Does Green Infrastructure Link to Green Building?

It is important to avoid confusing green building and green infrastructure.  Green infrastructure operates first at a landscape scale, looking across parcels and ownerships.  Ideally, green infrastructure planning occurs before development begins. Land can be designated appropriately for protection and/or restoration to provide wildlife habitat, recreation, stormwater treatment, energy savings, aesthetic values, improved community health, and sustainable economies. See Steps to Green Infrastructure Planning.

Green infrastructure is often confused with the field of green building. In the context of building "green," certification programs such as LEED (leadership in environment, energy and design) promoted by the U.S. Green Building Council, or Earthcraft, a rating system applied to energy efficient standards for homes are used for individual buildings.  LEED has recently expanded to include Neighborhood LEED.  However, Earthcraft and other building oriented programs do not do a good job of considering the landscape.  LEED pays some attention to this, such as recommending siting buildings on the land to achieve least impact, minimizing off-site impacts by capturing and treating stormwater, or orienting buildings to maximize heating and cooling efficiency. 

However, these programs do not require that a development seek to connect wildlife corridors or necessarily maximize tree cover on a site.  Landscape scale approaches are often missed as each developer protects some green space, but they often do not connect habitat across multiple parcels. Within sites, developers may build on inappropriate areas of a site that should instead be preserved for groundwater recharge or other “green infrastructure” functions.  For more on these approaches, see Appendix A.

Moving from the building envelope to the site itself, approaches such as Low Impact Development (LID) are often employed by progressive developers. Low impact development is a design strategy with a goal of maintaining or replicating the pre-development hydrologic regime through the use of design techniques to create a functionally equivalent hydrologic site design” (Low Impact Development DRAFT Technical Bulletin).   LID is used to offset practices of the built environment and operates at the site scale.  For example, a raingarden is a wonderful way to slow and filter stormwater and localities and builders are encouraged to employ raingardens in new building sites or, they can be utilized in watershed planning efforts to retrofit developed urban areas with better stormwater management.

There are ways to re-think development patterns so that growth incorporates essential resources. This presentation illustrates examples of a development process that involves green infrastructure concepts.

Land planning that begins within the context of local ecological systems can ensure that development is channeled to the most appropriate areas, such as nearer to existing grey infrastructure.  Within larger sites, such as 100 acres or greater, green infrastructure is evaluated within the site and across the landscape so that the site does not become disconnected from other important corridors, such as riparian systems, or large forests or dune systems. Green infrastructure planning provides an opportunity for communities to approach land use planning in a new way.

When considering development, scales should be linked and it is important that linkages flow both up and down. Consider impacts and opportunities at all four scales for an effective strategy. Begin with the regional scale in mind.

There is great confusion in the development community on what to do and how to think about this. As an LID expert says "LID is not a license to develop anywhere."   We need to separate approaches and scales and explain when and how to combine strategies.  A raingarden is a wonderful way to slow and filter stormwater at the site scale, while green infrastructure is a landscape planning tool that looks across sites at operates at larger scales.  In short, we can think of a forest as green infrastructure and a raingarden as a best management practice within an LID strategy, that is intended to mimic the forest’s function and mitigate impacts from the built environment. 

It is worth asking, why does this matter? Why should we distinguish green infrastructure from green building?  It’s all green so it’s all good, right?  The short answer is yes, but the order and scale of approach are critical to really ensuring that we develop not just green buildings, but also in ecological sound  patterns.  It is important that the development community think first of harnessing natural assets and taking advantage of what is already on the landscape. 

Consider this example.  A multiple unit housing project proposed by an affordable housing group and was touted as “green” because the homes would be built to “Earthcraft”  standards.  However, upon reviewing the site plan, it was evident that they planned to clear the site, remove the large native trees, plant smaller ‘urban’ trees and build raingardens to treat the excess stormwater generated.  Yet the large trees on the site could uptake a great deal more stormwater than any of the new smaller caliper trees that were proposed.   It was pointed out to the builder that leaving the large trees in place would be important to shading the houses, thus making them cooler and using less energy.

Based on these critiques, the group modified their site plan to conserve the site’s green assets, leaving the large shade trees intact and reorienting the buildings to maximize solar benefits.  This example shows how a development that is touted as “green” might not really be green at all, because the site’s best “green infrastructure” was not considered at the outset.

In another housing development, the developer touted their large areas of “green space” but built the development far back from the road in a rural area, thus fragmenting the forests more than necessary, paving more of the landscape with excess roads and increasing stormwater runoff. They also placed the houses on top of critical groundwater recharge areas for the community’s drinking water supply, thus reducing infiltration of water and natural filtering by trees.  Trails proposed for the development didn’t connect to the larger trail network. So, while the developer clustered the buildings closer together on the site, he didn’t put them in the right area or preserve important landscape connections. This example shows how only thinking of clustering the houses without considering the site’s relationship to a larger green network can result in development plans that are far more damaging than necessary. 

Finally, identification and economic assessment of a community’s natural assets are an important part of GI planning efforts. Placing a dollar value on stormwater mitigation or water filtration services provided by a natural system can help localities make more informed decisions about whether particular land areas are best suited for new development or should be set aside for a greenway or acquired for a wildlife refuge or parkland."  Those developers who take a “green infrastructure approach” can reap ecological and economic rewards.

Protecting Green Infrastructure Pays Dividends

• An old levee on Savannah River becomes a “riverwalk” with $8 million invested = a return of $198 million in new investment.
• National Association of Realtors Study (NAR) of homebuyers: 1-2% golfed, 5-6% swim and more than 50% use paths.
• NAR showed 57% of voters are more likely to purchase a home near to green space and 50% are willing to pay 10% more.
• Homes adjacent to a greenbelt in Boulder Colorado were valued 32% higher than those 3,200 feet distant (Correll et al, 1978)