Enhancing the Urban Environment Through Green Infrastructure

• Author: John R. Nolon
• Pages: 261-298

261

Chapter 7:

Enhancing the Urban

Environment Through

Green Infrastructure

I. The Advent of Green Infrastructure

A. Def‌inition

When viewed from 10,000 feet, a community’s gray infrastructure is clearly

visible. For vehicula r circulation to properly f unction, streets, roads, and

highways have to connect, and provide places for park ing, serving the bui lt

environment eciently. ese linked areas of impervious surfaces are read-

ily observable. An aeria l view shows the connected transportation whole

and it is obvious that these facilities have been carefully planned. Not so

with “green infra structure.” In fact, green spaces a re seriously impaired by

gray infrastructure, interrupting a community’s capacit y to convey water,

provide paths for species to move among t heir habitats, provide shaded

streetsc apes and buildings, and create natura l places for people to walk and

bike, rather than drive. From the air, they often appear as dysfunctional

fragments. Green infrastructure planning strives to connect the natural

assets of the community much in the same way that planners design a

localit y’s gray infrastructure.

Green infr astructure pla nning strives to con nect the natural a ssets of the commu nity much in the

same way that e ngineers desig n a locality’s gray inf rastructure . From left to right , images show exist ing,

convention al,and preferred d evelopment and the ir effects on gre en connectivit y. RPA.

262 Standing Ground

Planners concerned with green infrastructure calcu late the current green

space coverage and connectivity and gure out methodsof increasing it

to a healthy percentage of the sur face area of the community, so that a n

adequate percentage of the land is sheltered and shaded, with its soils held

intact and its ability to absorb and retain water preserved, if not enhanced.

Under the urban tree canopy and between intense zones of green, they

labor to connect streams and channels, provide pat hs for people and spe-

cies, direct and control the ow of water, and provide places along the way

for rest and play.

e elements of green infrastructure include green roofs, planters, rain-

water harvesting, street trees, preserved open space on building sites, natural

vegetated corridors and swales, permeable paved areas accented with green

features, xeriscaping, private gardens and public parks, detention basins, bio-

retention ponds and rain gardens, green building facades, and greened medi-

ans and edges along streets, paths, and rail lines. Parking lots can be greened

by adding trees and using permeable surfaces that allow inltration and per-

mit vegetative growth. W hen seen from the air, the community with robust

green infrastructure now appears more connected naturally and, in an ideal

circumstance, the green and the gray are complementary. is is a dicult

task in most places because of the fragmentation that the built environment

has already wrought on urban green space.

Some dene green infrastructure more narrowly as an approach to

stormwater management; it is often measured by its ability to prevent the

devastating eects of ooding on property and riparian landscapes. e

U.S. Environmenta l Protection Agency (EPA) is particularly keen on using

green infra structure techniques to manage stormwater as a method of guid-

ing and encouraging communities to comply with stormwater management

regulations mandated by Phases I and II of its Clean Water Act, which are

discussed in both Chapters 2 and 4. For this purpose, land use laws and

buildingcodes are reformed toensure that buildings have disconnected

downspouts; are equipped with rainwater harvesting devices; and that sites

are required to use permeable pavement, bioswales, pla nter boxes, and rain

gardens.Site plan and subdivision regulations are amended to include a

variety of low impact development (LID) features, the most ambitious of

which attempt to retain pre-development hydrological conditions on the

site. A new rating system, Susta inable Sites, has been created for developers

and communities to use to review the degree to which natural site features

are retained or restored during development. Other programs incorporat-

ing key elements of green infrastructure include: LEED-ND, Smart Codes,

Enhancing the Urban Environment Through Green Infrastructure 263

Complete Streets, and the New York Climate Smart Communities Certi-

cation Program, to name a few.

In one sense, this book is all about green infrastructure: balancing con-

servation and development, as discussed in Chapter 1. Chapters 3 and 4,

particularly, deal with land use techniques that preserve natural features of

the locality. When local land use law is used to protect a ridgeline, a stand

of trees, or a watershed, wetland, or view-shed, it is preserving that patch

of green infrastructure. When an overlay district is used to protect a criti-

cal environmental area, that area’s natural features are protected. What the

architects of green infrastructure, in its broadest sense, do is use these land

use techniques in an integrated fashion; they plan the entire community so

that its natural functions are connected, healthy, and serve to create healthy

and livable neighborhoods.

B. Benef‌its and Purpose

e broad view of green infrastructure sees it as a strategy for adapting to

climate change, bettering air quality, lowering heat stress, creating greater

biodiversity, conserving energy, providing ecological services, sequestering

carbon, preserving and expanding habitats, enhancing aesthetics, increas-

ing property values, and improving the livability of neighborhoods. Green

infrastructure—with tree canopies covering a third or more of the space at

the neighborhood level, green roofs, and pocket parks or other small patches

of green open space—lessens urban temperatures (the “heat island eect”)

and sequesters CO2.

Green infrastructure can bring economic benets to property owners and

municipalities. ese include increased property values, greater retail busi-

ness and sales, higher rents, lower energy costs and water bills, less damage

from oods, and increased job satisfaction and health for employees. Green

jobs associated with the greening of landscapes, buildings, and infrastruc-

ture can provide employment often in walking distance—or a short bus ride

away—from the homes of residents in lower income neighborhoods. On the

municipal side, these benets to building and business owners translate into

more property and sales tax revenue, reduced joblessness, and a more robust

local economy.

In recent years, EPA’s green infrastructure emphasis has broadened from

its initia l focus on stormwater management. In its 2014 Green Infrastruc-

ture Technical Assistance Program, which provides help to localities, EPA

describes its eorts to help communities across the country interested in