Analyzing potential surface areas for an integrated
green infrastructure network in the Boston
Metropolitan Area
Yaser Abunnasr
Assistant Professor
American University of Beirut
Beirut , Lebanon
Session D1
Green infrastructure solutions for climate change adaptation
May 30, 2014
Resilient Cities, 2014 - 5th Global Forum on Urban Resilience and Adaptation
Bonn, Germany 29-31, 2014
Content
• Introduction
• Framework
• Method
• Sample Results
• Four pronged approach
• Policy prioritization
• Other Applications
• Conclusion
May 30, 2014
Y.Abunnasr - RC2014-Session D1
2
Introduction
Green Infrastructure (GI) & Urban Adaptation (UA)
Synergies
• Complementarity
• No-regrets
•Reduce exposure and risk
Considerations
• Vulnerability to climate change (Gill et al., 2007)
• Multiple benefits versus single benefits
• Conflict with mitigation measures→ space versus
urban form (Hamin and Guran, 2008)
• Surface Infrastructure→ Area and space (Davies, 2009)
May 30, 2014
Y.Abunnasr - RC2014-Session D1
3
Objective
To develop a metropolitan scale system of green
infrastructure measures by prioritizing strategies
across the urban gradient through the analysis of
maximum pervious surface opportunities within
land-use categories
• Why pervious surfaces?
• Why land-use?
• Which GI measures
May 30, 2014
Y.Abunnasr - RC2014-Session D1
4
Why Pervious Surfaces?
Surface Area
• Green infrastructure → Ecosystem services
• Area of Active Hydrological surfaces → Pervious
Surfaces → Primary variable (Stone, 2012)
AREA
PERVIOUS
SURFACES
May 30, 2014
Y.Abunnasr - RC2014-Session D1
5
Why Land-use?
Land Use
• Morphology of surfaces
• Quality of soil and vegetation type
• ‘Permanency’ of green infrastructure →
context of adaptation
Compared based on 0.75 x 0.5 km grid
commercial
May 30, 2014
industrial
urban public/instit. residential
Y.Abunnasr - RC2014-Session D1
cemetery
golf course
6
Framework
Impact of
choice to
be studied
May 30, 2014
Y.Abunnasr - RC2014-Session D1
7
Urban Heat Island
Science
• Urbanization →Surface Change
• Surface Change →Urban
Climate (Alcoforado, 2008)
• UHI →Induced local climate
change (Oke, 1976, 1985)
Planning: GI Measures
• Increase hydro logically active
surfaces (Stone, 2012)
• Network of green roofs and tree
canopy (Rosenzweig et al., 2006)
• Parking surfaces over estimated
(Davis et al. ,2010); McPherson et al.,2001)
May 30, 2014
Y.Abunnasr - RC2014-Session D1
8
Method
1- Define study area
2- Percent Pervious
3- Develop pervious surface data set
4- Characterize study area
5- Assess opportunities and define criteria
Urbanization
Land use
Initial Condition
Land cover
UHI-Treatment
6- Assess opportunities relevant for UHI
7- Criteria of Assessment for UHI
pervious
8- Define gradient of
green infrastructure policies for UHI
May 30, 2014
Y.Abunnasr - RC2014-Session D1
Impervious
Policy
Recommendations
Results
9
Method - Study Area
Boston Metropolitan Area
• CMSA of Boston - 4 MSAs
• 161 towns - Area 7,230km2
• Pervious (72%) –
impervious(16%)
• 23 landuse classes Forest(41%), Urban(33%),
Agriculture(3%), water(18%)
• Loss of forest, 14% since 1971
(MassGIS)
• High resolution data
• UHI in Boston ≈3C° (ULTRA-EX project)
May 30, 2014
Y.Abunnasr - RC2014-Session D1
10
Method - Percent pervious metric
Percent Pervious (PP) =
Shrubs
Trees
𝐴𝑟𝑒𝑎𝑝𝑒𝑟
(𝑎𝑟𝑒𝑎𝑝𝑒𝑟 +𝐴𝑟𝑒𝑎𝑖𝑚𝑝 ) 𝑢𝑛𝑖𝑡 𝑜𝑓 𝑎𝑛𝑎𝑙𝑦𝑠𝑖𝑠
Ground Cover
Streets
Parking
Impervious Surfaces
Pervious Surfaces
May 30, 2014
Buildings
Y.Abunnasr - RC2014-Session D1
11
Method - Pervious Surface Data Set
Data Sets (Mass GIS, 2013)
•
•
•
•
•
•
Impervious surfaces
Land Use
Soil (not used)
Topography (not used)
Roads
Bldg. foot print
Pervious-Adapt (PER-ADPT)
Processing
Data Layer
Acron.
Attribute information
Scale
Pervious
Surfaces
PER
Town name, land use attributes
Study area
Roads
RD
Town name, land use attributes
Study area
Buildings
BLDG
Town name, land use attributes
Study area
Parking
PRKG
Town name, land use attributes
Study area
Study Area
SA
Town name, land use attributes
• Impervious →Raster to polygon
• Extract PER and IMP
• Errors /water extracted
Attributes
• Per & IMP
• BLDG, RD & PRKG
May 30, 2014
Y.Abunnasr - RC2014-Session D1
12
Method – Characterization into pervious gradient zones
• Classification: gradient zones
• Gradient: urban ecological gradient (Whittaker, 1967;Alberti, 2008, McDonnell &
Pickett 1990)
• valuation of ecosystem services (Gill et al., 2008, Radford and James, 2013)
• Metric: Percent Pervious (PP)
• Unit of analysis: Town/city
• Comparative analysis: road network & population density
Zone
Zone Name
1
2
3
4
5
6
Intense Urban
Urban core
Urban
Sub-urban
Peri-urban
Semi-rural
May 30, 2014
Pervious-toimpervious
PER:IMP≤1
1.0<PER:IMP≤1.5
1.5<PER:IMP≤2.35
2.35<PER:IMP≤4.0
4.0<PER:IMP≤9.0
PER:IMP>9.0
Percent
Pervious(PP)
PP≤50%
50%<PP≤60%
60%<PP≤70%
70%<PP≤80%
80%<PP≤90%
PP>90%
Gill et al. (2008) -Radford and
James (2013)
PP≤50%
Urban
12%<PP≤88%
Suburban
88%<PP≤95%
PP>95%
Y.Abunnasr - RC2014-Session D1
Peri-urban
Rural
Davis et al. (2010)
PP≤25%
High urban
25%<PP≤97%
Suburban
PP>97%
rural
13
Method - Assess % Pervious
• Unit: Gradient Zone
• Classification: PER-LU to
pervious per zone
Excluded: Forest aside
• Metric: Calculate %
pervious
Legend ( MassGIS )
May 30, 2014
Y.Abunnasr - RC2014-Session D1
14

Method –Percent pervious selection criteria for UHI
Tree Canopy intensification
• Contiguous Pervious patches≥4 Ha (Rosenzweig et al., 2006, Bowler et al, 2010)
• Other pervious: coefficient of area reduction

Green Roofs
• Flat roofs ≥ 200m2(Assessment of existing flat roofs)
• 70% effective roof surface(LEED)

Street shading
• Right of way less impervious
• All Classes, when possible

Green Streets
• Lower speed, local
• ½ qualifying area (Condon)

Parking
• Classification ≥ 1 Ha
• 30% to pervious (Davis et al. ,2010); McPherson et al.,2001)
May 30, 2014
Y.Abunnasr - RC2014-Session D1
15
Method – Gradient of policies
Define policy opportunities
• Results for each GI strategy summed
• Tabulated and plotted
• Contextualizing impact and policy - Mapped in GIS ,
compare to UHI imprint
GI Strategies
GI Measures
Contribution to temperature reduction
Conserve
Increase Protection: Maintain existing forest tree canopy
Cooling of urban breeze reduce surface
temperature; maintain moisture in soil and air.
Contiguous patches
PER:4Ha patches-Contiguous intensification: Establish new
forest cover on existing pervious surfaces such as open land or
agricultural land (when opportunity arises). Pursue aggressively
to increase stock of land
Cooling of urban breeze reduce surface
temperature; maintain moisture in soil and air.
Intensify
PER: Use Factor-Intensify: Increase tree canopy within pervious
surfaces in private property and street easements
Cooling of urban breeze reduce surface
temperature; maintain moisture in soil and air.
Transform impervious
to pervious
Reduce impact
Green roofs, green streets, parking surfaces
Increase albedo, reduce energy use and cool
upper urban canopy
Provide shade and increase albedo.
May 30, 2014
Street and Parking shading: Provide pervious surfaces within
parking, streets and residential property to reduce
Y.Abunnasr - RC2014-Session D1
16
Results – Characterization
Gradient Zones
% Pervious-Roads-Towns
Zone 6
Zone 6
Zone 3
Zone 5
Zone 4
Zone 2
Zone 1
Density-Roads-Towns
Zone 5
Zone 6
May 30, 2014
Y.Abunnasr - RC2014-Session D1
17
Results – Pervious surfaces
Zone1
Zone 2
Zone 3
Zone 4
Zone 5
Zone 6
Multi-Family Res High Density Res
Med. Density Res Med. Density Res Low Density Res.
High Density Res Multi-Family Res
High Density Res Low Density Res Very low Density Res. Medium density Res.
Urban Public Inst Participation Rec & Cemetery Multi-Family Res Multi-Family Res Open Land
Low Density Res.
Very low Density Res.
% Pervious Across Land Uses
May 30, 2014
Y.Abunnasr - RC2014-Session D1
How does pervious surface opportunity vary across land uses along the gradient?
18
Results - 4 Ha Patches
Zone1
Zone 2
Zone 3
Zone 4
Zone 5
Part. Recreation
High Density Res Med. Density Res Med. Density Res Low Density res.
Transportation
Golf Courses
Zone 6
Low Density Residential
High Density Res Low & Density Res Medium Density Res. V. Low Density Residential
High den. Res/Golf/open land Part. Recreation Multi-Family Res High Density Res Golf Courses
Golf Courses
CONTIGUOUS TREE CANOPY: % Pervious- 4 Hectare Patches
When
considering
of pervious surfaces
for green infrastructure measures 19
across
May
30, 2014 UHI, what is the maximum opportunity
Y.Abunnasr - RC2014-Session
D1
land-use categories?
Results – Green Roofs
Zone1
Zone 2
Zone 3
Zone 4
Zone 5
Zone 6
Commercial
High Density Res
High Density Res
High Density Res. Industrial
Industrial & Public/Instit
High Density Res Commercial
Commercial
Industrial
Commercial
Commercial
Urban Public Inst Industrial
Industrial
Commercial
High Density Res
High Density Res.
GREEN ROOFS: % Pervious- By Use Coefficient
When
considering
of pervious surfaces
for green infrastructure measures 20
across
May
30, 2014 UHI, what is the maximum opportunity
Y.Abunnasr - RC2014-Session
D1
land-use categories?
Results – Prioritizing Measures
• Opportunities of green infrastructure measures
Contiguous tree patches
All residential categories
Tree intensification
All residential, commercial, open land
Green Roofs
High density residential, commercial industrial
Street shading and green streets
Class 5, local roads
Parking shading & surface transform
Industrial & commercial
• Policy priorities
Priority 1
Priority 2
Priority 3
Zone 1 Parking shading/transform Green Roofs
Tree Intensification
Zone 2 Tree Intensification
Street shade & green streets
Contiguous tree patches
Zone 3 Green Roofs
Contiguous tree patches
Tree Intensification
Zone 4 Contiguous tree patches
Tree Intensification
Parking shading/transform
Zone 5 Contiguous tree patches
Tree Intensification
Parking shading/transform
Zone 6 Contiguous tree patches
Tree Intensification
Street shading
May 30, 2014
Y.Abunnasr - RC2014-Session D1
21
Results - Policy priority by GI measure
UHI-Boston
Green roofs
May 30, 2014
3Ha-Patches
Roads
Y.Abunnasr - RC2014-Session D1
Other Pervious
Parking
22
Results-Gradient of integrated GI policy measures
Hypothetical UHI
general trend for
Boston metro
Forest:41%
Protected: 15%
Potential: 26%
May 30, 2014
Y.Abunnasr - RC2014-Session D1
23
Some caveats
• Data Layers
• Tree canopy cover data layer
• Soil type data layer
• The social dimension
• Land Tenure
• Patch configuration
• Data limitations
May 30, 2014
Y.Abunnasr - RC2014-Session D1
24
Other Applications




Multi- Scale application: from region to
neighborhood scales
Other impacts of concern – differing attributes:
• Flooding
• Biodiversity planning
• Emergency Preparedness
• Urban Agriculture
Ecosystem Services Inventory
Assist as base information for participatory
planning
May 30, 2014
Y.Abunnasr - RC2014-Session D1
25
Conclusion
• Policy prioritization - varying urban contexts
• Local GI plans - nested in a metropolitan strategy
• Potential to assess extent of dependability
• A singular and explicit data layer for GI
• Possible planning species migration that may be
necessary
May 30, 2014
Y.Abunnasr - RC2014-Session D1
26
Thank you
May 30, 2014
Y.Abunnasr - RC2014-Session D1
27