by decreasing the amount of underground drainage piping and structures needed to manage stormwater, which reduces construction costs. Green infrastructure can reduce operations and maintenance costs associated with development properties. For example, a green roof can reduce heating and cooling costs for a building. Green roofs also last longer than conventional roofs, which reduces replacement costs. Pervious pavements have been shown to cost less to maintain over the long term than conventional pavements, resulting in accumulated savings that exceed higher initial installation costs. In some cities, green infrastructure saves property owners money by reducing or avoiding stormwater fees. No city in New Jersey levies stormwater fees — yet.


Will using green infrastructure on my projects increase my costs to meet building codes?
If designed thoughtfully, green infrastructure should not affect your ability to meet building codes. In most cases, green infrastructure can be sited far enough away from the building to avoid any potential concerns about infiltrating near foundations, etc. In the case of green roofs, these are most commonly integrated as part of the overall building design and any potential increase in structural loads are addressed through the normal design process. Before installing green infrastructure, it is always advisable to check municipal codes, design standards, and planning to determine potential impacts on the development process. There are different steps that can be taken to address issues that might arise as a result of regulations and codes. For more information, visit the US Environmental Protection Agency (EPA) website.


Does green infrastructure qualify me for any tax abatements or tax savings?
Currently, green infrastructure practices do not usually qualify for abatements or tax savings. Tax abatements or tax savings vary from municipality to municipality as each city or town decides what will or will not qualify for tax abatement or tax savings. Contact your local municipality for information about abatements or other incentives.


Will green infrastructure help me qualify for LEED certification?
Yes. The LEED rating system offers up to four points toward certification for managing rainwater on site. Points are awarded based on the percentile of regional or local rainfall events that are managed using green infrastructure. For example, managing rainfall in 80th percentile is worth one point, while the 95th percentile is worth four points. It is calculated using daily rainfall data and methodology.
(http://www.usgbc.org/node/2611408?return=/credits/neighborhooddevelopment-
plan/v4/green-infrastructure-%26amp%3B-buildings)
(http://www.usgbc.org/node/2613289?return=/credits/neighborhooddevelopment-
plan/v4/green-infrastructure-%26amp%3B-buildings)
(http://www.usgbc.org/node/2614047?return=/credits/neighborhooddevelopment-
plan/v4/green-infrastructure-%26amp%3B-buildings)


Where can I learn more about green infrastructure options to consider for my next project?
The Rutgers Cooperative Extension (RCE) has created the Rutgers Green Infrastructure Guidance Manual in which the different types and benefits of green infrastructure practices are described. The Rutgers manual can be found at http://www.water.rutgers.edu/. Other useful considerations can be provided by Georgetown Climate Center, EPA, University of New Hampshire, and the Center for Watershed Protection.
(http://water.rutgers.edu/GreenInfrastructureGuidanceManual.html)
(http://www.georgetownclimate.org/)
(https://www.epa.gov/green-infrastructure)
(https://www.unh.edu/unhsc/)
(http://www.cwp.org/)


Are there green infrastructure consultants?
Yes. Many engineering, landscape architecture and architecture firms in the region have professionals on staff who are knowledgeable about green infrastructure design, installation and maintenance. It is also true that some firms lack this expertise. Ask your design professional what he or she has designed or built. If they tell you green infrastructure doesn’t work or that it’s too expensive, get a second opinion.

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