svEPA
United States
Environmental Protection
Agency
2013 GREEN INFRASTRUCTURE TECHNICAL ASSISTANCE PROGRAM
City of Spartanburg and Northside Development Corporation
Spartanburg, SC
(Optional) Permeable pavement
parking or bike lane
Street planter with bioretention
media, gravel layer, and underdrain
Northside Neighborhood Green Infrastructure
Master Plan
Integrating Green Infrastructure into a Neighborhood Redevelopment Plan in
Spartanburg, South Carolina
Rendering credit: JHP Architects and Tetra Tech, Inc.
February 2015
EPA832-R-15-001
-------
About the Green Infrastructure Technical Assistance Program
Stormwater runoff is a major cause of water pollution in urban areas. When rain falls in undeveloped
areas, soil and plants absorb and filter the water. When rain falls on our roofs, streets, and parking lots,
however, the water cannot soak into the ground. In most urban areas, stormwater is drained through
engineered collection systems and discharged into nearby water bodies. The stormwater carries trash,
bacteria, heavy metals, and other pollutants from the urban landscape, polluting the receiving waters.
Higher flows also can cause erosion and flooding in urban streams, damaging habitat, property, and
infrastructure.
Green infrastructure uses vegetation, soils, and natural processes to manage water and create healthier
urban environments. At the scale of a city or county, green infrastructure refers to the patchwork of
natural areas that provides habitat, flood protection, cleaner air, and cleaner water. At the scale of a
neighborhood or site, green infrastructure refers to stormwater management systems that mimic
nature by soaking up and storing water. These neighborhood or site-scale green infrastructure
approaches are often referred to as low impact development.
The U.S. Environmental Protection Agency (EPA) encourages using green infrastructure to help manage
stormwater runoff. In April 2011 EPA renewed its commitment to green infrastructure with the release
of the Strategic Agenda to Protect Waters and Build More Livable Communities through Green
Infrastructure. The agenda identifies technical assistance as a key activity that EPA will pursue to
accelerate the implementation of green infrastructure. In October 2013 EPA released a new Strategic
Agenda renewing the Agency's support for green infrastructure and outlining the actions the Agency
intends to take to promote its effective implementation. The agenda is the product of a cross-EPA effort
and builds upon both the 2011 Strategic Agenda and the 2008 Action Strategy.
EPA is continuing to provide technical assistance to communities working to overcome common barriers
to green infrastructure. Selected communities received assistance with a range of projects aimed at
addressing common barriers to green infrastructure, including code review, green infrastructure design,
and cost-benefit assessments.
For more information, visit water.epa.aov/infrastructure/areeninfrastructure/gi support.cfm.
-------
Acknowledgements
Principal USEPA Staff
Tamara Mittman, USEPA
Christopher Kloss, USEPA
Eva Birk, USEPA
Katie Snyder, USEPA Region 4
Community Team
Jay Squires, City of Spartanburg
Curt McPhail, Northside Development Corporation
Consultant Team
Jonathan Smith, Tetra Tech
Christy Williams, Tetra Tech
Bobby Tucker, Tetra Tech
Martina Frey, Tetra Tech
This report was developed under EPA Contract No. EP-C-11-009 as part of the 2013 EPA Green
Infrastructure Technical Assistance Program.
-------
Contents
1 Executive Summary 1
2 Introduction 2
2.1 Northside Neighborhood 2
2.2 Northside Redevelopment Goals 5
2.3 Role of Green Infrastructure in the Northside Redevelopment 9
3 Stormwater Management Toolbox 13
3.1 Green Infrastructure Policies, Regulations, and Incentives 13
3.1.1 Planning 13
3.1.2 Parking Requirements and Lot Design 15
3.1.3 Street Design 18
3.1.4 On- and Off-site Stormwater Controls 19
3.1.5 Buffer Requirements 24
3.1.6 Urban Agriculture 24
3.2 Structural Green Infrastructure Practices 27
3.2.1 Bioretention Facilities 27
3.2.2 Permeable Pavement 30
3.2.3 Green Roofs 31
3.2.4 Rainwater Harvesting 33
3.2.5 Infiltration Basins 34
3.2.6 Urban Agriculture Integration 35
4 Conceptual Designs 37
4.1 Design Assumptions and Methodology 37
4.2 Residential Block 39
4.3 Green Street 42
5 Preliminary Opinion of Probable Costs 47
5.1 Unit Cost Data 47
5.2 Typical Residential Block 47
5.3 Green Street 48
6 Operations and Maintenance 49
7 Conclusions 51
8 References 52
-------
Figures
Figure 1. View from Folsom Street looking southeast 2
Figure 2. View of Brawley Street looking northwest 2
Figure 3. Existing conditions 3
Figure 4. Northside Redevelopment Plan properties 4
Figure 5. Site plan for Healthy Food Hub on Howard Street 5
Figure 6. Artist's rendering of new gateway into the Northside 6
Figure 7. Artist's rendering of the daylighted creek 7
Figure 8. Full Northside Redevelopment Plan developed at the Public Workshop 8
Figure 9. Walking distances in the Northside redevelopment area 11
Figure 10. Examples of bioretention incorporated into rights-of-way 18
Figure 11. Comparison of bioretention discharge and predevelopment streamflow 20
Figure 12. Rainfall/runoff response before and after retrofitting of rain gardens in an existing
development 21
Figure 13. Brooklyn Navy Yard rooftop farm 25
Figure 14. Chicago Botanical Rooftop Garden 25
Figure 15. Detroit Urban Farm on a previously vacant lot 25
Figure 16. Ohio City Farm 25
Figure 17. Bioretention incorporated into a right-of-way 28
Figure 18. Bioretention incorporated into traditional parking lot design 28
Figure 19. Planter box within the street right-of-way (top) and flow-through planter box attached
to a building (bottom) 29
Figure 20. Tree box using grate inlets in street 29
Figure 21. Pervious concrete (above) and permeable interlocking concrete paver (below) parking
stalls 30
Figure 22. Furman Company, Greenville, South Carolina (top left), Riverside High School, Greer,
South Carolina (bottom left), Charleston VA Medical Center, Charleston, South Carolina (right) 32
Figure 23. Belowground cistern (left) and wood-wrapped cistern (right) 33
Figure 24. Infiltration basin as recreation area 34
Figure 25. Stormwater reuse concept for urban agriculture in the Northside 35
Figure 26. Residential block used for concept plan 40
Figure 27. Scenario 4 concept plan with equivalent BMP footprint areas 42
Figure 28. Section of Evins Street extension used for green street concept plan 43
Figure 29. Scenario 1 green street concept plan with street planters 44
Figure 30. Section view of green street concept plan with street planters 45
IV
-------
Tables
Table 1. Studies estimating percent increase in property value from green infrastructure 12
Table 2. Comparative volumetric unit costs of stormwater control measures 22
Table 3. Advantages and limitations of rainwater harvesting 34
Table 4. Annual runoff reduction rates for selected BMPs (Hirschman et al. 2008) 38
Table 5. Site and soil information used in EPA's Stormwater Calculator 39
Table 6. Proposed land cover for typical residential block 40
Table 7. Hydrologic results from EPA's Stormwater Calculator for residential block concept plan 41
Table 8. Hydrologic results from EPA's Stormwater Calculator for green street concept plan 44
Table 9. Green infrastructure planning level unit costs per acre treated (King and Hagen 2011) 47
Table 10. Preliminary implementation cost estimates for the typical residential block project site 48
Table 11. Preliminary implementation cost estimates for the green street project site 48
Table 12. Bioretention operations and maintenance considerations 49
Table 13. Permeable pavement operations and maintenance considerations 50
-------
I Executive Summary
The Northside Community near downtown Spartanburg, South Carolina is home to one of the most
ambitious revitalization efforts in the City's history. Known as the Northside Initiative, the project aims
to redevelop approximately 400 acres of an economically distressed, old textile mill neighborhood into a
vibrant, diverse community. At the core of the initiative is the draft Northside Redevelopment Plan
(Redevelopment Plan). The Redevelopment Plan was cultivated through public input and includes
affordable housing, mixed-use commercial development, urban agriculture, innovative school programs,
community recreation facilities, health care, social services, and restored parks and green space.
The goal of this effort is to help incorporate green infrastructure into the Redevelopment Plan. Green
infrastructure can help realize the vision of a more vibrant, livable Northside by promoting many
community objectives, including:
• Improving and protecting water resources;
• Enhancing potable and non-potable water supplies;
• Increasing enjoyment, aesthetics, and overall well-being in the neighborhood;
• Promoting urban agriculture and a community-supported local food system;
• Increasing safety and reducing crime; and
• Raising property values
Based on feedback from Northside's residents during a public workshop, a set of green infrastructure
goals was prioritized. The Northside neighborhood residents indicated that they wanted more green
space, access to fresh food, more opportunities to recreate outdoors, and more walkable
neighborhoods. To accomplish these overall goals, the community selected five site-specific
transformational projects to be designed and implemented in the redevelopment area. Each of these
projects will incorporate green infrastructure principles such as green space, street trees, urban
agriculture, and a riparian greenway.
Given the early phase of the overall redevelopment project, this effort developed a set of conceptual
green infrastructure recommendations to advance the community's vision. Recommendations are
presented at two scales. First, the Stormwater Management Toolbox (Section 3) discusses a suite of
nonstructural and structural practices that apply to the block densities and streetscape styles proposed
for the Northside redevelopment area. Second, the Conceptual Designs (Section 4) develop green
infrastructure scenarios for two land use typologies characteristic of the proposed Redevelopment Plan.
This report describes key findings that can be applied to the Northside neighborhood and to similar
redevelopment projects, demonstrating how green infrastructure can support and enhance infill, mixed
use development.
-------
2 Introduction
2.1 Northside Neighborhood
The Northside neighborhood of Spartanburg, South Carolina (referred to as "the City" throughout this
document) was once a regional transportation hub and viable, thriving mixed-income community with
retail shops and community amenities. The economic downturn and a decline in manufacturing left the
neighborhood severely distressed, suffering from deteriorated and dilapidated homes, overcrowding,
and vacant lots. Figure 1 and Figure 2 show street views of the neighborhood, and Figure 3 provides an
aerial view of existing conditions. The following are some of the basic challenges facing the Northside
neighborhood:
• Almost 1,000 residents moved out of the greater Northside area between 2000 and 2010, a
19 percent drop in population, according to census data.
• Nearly one in every two houses is vacant.
• The Northside was the hardest-hit neighborhood in the City by the mortgage crisis.
• Unemployment in the neighborhood was 26.1 percent in 2012.
• For many years, parts of the Northside community had the highest crime rates in the City.1
• The Spartanburg County School District 7, which serves the neighborhood, had a graduation rate
of only 65.8 percent in a recent year.2
Source: Tetra Tech, Inc.
Figure I. View from Folsom Street looking
southeast.
Source: Tetra Tech, Inc.
Figure 2. View of Brawley Street looking northwest.
1 purposebuiltcommunities.org/success-stories/spartanburg/
2 portal.hud.gov/hudportal/documents/huddoc?id=FY12CNPIangGrantSummaries.pdf
-------
Source'. Google Earth
Figure 3. Existing conditions.
The Northside neighborhood is also home, however, to one of the most ambitious revitalization efforts
in the City's history. Known as the Northside Initiative, the project aims to redevelop approximately
400 acres of the economically distressed, old textile mill neighborhood into a vibrant, diverse
community. One of the initiative's greatest strengths is the committed support of diverse private and
public organizations, businesses, and citizen groups in the City and beyond. At the foundation of the
initiative is the Northside Development Corporation (NDC), a nonprofit started in 2010 to lead the
revitalization project. The purpose of the NDC is to acquire vacant, foreclosed, or distressed properties
in the area. NDC has raised more than $2.5 million dollars through grants and private and public funding
avenues, and acquired nearly 100 parcels of vacant and distressed property in the area. The City has
used federal dollars to purchase almost 50 properties. These properties, outlined in Figure 4, have been
acquired for the purpose of enabling cost-effective additions of new housing and other area amenities.
-------
JHP
ntil rrn)l«il pni4f*»
Northside Redevelopment Plan
Spartanburg.SC
Pa reel Ownership
NTS
01.08.2014 [201^064.00
Source: JHP Architects
Figure 4. Northside Redevelopment Plan properties.
4
-------
Although the NDC is spearheading the initiative, the project has gained momentum from many local and
federal players' contributions. The Northside community is anchored by multiple institutions—Edward
Via College of Osteopathic Medicine (VCOM), Wofford College, Cleveland Academy of Leadership, and
Spartanburg Regional Medical Center—all of which bring people and energy to initiate community-
driven, sustainable redevelopment. In addition, when it opens in the Northside neighborhood in May
2014, the Healthy Food Hub (see Figure 5) will become home to the Hub City Farmer's Market, the
Butterfly Foundation and its culinary arts program, and a community garden and cafe. The Healthy Food
Hub will bring many benefits to the Northside, including increased access to healthy foods and fresh
fruits and vegetables among a "food desert" community, new jobs and vocational training, productive
green space, and a safe place for community interaction and recreation.
Source: City of Spartanburg
Figure 5. Site plan for Healthy Food Hub on Howard Street.
2.2 Northside Redevelopment Goals
In 2012 the City secured a $300,000 Choice Neighborhoods Program planning grant through the
U.S. Department of Housing and Urban Development to develop a Transformation Plan for the
community. Up to this point, no such planning effort had been conducted in the Northside. As a part of
the planning effort, NDC and the City hosted a public planning and design workshop in January 2014 to
solicit citizen and stakeholder input for developing the overall master Redevelopment Plan. NDC and the
City invited EPA to participate in this effort to educate participants on the multiple benefits of
incorporating green infrastructure into the redevelopment project.
During the 3-day charrette, facilitators recorded the desires of the community and conceptualized five
transformative projects described by participants, which will comprise the community's Redevelopment
Plan:
1. Transforming the awkward Asheville Highway/Church Street/Magnolia Street intersection into a
striking new gateway (Figure 6) into the Northside and the City. The plan would require the
-------
closure of Magnolia Street between Pearl Street and Asheville Highway, and would replace it
with a green space highlighted by public art.
Source: JHP Architects
Figure 6. Artist's rendering of new gateway into the Northside.
2. Extending Evins Street across Church Street, creating a new artery into the heart of the
Northside that would dead-end at the new Healthy Food Hub on Howard Street. The Evins
Street extension would accomplish one of the major goals identified by the workshop
participants—helping people get across Church Street, thereby creating new and better
connections between the Northside, Wofford College, and Spartanburg Regional Medical
Center.
3. Transforming Pearl Street into the "Main Street" of the Northside by widening it; adding bike
lanes, on-street parking, wider sidewalks, street trees, and other landscaping; and zoning it for
multi-use development, with retail and office space on the bottom floor and residential units on
the upper floors of the three- to four-story buildings to come.
4. Creating a multipurpose, educational, recreational, and community services campus on and
adjacent to the current Cleveland Academy of Leadership. Students at Cleveland Academy
voiced their desire for their school—which currently houses kindergarten through 5th grade—to
be expanded to include grades 6-8. Spartanburg School District 7 is considering the idea. In
addition to the expansion required by that move, if it were to happen, planners identified the
area around Cleveland as the logical destination for the new T.K. Gregg Community Center
(which City Council has already committed to building by 2017), a new Early Childhood
-------
Education Center (which has $1.5 million in funding committed through the Mary Black
Foundation), and new ball fields.
5. Daylighting a neighborhood creek that has been paved over and covered up for decades. Locals
call the creek the "Nasty Branch/' but it will be renamed Butterfly Creek. The daylighted creek
and adjoining greenway on either side (Figure 7) would be not just the central feature of the
new Northside, but a significant new environmental asset for the City.
Source: JHP Architects
Figure 7. Artist's rendering of the daylighted creek.
The master Redevelopment Plan diagram (Figure 8) shows the approximate location of buildings,
sidewalks, alleys, and streets for the proposed redevelopment. For this project's purposes, the draft
Redevelopment Plan is used as a framework in which to embed green infrastructure and provide
multiple benefits to residents, as Section 2.3 describes. Section 2.3 also describes specific
implementation options for the above transformative projects and general neighborhood development.
Section 4 provides conceptual drawings to give a visual interpretation of some of these options.
-------
Archibald
FturJedge Tower
;H^,-
Enhanced SidewaUi
and Urban S'-octscap
along Church St )
Sparunburg Fiegional Hospital
Mixed-use Storefront with
Library at Ground level
and Housing Above
Future Medical
services or Offices
Jture Retail
CommunftService
Future ! dWoodwardf
with mtsrpration and
il FieS HrklrKj Coiifi
^^ •
Jf«v*»*4jj ct,urcfl
~ f -1 > -*- i ~ ' «
Incubator Anist Lofts
raded Arch
St Connection
01.11.2014 2013064,00
Master Plan
Scale 1'=100'
Northside Redevelopment Plan
Spartanburg, SC
Source: JHP Architects
Figure 8. Full Northside Redevelopment Plan developed at the Public Workshop.
8
-------
2.3 Role of Green Infrastructure in the Northside Redevelopment
The redevelopment efforts in the City present a unique opportunity to incorporate green infrastructure
into the Northside neighborhood's urban fabric, particularly when these efforts involve redeveloping
vacant lots. By identifying appropriate green infrastructure techniques early in the planning process, this
project seeks to seamlessly integrate green infrastructure practices into the revitalization of the
Northside neighborhood, demonstrating how community-oriented infill projects can serve a wide
variety of stakeholder and community needs.
Green infrastructure is most effective when the following strategies are implemented:
• Minimize effective or connected impervious area.
• Preserve and enhance the hydrologic function of unpaved areas.
• Harvest rainwater to enhance potable and nonpotable water supply.
• Allow and encourage the use of multi-use stormwater controls.
• Manage stormwater to sustain stream functions.
Green infrastructure uses vegetation and soil to manage rainwater where it falls, resulting in multiple
benefits for a community like Spartanburg. Of course, one of the primary benefits is to protect and
improve water quality. Green infrastructure could achieve this benefit in two different ways. First, green
infrastructure will help protect the pristine water quality present in the unjustly named "Nasty Branch"
(soon to be renamed Butterfly Creek). Second, implementing green infrastructure concepts within the
Northside neighborhood will help protect the proposed Butterfly Creek stream restoration effort
through peak flow reduction and improved water quality in the watershed, which will drain to the newly
daylighted stream.
Green infrastructure not only serves as an important design strategy for protecting water quality but can
also provide environmental, social, and economic benefits for the Northside community. The following
are some examples of the benefits that green infrastructure can provide to the Northside residents and
the City:
• Increased enjoyment of surroundings: Implementing green infrastructure practices that
enhance vegetation within the Northside will help create a more pedestrian-friendly
environment that encourages being outdoors, walking, and physical activity. This can improve
the health of residents, reduce the use of cars, and encourage pedestrian traffic through
residential and commercial areas (e.g., Howard Street) planned in the Northside. The Healthy
Food Hub and downtown will be within walking distance (see Figure 9) of the planned
residential areas within the redevelopment area and the Cleveland Leadership Academy.
Incorporating the greenway and planning for greener streets will encourage people to walk and
take advantage of the healthy food options coming to the area. Research suggests that people in
greener neighborhoods judge distances to be shorter and make more walking trips (Wolf 2008).
In addition, incorporating green space into the multi-family residential units in the Northside will
encourage residents to spend more time outdoors, which benefits the heart in many ways. A
large study of inner-city Chicago found that one-third of the residents surveyed said they would
use their courtyard more if trees were planted (Kuo 2003). Residents living in greener, high-rise
-------
apartment buildings reported significantly more use of the area just outside their building than
did residents living in buildings with less vegetation (Hastie 2003; Kuo 2003).
Increased safety and reduced crime: Greener streets and housing areas in the Northside might
also make the neighborhood a much safer place to live. As noted above, people generally walk
more on greener streets. This increases pedestrian traffic and reduces the opportunity for
crime. Also, if properly designed, narrower green streets decrease vehicle speeds and make
neighborhoods safer for pedestrians (Kuo 2001; Wolf 1998). The stress-reducing and traffic-
calming effects of trees are also likely to reduce road rage and improve the attention of drivers.
In addition, contrary to common belief, more vegetation does not lead to more crime, and can
actually be related to a decrease in crime. Researchers examined the relationship between
vegetation and crime for 98 apartment buildings in an inner-city neighborhood. The study found
that the greener a building's surroundings, the fewer crimes were committed (including violent
and property crimes), and that levels of nearby vegetation explained 7 to 8 percent of the
variance in crimes reported by building (Kuo 2001).
Increased sense of well-being: There is a large body of literature indicating that green space
makes places more inviting and attractive and enhances people's well-being. Increasing the
green space in the Northside could improve the landscape, which is currently blighted with
abandoned buildings and parking lots. People living and working with a view of natural
landscapes appreciate the various textures, colors, and shapes of native plants, and the
progression of hues throughout the seasons (Northeastern Illinois Planning Commission 2004).
Birds, butterflies, and other wildlife attracted to the plants add to the aesthetic beauty and
appeal of green spaces and natural landscaping. Attention restorative theory suggests that
exposure to nature reduces mental fatigue, with the rejuvenating effects coming from a variety
of natural settings including community parks and views of nature through windows. In fact,
desk workers who can see nature from their desks experience 23 percent less time off sick than
those who cannot see nature, and desk workers who can see nature also report a greater job
satisfaction (Wolf 1998).
Increased property values: Many aspects of green infrastructure could potentially increase
property values in the Northside neighborhood by improving aesthetics, drainage, and
recreation opportunities. These in turn can help restore, revitalize, and encourage growth in
economically distressed areas. Table 1 summarizes recent studies that have estimated the effect
that green infrastructure or related practices have on property values. The studies used
statistical methods for estimating property value trends from observed data.
10
-------
O Cleveland Park
O Cleveland Academy
O Spartanburg Regional
Medical Center
O Downtown Spartanburg
15 minutes walk
• 10 minutes walk
1 15 minutes walk
Northside Redevelopment Plan
Spartanburg, SC
Source: JHP Architects
Figure 9. Walking distances in the Northside redevelopment area.
Walking Distance
NTS
01.08.2014
11
-------
Table I. Studies estimating percent increase in property value from green infrastructure
Source
Percent increase
in property value
Notes
Ward et al. (2008) 3.5%-5%
Shultz and Schmitz (2008) 0.7%-2.7%
Wachter and Bucchianeri 2%
(2006)
Anderson and Cordell 3.5%-4.5%
(1988)
Voicu and Been (2008) 9.4%
Espey and Owasu-Edusei 11%
(2001)
Pincetl et al. (2003) 1.5%
Hobden et al. (2004) 6.9%
New Yorkers for Parks and 8%-30%
Ernst & Young (2003)
Estimated effect of green infrastructure on adjacent properties
relative to those farther away in King County (Seattle area),
Washington
Referred to effect of clustered open spaces, greenways, and
similar practices in Omaha, Nebraska
Estimated the effect of tree plantings on property values for
select neighborhoods in Philadelphia
Estimated value of trees on residential property (differences
between houses with five or more front yard trees and those
that have fewer), Athens-Clarke County (Georgia)
Referred to property within 1,000 feet of a park or garden and
within 5 years of park opening; effect increases over time
Referred to small, attractive parks with playgrounds within
600 feet of houses
Referred to the effect of an 11% increase in the amount of
greenery (equivalent to a one-third acre garden or park) within
a radius of 200 to 500 feet from the house
Referred to greenway adjacent to property
Referred to homes within a general proximity to parks
12
-------
3 Stormwater Management Toolbox
To meet the project and design goals discussed above, the team identified a set of green infrastructure
practices appropriate for the Northside redevelopment. These practices manage stormwater at the
source and provide neighborhood amenities by integrating planning and multifunctional stormwater
practices into the planned development.
To assist the Northside developers with incorporating green infrastructure practices into the final
Redevelopment Plan, the following discussion addresses constraints and opportunities associated with
each stormwater management practice.
3.1 Green Infrastructure Policies, Regulations, and Incentives
Multiple green infrastructure practices can be incorporated into the Northside Development to
complement and enhance the proposed layout while also providing water quality treatment and volume
reduction. The following sections describe the proposed green infrastructure programmatic approaches
that are well suited for the City and the Northside Development project and will help meet green
infrastructure goals. It is important for the City to keep in mind when considering any of these
approaches that green infrastructure is more likely to be accepted in the community and used in the
Northside Development if plans encourage and the code allows such best management practices (BMPs)
to be in required open space, recreation, landscaped, and right-of-way (ROW) areas.
3.1.1 Planning
The proposed Redevelopment Plan as presented in January 2014 already incorporates several key
planning concepts that support green infrastructure including mixed-use development and
redevelopment of brownfields, greyfields, and infill areas. Mixed-use development areas are proposed
for Howard Street, Magnolia Street, and near VCOM. These areas allow for the co-locating of land uses,
which decreases impervious surfaces associated with parking and decreases vehicle miles traveled-
resulting in a reduction of hydrocarbons left on roadways and reduced air deposition. The Northside will
also realize a significant reduction in regional runoff because the City is taking advantage of underused
properties within the project area. Redeveloping already degraded sites such as the abandoned
warehouses near Cleveland Academy rather than paving undeveloped sites for new development can
dramatically reduce total impervious area while allowing the City to experience the benefits and
opportunities associated with infill growth.
Additional municipal planning approaches could be used to support using green infrastructure within
the Northside and the entire City.
The City's 2004 comprehensive plan and City parks plans could be updated to increase open space and
pervious areas by incorporating a greenway park along Butterfly Creek and smaller "pocket parks"
throughout the project area. The plan can also identify additional public retrofit projects that could use
green infrastructure stormwater management techniques (e.g., Cleveland Academy, community center,
Evins Street roundabout, fairgrounds, and artists' incubator). Open space areas contribute little
pollution to stormwater and can provide large areas to infiltrate and treat stormwater. Urban tree
canopy—for example, along streets or within off-street parking—can improve water quality while also
providing shade, reducing the urban heat island effect, and improving air quality. Adopting a tree
canopy coverage goal in the comprehensive plan could support increasing canopy cover with the
Northside neighborhood. Greenways can provide community connectivity, healthy recreation, and
13
-------
water quality benefits. Parks can provide active and passive recreational facilities and accommodate
green infrastructure BMPs.
Including a watershed protection zone in the City's comprehensive plan for the Butterfly Creek
watershed would help support code changes and guide land use decisions designed to support and
promote green infrastructure. Updating the City comprehensive plan to endorse context-sensitive street
design with narrower streets in appropriate locations around the Butterfly Creek zone, as well as biking
and walking, would provide the guidance necessary to encourage the use of green streets concepts by
the City and by private developers.
In conjunction with developing a watershed protection zone for Butterfly Creek in the comprehensive
plan, delineating a development overlay district in the zoning regulations for the watershed with specific
development requirements or incentives for implementing green infrastructure would allow the City to
institute a variety of development regulations and incentives applicable only to development within the
watershed. The base zoning would not change. This could allow the City to use the Northside
neighborhood as a test case for more progressive green infrastructure practices while ensuring that the
restored Butterfly Creek is adequately protected. For example, Lancaster County, South Carolina, has
established an overlay district to protect the Carolina Heelsplitter, an endangered species of fish in the
Six Mile Creek watershed. The ordinance requires specific riparian buffers associated with the creation
of impervious area as well as the required purchase of credits from the Carolina Heelsplitter
Conservation Bank. Charlotte-Mecklenburg County in North Carolina has established multiple
watershed overlay districts to protect potable water sources which specifies uses, buffers, density, and
post-construction stormwater BMPs.
Note that the implementation options presented in the remainder of this section assume that an overlay
district will be created. If the City chooses citywide adoption of a variety of the green infrastructure
implementation options described below rather than just in a specified overlay district, a dedicated
green infrastructure ordinance would consolidate the requirements into one document and could help
developers more easily comply with and take advantage of incentives described in subsequent sections
of this report.
14
-------
Helpful Resources
Delaware River City Corporation. North Delaware Riverfront Greenway Design Guidelines.
www.drcc-Dhila.ora/reDorts/NorthDelawareRiverfrontGreenwavDesian%20Guildelines Final.pdf.
This document establishes required criteria for constructing the North Delaware Riverfront Greenway in Philadelphia by
providing design guidelines to developers and others who will be responsible for its implementation.
National Park Service. Economic Impacts of Protecting Rivers, Trails, and Greenway Corridors: A Resource Book.
www.nps.Qov/pwro/rtca/econ all.pdf.
The Rivers, Trails, and Conservation Assistance program of the National Park Service has produced this resource book to
help local-level planners, park and recreation administrators, citizen activists, and nonprofit groups understand and
communicate the potential economic impacts of their proposed or existing corridor project.
Town of Huntersville, North Carolina. Low Impact Development Ordinance.
ftp://ftpl.co.mecklenbum.ncMS/WaterQuality/PCO%20Ordinances/Huntersville%20Post-
Construction %20Ordin ance%20FINAL. pdf.
The Town of Huntersville adopted a water quality ordinance that specifically promotes and defines green infrastructure
practices and low impact development stormwater management requirements. The ordinance refers to an external water
quality design manual for specific guidance.
County of Lancaster, South Carolina. Heelsplitter Overlay District Ordinance.
www.mylancastersc.orci/vertical/sites/%7BA02FC01E-6C41-44F4-BE02-9B73FC0206C5%7D/uploads/%7B4B3C3CD3-lB49-
4329-B 754-E3652E697F81 % 7D. PDF.
The County of Lancaster adopted an overlay district in 2008 to allow development within the watershed while placing
restrictions and limitations on the development to protect the Carolina Heelsplitter, an endangered species.
City of Charlotte, North Carolina. Zoning Ordinance Chapter 10: Watershed Overlay Districts.
charmeck.orci/stormwater/reciulations/Documents/Water%20Supply%20Watershed%20Documents/CityZonin ciOrdChapl0.pdf.
The City of Charlotte has developed multiple overlay districts to protect potable water supplies.
3.1.2 Parking Requirements and Lot Design
Inflexible parking requirements that do not allow for alternative approaches, as well as standards that
require too much parking for specific uses, could increase the amount of impervious surface in the
Northside project area, which will increase overall volume and velocity of runoff into Butterfly Creek.
Requiring too much parking for the need allows parking spaces to sit empty while increasing the overall
imperviousness of a watershed. Greenville, South Carolina, found that 37-65 percent of City parking
spaces sit empty, even during peak hours. Oversupplying parking also encourages greater vehicle use
and detracts from the overall pedestrian environment. Off-street parking and driveways contribute
significantly to the impervious areas on a residential lot. Reducing such dimensions can therefore
minimize the effective impervious cover, reduce the amount of stormwater runoff from a site, and
improve water quality. Incorporating the regulations and incentives below into parking space
requirements in the overlay district will create the opportunity to meet the Northside's parking demand
with less impervious cover.
• Allow flexibility in meeting parking space requirements at municipal-owned facilities through
shared parking, off-site parking, and similar approaches. For example, allow users of the
proposed athletic fields and playgrounds to use the Cleveland Academy parking lots on the
weekends and during the summer when school is out.
• Give credit for adjacent on-street parking, which can count for local parking requirements.
15
-------
• Permit businesses with different peak demand periods to share their required parking spaces.
• Revise parking regulations to reduce minimums below standard Institute of Transportation
Engineers' requirements based on analysis of actual parking demand/experience for existing and
proposed commercial businesses within the overlay district.
• Create zones with reduced by-right parking requirements or waive all parking minimums in
areas meant to serve pedestrian traffic (e.g., Healthy Food Hub area and Magnolia Street mixed-
use area) or within the overlay district.
• Adopt maximum parking caps (e.g., 125 percent above minimum) for the planned Northside
multi-family residential areas and commercial corridor along Magnolia and Church streets.
• Permit reduction in vehicle parking spaces through the provision of a minimum number of
bicycle parking spaces in the mixed-use and student housing areas.
In addition, including the following green infrastructure practices into the overlay district's parking lot
design standards will further reduce the environmental impact of parking required within the Northside
Development, could afford additional community benefits by providing shade and, if appropriately
placed, creating natural barriers between pedestrians and cars. These implementation options are
recommended throughout the overlay district; however, they are specifically suited and recommended
for the parking courtyards with common green space proposed for the multi-family residential housing
developments proposed between Magnolia, Vernon, and Howard streets.
• Adopt standards requiring a minimum area of the parking lotto drain into landscaped areas and
require the management of runoff from parking lots through green infrastructure practices
including trees, vegetated islands, swales, rain gardens, or other approaches. The parking lot
landscaping regulations should specify the types and sizes of shrubs and trees most appropriate
for controlling and reducing stormwater runoff.
• Allow alternative or innovative landscaping solutions that provide stormwater management
functions to count towards perimeter or other landscaping requirements.
• Adopt parking lot landscape regulations that require provision of trees, minimum percent of
parking lot interior area to be landscaped (e.g., 10 percent), and minimum-sized landscaping
areas (e.g., minimum of 25 square feet for island planting areas).
• Reduce drive aisle widths in parking lots to decrease the amount of pervious surface. For multi-
family developments, drive aisles can be shared. In commercial developments, typical drive
aisles can be reduced 5-10 percent.
• Create formal program offering incentives (e.g., cost sharing, reduction in street widths and
parking requirements, and assistance with maintenance) for property owners who use pervious
pavement elements.
• Adopt a requirement that some percentage of parking lots use pervious materials.
• Allow parking lot landscaping and green roofs on parking structures to be credited towards
meeting local stormwater management requirements.
16
-------
Helpful Resources
USEPA. Parking Spaces/Community Places: Finding the Balance through Smart Growth Solutions.
www.eDa.aov/DiedDaae/Ddf/EPAParkinaSDaces06.Ddf.
EPA developed this guide for local government officials, planners, and developers to demonstrate the significance of
parking decisions in development patterns; illustrate the environmental, financial, and social impact of parking policies;
describe strategies for balancing parking with other community goals; and provide case studies of places that are
successfully using these strategies.
Metropolitan Transportation Commission. Developing Parking Policies to Support Smart Growth in Local Jurisdictions:
Best Practices.
www.mtc.ca.aov/Dlanning/smart growth/parking/parking study/ADril07/bestDractice 042307.pdf.
This report explores approaches to parking policies that support infill, transit-oriented development, and downtown
development and provides examples of best practices and innovations from the Bay Area and beyond.
Maryland Governor's Office of Smart Growth. Driving Urban Environments: Smart Growth Parking Best Practices.
contextsensitivesolutions.org/content/reading/parking md/resources/parking paper md/.
This study presents an overview of parking strategies that meet the challenges that projects face in the context of smart
growth.
Metropolitan Area Planning Council. Eliminating Minimum Parking Requirements.
www.maDC.ora/resources/Darkina-toolkit/strateaies-toDic/eliminate-minimum-regs.
17
-------
3.1.3 Street Design
Source: Tetra Tech
Source: Tetra Tech
Streets, sidewalks, and other hard surfaces contribute a large
portion to Butterfly Creek watershed's total imperviousness.
Making these impervious surfaces more permeable will protect
the creek's pristine water quality, reduce flooding, and can help
with recharging ground water. The width of street travel lanes,
parking lanes, and sidewalks should be tailored to the Northside
neighborhood. Where appropriate, narrowing travel lane width
to 10-11 feet, rather than the standard 12-13 feet, can
significantly reduce the total amount of impervious surfaces.
Including vegetative green infrastructure practices (see Figure
10) in the median and ROW also can improve conditions for
walking, biking and transit use, which reduces automobile use
and overall demand for parking spaces, and will encourage
walking around the Northside neighborhood and perhaps
improve the pedestrian connection with surrounding amenities
such as Wofford and downtown shopping areas. Applying an
appropriate and feasible combination of all of the
implementation approaches described below to create green
streets at key locations can yield multiple benefits in the
Northside Development.
• Incorporate green streets concepts into all new and
realigned streets in the Northside such as bioretention
in medians and bump-outs as well as using roadside
planters, green features, and street trees in ROW.
• Revamp the City's street design specifications to allow
context-sensitive, innovative street design with
narrower travel lanes in appropriate circumstances—for
example, residential streets within the project area.
• Allow street-side swales to replace conventional curb
and gutter for managing stormwater and for separating
sidewalks from street traffic in appropriate
circumstances.
• Adopt technical specifications and design templates for
green infrastructure practices, such as bioretention, in
private and public rights-of-way.
• Adopt technical street specifications which allow
pervious paving materials in appropriate circumstances.
• Adopt a requirement that some percentage of alleys or
roads within the overlay district use pervious materials.
Source: Tetra Tech
Figure 10. Examples of bioretention
incorporated into rights-of-way.
18
-------
Helpful Resources
Institute of Transportation Engineers. Context Sensitive Solutions in Designing Major Urban Thoroughfares for Walkable
Communities.
www. ite. ora/css/.
USEPA. Stormwater Guidelines for Green, Dense Redevelopment: Stormwater Quality Solutions for the City of
Emeryville.
www.eDa.gov/dced/Ddf/Stormwater Guidelines.pdf
San Mateo County, California Water Pollution Prevention Program. Sustainable Green Streets and Parking Lots Design
Guidebook.
www.flowstobav.om/documents/municipalities/sustainable%20streets/San%20Mateo%20Guidebook.pdf.
Portland Metro. Green Streets: Innovative Solutions for Stormwater and Stream Crossings.
www.oreaonmetro.aov/tools-partners/auides-and-tools/auide-safe-and-healthv-streets.
This handbook describes basic Stormwater management strategies and illustrates street designs with features such as
street trees, landscaped swales, and special paving materials that allow infiltration and limit runoff. The handbook also
provides guidance on balancing the needs of protecting stream corridors and providing access across those streams.
Canadian Institute of Transportation Engineers. Promoting Sustainable Transportation through Site Design: An Institute
of Transportation Engineers Proposed Recommended Practice.
www.cite7.ora/resources/documents/ITERP-PromotinaSustainableTransportationThrouahSiteDesian.pdf.
This report recommends site design practices that can be applied through the land development process to promote using
more sustainable modes of passenger transportation such as walking, cycling, and transit.
USEPA. Managing Wet Weather with Green Infrastructure: Green Infrastructure Municipal Handbook - Green Streets.
water.epa.aov/infrastructure/areeninfrastructure/upload/ai munichandbook green streets.pdf.
This handbook is a series of documents to help local officials implement green infrastructure in their communities.
3.1.4 On- and Off-site Stormwater Controls
Design standards should be in place that replicate the predevelopment hydrology of the site (to the
extent practicable), maintain the water quality functions of the watershed, and minimize channel
erosion and downstream flooding. As described in the Spartanburg County Storm Water Management
Design Manual (Spartanburg County 2009), the City currently requires that projects disturbing more
than 5,000 square feet meet both water quantity and quality standards as follows:
• The water quantity standards require that a developer provide extended detention of the first
inch of runoff over the entire site and release it over a period of 24 to 72 hours; that post-
development discharge rates from the entire development area must not exceed
predevelopment discharge rates for the 2- and 10-year frequency 24-hour duration storm
events; and that post-development discharge velocities in receiving channels must be
nonerosive flow velocities and must be equal to or less than the predevelopment 2-year 24-hour
storm event flow velocities.
• The water quality standards require that projects meeting the threshold install permanent
controls. Detention structures must be designed to store and release the first half inch of runoff
from the site over a minimum period of 24 hours; retention water quality structures must be
designed to store and release the first inch of runoff from the site over a minimum period of
24-hours; and permanent water quality infiltration practices must be designed to accommodate,
at a minimum, the first inch of runoff from impervious areas on the site.
19
-------
These standards do not require or indicate a preference for on-site infiltration, reuse, or
evapotranspiration on-site through implementing green infrastructure. As Figure 11 indicates, green
infrastructure can closely mimic predevelopment streamflows.
^ 0.35
IS"
w 0.30
| 0.25
I
0.20
2 0.15
I
0.10
0.05
0.00
-Streamflow
Bioretention
50
0 10 20 30 40
Time Since Beginning of Flow (hr)
Source: DeBusk et al. 2011
Figure I I. Comparison of bioretention discharge and predevelopment streamflow.
Furthermore, retrofitting existing sites with infiltration practices—such as the rain gardens used in the
controlled study described in Figure 12—can result in a dramatic reduction in flow volumes from
developed sites. A paired watershed study conducted in Burnsville, Minnesota, demonstrated that
retrofitting a residential subdivision with rain gardens reduced the runoff volumes by approximately
90 percent (Barr Engineering Company 2006).
In many instances, on-site green infrastructure approaches are more effective and cost-efficient than
conventional stormwater management practices. The American Society of Landscape Architects (ASIA)
conducted a study in April 2012 that looked at 479 case studies around the United States of
developments where the costs of using green infrastructure projects were compared to using grey
infrastructure. The study found that using green infrastructure raised costs in about a quarter of
projects. In about 31 percent the costs were projected to be the same, and in more than 44 percent
using green infrastructure actually brought costs down. This can be explained, in part, because green
infrastructure reduces built capital (equipment and installation) costs, operation costs, land acquisition
costs, repair and maintenance costs, external costs (off-site costs imposed on others),and infrastructure
replacement costs over grey infrastructure. Table 2 provides a comparison of typical green and grey
infrastructure control measures.
20
-------
Fee-Construction Runoff Data
June 6, 2003
0.50" Ratnfall
SAM 7AM 9AM 11AM 1PM 3PM 5PM 7PM 9PM 11PM 1AM 3AM 5AM
Tlmt
Post-Ccnstrucilon Runoff Data
May 29, 2004
0.71 "Rainfall
12AM 2AM 4AM flAM HAM 1QAM 12PM 2PM
Source: Barr Engineering Company 2006
Figure 12. Rainfall/runoff response before and after retrofitting of rain gardens
in an existing development.
21
-------
Table 2. Comparative volumetric unit costs of stormwater control measures
Construction Cost per
Volume of Water Stored within
Stormwater Control Measures Cross-Section of Practice ($/CF)
Green Infrastructure
Bioretention $7
Planter Box $9
Permeable Pavement $22
Green Roof $200
Tree Box $67
Gray Infrastructure
Underground Detention/Retention
Subsurface Pipe Storage (Triton Stormwater Solutions) $9
Interlocking Plastic Blocks (Cudo cube) $15
Cast-in-Place Concrete Tank3 $26
Precast Concrete Vaultb $28
Source: American Rivers et al. (2012).
Notes:
a. The cast-in-place concrete tank cost and the precast concrete vault cost are based on engineering estimates for construction
of a 6,400-cubic-foot storage unit.
b. The cost of a precast unit varies depending on how closely the storage capacity of the manufactured product matches the
storage need.
Mitigation and In-Lieu Options
The City's standards also do not appear to provide for any alternative means of complying if meeting the
standards on-site is not feasible. Allowing mitigation or in-lieu options to facilitate off-site green
infrastructure implementation might be a way to increase the use of green rather than grey
infrastructure within the Butterfly Creek watershed. There could be opportunities for regional green
infrastructure practices within the greenway proposed along the Butterfly Creek daylighting project or in
the headwaters of the watershed.
In addition to amending post-construction stormwater controls performance standards and methods of
complying with the standard, the following implementation options will also support and promote green
infrastructure in the overlay district:
• Amend plumbing and building codes to support opportunities for residential and commercial
rainwater harvesting. For example, downspout disconnection/redirection, rain barrels, and
cisterns can be used for outdoor water supply purposes such as irrigation and indoor uses such
as toilet flushing.
• Create development incentives for green roofs (e.g., increased floor area ratio bonus, additional
building height).
22
-------
• Allow green infrastructure practices to count towards open space requirements (including green
roofs).
• Allow additional open space credits for green infrastructure, which also has public recreational
purposes (e.g., sports fields).
• Reduce stormwater management facility requirements for developments employing
comprehensive rainwater harvesting.
It is important for the City to remember that green infrastructure practices must be maintained properly
to operate as designed for the anticipated life span of the controls (see Table 12 and Table 13 for typical
maintenance activities for select green infrastructure practices). Requirements for long-term
maintenance agreements that allow for public inspections of the management practices and account for
transfer of responsibility in leases or deed transfers or both are necessary to ensure proper
maintenance. It is advisable to conduct inspections—either by City staff or certified self-inspections by
property owners—every 3 to 5 years, prioritizing properties on the basis of risk to water quality and
inspecting at least 20 percent of approved facilities annually.
Helpful Resources
USEPA. Reducing Stormwater Costs through Low Impact Development (LID) Strategies and Practices.
water.epa.gov/polwaste/green/costs07 index.cfm.
This report provides information to cities, counties, states, private sector developers, and others on the costs and benefits
of using low impact development strategies and practices to help protect and restore water quality and provides
information on the cost savings and benefits that can be achieved by implementing low impact development practices
versus conventional stormwater practices.
American Rivers, the Water Environment Federation, the American Society of Landscape Architects, and ECONorthwest.
Banking on Green: A Look at How Green Infrastructure Can Save Municipalities Money and Provide Economic Benefits
Community-wide.
www.asla.ora/uploadedFiles/CMS/Government Affairs/Federal Government Affairs/Bankina%20on%20Green%20HiahRes.pdf.
This report looks at the most cost-effective options for managing polluted runoff and protecting clean water, and finds that
green infrastructure solutions save taxpayer money and provide community benefits by managing stormwater where it
falls.
EcoNorthwest. The Economics of Low Impact Development: A Literature Review.
www.econw.com/media/aD files/ECONorthwest-Economics-of-LID-Litemture-Review 2007.pdf.
Santa Clara Valley Urban Pollution Prevention Program. Operations and Maintenance of Treatment Best Management
Practices.
www.scvurpDD-w2k.com/om workproduct links.htm.
Stormwater Center Maintenance Agreements Guidance and Case Studies.
www.stormwatercenter.net/Manual Builder/Maintenance Manual/4Maintenance Agreements/Maintenance%20Agreem
ents%20lntroduction.htm.
USEPA. Managing Wet Weather with Green Infrastructure: Green Infrastructure Municipal Handbook - Rainwater
Harvesting Policies.
water.epa.fiov/infrastructure/fireeninfrastructure/upload/fii munichandbook harvestinci.pdf.
This municipal handbook is a series of documents to help local officials implement green infrastructure in their
communities.
23
-------
3.1.5 Buffer Requirements
Section 501.15 of the City's General and Supplemental Regulations specifies the requirements in the
Riparian Buffer Overlay District; however, the requirements do not seem to apply to Butterfly Creek. In
addition, a no-development buffer on both sides of Butterfly Creek and its tributaries would be more
protective of the daylighted stream than a buffer area re-vegetated after damage during construction.
The lead stream designer for the daylighting effort, Dr. Jon Calabria, recommended a 150 vegetated
buffer along the daylighted reach. However, if the City allowed buffer areas to qualify for credit against
local open space dedication/set-aside regulations, developers might be more inclined to comply with a
buffer requirement rather than no development. Finally, if development within the buffer is allowed, a
2-to-l mitigation requirement would provide additional protection.
Helpful Resources
USEPA. Model Ordinances to Protect Local Resources: Aquatic Buffers.
water.epa.gov/polwaste/nps/ordinance index.cfm.
Center for Watershed Protection. Buffer Model Ordinance.
www.stormwatercenter.net/Model%20Ordinances/buffer model ordinance.htm.
Carl Vinson Institute of Government and the University of Georgia. Protecting Stream and River Corridors: Creating
Effective Local Riparian Buffer Ordinances.
www.rivercenter.ucia.edu/publications/pdf/riparian buffer guidebook.pdf.
This paper is a resource for local governments that plan to develop comprehensive riparian buffer ordinances. It presents
scientifically based guidelines which evolved from an analysis of published scientific literature.
3.1.6 Urban Agriculture
By one definition, urban agriculture is the cultivation, processing, marketing, and distribution of food in
urbanized areas, and ranges in scale from backyard or community gardens to suburban farms and
resource distribution pathways between city and rural area. The existing field of research regarding soil
and water interactions with ecologically based food production systems supports the assertion that
large-scale implementation of urban agriculture can significantly help restore urban hydrology and
water quality. Converting compacted soils or impervious rooftops to productive ecosystems can cause
the following impacts to urban environments:
• Restore compacted urban soils to retain more rainwater through infiltration or soil absorption
or both.
• Create a demand and end use for rainwater harvesting systems from rooftops.
• Change public perception of rainwater runoff to that of a resource that better serves their direct
needs.
• Engage the public in management of on-site stormwater runoff.
• Recycle nutrients from municipal solid waste streams and atmospheric deposition.
• Cost-effectively covert unused rooftops (see Figure 13 and Figure 14) and vacant lots (see
Figure 15 and Figure 16) to productive and beneficial systems.
24
-------
Community members clearly expressed their desire for community gardens and access to fresh food at
the January 2014 Public Workshop. Fortunately, the green infrastructure aspects of urban agriculture
are gaining attention across the United States as a means to provide a larger set of benefits to
communities. Urban agriculture also provides food security to densely populated areas, improves public
health and fresh food access (especially in urban communities considered "food deserts"), and supports
local economies (including new job opportunities). Although the Healthy Food Hub in the Northside (and
its urban microfarm) will become a significant amenity to community health and well-being, the planned
integration of urban agriculture and green infrastructure design can further meet the needs and goals of
all stakeholders.
Source: Brooklyn Grange
Figure I 3. Brooklyn Navy Yard rooftop farm.
Source: National Public Radio
Figure 14. Chicago Botanical Rooftop Garden.
Source: The Anthropik Network
Figure 15. Detroit Urban Farm on a previously
vacant lot.
Source: CCC Food Policy Coalition
Figure 16. Ohio City Farm.
By integrating urban agriculture into green infrastructure initiatives, the Northside neighborhood could
turn a perceived problem into a potential solution. For example, the green infrastructure goal to harvest
stormwater to enhance both potable and nonpotable water supplies can help urban farmers solve one
of their biggest challenges—reliable access to water (and nutrient inputs). Likewise, the embedded
nutrients, higher oxygen content, and lower cost of stormwater runoff can make it a more ideal source
of irrigation water compared to potable municipal or well water supplies.
25
-------
A significant asset for promoting the benefits associated with urban agriculture within the Northside
neighborhood is through the new community-supported Healthy Food Hub. Not only will this facility
host multiple food-related entities (e.g., a local farmer's market, a small urban farm, a cafe, and a
culinary training program), it can also serve as an important hub for engaging the public and creating a
pathway to solicit the City's support and guidance to effectively expand urban agriculture. The following
are examples of where various forms of urban agriculture can be cultivated throughout the Northside
redevelopment:
• Education gardens at Cleveland Academy or other public institutions.
• Resident gardens throughout residential parking/courtyards.
• Edible perennial forest gardens along the restored Butterfly Branch stream corridor and
greenway.
• Community gardens (or private microfarms) on existing vacant lots slated for later phases of
development.
• Rooftop gardens (using intensive green roof design) on multi-story residential buildings.
• Commercial aquaponic, hydroponic, or mushroom operations at existing warehouses or the
adaptive reuse artist incubator loft site.
The following implementation options might be necessary to support and promote urban agriculture in
the Northside community:
• Amend the City's comprehensive plan to explicitly support using urban agriculture in residential
and commercial areas and on municipal properties.
• Amend plumbing and building codes to support opportunities for residential and commercial
rainwater harvesting and irrigation of urban agriculture.
• Review zoning regulations to ensure no barriers exist to using residential or commercially zoned
land for urban agriculture.
Helpful Resources
Seeding the City: Land Use Policies to Promote Urban Agriculture. 2012.
www.NPLAN.org.
EcoDesign Resource Society. Urban Farming Guidebook.
www.refbc.com/sites/default/files/Urban-Farmina-Guidebook-2013.pdf.
Fresh Water Society. Urban Agriculture as a Green Stormwater Management Strategy.
www.arboretum.umn.edu/UserFiles/File/2012%20Clean%20Water%20Summit/Freshwater%20Urban%20Aa%20White%20
Paoer%20Final. odf.
Urban Design Lab. The Potential for Urban Agriculture in New York City.
www.urbandesianlab.columbia.edu/sitefiles/file/urban agriculture nvc.pdf.
Liebman, M.B., O.J. Jonasson, and R.N. Wiese. 2011. The Urban Stormwater Farm.
www.ncbi.nlm.nih.gov/Dubmed/22053481.
26
-------
3.2 Structural Green Infrastructure Practices
Many of the land use planning concepts discussed in Section 3.1 are useful to establish a foundation and
framework for implementing a comprehensive green infrastructure strategy. Thoughtful land use and
site-specific planning to minimize runoff can considerably decrease the size (and cost) of structural
practices required to meet regulatory requirements or minimize water quality impacts. Once a site's
configuration is optimized to reduce stormwater and pollutant sources, runoff from the remaining
impervious surfaces should be intercepted and treated by structural green infrastructure practices
which treat runoff using one or more of three basic elements: (1) infiltration, (2) retention/detention,
and (3) biofiltration.
Although green infrastructure can fulfill both water quality and peak flow requirements on sites with
adequate open space (and thus avoid the cost of separate detention facilities), urban redevelopment
projects often pose space constraints that limit the application of green infrastructure. For infill projects
with limited open space such as the Northside, green infrastructure can reduce the size and cost of
required detention facilities, but might not be able to eliminate the need for detention facilities entirely.
The following sections briefly describe several structural green infrastructure practices that are
proposed for the Northside redevelopment. These practices are well suited to higher density urban
areas and helping mitigate the peak flow and volume reduction goals for the Butterfly Creek watershed.
Refer the South Carolina Department of Health and Environmental Control (SCDHEC) Stormwater BMP
Handbook for more detailed design information (SCDHEC 2005) unless otherwise noted.
3.2.1 Bioretention Facilities
Bioretention facilities are shallow, depressed areas with a fill soil and vegetation that infiltrate runoff
and remove pollutants through a variety of physical, biological, and chemical treatment processes. The
depressed area is planted with small- to medium-sized vegetation including trees, shrubs, grasses, and
perennials, and may incorporate a vegetated ground cover or mulch that can withstand urban
environments and tolerate periodic inundation and dry periods. Bioretention may be configured
differently depending on the site context and design goals. This section summarizes general design
considerations for bioretention facilities, and then describes two configurations designed for dense
urban areas such as the Northside redevelopment area—planter boxes and tree boxes. Note that using
these practices within the public ROW along streets in the Northside will require prior approval from the
City.
Bioretention is well suited for removing stormwater pollutants from runoff, particularly for smaller
(water quality) storm events, and can be used to partially or completely meet stormwater management
requirements on smaller sites. Bioretention areas can be incorporated into the Northside to capture roof
runoff and parking lot runoff on private property such as the multi-family residential units proposed in
the Northside and within rights-of-way to capture sidewalk and street runoff (Figure 17 and Figure 18).
These types of bioretention areas can also serve to green streets hoping to attract pedestrian traffic
such as Howard Street.
The following is general bioretention design guidance to consider for the Northside area:
• For unlined systems, maintain a minimum of 5 feet between the facility and a building and at
least 10 feet with a basement.
27
-------
• A planting mix with a minimum hydraulic conductivity or permeability of 0.5 inches per hour
(in/hr), either through infiltration with soils of sufficient percolation capacity or with an
underdrain system and outlet to a drainage system. Although the soils in the Northside area are
classified as having moderately low runoff potential (Hydrologic Soil Group [HSG] B
classification), SCDHEC requires that all bioretention areas contain an underdrain system to
ensure adequate drawdown times.
• Planted with native and noninvasive plant species that have tolerance for urban environments,
frequent inundation, and the City's hot and temperate climate. For more information, refer to
the following rain garden planting guide from Clemson University Public Service Activities (Clear
and Giacalone 2009): www.clemson.edu/psapublishina/pages/HORT/IL87.PDF.
• Inclusion of an overflow structure with a nonerosive overflow channel to safely pass flows that
exceed the capacity of the facility or design the facility as an off-line system.
• Inclusion of a pretreatment mechanism such as a grass filter strip, sediment forebay, or grass
swale upstream of the practice to enhance the unit's treatment capacity.
Source: Tetra Tech, Inc.
Figure 17. Bioretention incorporated
into a right-of-way.
Source: Biological and Agricultural Engineering
Department, NCSU
Figure 18. Bioretention incorporated into
traditional parking lot design.
28
-------
Planter Box
Source: Tetra Tech, Inc.
Figure 19. Planter box within the street right-of-way (top) and flow-
through planter box attached to a building (bottom).
Planter boxes are
bioretention facilities
contained within a concrete
box, allowing them to be
incorporated into tighter
areas with limited open
space. Runoff from a street
or parking lot typically enters
a planter box through a curb
cut, while runoff from a roof
drain typically enters
through a downspout.
Planter boxes are often
categorized either as flow-
through planter boxes or
infiltrating planter boxes.
Infiltrating planter boxes
have an open bottom to
allow infiltration into the
underlying soils. Flow-
through planter boxes are
completely lined and have an
underdrain system to convey flow that is not taken up by plants
to areas that are appropriate for drainage away from building
foundations. Planter boxes are well suited to narrow areas
adjacent to streets and buildings
(Figure 19).
Tree Box
Tree boxes are bioretention facilities configured for dense urban
areas that use the water-uptake benefits of trees. They are
generally installed along street corridors with curb inlets
(Figure 20). Tree boxes can be incorporated immediately
adjacent to streets and sidewalks with the use of a structural
soil, modular suspended pavement, or underground retaining
wall to keep uncompacted soil in place. Tree boxes typically
contain a highly engineered soil media to enhance pollutant
removal while retaining high infiltration rates. The uncompacted
media allows urban trees to thrive, providing shade and an
extensive root system for water uptake. For low to moderate
flows, stormwater enters through the tree box inlet and filters
through the soil. For high flows, stormwater will bypass the tree
box if it is full and flow directly to the downstream curb inlet.
Source: Tetra Tech, Inc.
Source: Tetra Tech, Inc.
Figure 20. Tree box using grate
inlets in street.
29
-------
3.2.2 Permeable Pavement
In contrast to traditional pavements, permeable
pavements contain small voids that allow water
to drain through the pavement to an aggregate
reservoir and then infiltrate into the soil beneath
impervious surfaces. Permeable pavement can be
developed using modular paving systems (e.g.,
concrete pavers, grass pavers, or gravel pavers) or
pour-in-place solutions (e.g., pervious concrete or
permeable asphalt). Permeable pavements are
most often used in constructing pedestrian
walkways, sidewalks, driveways, low-volume
roadways and parking areas of office buildings,
recreational facilities, and shopping centers
(Figure 21). However, composite designs using
conventional asphalt or concrete in high-traffic
areas adjacent to permeable pavements along
shoulders or in parking areas can provide a more
cost-effective solution for achieving both
transportation and stormwater management
goals.
The general native soil conditions in the
Northside area (HSG B classification) are relatively
well suited for permeable pavements because the
higher percolation capacities increase infiltration
and reduce the requirements for underdrains or
excessive sub-base depths. Site-specific design
criteria for permeable pavement are included in
pages 150-151 of SCDHEC (2005) and in the
following publication from Clemson University
(Young 2013):
(www. clemson.edu/extension/hoic/water/resource
s stormwater/introduction to porous pavement.
html).
Source: Tetra Tech, Inc.
Source: Tetra Tech, Inc.
Figure 21. Pervious concrete (above) and permeable
interlocking concrete paver (below) parking stalls.
Some additional guidelines for applying permeable pavement in the Northside area are as follows:
• Porous pavements are a good option in ultra-urban areas of the redevelopment because they
are dual-purpose and consume no pervious area. One of the best applications of porous
pavement for retrofits is on individual sites where a parking lot is being resurfaced.
• Although the Northside area soils are classified HSG B, soil borings to 4-inch depth need to be
conducted at each site to determine if low-permeability soils, bedrock, or high water tables will
require an underdrain system in the sub-base reservoir.
• An impermeable liner can be installed between the sub-base and the native soil to prevent
water infiltration when clay soils have a high shrink-swell potential or if a high water table or
bedrock layer exists.
30
-------
• The minimum soil infiltration rate must be 0.3-0.5 in/hr.
• Measures should be taken to protect permeable pavements from high sediment loads,
particularly fine sediment, to reduce maintenance. Typical maintenance includes removing
sediment with a vacuum truck (SCDHEC 2005). See Table 13 for operation and maintenance
activities for porous pavement.
3.2.3 Green Roofs
Green roofs introduce vegetation and soil media onto sections of rooftops to reduce imperviousness
and absorb and filter rainfall. At a minimum, a green roof consists of a waterproof membrane and root
barrier system to protect the roof structure, a drainage layer, filter fabric, a lightweight soil media, and
vegetation that filter, absorb, and retain/detain the rainfall. Rainfall that infiltrates into the green roof is
lost to evaporation or transpiration by plants, or, once the soil has become saturated, percolates
through to the drainage layer and is discharged through the roof downspouts. Typically, a green roof is
part of a treatment train with the green roof draining to another stormwater control measure such as a
bioretention cell, bioswale, or cistern. They are fairly expensive compared to other green infrastructure
practices, but might be a worthwhile asset if designed to allow human access.
Green roofs can cover large sections of a roof while maintaining access for utilities, maintenance, or
recreation. The intended use for the space dictates the green roof design. The intended use can range
from serving solely a water quality treatment mechanism (i.e., extensive green roof), to serving as a
recreational space for building tenants (Figure 22). The soil media of extensive green roof systems is
typically shallow (i.e., 2 to 6 inches) while the soil media for intensive systems is deep (i.e., more than
6 inches). Green roofs are most often applied to buildings with flat roofs, but can be installed on roofs
with slopes using mesh, stabilization panels, fully contained trays, or battens. Alternatively, detention on
roofs without vegetation (i.e., blue roofs) might be an option as long as the water drains through a
biological filter, such as at ground level.
SCDHEC (2005) does not include green roofs; therefore, further design details should reference Chapter
19 of the North Carolina BMP Manual (NCDENR 2007).
General guidelines and components for installing green roofs are as follows:
• The building roof must be designed to safely support the saturated weight of the green roof,
which varies depending on the green roof design and manufacturer.
• Extensive green roofs, with soil depths of 2 to 6 inches, are most commonly used for stormwater
management.
• The soil media for green roofs should be light-weight and largely inorganic.
• Plants selected for green roofs should be hardy, self-sustaining, drought-resistant plants able to
withstand daily and seasonal variations in temperature and moisture on rooftops. Typical plants
used for extensive roofs are from the genera Sedum and Delosperma, or other succulents and
hardy native perennials.
• At a minimum, a temporary irrigation system should be used to establish plants and ensure
success during drought.
• A drainage layer installed beneath the green roof routes excess runoff from the roof to the
downspouts.
31
-------
• A root barrier installed below the drainage layer prevents plant roots from damaging structural
roof membranes.
• A waterproof membrane is used to prevent transmission of moisture from the green roof to the
structural roof.
• An insulation layer between the green roof and structural roof can improve the system's
thermal qualities.
• An optional leak detection membrane can be used to assess the integrity of the waterproof
membranes.
Source'. Tetra Tech, Inc.
Source: Upstate Forever
Source: Green Roof Outfitters
Figure 22. Furman Company, Greenville, South Carolina (top left), Riverside High School, Greer, South
Carolina (bottom left), Charleston VA Medical Center, Charleston, South Carolina (right).
32
-------
3.2.4 Rainwater Harvesting
Cisterns or their smaller counterpart, rain barrels, are containers that capture runoff and store it for
future use (Figure 23). With control of the timing and volume, the captured stormwater can be more
effectively released for irrigation or alternative grey water uses between storm events. Rain barrels tend
to be smaller systems, less than 100 gallons. Cisterns are larger systems that can be self-contained
aboveground or belowground systems generally larger than 100 gallons. Belowground systems often
require a pump for water removal. Cisterns and rain barrels primarily provide control of stormwater
volume; however, water quality improvements can be achieved when cisterns and rain barrels are used
for landscape irrigation or discharged to bioretention areas. Water in cisterns or rain barrels can be
controlled by permanently open outlets or operable valves depending on project specifications. Cisterns
and rain barrels can be a useful method of reducing stormwater runoff volumes in urban areas where
site constraints limit the use of other BMPs. Table 3 outlines the advantages and limitations of rainwater
harvesting.
Source: Tetra Tech, Inc. Source: Tetra Tech, Inc.
Figure 23. Belowground cistern (left) and wood-wrapped cistern (right).
Cisterns are typically placed near roof downspouts so that flows from existing downspouts can be easily
diverted into the cistern. Runoff enters the cistern near the top and is filtered to remove large sediment
and debris. Collected water exits the cistern from the bottom or can be pumped to areas more
conducive to infiltration. Cisterns can be used as a reservoir for temporary storage or as a flow-through
system for peak flow control. Cisterns are fitted with a valve that can hold the stormwater for reuse, or
they release the stormwater from the cistern at a rate below the design storm rate. Regardless of the
intent of the storage, an overflow must be provided if the cistern's capacity is exceeded. The overflow
system should route the runoff to a BMP for treatment or safely pass the flow into the stormwater
drainage system. The overflow should be conveyed away from structures. The volume of the cistern
should be allowed to slowly release, preferably into a BMP for treatment or into a landscaped area
where infiltration has been enhanced.
Cisterns have been used for millennia to capture and store water. Droughts in recent years have
prompted a resurgence of rainwater harvesting technology as a means of offsetting potable water use.
Studies have shown that adequately designed and used systems reduce the demand for potable water
and can provide important hydrologic benefits (DeBusk et al. 2012; Vialle et al. 2012). Hydrologic
performance of rainwater harvesting practices varies with design and use; systems must be drained
33
-------
between rain events to reduce the frequency of overflow (Jones and Hunt 2010). When a passive
drawdown system is included (e.g., an orifice that slowly bleeds water from the cistern into an adjacent
vegetation bed or infiltrating practice), significant runoff and peak flow reduction can be achieved
(AECOM Technical Service, Inc. 2011; DeBusk et al. 2012).
Table 3. Advantages and limitations of rainwater harvesting
Advantages
Limitations
Provides peak flow mitigation for frequent and
infrequent storm events
Aids in infiltration by delaying runoff
Variable configurations to meet site constraints
Can reduce the size of infiltration BMPs
Can be designed for high visibility to raise stormwater
awareness or can be hidden from view
Effective where underground utilities or other
constraints preclude use of surface/subsurface storage
BMPs
Can be designed to supplement or replace nonpotable
water supplies (for nonresidential uses) or for irrigation
(residential or nonresidential)
Requires regular maintenance of inlet filters
and mosquito control screens
Can require structural support
Reuse systems might require filtration and
disinfection per intended use and local
plumbing codes
3.2.5 Infiltration Basins
Infiltration basins are shallow depressions
filled with grass or other natural vegetation
that capture runoff from adjoining areas
and allow it to infiltrate into the soil
(Figure 24). Using the soil's natural filtering
ability to remove stormwater pollutants,
infiltration facilities store runoff until it
gradually discharges through the soil and
eventually into the water table. This
practice has high pollutant removal
efficiency and can also help recharge
ground water, thus helping to maintain low
flows in stream systems.
-
Source', www.stormwaterpa.org
Figure 24. Infiltration basin as recreation area.
Infiltration basins can provide a useful BMP for the Northside redevelopment for several reasons.
Although soil conditions often limit implementation of infiltration basins, the Northside area's HSG B soil
classification indicates that recommended minimum infiltration rates (0.5 in/hr) would be met.
However, the soil structures observed in the Northside area are fine enough to prevent ground water
contamination from excessive stormwater infiltration. Also, because infiltration basins can be designed
as a dual-purpose BMP with turf cover for recreation, this green infrastructure practice would be ideal
for the common green space areas proposed for the residential courtyard blocks.
34
-------
SCDHEC (2005) does not include infiltration basins as described above; however, further design
guidance can be found in Chapter 16 of the North Carolina BMP Manual (NCDENR 2007). Some of the
design considerations for infiltration basins include the following:
• Infiltration basins are not suitable on fill sites or steep slopes.
• Soils should have a minimum 0.52 in/hr infiltration rate.
• Basin should be a minimum of 15 feet downgradient of any structure.
• Upstream drainage area should be completely stabilized before construction.
• Pretreatment devices should be provided to prevent clogging.
3.2.6 Urban Agriculture Integration
The safe and effective integration of green infrastructure practices with urban agriculture in the
Northside neighborhood is outlined in Figure 25 and further described below. Although these linkages
are only a guideline and can vary from site to site, the outline demonstrates how the source and
associated water quality of stormwater runoff can be matched with a management practice and
beneficial reuse.
Source
Rooftops
•^
Managed Pervious
On-lot Impervious
Storage or Treatment
Cisterns
(Intensive) Green Roofs
LID Features
Agro-swales
Rain Gardens
Landscape Storage
Active Irrigation
Annual Vegetables
Aqua/Hydroponics
Mushrooms
Passive Irrigation
Edible Perennials
Residential Roadways
Parking Areas
Engineered BMPs
Bioretention
Stormwater Wetlands
Wet Ponds
Permeable Pavement
Treated Effluent
Native Beneficial
Plants
Source: Tetra Tech, Inc.
Figure 25. Stormwater reuse concept for urban agriculture in the Northside.
The cleanest source of urban stormwater runoff is typically from rooftops. However, access to open
space for soil or reservoir storage can be limited in some of the higher density blocks. As a result,
aboveground or belowground cisterns become viable options for preserving the quality of rooftop
runoff and storing it for subsequent irrigation of higher value food crops. Annual vegetables, commercial
mushroom operations, and aquaponic or hydroponic systems—all of which require both a relatively
clean and constant water supply—are ideal uses for cistern water. From a stormwater management
35
-------
perspective, these proposed revenue-generating, beneficial end uses establish a reliable incentive for
stormwater volume and nutrient load reductions. Note that intensive green roofs are included because
rooftop vegetable farms provide additional production area for cistern water demand and create
economic incentive for implementing this other green infrastructure BMP.
Although often discredited, urban soils, vacant land, and managed open space can contribute significant
volumes of stormwater runoff and nutrient and sediment loads. Soil compaction, low organic matter
contents, minimal vegetative cover, and improper or over-application of soluble fertilizers, among other
things create stormwater runoff conditions from pervious areas that are more characteristic of
impervious surfaces. These managed open space areas can be transitioned from mono-cultured lawns or
compacted vacant lots to more productive ecosystems. From installing raised vegetable production beds
on contour to building multifunctional swales and rain gardens planted with useful perennial species,
urban agricultural practices can capture and infiltrate stormwater and build soil organic matter. Off-site
runoff from impervious roadways and parking areas needs to be treated before the water is used for
urban agriculture.
As the demand for urban agriculture continues to increase in U.S. cities, publicly owned open space can
become a unique opportunity for public-private synthesis. By one scenario, if community gardens (or
publicly supported microfarms) are integrated onto these public open space areas along with the
stormwater practices listed in Figure 25, a mutually beneficial relationship can be created. Although the
stormwater BMPs and management practices can provide irrigation supply and improved site ecology
for urban agriculture systems, the renewed public perception towards BMPs as a resource to their
community can help instill responsibility and ownership in BMP maintenance and operation—a popular
concern of distributed stormwater practices among municipalities.
36
-------
4 Conceptual Designs
One of the purposes of this report is to provide a conceptual stormwater management design for
incorporation into the Redevelopment Plan. Because the final Redevelopment Plan will not be
completed until late 2014, the conceptual green infrastructure practices presented here are template
examples that apply to the block densities, streetscape styles, and typical development patterns
selected during the Public Workshop held in January 2014. However, several redevelopment ideas
discussed in Section 2 are conclusive enough to develop conceptual, site-specific green infrastructure
designs. This report presents conceptual designs for both a typical residential block and a secondary
street corridor. For these examples, the conceptual green infrastructure practices are designed, as much
as possible, to meet the City's stormwater design criteria. A stormwater management professional
should complete the final green infrastructure designs in conjunction with the final design of specific
blocks, buildings, and street layouts.
The design professionals responsible for the final design of green infrastructure features will need to
account for the final site/building layout, soil infiltration rates, and detailed survey information, which
will dictate the final layout, sizing, and outlet control of the proposed stormwater control measures. The
scenarios demonstrate how green infrastructure can complement and enhance the proposed layout
while also providing water quality treatment and volume reduction.
4.1 Design Assumptions and Methodology
The overall conceptual design goal was to optimize the implementation of several green infrastructure
scenarios into two proposed site plans while considering both the City's stormwater standards and
available footprint areas. Each scenario (2-4 for each site) incorporates a unique collection of green
infrastructure practices working collaboratively to address the site's stormwater management needs.
Based on the Spartanburg County Storm Water Management Design Manual (Spartanburg County 2009)
and discussions with City stormwater staff, much of the future redevelopment may qualify for a waiver
from the City's runoff quantity requirements so long as there is adequate capacity in the downstream
conveyance system to prevent flooding. Because predevelopment conditions are similar in impervious
area compared to proposed conditions, it is anticipated that much of the Northside redevelopment may
qualify for the waiver. City stormwater quality requirements, however, dictate the capture, treatment,
and 24- to 72-hour extended detention of runoff from the 1-inch runoff event.
Although lower density areas of redevelopment within the Northside may be exempt from stormwater
quantity control, the proposed higher density blocks will likely require control of the 2- and 10-year,
24-hour peak flow event to meet predevelopment discharge rates. In absence of detailed site
information necessary to estimate peak flow rates for the conceptual designs, annual runoff volume was
used as the preliminary design criterion to quantify the hydrologic impacts of the proposed green
infrastructure practices. Where space was available based on the Phase I site plans, the BMPs were sized
to capture and treat the 1-inch runoff event per the City's design standard. Otherwise, the BMP
footprint was maximized within the available open space area depicted in the Phase I concept plans. As
specified in the Spartanburg County Storm Water Management Design Manual (Spartanburg County
2009), the Composite Natural Resources Conservation Service (NRCS) Curve Number Method was used
to determine the required water quality volume for each conceptual site.
Although local stormwater regulations might not explicitly require green infrastructure controls for most
of the Northside redevelopment, the mitigation of watershed impervious area and hydrologic impacts
necessary to protect the restored Butterfly Creek is also an important objective for community
37
-------
stakeholders. Green infrastructure controls can help reduce effective impervious surface in the drainage
area to meet target thresholds. According to the reformulated Impervious Cover Model (ICM) (Schueler
2008), 25 percent watershed impervious area is considered the threshold when streams transition from
"impacted" to "non-supporting." Beyond 25 percent impervious area in a watershed, receiving water
bodies become conduits for stormwater flows and can no longer support a diverse stream community;
stream instability causes bank erosion, incision, and loss of important morphological features. The
stream restoration professional advocating for the restoration of Butterfly Branch, Dr. Jon Calabria,
verified this objective during the Northside redevelopment charrette.
In addition to the planning and zoning tools discussed in Section 3, the 25 percent ICM threshold can be
achieved through a runoff reduction approach using structural green infrastructure practices. Runoff
reduction can be defined as the total annual runoff volume reduced through canopy interception, soil
infiltration, evapotranspiration, rainfall harvesting, engineered infiltration, or extended filtration at small
sites. Depending on watershed impervious cover and ICM classification (i.e., sensitive, impacted, non-
supporting, urban drainage), the annual runoff reduction target varies. For streams in "non-supporting"
watersheds (more than 25 percent impervious area), the proposed runoff reduction target is the
90 percent or water quality event (Schueler 2008). The green infrastructure practices proposed for the
conceptual designs and discussed in Section 3.2 were identified as having the highest runoff reduction
rates compared to other BMPs (see Table 4).
Table 4. Annual runoff reduction rates for selected BMPs (Hirschman et al. 2008)
BMP
Infiltration
Bioretention
Pervious Pavers
Green Roof
Cisterns
Annual Runoff Reduction Rate
50%-90%
40%-80%
45%-75%
45%-60%
40%
EPA's Stormwater Calculator was used to evaluate site hydrology and annual runoff reduction for each
concept plan and scenario. The calculator estimates the total annual stormwater runoff, infiltration, and
evapotranspiration generated for a particular site under different development and control conditions
over a long-term period of historical rainfall. The tool accounts for soil conditions, topography, local
meteorology, and land cover, and it can simulate a variety of structural low impact development
practices with custom modifications.
Model inputs for soil and topographic information were the same for both concept plan sites. Based on
the U.S. Department of Agriculture's Soil Web Survey data (directly accessed through the calculator),
Table 5 presents the model input for both concept plan sites. Meteorological input data used for the
long-term simulation were derived from the Spartanburg 3 SSE location for years 1983-2006.
38
-------
Table 5. Site and soil information used in EPA's Stormwater Calculator
Land Cover Residential Block Concept Green Street Concept
Site Area (ac) 6.0 0.4
Soil Series Cecil-urban land complex Cecil-urban land complex
Soil HSG B B
Soil Drainage (in/hr) 0.336 0.336
Topography Moderately Steep (10% slopes) Moderately Steep (10% slopes)
One of the derivatives within the calculator used to size the low impact development practices is
capture ratio, which is the ratio of BMP footprint area to the impervious drainage area it collects.
Capture ratio can be automatically calculated within the model for a specified design storm, or it can be
manually entered if a BMP is undersized or oversized. This design factor, which is referred to in the
conceptual design descriptions below, will be useful to future developers when determining the relative
amount of open space required for green infrastructure practices and their associated hydrologic
impacts.
One of the proposed residential blocks surrounding the pocket park on Vernon Street was selected to
represent the residential land use typology. This block was selected because it is representative of the
mixed-use development types that could be used throughout the Northside and draining directly to
Butterfly Creek, and it is part of a multiblock area initially targeted as Phase I of the redevelopment
activities. As depicted in Figure 26, the block consists of a mixture of two-story flats, town houses, and
several public services buildings encircling a parking courtyard with common green space. The block,
which does not include the adjacent publicly owned ROW, occupies approximately 6 acres and is
characterized by the land use composition shown in Table 6. The land use characterization is based on
the concept plan sketches developed during the Northside redevelopment charrette. The proposed land
cover composition yields an impervious percentage for the site of approximately 61 percent and a
composite Curve Number value of 88.6. Based on the NRCS method, a water quality volume of
approximately 65,200 gallons of runoff from the 6-acre block will need to be detained and treated to
meet the City's stormwater requirements.
39
-------
Howard St
Source: JHB Architects
Figure 26. Residential block used for concept plan.
Table 6. Proposed land cover for typical residential block
Land Cover
Building
Parking
Sidewalk
Roadway
Lawn
Total Impervious
Percent of Total Site Area
28%
17%
5%
11%
39%
61%
Four green infrastructure scenarios were developed for the residential block, with each scenario
applying a different suite of structural green infrastructure practices selected as appropriate for the
proposed site conditions and preferred by the Northside community. For each scenario, the proposed
practices were evaluated to meet the volume reduction criterion described above, and conceptual
drawings were produced to demonstrate how the proposed practices could be integrated into the site
layout.
• Scenario 1: Includes a 5,064 sq. ft. infiltration basin in the courtyard that treats all of the internal
roadway and parking areas. Internal roadway and parking areas account for approximately
45 percent of the total site impervious area, or 30 percent of the total site area. The infiltration
basin was designed with 6-inch ponding height and an assumed infiltration rate of 0.336 in/hr
based on the native soil characteristics. Using the maximum available area within the parking
40
-------
courtyard, the proposed infiltration basin footprint yields a capture volume of 18,940 gallons,
which is 29 percent of the required water quality volume for the site.
• Scenario 2: Same as Scenario 1, but with a 12-inch ponding height for the infiltration basin
yielding a capture volume of 37,890 gallons (or 58 percent of the water quality volume for the
site). Similar to Scenario 1 the infiltration basin maximizes the available area in the courtyard
but does not meet the design criteria.
• Scenario 3: Same as Scenario 2, but also includes rain gardens that treat all of the rooftops on
the site, which account for 46 percent of the total impervious area (or 28 percent of the total
site area). Collectively, the infiltration basin and rain gardens treat 92 percent of the total site
impervious area. Using default parameters in the model, the rain gardens were assigned a
6-inch ponding height, a 12-inch soil media thickness, and soil media conductivity of 10 in/hr.
The rain garden footprint areas, which were designed into the available open space around the
proposed building footprints according to the Redevelopment Plan, yield a capture volume of
27,800 gallons. Combined with storage and treatment from the infiltration basin with 12-inch
ponding depth, the Scenario 3 concept design treats 100 percent of the required water quality
volume.
• Scenario 4: Same as Scenario 2, but used rainwater harvesting for all of the rooftops. The
cisterns were designed to capture the 1-inch runoff water quality volume for the City (or roughly
1.2 inches of rainfall), which equates to 46,120 gallons of runoff. As part of the water balance
calculations, the emptying rate (gal/day) was based on an assumed landscape irrigation rate of
1 inch of water per week that covered 50 percent of the open space on the site. Combined with
the infiltration basin with 12-inch ponding depth, Scenario 4 exceeds the City's water quality
standard and treats 129 percent of the required capture volume.
Table 7 shows the hydrologic results from EPA's Stormwater Calculator for all four green infrastructure
scenarios, including the baseline condition. Compared to the baseline scenario (i.e., the proposed
redevelopment land cover conditions without stormwater controls), Scenarios 3 and 4 reduce long-term
annual runoff volumes by more than 50 percent and increase annual infiltration by approximately
70 percent. Most importantly, the captured water quality volume provided by each of the design
scenarios is also shown, indicating that both Scenario 3 and 4 either meet or exceed the required target.
Table 7. Hydrologic results from EPA's Stormwater Calculator for residential block concept plan
Scenario
Baseline
Scenario 1
Scenario 2
Scenario 3
Scenario 4
Runoff
55%
40%
36%
27%
29%
Infiltration
38%
53%
57%
66%
62%
Evapotranspiration
7%
7%
7%
9%
9%
% of WQ Volume
0%
29%
58%
100%
129%
41
-------
An additional analysis was also conducted with EPA's Stormwater Calculator to determine the
equivalent impervious area for the site that would yield the same hydrologic impact as the proposed
land cover with green infrastructure controls. Using the hydrologic results from Scenarios 3 and 4, which
were statistically identical in regards to their impact on annual site hydrology, the calculator estimated
that the proposed residential block with Scenario 3 or 4 green infrastructure controls is equal to a site
with only 26 percent total impervious area, which is nearly equivalent to the 25 percent impervious
watershed threshold recommended to protect the restored Butterfly Branch.
Figure 27 shows a site layout for the Scenario 4 concept plan, which includes the infiltration basin in the
common courtyard and an underground cistern for landscape irrigation. The infiltration basin can
contain turf grass or landscaped vegetation or both, and will only have ponded water during or
immediately after significant storm events. Otherwise, this stormwater practice can also provide area
for recreation and green open space. The 1,250 sq. ft. footprint area for the underground cistern
represents the total area required to store the water quality volume from the rooftops (46,124 gallons)
in a 5-foot-deep vault. Depending on final site conditions, several smaller cisterns would be distributed
throughout the block to more effectively capture and reuse throughout the landscape.
EQUIVALENT FOOTPRINT
AREA FOR UNDERGROUND
\- CISTERN Wl S-f OOT STORAGE
DEPTH
Howard St
Source: JHB Architects and Tetra Tech, Inc.
Figure 27. Scenario 4 concept plan with equivalent BMP footprint areas.
4.3 Green Street
The second concept plan involved a green street design for a proposed road extension of Evins Street
that will connect with Howard Street, directly east of the residential block used for the first concept
plan. As mentioned during the January 2014 Public Workshop, the intent for extending Evins Street was
to provide better pedestrian connectivity between Wofford College and central Northside (particularly
the Healthy Food Hub and farmer's market).
42
-------
Figure 28 shows the extent of the green street plan for the Evins Street expansion. Based on the
proposed Redevelopment Plan and general secondary road standards for the City, a 50-foot-wide ROW
was used for the green street. For the purposes of the concept plan, it was assumed that the ROW
would contain 5-foot-wide sidewalks on both sides of the street, two 10-foot-wide parking lanes
(including curb and gutter), and two 10-foot travel lanes. Approximately 5 percent of the ROW was
allocated as street corner planting strips. Using the NRCS method and a composite Curve Number of
97.5, the proposed green street section will require a water quality treatment volume of 10,950 gallons
of runoff.
. .
with com mo
greenspace
***„
<
,
V
* Parking Cour;
0- with common
greenspace
c, •B.
s 'arking Courtyard
i th common
greenspace
Howard St
Neighborhood
<;prvirp^ at
Source: JHB Architects and Tetra Tech, Inc.
a* a
Figure 28. Section of Evins Street extension used for green street concept plan.
Two green street scenarios were developed and evaluated for the concept plan.
• Scenario 1: Uses street planters (i.e., bioretention planter boxes) to treat 100 percent of the
impervious area in the ROW, including sidewalks, parking lanes, and travel lanes. The street
planters were designed to capture the 1-inch runoff water quality volume using 6 inches of
ponding height, 18-inch media depth, a 12-inch gravel bed thickness, and an assumed soil
conductivity of 10 in/hr. The required capture ratio (ratio of street planter area to total treated
impervious area) was approximately 5 percent.
• Scenario 2: The second scenario used permeable pavement in the parking lanes to treat
81 percent of the ROW impervious area (excluding sidewalks). This configuration yields an
oversized capture ratio of 38 percent, although permeable pavement is often recommended
with a 1-to-l capture ratio. The permeable pavement was simulated with a 6-inch pavement
thickness and an 18-inch gravel thickness.
43
-------
Table 8 shows the hydrologic results from EPA's Stormwater Calculator for the two green street
scenarios. Both the street planter and permeable pavement scenarios reduce the annual baseline runoff
volumes by approximately 400 percent. With regards to the City's water quality standard, Scenario 1
treats 100 percent of the required capture volume while Scenario 3 stores and treats more than three-
times the target.
Using a similar equivalent impervious area analysis for Scenario 1, the hydrologic impact from treating
the 1-inch runoff volume with street planters is equal to the same street ROW with 17 percent
impervious area and no stormwater control practices.
Table 8. Hydrologic results from EPA's Stormwater Calculator for green street concept plan
Scenario
Baseline
Scenario 1
Scenario 2
Runoff
84%
18%
17%
Infiltration
5%
67%
75%
Evapotranspiration
11%
15%
8%
% of WQ Volume
0%
100%
345%
Figure 29 shows the Scenario 1 green street plan with the relative areas of the street plants represented.
The required area for the street planters to treat the water quality volume is equal to about four parking
stalls, which would be lost to implement the proposed green infrastructure.
Parking
witheomi
greensp.
Source: JHB Architects and Tetra Tech, Inc.
Figure 29. Scenario I green street concept plan with street planters.
44
-------
Figure 30 shows a sectional view of the planter box with an optional permeable pavement lane overlaid
on one of the residential block renderings developed at the January 2014 Public Workshop.
(Optional) Permeable pavement
parking or bike lane
KIHB
Street planter with bloretention
madia, gravel layer, and underdrain
Source: JHB Architects and Tetra Tech, Inc.
Figure 30. Section view of green street concept plan with street planters.
45
-------
This page is intentionally blank.
46
-------
5 Preliminary Opinion of Probable Costs
The purpose of this section is to provide guidance on the likely cost of implementation for the green
infrastructure components identified for each project site and scenario described in Section 4 and
representative of costs associated with green infrastructure throughout the Northside redevelopment
area. Given the preliminary nature of the Northside master plan and the level of uncertainty regarding
final site features, site conditions, and green infrastructure practice configurations it is not appropriate
or possible to develop cost estimates based on a construction/bid item quantities and unit costs. Rather,
the cost estimates reported below are based on unit area or unit treatment costs available from
relevant published sources. Although the level of uncertainty in these cost estimates might be relatively
high they provide a representative level of cost for implementing green infrastructure, which can be
applied throughout the Northside redevelopment area where site conditions are similar to the two
project sites.
The cost estimates provided in Table 9 are based on planning level unit cost values published for each of
the respective green infrastructure practices recommended as part of the project site scenarios detailed
in Section 4. King and Hagen (2011) reported unit cost data for a variety of stormwater practices
including both traditional and green infrastructure as well as nonstructural practices. Although these
unit cost estimates are based on projects in Maryland, they are appropriate for use throughout the mid-
Atlantic and southeast given the similar climate and practice design standards and are appropriate for
use in the South Carolina Upstate.
Table 9. Green infrastructure planning level unit costs per acre treated (King and Hagen 201 I)
Gl Practice
Infiltration
Bioretention, Urban
Permeable Pavement
Preconst ruction
$17,500
$52,500
$21,780
Construction
$43,750
$131,250
$217,800
Annual O&M
$906
$1,531
$2,188
Total 20-yr
$4,219
$10,869
$14,167
Unit cost data for rainwater cistern systems is highly variable and dependent on cistern configuration
and the rainwater utilization system. Unit construction cost was estimated at $1 per gallon of storage
based on similar project installations in North Carolina (Hunt 2013) and an additional $1 for utilization
system based on professional judgment. Other unit costs were based on best professional judgment and
experience in implementing rainwater cistern applications in similar settings.
5.2 Typical Residential Block
Table 13 summarizes preliminary implementation costs for the typical residential block project site.
Published unit construction costs for the infiltration basin in scenarios 2, 3, and 4 were escalated by
2 percent to account for the additional excavation depth necessary to accommodate the additional
6 inches of storage depth relative to the infiltration basin configuration evaluated under scenario 1. Rain
garden costs were assumed to be approximated by published bioretention unit costs for rural or
suburban settings.
47
-------
Table 10. Preliminary implementation cost estimates for the typical residential block project site
Scenario
Scenario 1
Infiltration (6-in storage)
Scenario 2
Infiltration (12-in storage)
Scenario 3
Infiltration
Rain garden
Scenario 4
Infiltration
Cistern
*gallons of cistern storage.
5.3 Green Street
Acres treated/
storage
2
2
2
1.7
2
46,120*
Preconst ruction
$34,825
$35,522
$34,825
$15,938
$34,825
20,000
Construction
$87,063
$87,063
$87,063
$63,750
$87,063
$92,420
Annual O&M
$1,803
$1,803
$1,803
$2,603
$1,803
$1,000
Total 20-yr
$157,946
$157,946
$158,643
$158,643
$290,385
$158,643
$131,742
$291,063
$158,643
$132,420
Table 11 summarizes preliminary implementation cost estimates for the green street site. Unit costs for
the planter boxes were assumed to be represented by bioretention in highly urban settings given the
necessary curbing and other hardened infrastructure adjacent to the planter box.
Table I I. Preliminary implementation cost estimates for the green street project site
Scenario
Acres
treated Preconst ruction Construction Annual O&M Total 20-yr
Scenario 1
Planter Boxes 0.43
Scenario 2
Permeable Pavement 0.33
$22,532
$7,187
$56,438
$71,874
$658
$722
$92,136
$93,502
48
-------
6 Operations and Maintenance
Maintenance activities should focus on the major system components, especially landscaped areas and
permeable pavement. Landscaped components should blend over time through plant and root growth
and organic decomposition, and should develop a natural soil horizon (Table 12). The biological and
physical processes over time will lengthen the facility's life span and reduce the need for extensive
maintenance. The primary maintenance requirement for permeable pavement consists of regular
inspection for clogging and sweeping with a vacuum-powered street sweeper (Table 13).
Irrigation for the bioretention systems might be needed, especially during plant establishment periods
or in periods of extended drought. Irrigation frequency will depend on the season and type of
vegetation. Native plants will likely require less irrigation than nonnative plants.
The following tables outline the required maintenance tasks, their associated frequency, and notes to
expand upon the requirements of each task.
Table 12. Bioretention operations and maintenance considerations
Task
Monitor
infiltration and
drainage
Pruning
Mowing
Mulching
Mulch removal
Watering
Fertilization
Remove and
replace dead
plants
Inlet inspection
Outlet
inspection
Frequency
Maintenance notes
1 time/year
1-2 times/year
2-12 times/year
1-2 times/year
1 time/2-3 years
1 time/2-3 days for first
1-2 months;
sporadically after
establishment
1 time initially
2 times/year
Once after first rain of
the season, then every 6
months
Once after first rain of
the season, then
monthly during the rainy
season
Inspect drainage time (12-24 hours). Might have to determine
infiltration rate (every 2-3 years). Turning over or replacing the
media (top 2-3 inches) might be necessary to improve infiltration
(at least 0.5 in/hr).
Nutrients in runoff often cause bioretention vegetation to flourish.
Frequency depends on the location, plant selection, and desired
aesthetic appeal.
Recommend maintaining 1- to 3-inch uniform mulch layer.
Mulch accumulation reduces available water storage volume.
Removing mulch also increases surface infiltration rate of fill soil.
If drought conditions exist, watering after the initial year might be
required.
One-time spot fertilization for first year vegetation (optional).
Within the first year, 10% of plants can die. Survival rates increase
with time.
Check for sediment accumulation to ensure that flow into the
retention area is as designed. Remove any accumulated sediment.
Check for erosion at the outlet and remove any accumulated mulch
or sediment.
49
-------
Task
Frequency
Maintenance notes
Underdrain
inspection
Miscellaneous
upkeep
Once after first rain of
the season, then yearly
during the rainy season
12 times/year
Check for accumulated mulch or sediment. Flush if water is ponded
in the bioretention area for more than 72 hours.
Tasks include trash collection, plant health, spot weeding, and
removing mulch from the overflow device.
Table 13. Permeable pavement operations and maintenance considerations
Task
Frequency
Maintenance notes
Impervious to
pervious
interface
Vacuum street
sweeper
Replace fill
materials
(applies to
pervious pavers
only)
Miscellaneous
upkeep
Once after first rain of
the season, then
monthly during the rainy
season
Twice per year as
needed
1-2 times per year (and
after any vacuum truck
sweeping)
4 times per year or as
needed for aesthetics
Check for sediment accumulation to ensure that flow onto the
permeable pavement is not restricted. Remove any accumulated
sediment. Stabilize any exposed soil.
Portions of pavement should be swept with a vacuum street
sweeper at least twice per year or as needed to maintain infiltration
rates.
Fill materials will need to be replaced after each sweeping and as
needed to keep voids with the paver surface.
Tasks include trash collection, sweeping, and spot weeding.
50
-------
7 Conclusions
The conceptual stormwater management design developed for the Northside redevelopment project
demonstrates how green infrastructure approaches can complement smart growth principles-
providing innovative stormwater management while accommodating and supporting infill, mixed-used
development and affordable housing.
The Northside neighborhood residents indicated that they wanted more green space, access to fresh
food, more opportunities to recreate outdoors, and more walkable neighborhoods. To accomplish these
overall goals, the community selected five site-specific transformational projects to be designed and
implemented in the redevelopment area. Based on input from the project team, each of these projects
will incorporate green infrastructure principles such as green space, street trees, urban agriculture, and
a riparian greenway per the desires expressed by the residents. In addition, the City project team
expressed an interest in the development of generic conceptual designs that could be incorporated
throughout the redevelopment area. Due to the early phase of the overall redevelopment project,
these conceptual designs were not based on a specific location; rather, they were developed based on
certain basic design assumptions incorporating bioretention, permeable pavement, green roofs,
rainwater harvesting infiltration basins, and urban agriculture. Both the Residential Block and Green
Street design can be used in multiple locations throughout the redevelopment area—including the
transformation projects described during the public workshop—and will support the vision of the
master Northside Redevelopment Plan.
In addition, the City project team expressed an interest in revising existing plans, codes, and ordinances
to better support the implementation of green infrastructure during the redevelopment of the
Northside neighborhood and throughout the City. This report also provides specific guidance regarding
how City planning documents and regulations can be revised to remove barriers and integrate the use of
green infrastructure into the development ideology of the City.
As cities and towns seek to revitalize historic neighborhoods and redirect growth into existing urban
areas, green infrastructure can complement redevelopment efforts. In addition to meeting stormwater
management goals, this project illustrates how green infrastructure can help create a more attractive
and livable landscape that weaves functional natural elements into the built environment.
51
-------
8 References
AECOM Technical Service, Inc. 2011. Leon Creek Watershed Master Plan. Prepared for San Antonio River
Authority, San Antonio, TX.
American Society of Landscape Architects (ASIA), American Rivers, and Water Environment Federation.
2012. Banking on Green: A Look at How Green Infrastructure Can Save Municipalities Money
and Provide Economic Benefits Community-wide, www.asla.org/.
Anderson, L., and H. Cordell. 1988. Influence of trees on property values in Athens, Georgia (USA): A
survey on actual sales prices. Landscape and Urban Planning 15(1-2):153-164.
Barr Engineering Company. 2006. Burnsville Stormwater Retrofit Study. Minneapolis, MN.
www.ci.burnsville.mn.us/DocumentCenter/Home/View/449.
Clear, C, and K. Giacalone. 2009. Rain Gardens: A Rain Garden Manual for South Carolina. Accessed June
17, 2014. www.clemson.edu/psapublishina/paaes/HORT/IL87.PDF.
DeBusk, K. M., W. F. Hunt and D. E. Line. 2011. Bioretention Outflow: Does it Mimic Non-Urban
Watershed Shallow Interflow? Journal of Hydrologic Engineering 16(3): 274-279.
DeBusk, K.M., W.F. Hunt, M. Quigley, J. Jeray, and A. Bedig. 2012. Rainwater harvesting: Integrating
water conservation and stormwater management through innovative technologies. World
Environmental and Water Resources Congress 2012: Crossing Boundaries, Proceedings of the
2012 Congress, pp. 3703-3710.
Espey, M., and K. Owusu-Edusei. 2001. Neighborhood Parks and Residential Property Values in
Greenville, South Carolina. Journal of Agricultural and Applied Economics 33(3):487-492.
Hastie, C. 2003. The Benefit of Urban Trees. A summary of the benefits of urban trees accompanied by a
selection of research papers and pamphlets. Warwick District Council. Accessed September
2010. www.naturewithm.info/UF/TreeBenefitsUK.pdf.
Hirschman, D., K. Collins, and T. Schueler. 2008. Runoff Reduction Method Technical Memo. Center for
Watershed Protection and Chesapeake Stormwater Network, Ellicott City, MD.
Hobden, D., G. Laughton, and K. Morgan. 2004. Green space borders—a tangible benefit? Evidence from
four neighbourhoods in Surrey, British Columbia, 1980-2001. Land Use Policy 21(3):129-138.
Hunt, W.F., 2013. Regulatory and Research Update. Workshop Presentation made at the 2013 APWA-NC
Stormwater Management Division Conference Wilmington, NC, September 16, 2013.
Jones, M.P., and W.F. Hunt. 2010. Effect of stormwater wetlands and wet ponds on runoff temperature
in trout sensitive waters. Journal of Irrigation and Drainage Engineering 136(9):656-661.
King, D. and Hagan, P. 2011. Costs of Stormwater Management Practices in Maryland Counties:
Technical Report Series No. TS-626-11 of the University of Maryland Center for Environmental
Science, Solomons, MD.
Kou, F., and W. Sullivan. 2001. Environment and Crime in the Inner City: Does Vegetation Reduce Crime.
Environment and Behavior 33(3):343-367.
52
-------
Kuo, F. 2003. The role of arboriculture in a healthy social ecology. Journal of Arboriculture 29(3):148-
155.
NCDENR, 2007. Stormwater Best Management Practices Manual. North Carolina Department of
Environment and Natural Resources: Division of Water Quality. Raleigh, NC.
portal. ncdenr.ora/web/lr/bmiD-manual.
New Yorkers for Parks and Ernst & Young. 2003. Analysis of Secondary Economic Impacts Resulting from
Park Expenditures. New Yorkers for Parks, New York, NY.
Northeastern Illinois Planning Commission (NIPC). 2004. Sourcebook on Natural Landscaping for Local
Officials. Accessed December 2012.
www.chicaaowilderness.ora/files/4413/3087/4878/natural landscaping sourcebook.pdf.
Pincetl, S., J. Wolch, J. Wilson, and T. Longcore. 2003. Toward a Sustainable Los Angeles: A Nature's
Services Approach. University of Southern California Center for Sustainable Cities, Los Angeles,
CA.
SCDHEC. 2005. BMP Handbook. South Carolina Department of Health and Environmental Control:
Bureau of Water. Columbia, SC.
http://www.scdhec.Qov/Environment/WaterQ.ualitv/Stormwater/BMPHandbook/.
Schueler, T. 2008. Technical Support for the Bay-wide Runoff Reduction Method. Chesapeake
Stormwater Network, Baltimore, MD. www.chesaipeakestormwater.net.
Shultz, S., and N. Schmitz. 2008. How Water Resources Limit and/or Promote Residential Housing
Developments in Douglas County. University of Nebraska-Omaha Research Center, Omaha, NE.
http://watercenter.unl.edu/ResearchDB/publications/Wtr%20Res%20Housind%20Dev%20Studv
%20Doucilas%20Co.pdf. Accessed September 1, 2008.
Spartanburg County. 2009. Spartanburg County Storm Water Management Design Manual. Accessed
June 10, 2014.
www.srjartanburacountv.ora/aovt/derJts/[}ubwrks/docs/StormWater/DesianManual.rjdf.
USEPA. 2011. A Strategic Agenda to Protect Waters and Build More Livable Communities Through Green
Infrastructure. Accessed June 10, 2014.
water.epa.gov/infrastructure/greeninfrastructure/upload/gi agenda protectwaters.pdf.
USEPA. 2013. Green Infrastructure Strategic Agenda 2013. Accessed June 17, 2014.
water.epa.gov/infrastructure/greeninfrastructure/upload/2013 Gl FINAL Agenda 101713.pdf.
Vialle, C., C. Sablayrolles, M. Lovera, M.-C. Huau, S. Jacob, and M. Montrejaud-Vignoles. 2012. Water
quality monitoring and hydraulic evaluation of a household roof runoff harvesting system in
France. Water Resource Management 26:2233-2241.
Voicu, I., and V. Been. 2008. The Effect of Community Gardens on Neighboring Property Values. Real
Estate Economics 36(2):241-283.
Wachter, S. M. and G.W. Bucchianeri. 2006. What is a Tree Worth? Green-City Strategies and Housing
Prices. Real Estate Economics 36(2):213-239. ssrn.com/abstract=1084652.
Ward, B., E. MacMullan, and S. Reich. 2008. The Effect of Low-impact Development on Property Values.
ECONorthwest, Eugene, OR.
53
-------
Wolf, K.L. 1998. Urban Nature Benefits: Psycho-Social Dimensions of People and Plants. Human
Dimension of the Urban Forest. Fact Sheet #1. Center for Urban Horticulture. University of
Washington, College of Forest Resources.
Wolf, K.L. 2008. With Plants in Mind: Social Benefits of Civic Nature. MasterGardener 2(1):7-11.
Young, T. 2013. An Introduction to Porous Pavement. Accessed June 17, 2014.
www.clemson.edu/extension/hgic/water/resources stormwater/introduction to porous pavement.
html.
54
------- |