Analyzing potential surface areas for an integrated green infrastructure network in the Boston Metropolitan Area

Transcription

1 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, th Global Forum on Urban Resilience and Adaptation Bonn, Germany 29-31, 2014

2 Content Introduction Framework Method Sample Results Four pronged approach Policy prioritization Other Applications Conclusion May 30, 2014 Y.Abunnasr - RC2014-Session D1 2

3 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

4 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

5 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

6 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 industrial urban public/instit. residential cemetery golf course May 30, 2014 Y.Abunnasr - RC2014-Session D1 6

7 Framework Impact of choice to be studied May 30, 2014 Y.Abunnasr - RC2014-Session D1 7

8 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

9 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 Initial Condition Land use Land cover 6- Assess opportunities relevant for UHI 7- Criteria of Assessment for UHI pervious Impervious UHI-Treatment 8- Define gradient of green infrastructure policies for UHI Policy Recommendations Results May 30, 2014 Y.Abunnasr - RC2014-Session D1 9

10 Method - Study Area Boston Metropolitan Area CMSA of Boston - 4 MSAs 161 towns - Area 7,230km 2 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

11 Method - Percent pervious metric Percent Pervious (PP) = Area per (area per +Area imp ) unit of analysis Shrubs Trees Ground Cover Streets Buildings Parking Pervious Surfaces Impervious Surfaces May 30, 2014 Y.Abunnasr - RC2014-Session D1 11

12 Method - Pervious Surface Data Set Data Sets (Mass GIS, 2013) Impervious surfaces Land Use Soil (not used) Topography (not used) Roads Bldg. foot print Processing Impervious Raster to polygon Extract PER and IMP Errors /water extracted Pervious-Adapt (PER-ADPT) 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 Attributes Per & IMP BLDG, RD & PRKG May 30, 2014 Y.Abunnasr - RC2014-Session D1 12

13 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 Pervious-toimpervious Percent Pervious(PP) Gill et al. (2008) -Radford and James (2013) Davis et al. (2010) 1 Intense Urban PER:IMP 1 PP 50% PP 50% Urban PP 25% High urban 2 Urban core 1.0<PER:IMP %<PP 60% 12%<PP 88% Suburban 3 Urban 1.5<PER:IMP %<PP 70% 4 Sub-urban 2.35<PER:IMP %<PP 80% 25%<PP 97% Suburban 5 Peri-urban 4.0<PER:IMP %<PP 90% 88%<PP 95% Peri-urban 6 Semi-rural PER:IMP>9.0 PP>90% PP>95% Rural PP>97% rural May 30, 2014 Y.Abunnasr - RC2014-Session D1 13

14 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

15 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 200m 2 (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

16 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 Street and Parking shading: Provide pervious surfaces within parking, streets and residential property to reduce Increase albedo, reduce energy use and cool upper urban canopy Provide shade and increase albedo. May 30, 2014 Y.Abunnasr - RC2014-Session D1 16

17 Gradient Zones Results Characterization % 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

18 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. 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 Very low Density Res. % Pervious Across Land Uses May 30, 2014 Y.Abunnasr - RC2014-Session D1 18 How does pervious surface opportunity vary across land uses along the gradient?

19 Results - 4 Ha Patches Zone1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 Part. Recreation High Density Res Med. Density Res Med. Density Res Low Density res. Low Density Residential Transportation Golf Courses 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 May considering 30, 2014 UHI, what is the maximum opportunity Y.Abunnasr - RC2014-Session of pervious surfaces D1 for green infrastructure measures 19 across land-use categories?

20 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 May considering 30, 2014 UHI, what is the maximum opportunity Y.Abunnasr - RC2014-Session of pervious surfaces D1 for green infrastructure measures 20 across land-use categories?

21 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

22 Results - Policy priority by GI measure UHI-Boston 3Ha-Patches Other Pervious Green roofs Roads Parking May 30, 2014 Y.Abunnasr - RC2014-Session D1 22

23 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

24 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

25 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

26 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

27 Thank you May 30, 2014 Y.Abunnasr - RC2014-Session D1 27