The document discusses the importance of blue-green infrastructure (BGI) in managing urban water resources as cities face challenges from climate change and urbanization. It outlines the shift from traditional grey infrastructure to BGI, highlighting various cities like Copenhagen, New York City, and Singapore that have implemented innovative policies to enhance resilience and sustainability. The book emphasizes the role of adaptive management in effectively planning and utilizing BGI to improve urban water management and environmental health.

1. Blueand
GreenCitiesThe Role of Blue-Green Infrastructure
in Managing Urban Water Resources
Robert C. Brears

2. Blue and Green Cities

3. Robert C. Brears
Blue and Green
Cities
The Role of Blue-Green Infrastructure in Managing
Urban Water Resources

4. Robert C. Brears
Founder of Mitidaption,
Christchurch, Canterbury,
New Zealand
ISBN 978-1-137-59257-6 ISBN 978-1-137-59258-3 (eBook)
https://doi.org/ 10.1057/978-1-137-59258-3
Library of Congress Control Number: 2017939146
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5. ACKNOWLEDGEMENTS
I wish to first thank Rachael Ballard, who is not only a wonderful com-
missioning editor but a visionary who enables books like mine to come to
fruition. Second, I would like to thank all the people who have taken time
out for an interview, provide primary materials and offer invaluable
insights. Without your help this book would not have been possible.
Specifically I wish to thank Lykke Leonardsen (City of Copenhagen);
Niels-Peter Bertram, Franziska Meinzinger, Axel Waldhoff and Juliane
Ziegler (Hamburg Wasser); Alan Cohn (New York City Department of
Environmental Protection); Debra McCarty (Philadelphia Water
Department); Arnoud Molenaar (City of Rotterdam); Tan Nguan Sen,
Cheng Geok Ling and Ai Choo Quek (Singapore Public Utilities Board)
and Bethany Bezak (DC Water). Finally I wish to thank Mum, who has a
great interest in the environment and water-related issues and has sup-
ported me in this journey of writing the book.
v

6. CONTENTS
1 From Traditional Grey Infrastructure to Blue-Green
Infrastructure 1
2 Blue-Green Infrastructure in Managing Urban Water
Resources 43
3 Adaptive Management and Blue-Green Infrastructure 63
4 Copenhagen Becoming a Blue-Green City 99
5 New York City Becoming a Blue-Green City 127
6 Philadelphia Becoming a Blue-Green City 153
7 Rotterdam Becoming a Blue-Green City 183
8 Singapore Becoming a Blue-Green City 205
9 Washington D.C. Becoming a Blue-Green City 231
10 Mini Case Studies of Cities Implementing Blue-Green
Infrastructure 265
vii

7. 11 Best Practices 291
Conclusions 303
Index 311
viii CONTENTS

8. LIST OF FIGURES
Fig. 3.1 General process for adaptation planning 68
Fig. 3.2 Components of the adaptive management decision-making
framework 77
ix

9. LIST OF TABLES
Table 1.1 Change in watershed characteristics after urbanisation 3
Table 1.2 Effects of pollutants from road runoff 5
Table 1.3 Climate change risks to cities 6
Table 1.4 Barriers to the implementation of Blue-Green
Infrastructure 19
Table 2.1 Benefits of bioretention- and infiltration-specific systems 44
Table 2.2 Green roof-specific benefits 49
Table 2.3 Rainwater harvesting-specific benefits 51
Table 2.4 Pervious pavement-specific benefits 53
Table 2.5 Benefits of planting trees 55
Table 3.1 Framework for establishing stormwater fee discounts and
credits 80
Table 3.2 Size of green roof required under Toronto’s Green Roof
Bylaw 87
Table 4.1 BGI creating synergies with existing green infrastructure 102
Table 4.2 Economic benefits of climate adaptation measures 103
Table 4.3 Economic consequences of floods 106
Table 4.4 Breakdown of investment costs 106
Table 4.5 Method of financing the Cloudburst Management Plan 107
Table 4.6 Copenhagen’s adaptive management decision-making
framework 122
Table 5.1 2030 green infrastructure implementation targets 131
Table 5.2 BGI implementation 135
Table 5.3 BGI measures used by sites and houses affected by the
stormwater performance standard 139
Table 5.4 DEP’s adaptive management decision-making framework 148
xi

10. Table 6.1 Breakdown of impervious cover within combined sewer
system 154
Table 6.2 Above-ground green stormwater infrastructure tools 159
Table 6.3 Below-ground green stormwater infrastructure tools 160
Table 6.4 Triple bottom line benefits of green stormwater
infrastructure 162
Table 6.5 Greened Acre Retrofit Program Grant project evaluation
criteria 165
Table 6.6 Cost of rain check stormwater tools 166
Table 6.7 PWD’s adaptive management decision-making framework 176
Table 7.1 Impacts of climate change on Rotterdam 184
Table 7.2 Adaptive approach in Rotterdam 188
Table 7.3 Rotterdam’s adaptive management decision-making
framework 200
Table 8.1 Source, pathway and receptor solutions 208
Table 8.2 ABC Waters design features incorporating BGI 210
Table 8.3 ABC Waters point system 213
Table 8.4 Active Category: point system 214
Table 8.5 Beautiful Category: point system 215
Table 8.6 Clean Category: point system 215
Table 8.7 Innovative Category: point system 216
Table 8.8 Singapore’s adaptive decision-making management
framework 225
Table 9.1 Six-tiered stormwater fee rate structure for residential
properties 239
Table 9.2 Tiered rate structure for single family residences 240
Table 9.3 RiverSmart Innovation grant project scoring 244
Table 9.4 Comparison between the DC Water and RiverSmart
Rewards programmes 245
Table 9.5 Green Infrastructure Challenge criteria 249
Table 9.6 Green Infrastructure Challenge awards per category 250
Table 9.7 Green Infrastructure Challenge ranking criteria and points
possible per category 251
Table 9.8 Green Infrastructure Mentor-Internship Program 252
Table 9.9 DC Water and DOEE’s adaptive management decision-
making framework 257
Table 10.1 Actions to improve existing BGI in Manchester 275
Table 10.2 Actions to implement BGI in new developments 276
Table 10.3 GSI implementation baseline, 2000–2012 283
xii LIST OF TABLES

11. LIST OF ACRONYMS
ABC Waters Active, Beautiful, Clean Waters
BCA Building and Construction Authority
BGI Blue-Green Infrastructure
CAP Climate Adaptation Plan
CCRA Climate Change Risk Assessment
CMP Cloudburst Management Plan
COP Code of Practice
CPI City Parks Initiative
CRIAC Clean Rivers Impervious Area Charge
CSIA Combined Sewer Impervious Area
CSOs Combined Sewer Overflows
DC Water District of Columbia Water and Sewer Authority
DCP Department of City Planning
DEC Department of Environmental Conservation
DEP Department of Environmental Protection
DOB Department of Buildings
DOEE Department of Energy and Environment
DOT Department of Transportation
DPR Department of Parks and Recreation
EAD Expected Annual Damage
EDC Economic Development Corporation
EPA Environmental Protection Agency
ERU Equivalent Residential Unit
GARP Greened Acre Retrofit Program
GIS Geographic Information Systems
GRTA Green Roof Tax Abatement
xiii

12. GSDM Green Streets Design Manual
GSI Green Stormwater Infrastructure
HDB Housing Development Board
IES Institution of Engineers, Singapore
LEED Leadership in Energy and Environmental Design
LTA Land Transport Authority
LTCPs Long Term Control Plans
MoU Memorandum of Understanding
MS4 Municipal Separate Stormwater Sewer System
MTA Metropolitan Transportation Authority
MWRD Metropolitan Water Reclamation District of Greater Chicago
NParks National Parks Board
NPDES National Pollutant Discharge Elimination System
NUS National University of Singapore
NYCHA NYC Housing Authority
OGI Office of Green Infrastructure
PEG Prefabricated Extensive Greening
PPR Philadelphia Parks and Recreation
PUB Public Utilities Board
PWD Philadelphia Water Department
RFI Request for Information
RISA Rain InfraStructure Adaptation
ROW Rights of Way
SBI Sites of Biological Importance
SCBA Societal Cost Benefit Analysis
SDOT Seattle Department of Transportation
SIA Singapore Institute of Architects
SILA Singapore Institute of Landscape Architects
SMIP Stormwater Management Incentives Program
SPARC Seattle Parks and Recreation
SPDs Stormwater Planning Districts
SPU Seattle Public Utilities
SRC Stormwater Retention Credit
SWB Sewerage and Water Board of New Orleans
TARP Tunnel and Reservoir Plan
TPL Trust for Public Land
UHI Urban Heat Island
URA Urban Risk Assessment
VA Vulnerability Assessment
WEF Water Environment Federation
WHG Workforce Housing Group
xiv LIST OF ACRONYMS

13. WSUD Water Sensitive Urban Design
WTD Wastewater Treatment Division
WWTPs Wastewater Treatment Plants
IMPERIAL TO METRIC CONVERSION TABLE
For use with chapters 5, 6 and 9: conversions are rounded up to two decimal places
1 gallon = 4.55 litres
1 mile = 1.61 kilometres
1 acre = 0.40 hectare
1 foot = 0.30 metre
1 square foot = 0.09 square metre
1 cubic foot = 0.03 cubic metre
1 pound = 0.45 kilogram
LIST OF ACRONYMS xv

14. INTRODUCTION
Cities are home to half the world’s population and serve as global eco-
nomic hubs, generating almost 80 percent of the world’s GDP. With cities
facing extreme weather events and rapid urban growth leading to the over-
use of natural resources and creating environmental degradation, urban
centres around the world need to become more resilient to climate change
and reduce their ecological footprints.
Green Cities are concerned with how to design the whole city in a more
sustainable, efficient, adaptive and resilient way. Green Cities recognise
connections between different sectors and support development strategies
that fulfil multiple functions and create multiple benefits for society and
urban ecosystems. In the context of urban water resource management, a
Blue-Green City calls for the holistic planning and management of water,
wastewater and stormwater across the whole city to ensure that popula-
tions are resilient to climate change and extreme weather events while
ensuring the health of aquatic ecosystems.
Traditionally, urban water managers have relied on grey infrastructural
solutions, including dams and levees, to mitigate risks – with numerous
environmental and economic consequences. For instance, traditional
stormwater drainage systems, designed to prevent localised flooding,
have created downstream flooding risks as well as stormwater overflows
into waterways. At the same time, traditional systems have impacted the
local hydrological cycle with less groundwater recharge and lower base-
flows of waterways, impacting availability of water for humans and nature.
In addition, traditional systems are inadequate to deal with climate change-
related extreme weather events, with systems unable to cope with sudden
xvii

15. large volumes of precipitation. Traditional systems also impact water qual-
ity, with runoff washing pollutants into nearby waterways. Furthermore,
runoff causes turbidity as well as thermal pollution which can impact
drinking water quality. In addition to climate change impacting water
quality and quantity, urbanisation is resulting in environmental degrada-
tion. Finally, cities are facing regulatory challenges in simultaneously mana-
ging floods while also restoring the health of waterways.
In a Blue-Green City, Blue-Green Infrastructure (BGI) involves the use
of natural or man-made systems to enhance ecosystem services in the
management of water resources and increase resilience to climate risks.
BGI solutions can also be used to support the goals of multiple policy
areas. For example, green spaces and restored lakes and wetlands can
reduce flooding risks to neighbourhoods while simultaneously supporting
urban agricultural production and wildlife, in addition to providing recrea-
tional and tourism benefits. In Blue-Green Cities, urban water managers
also use a variety of innovative fiscal and non-fiscal tools to encourage the
implementation of BGI on public and private property to sustainably
manage water resources and increase resilience to climate risks.
Nonetheless, our understanding of the role urban water managers have
in implementing BGI to mitigate climate risks while reducing environ-
mental degradation lags significantly behind engineering knowledge on
water resource management. As such, little has been written on the actual
implementation of policy innovations at the urban level that promote the
application of BGI projects that not only reduce climate risk but also
restore ecosystems and the numerous services they provide. In addition,
because the application of BGI requires holistic planning, little has been
written on how innovative policies have been developed to ensure BGI
water projects fulfil multiple functions and policy goals and create multiple
benefits for society and urban ecosystems.
This book provides new research on urban policy innovations that
promote the application of BGI in managing water resources sustainably.
In particular, the book contains case studies that illustrate how cities, of
differing climates, lifestyles and income levels, have implemented policy
innovations that promote the application of BGI in managing water,
wastewater and stormwater sustainably to enhance resilience to climate
change and reduce environmental degradation. The six case studies review
leading cities that have implemented a variety of fiscal and non-fiscal policy
tools to encourage the implementation of BGI on both public and private
property to reduce stormwater runoff volumes, enhance the health of
xviii INTRODUCTION

16. waterways, enhance resilience to climate change and meet regulatory
requirements. Data for each case study have been collected from inter-
views conducted with, and primary materials provided by each city’s
respective department or utility in charge of implementing BGI. The six
cities are Copenhagen, New York City, Philadelphia, Rotterdam,
Singapore and Washington D.C., each of which are considered leaders in
terms of their approach to sustainability, environmental and water
resource management according to various sustainability indexes. The
latter include Arcadis’ Sustainability Index, which ranks cities on three
pillars of sustainability: people, planet and profit, as well as the Siemens
Green City Index, a research project conducted by the Economist
Intelligence Unit and sponsored by Siemens. Copenhagen has been
selected because it is a pioneer in showing that adaptation, in addition to
managing excess stormwater, also provides significant social, environmen-
tal and economic benefits to the city. Meanwhile New York City is leading
the way in combining BGI with traditional grey infrastructure to reduce
combined sewer overflows. Philadelphia is implementing BGI to meet
regulatory requirements and while doing so is ensuring that it creates a
legacy for future generations to enjoy. Rotterdam is implementing a
variety of BGI measures to help it become climateproof. Singapore, facing
space constraints in developing grey infrastructure, is integrating green
and blue spaces while mitigating the impacts of climate change. Finally,
Washington is implementing BGI to improve the health of the city’s
waterways while reducing stormwater volumes that are predicted to
increase with climate change. The book also contains a series of mini
case studies of various cities around the world in the planning or imple-
mentation stage of initiating BGI to meet various challenges to their
traditional grey infrastructure.
The book will introduce readers to the adaptive management frame-
work that guides cities in their implementation of BGI in order to increase
resilience to climate change and reduce environmental degradation. In the
context of climate change, adaptive management is a process where deci-
sion-makers take action in the face of uncertainty. It is through this
process of quantifying and acknowledging uncertainty that a society can
decide how best to manage climate risk. Adaptive management also seeks
to improve scientific knowledge and develop management practices that
consider a range of future possibilities and even take advantage of unanti-
cipated climatic events. In the context of natural resource management,
adaptive management is the process of hypothesising how ecosystems
INTRODUCTION xix

17. work and modifying management decisions to achieve environmental
objectives through improved understanding. Adaptive management can
be used to restore or enhance ecosystems damaged by the impacts of
urbanisation as the framework recognises that resource systems are only
partially understood and that there is value in tracking responses of natural
resources to management decisions. In Blue-Green Cities, adaptive man-
agement relies on monitoring, investigating and researching to build
knowledge on waterways and understand the outcomes of management
decisions on the environment and the effects of climate change.
In the operationalisation of BGI, the adaptive management decision-
making framework involves the planning, designing, implementing and
monitoring of BGI to achieve the multiple benefits it provides. Blue-
Green Cities use a variety of fiscal tools to encourage the implementation
of BGI practices on both public and private property, including new and
existing developments. Fiscal tools are easy to implement and provide
decision-makers with the flexibility and creativity to meet specific priorities
as well as provide the opportunity to pilot new incentives before citywide
application. Meanwhile, non-fiscal tools encourage the implementation of
BGI on both public and private property and allow policy-makers to test
and refine BGI programmes that could one day become mandatory
requirements.
The book’s chapter synopsis is as follows:
Chapter 1 provides an introduction to traditional grey infrastructure
stormwater systems; this is followed by a review of the impacts of tradi-
tional grey infrastructure on water quantity and water quality before
discussing the challenges posed by climate change, rapid urbanisation
and meeting regulatory requirements. The chapter then introduces read-
ers to BGI and its multiple benefits before finally discussing the barriers to
its implementation.
Chapter 2 discusses two types of BGI: natural and man-made water
features, both of which provide numerous multifunctional benefits in
addition to managing water quantity and quality.
Chapter 3 defines urban resilience and reviews the measures that can be
taken to increase it. It then introduces the concept of adaptive manage-
ment and how BGI can be operationalised using an adaptive management
framework. Finally, the chapter discusses how cities can use a variety of
fiscal and non-fiscal tools to encourage the development of BGI.
xx INTRODUCTION

18. Chapters 4–9 comprise case studies on the implementation of BGI, as part
of the process of becoming a Blue-Green City, in the following cities:
Copenhagen (Chapter 4), New York City (Chapter 5), Philadelphia
(Chapter 6), Rotterdam (Chapter 7), Singapore (Chapter 8) and
Washington (Chapter 9).
Chapter 10 includes a series of mini case studies of other cities in the
implementation stage of initiating BGI to become Blue-Green Cities.
Chapter 11 includes a summary of best practices from the selected case
studies for other cities planning to implement BGI in an attempt to
become Blue-Green Cities.
INTRODUCTION xxi