Toronto's

Green RoofBylaw

A Water Governance Assessment

Authors:

Karmen van Dyck: 3673839

Guillaume Cardon: 5498988

Jonas Bunsen: 4288017

Words: 6890

Image: http://www.gardinergreenribbon.com/green-roof/ accessed 17.06.2015

DIRECTORY D

Directory...................................................................................................................................................1

Abstract.....................................................................................................................................................2

Introduction..............................................................................................................................................3

Green Roofs.........................................................................................................................................3

Objective..............................................................................................................................................3

Assessment of Water Governance and Management.......................................................................4

Methodology.......................................................................................................................................4

Water System Knowledge.................................................................................................................5

Values, Principles, Policy Discourses...............................................................................................7

Stakeholder Involvement..................................................................................................................7

Trade-offs between Social Objectives............................................................................................8

Responsibility, Authority and Means..............................................................................................9

Regulations and Agreements........................................................................................................10

Financial Agreements......................................................................................................................10

Engineering and Monitoring..........................................................................................................11

Enforcement.....................................................................................................................................12

Conflict Prevention and Resolution..............................................................................................13

Conclusion and Recommendations....................................................................................................14

Discussion..........................................................................................................................................14

Policy Effectiveness.........................................................................................................................15

Conclusion.........................................................................................................................................16

Recommendations for Policy Improvement...............................................................................16

Bibliography...........................................................................................................................................17

Water Governance Assessment of the Green Roof Policy in Toronto | Directory | 1

ABSTRACT A

Green roofs are an increasingly popular measure to address shortcomings of urban watersystems as for example the inability to cope adequately with excessive rainfall. Toronto inCanada was the first city in North America to enact a bylaw which obliges specific buildingprojects to have a green roof implemented. This report applied the “Assessment of WaterManagement and Governance” method by Rijswick et al. (2014) in order to identify strengthsand weaknesses of Toronto's green roof policy. In general, the city of Toronto has a soundgreen roof policy in place which resulted from a consultative policy making progress. Still, thepolicy should be subjected to constant review and enhancements. The latter one may beencouraged by findings of this reports and the formulated recommendations for policyimprovements such as as a more diverse green roof incentive program, incorporation ofphotovoltaic technologies within green roof construction, stimulation of economy of scaleprocesses for green roof construction units and materials as well as advanced monitoring toquantify benefits of green roofs for the city of Toronto and green roof performancemaximization in consideration of local peculiarities.

Water Governance Assessment of the Green Roof Policy in Toronto | Abstract | 2

INTRODUCTION 1

Green RoofsDuring the last decade, green roofs have becomea prominent tool to address problems in urbanareas as for instance stormwater management,air quality, energy consumption and the urbanheat island effects (Greenroofs.org, 2007). Manycities all around the world have devised greenroof incentive programs or even oblige owners of(new) buildings to construct green roofs.

In Portland in the United States, green roofs arepromoted as a metasure to decrease stormwaterrunoff during precipitation events. In order tofacilitate the construction of green roofs,landowners have to pay a monthly fee per 1000square feet impermeable surface area. Inaddition, all new buildings which are owned bythe city are obliged to have a green roof coverageof at least 70%. The city of Chicago promotes theimplementation of green roofs in order todecrease the urban heat island effect. Similarlyto Oregon, green roofs are not a mandatorymeasure in Chicago but suitable projects canqualify for financial support by the city's greenroof incentive program. Stuttgart in Germanyfacilitated green roof construction as a measureto enhance air quality and introduced a subsidyprogram for private house owners (White, 2010).

Based on the depth of the vegetation layer, twocategories of green roofs are to be distinguished:Extensive and intensive green roofs. The formerone has a vegetation layer of up to 15 cm depthwhile the latter one can have a vegetation layerof up to 65 cm depth (Currie, 2010). Even though,both types of green roofs perform the samefunction, their efficiency and costs varydepending on the underlying constructionstandards and ecological characteristics.

In Toronto green roofs have been established asearly as during the 1990s. The city mainlyfacilitates the construction of green roofs as ameasure for stormwater management and in

order to mitigate the urban heat island effect.Green roofs as a means for stormwatermanagement gained attention after the city wasaffected by sever flooding in 2005 (Mees andDriessen, 2011). Both, excessive stormwaterrunoff and the urban heat island effect, areexpected to worsen with the advance of climatechange in the future (Mees, 2010).

The municipality of Toronto was the first in NorthAmerica to enact a bylaw that mandates theconstruction of green roofs for specific buildingprojects. The city's bylaw resulted from a long-term consultation and implementation processwhich consisted of several phases (White, 2010).First, the city commissioned a report which wasconducted by the Ryerson University andassessed the potential large-scale economicbenefits of green roofs for the city of Toronto inconsideration of various scenarios. The mainaspects under consideration were combinedsewer overflows, air quality, the urban heatisland effect and energy use of buildings(Banting, 2005). The findings were supportive forthe plan of widespread green roofimplementation and drafts of a bylaw weredevised through workshops and stakeholderparticipation. In 2006, the implementationstrategies were presented to the city council andfinally lead to a bylaw which required green roofconstruction on eligible building projects. Thebylaw was enacted on January 31st 2010 andaffects commercial, institutional and residentialbuildings.

ObjectiveThe objective of this report is to use the"Assessment of Water Management andGovernance" method by van Rijswick et al. (2014)in order to evaluate the green roof policy of thecity of Toronto. Based on this assessment, aconclusion about the policy's strengths anddeficiencies will be drawn and used to identifyleverage points for future policy improvement.

Water Governance Assessment of the Green Roof Policy in Toronto | Introduction | 3

ASSESSMENT OF WATER GOVERNANCE AND MANAGEMENT 2

MethodologyWater systems often exist within aframework of multiple administrativelevels, have implications on differenttemporal and spatial scales and affectvarious actors (“multilevel, multi-scaleand multi-actor”). In order to addresstheir governance and management in acorrespondingly comprehensive andintricate way, a multidisciplinaryapproach of assessment is required.

The ten building blocks assessmentmethod (figure 1) by Rijswick et al.(2014) tries to address this requirementand integrates various disciplines suchas water system knowledge; stakeholderanalysis and conflict prevention; socialobjectives; law and public admin-istration; economics and engineeringwithin a theoretical framework ofassessment, organisation and imple-mentation of water governancemeasures.

This report is based on systematicliterature research. The underlyinginformation were either published bythe city of Toronto or third parties.

A precise overview of all used sources can befound in the Bibliography on page 17.

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Figure 1: The ten building blocks of the Assessment of theWater Management and Governance Method by van Rijswicket al. (2014)

Implementation

Organisation

Content

Assessment of Water Management and Governance

2. Values, Principles, Policy Discourses

3. Stakeholder Involvement

4. Trade-offs between Social Objectives

5. Responsibility, Authority, Means

7. Financial Arrangements

8. Engineering and Monitoring

9. Enforcement

1. Water System Knowledge

6. Regulations and Agreements

10. Conflict Prevention and Resolution

Water System Knowledge

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Assessment criteria: Is there sufficient knowledge of the existing water system in order todeliver the required service level of societal functions? If not, what are the gaps; issufficient knowledge available to assess the impact on the water system because ofchanges in environment and societal functions? (van Rijswick, 2014)

Green roofs potentially support a variety ofsocietal, economical and environmentalfunctions. Most notable reduction of energycosts, mitigation of the urban heat island effect,stormwater flow reduction, lowering of peakdischarges, less instances of combined sewageoverflows (CSO), improvement of air quality,increase in biodiversity as well as aestheticimprovements (Banting, 2005).

Green roofs are widely used as a measure toinfluence the urban water cycle. The urban watercycle consists of natural physical componentssuch as precipitation, evapotranspiration, runoffand unnatural components such as man-madeinfrastructure which is disruptive to naturalwater flows. Within the context of watergovernance assessment and Toronto's urbanwater system, the most relevant function ofgreen roofs is reduction of stormwater runoffafter extreme precipitation events.

In order to assess the potential impact of greenroofs on the city of Toronto, the Toronto andRegion Conservation Authority (TRCA) initiated agreen roof pilot site at Toronto's York University.Additionally, a comprehensive study wascommissioned and conducted by the RyersonUniversity to quantify economic effects of greenroofs.

According to the study, green roofs are likely tohave a positive impact on the city’s stormwatermanagement, air quality, energy use of buildingsand will reduce the urban heat island effect(Banting, 2005). Excessive stormwater runoff inurban areas is critical because of the high shareof impermeable surface in overall area. Muchwater is channelled into drainage infrastructureinstead of infiltrating into the ground (as it wouldbe the case in most natural ecosystems).Drainage systems carry water towardswastewater treatment plans which only have alimited capacity to deal with water inflow. Several

negative aspects are attached to this practice: Incase of combined sewer overflows (CSO; inflowexceeds the plants capacity), sewage water and(possibly with pollutants contaminated) runoffare released into the environment and maycause negative effects. Furthermore, intensivewater flows can cause erosion of infrastructurewhich increases recurrent costs for maintenance.

The construction of green roofs addresses theseproblems in several ways. First of all, stormwaterrunoff is reduced in quantity which results in lessurban flood risk and effects of erosion.Additionally, green roofs absorb water. Thisreduces the overall amount of discharge andcauses a delay of peak discharge as water isreleased from green roofs in relatively slow rates.Depending on the depth and properties of theapplied growing substrate, green roofs haveproven to absorb or delay as much as 60 to 100%of all stormwater discharge (Banting, 2005). Lessintense stormwater discharge in drainagesystems also reduces the risk of combinedsewage overflows. In addition, the quality ofstormwater runoff increases because much ofthe contaminants are absorbed by plant growthor growing substrate where certain pollutantsmight even dissolve.

The “Report on the Environmental Benefits andCosts of Green Roof Technology for the City ofToronto” quantified initial and annual savings ofwidespread green roof implementation underthe assumption that green roofs are constructedon 100% of the suitable area (an area equal to5,000 ha). The results (compare table 1, p.6)suggest high economic value of green roofs forthe city of Toronto. This is even more the casewith respect to climate change as Toronto isexpected to receive less snow and higheramounts of rainfall during the winter months(City of Toronto, 2012).

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Table 1: Quantification of the expected environmental benefits due to widespread construction of green roofs in the city of Toronto. Based on (Banting, 2005).

Category ofbenefit

Initial costsavings

Annual costsavings

Stormwater

Alternate bestpractice cost

avoidance$ 79,000,000

Pollutant controlcost avoidance

$ 14,000,000

Erosion controlcost avoidance

$ 25,000,000

Combined SewerOverflow (CSO)

Storage CostAvoidance

$ 46,000,000

Reduced beachclosures

$ 750,000

Air Quality

Impacts ofreduction in GHG1 $ 2,500,000

Building energy

Annual energyuse

$ 21,000,000

Peak demandreduction

$ 68,700,000

CO2 reduction $ 563,000

Urban HeatIsland

Annual energyuse

$ 12,000,000

Peak demandreduction

$ 79,800,000

CO2 reduction $ 322,000

1 Greenhouse gases

Green roofs also being regarded as a “no-regret”measure since no major drawbacks are known tobe attached to the construction of green roofs.Much theoretical knowledge about the benefitsof green roofs is available to support the decisionof policy-makers. The knowledge results fromreal-world application in many other cities and(for some instances) also within the city ofToronto.

Theoretical knowledge is based on the RyersonUniversity's report which suggests initial costsavings (capital costs) of $313,100,000 andannual cost savings of $37,000,000 (Banting,2005).

The study assumes that green roofs areimplemented on 100% of all area which issuitable for green roofs (flat roofs with an areaabove 350 square metres). In total, this resultson an area of 50,000,000 square metres.Furthermore, it was assumed that all green roofshave a minimum depth of 150 mm and a runoffcoefficient of 50%.

The study suggest very promising economicbenefits. However, it is questionable whether theassumed conditions will ever be fulfilled. Even inthe long-term a covering of 100% suitable roofarea under the above-mentioned conditionsseems unlikely because the bylaw is only valid fornew construction projects and many buildingswill remain without green roofs. To address thisissue, the city of Toronto should commission astudy which focuses on the benefits of green roofimplementation on a smaller scale.

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Values, Principles, Policy Discourses

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Assessment criteria: Is there sufficient knowledge of shared or conflicting values,viewpoints and principles (represented by different policy discourse coalitions) for waterissues and their consequences for facing water management issues? (van Rijswick, 2014)

Several stakeholders are affected by Toronto'sgreen roof policy and represent variousenvironmental, economic and societal valueSome values are characteristic for singlestakeholders, others for a group of stakeholdersand again others converge among stakeholders.

Stakeholders representing rather economicaspects look at the financial benefits attached togreen roofs (e.g. construction contracts, energysavings, savings because of less infrastructuredamage because of erosion, ecosystem recovery,etc.). Environmentalists, conservationist as wellas the public see green roofs as a measure toenhance the urban ecology and decrease airpollution and thus share values of aesthetics,environmental conservation and human well-being. These values mainly converge with publicvalues. However, the public additionallyemphasises flood safety as an important benefitof green roofs. Many stakeholders which are infavour of green roofs work in close collaborationwith Toronto's public authorities to maximise theperformance of green roofs (Mees and Driessen,2011).

For the municipality, green roofs were mostimportantly regarded as a tool to improve the

city's stormwater management.

Within the context of urban water management,this can be regarded as a precautionary measureto prevent flood hazards and damages as well ascombined sewer overflows. The following part“Stakeholder Involvement” will elaborate on theinvolvement and consideration of variousstakeholders.

No major drawbacks are known to accompanythe installation of green roofs (“no regretmeasure”) and the potential for conflicting valuesis relatively low as they comply with the currentcultural mindset of the public.

No policy-discourses accompany the imple-mentation of green roofs in Toronto. The greenroofs bylaw converges with the city’s long-termplanning manifested in the “Green Standard”,Wet Weather Flow Master Plan, the policy todouble tree canopy and the Clean Air Partnership(Mees and Driessen, 2011).

Overall, sufficient knowledge exists about thevalues of all involved stakeholders and does notsuggest a major potential for conflict. The onlynoteworthy complain arises from the economicburden of green roof construction for businessesand will be discussed in the following paragraph.

Stakeholder Involvement

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Assessment criteria: Are all relevant stakeholders involved? Are their interests, concernsand values sufficiently balanced considered in the problem analysis, solution searchprocess and decision-making? (van Rijswick, 2014)

As discussed in the previous section,stakeholders can mainly be categorised in threegroups representing environmental, economicand societal values. Hereby, it is important tonotice that the boundaries between groups and

interests are not always sharp but may convergeor overlap in certain cases.

Important and influential public stakeholders arefor instance the city of Toronto and the Toronto

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and Region Conservation Authorities (TRCA).Typically, public authorities are very influentialbecause they are responsible for spatial planningthrough municipal and planning acts. The city ofToronto can be regarded as highly influentialbecause of devising the green roof policy and thepassing of the green roof bylaw. The TRCA playsan important role in adopting the strategic planof the city of Toronto as it is the TRCA'sresponsibility to ensure environmental conser-vation and to address climate change issues.Both were involved in several round tablesessions which were initiated to communicatevalues of different stakeholders. These publicconsultation meetings involved for exampleowners and developers of industrial usebuildings, stakeholders representing commercialdevelopment, the Ontario Industrial RoofingAssociation and members of the public (City ofToronto, 2009). Accordingly, the process ofparticipation can be regarded as wide becausepublic consultation processes were open to anyinterested person.

The depth of stakeholder involvement however,is rather limited. While some of the stakeholdersuggestions have been implemented in the greenroof bylaw, it becomes obvious that govern-mental bodies are still dominant in the processof decision making (van Rijswick et al., 2014).However, since Torontonians are mainly in favourof the green roof bylaw, there is no extensiveevidence of conflicting values between thegovernment and the public (City of Toronto,2006). It is noteworthy that most stakeholdersbenefit from green roofs and the municipalityhas granted exemptions for green roofs as urbangardens to some of the stakeholders (Adelmann,2014). Owners and developers of industrial usebuildings expressed concern that green roofswere impractical from an economic and technicalviewpoint and threatened that green roofs posea burden to employment (City of Toronto, 2009).The municipality defied this argument but stilloffers eligible projects subsidies to decrease thefinancial burden.

Trade-offs between Social Objectives

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Assessment criteria: Are agreed service-level decisions based on trade-offs of costs,benefits and distributional effects of various alternatives? (van Rijswick, 2014)

Allocation: The leading principle of green roofimplementation is to enhance the city's urbanwater system especially with respect tostormwater management. This can have impactson aspects of the water use system such ascombined sewer overflows, water quality anddamages due to flooding but also on non-water-use-system-related aspects such as the urbanheat island effect, energy savings, etc. (compare“Water System Knowledge“ p.5).

Conflict may arise among house owner who areobliged to install a green roof against their ownwill on basis of the bylaw if they would prefer toutilize the roof area for other purposes such assolar power or urban agriculture. In general,trade-offs of green roofs are likely to be similar indifferent cities.

With respect to the urban water system, alterna-

tives for green roofs potentially comprisepermeable paving or extensive drainageinfrastructure. With regard to other benefits suchas the reduction of energy costs and the urbanheat island effect, measures such as brown roofs,cool roofs or sophisticated insulation may posean alternative.

Reallocation: Whether there is a majorreallocation of costs or benefits depends on howwell green roofs perform on an economicperspective. The “Eco-Incentive” program thatsubsidises the construction of green roofs(compare “Financial Agreements“ p.10) isfinanced by public money. Accordingly, thebenefits of widespread green roofimplementation are hoped to outweigh the costsfor subsidies.

Whether green roofs are a burden to eligible

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construction projects depends on long-termbenefits such as recurrent savings of energyexpenditures.

Allocation mechanism: The mechanism tofacilitate green roof constructions is a mixturebetween mandatory implementation andfinancial incentives for voluntary implementation(compare “Enforcement“ p.12). The investmentsin subsidies for eligible projects are regarded as

a long time investment in order to improve thecity's stormwater management, energy use, airquality, etc. (compare “Water System Knowledge“p.5). It is distinguished between installationsenforced by the bylaw and installationspromoted by incentive programs. The formerone represents 50 to 60 installations per yearand the latter one 10 to 12 installations (Meesand Driessen, 2011).

Responsibility, Authority and Means

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Assessment criteria: What are the responsibilities and authorities related to water? Whatare the property rights? How are they restricted? What is the participative capacity of thepublic domain? What is the integrative capacity of the public domain? (Rijswijck et al,2014)

Green roofs are by definition part of buildingswhich are in many cases private property ofhouse owners, businesses or public institutions.Property rights in Toronto are defined in the Bill190 of the Property Rights and ResponsibilitiesAct (Barrett, 2009). In Canada property rights arethe responsibility of the province. Toronto lieswithin the province of Ontario and hence issubject to Ontario's property legislation. Propertyis legally seen as the combination of legalindividual rights with respect to objects and theobligations owed them by other parties andguaranteed and protected by the government(Bale, 2014). According to the property rights andresponsibilities act amended in 2009, everyonehas a right to own the real and personal propertythat they have acquired in line with the law to theextent provided by the law. However, the law canstill restrict how responsibilities for propertiesare managed. This is because owners are morallyresponsible to ensure their property ismaintained to a standard in accordance with thelegal uses of the property and the character ofthe community where the property is situated(Barrett, 2009). This means property owners arestill obliged to comply with the legalrequirements and are not completely free to doas whatever they want. This gives the respectiveauthorities enough power to enforce measuressuch as the green roof bylaw.

Allocating authority and responsibilities: In

Canada, provinces delegate planning authoritiesto the municipalities through municipal andplanning acts and supervise them. Municipalitiesdevise detailed spatial plans to adopt by-laws,regulate zoning, environmental regulations,building regulations, etc. and enforce theirimplementation (Mees, 2010).

Participative capacity of the public domain: Thecity of Toronto established an AdaptationSteering Group to facilitate cooperation amongthe public domain. The group consisted ofdirectors from all the major city divisions andwas coordinated by a staff member of theEnvironment Office. After successfully leadingthe adaptation strategy for green roofs, thegroup became less important (Mees, 2010).

The creation of multi-stakeholder working groupsconsisting of governmental, academic andenvironmental organisations was aimed to assistdecision makers with the policy development andpromote stakeholder participation (Mees, 2010).

Integrative capacity of the public domain: Theinternal policy coordination is supported byexternal knowledge exchange networks such asthe Toronto Urban Climate Network whichpromotes the exchange of green roof knowledgebetween its members and the public (TUCCN,2009). In addition, Toronto is part of the C40cities network that organises activities to shareknowledge and practices of measures to counterclimate change (Mees, 2010).

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Regulations and Agreements

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Assessment criteria: Are regulations and agreements legitimate and adaptive, and if not,what are the main problems with regard to the above mentioned legitimacy aspects? (vanRijswick, 2014)

Appropriateness: No information suggest thatthe green roof policy conflicts with cultural,political or religious values or institutionalcircumstances prevalent in the city of Toronto.Financial empowerment by means of a subsidyprogram (compare “Financial Agreements“ p.10)established appropriate economic conditions forgreen roof implementation. Since green roofs areregarded as a no-regret measure, they complywith governmental regulations to protect anddevelop public works, protect ecosystems and toenhance the performance of the urban watersystem. Round tables involved non-governmentalactors and the public during the policydevelopment process.

Legal capacity and adaptiveness: The green roofbylaw was devised by the Planning and GrowthManagement Committee and adopted by theToronto City Council based on authorisationthrough section 108 of the City of Toronto Act(City of Toronto, 2015a; City of Toronto Council,2011) which defines the structure andresponsibilities of the municipality. The

municipality of Toronto is governed by multiplecouncils with elected councillors. A new council iselected every four years and has a head ofcouncil also referred to as mayor (AMO, 2013).

The rules accompanying the construction ofgreen roofs are formulated in the city ofToronto's by-law No. 583-2009 §492-1 (compare“Engineering and Monitoring“ p.11 and“Enforcement“ p.12).

The green roof bylaw can be amended and infact, the municipal code states that the chiefbuilding official should periodically review theToronto green roof construction standards andconsult a “Technical Advisory Group” (compare“Engineering and Monitoring“ p.11 in order toassess possible enhancements. Still, flexibility islimited as green roofs are an inherent technicalaspect for the construction of new houses. Oncea green roof has been built, flexibility is ratherlimited. The strictness of green roofimplementation is discussed under“Enforcement“ (p.12).

Financial Agreements

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Assessment criteria: Are SLAs sufficiently available (implicit or explicit) in order to redesignthe existing infrastructure? Are the design and consequences of different alternativessufficiently available? Is there sufficient monitoring of the system and are the dataanalysed? (Rijswijck et al, 2014)

Funding of green roofs is aided by an “Eco-RoofIncentive Program” which financially supportsexisting residential, industrial, commercial andinstitutional buildings as well as newlyconstructed buildings that are not subject to thegreen roof bylaw. Whether a building project issubject to the by-law depends on its gross floorarea (compare “Engineering and Monitoring“p.11). Eligible projects receive $75 per squaremeter up to a maximum of $100,000 (City of

Toronto, 2015b). Owners of existing buildingswith a gross floor area lower than 2000m² areexempted from the by-law. Also other parties areequally able to receive funding by the “Eco-RoofIncentive Program” to become financiallyempowered. An exemption from the green roofby-law has to be approved by the Toronto ChiefPlanner and, if accepted, costs $200 per squaremeter (City of Toronto, 2015a; Viola, 2013).

The actual costs of green roofs vary for most

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projects. According to Acks (2003) and Wong etal. (2003) the costs for standard roofs are 50 to90$ while green roof cost 90 to 240$. However, inpractice some green roof projects in Torontoeven cost up to 400$ per square meter (EsriCanada, n.d.; Harvey, 2009). The costs for greenroofs are not fixed and depend on every greenroof's individual design. Most decisive for thecosts of the green roof is whether it is intensiveor extensive (compare “Green Roofs“ p.3).Additional costs may arise due to maintenance orreplacements if a long period of time isconsidered. Possibly, widespreadimplementation of green roofs will stimulate the

green roof construction market and cause aneconomy of scale effect that results in lower perunit prices.

The subsidy program which is financed by the municipality (a decentralised authority) from public money (solidarity principle) under the assumption that the construction of green roofs will benefit the public. Whether the subsidy program is financially empowering is different for every single green roof project. Therefore, it is difficult to judge whether the Eco-Incentive program is powerful enough or not. This aspect will further be discussed under “Conclusion andRecommendations“ (p.14).

Engineering and Monitoring

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Assessment criteria: Are SLAs (service level agreements) sufficiently available (implicit orexplicit) in order to redesign the existing infrastructure? Are the design and consequencesof different alternatives sufficient available? Is there sufficient monitoring of the systemand are the data analysed? (van Rijswick, 2014)

The city of Toronto's by-law No. 583-2009 §492-1defines a green roof as “an extension of an abovegrade roof, built on top of a human madestructure, that allows vegetation to grow in agrowing medium and which is designed,constructed and maintained in accordance withthe Toronto Green Roof Construction Standard”(Toronto Municipal Code, 2015). Comprehensiveinformation about the service level agreementswhich govern the required standards forengineering and monitoring of green roofs inToronto can be found in article IV of Chapter 491of the Toronto Municipal code which is freelyaccessible to any interested party (TorontoMunicipal Code, 2015).

The city of Toronto published several brochuressuch as the “Toronto Green Roof ConstructionStandard Supplementary Guidelines” and the“City of Toronto Guidelines for Biodiverse GreenRoofs” with the aim to sufficiently supplyprospective users with advice on the constructionof green roofs. The former addressesengineering aspects such as vegetation, growingmedia, drainage panel and filter fabric,insulation, membrane protection and rootbarrier, roofing membrane and structuralsupport (Hitesh, n.d.). The latter one containsrecommendations for prospective users on how

to maximise ecological benefits of green roofs forthe city of Toronto (Torrance, 2013). In additionprospective users can consult a green roofstechnical advisory group.

For safety reasons planning of green roofs has tocomply with the Ontario Building Code (OBC)part 4.1 Structural Loads and Procedures. If thisis not the case, amendments in a buildingsstructure may be considered. The OBC is easilyaccessible and contains all required informationfor prospective owners of green roofs andinvolved parties to fulfil the standards for greenroofs in Toronto.

In addition, a maintenance plan is stipulated bythe Toronto Municipal Code in order to monitorthe performance of green roof components andidentify locations for replanting if necessary(Toronto Municipal Code, 2015). Compulsorymonitoring is meant to serve the assessment andmaintenance of individual green roofperformances, rather than for large-scaleresearch purposes about the performance ofgreen roofs in Toronto. This issue should beaddressed by monitoring and studies about theoverall performance and impact of green roofson intended issues such as stormwatermanagement, urban heat island effect, etc.

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(compare “Water System Knowledge“ p.5).

However, the application of green roofs is usuallylimited to roofs which are either flat or onlyslightly inclined. Many traditional pitched roofs

are not suited for the construction of greenroofs. The construction of green roof alternativeswill be addressed under “Conflict Prevention andResolution“ p.13).

Enforcement

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Assessment criteria: Are regulations and agreements enforceable by public and/or private parties, and are there appropriate remedies available? (van Rijswick, 2014)

The implementation of green roofs in Toronto isenforced by law and the corresponding juridicalframework. In 2010 Toronto became the first cityin North America to enact a new by-law whichrequires newly built commercial, institutionaland multifamily residential building with a grossfloor area of at least 2,000m² to partially becovered by a green roof (Benfield, 2010). Non-compliance with the bylaw can be fined with upto 100,000$ (City of Toronto, 2009). The city’starget is to double its tree canopy by 2050 whichcan partly be achieved by creation of green roofs(Mees and Driessen, 2011). Currently, theproportion of the total area of the roof whichneeds to fulfil the requirements of a green roof,ranges from 20 to 60% depending on the grosssize of the buildings floor area (compare table 2;Toronto Municipal Code, 2015).

However, many private households are notaffected by the law because their houses do notexceed a gross floor area of at least 2000m² andthus do not require a green roof. In order toachieve an implementation of green roofs on abroad scale Toronto started an “Eco RoofIncentive” programme which is part of the city'swider climate change action plan. Theprogramme subsidies eligible projects forresidential, industrial, commercial andinstitutional buildings with 75$ per square metregreen roof (City of Toronto, 2015b). Accordingly,green roof projects with an projected area of upto 1333 square metre green roof are supported2.

Overall, the measures taken by the city ofToronto to enforce the implementation of greenroofs are good but can still be enhances(compare “Recommendations for Policy

2 100,000$ / 75$/m² = 1333 m²

Improvement“ p.16). During the last five years,260 new green roofs were built (City of Toronto,2015a). Still, in order to further facilitate thecreation of green roofs, the city of Torontoshould carry out research in order to quantifysocial , economic and environmental benefitsand communicate them among stakeholders.Furthermore, logistical, financial and technicalsupport may persuade prospective users totransform their roof into a green roof (Banting,2005).

Table 2: Required Size of green roof according to “TorontoMunicipal Code, Chapter 492, Green Roofs” (City of Toronto, 2015a)

Size of Building/

Gross Floor Area

Coverage of Available RoofSpace

≤ 2,000 m² Not mandatory

2,000 – 4,999 m² 20%

5,000 – 9,999 m² 30%

10,000 – 14,999 m² 40%

15,000 – 19,999 m² 50%

≥ 20,000 m² 60%

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Conflict Prevention and Resolution

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Assessment criteria: Are there sufficient conflict prevention and resolution mechanisms inplace? (van Rijswick, 2014)

The most controversial subjects attached togreen roofs are aesthetic concerns by residents,costs, attraction of non-native wildlife, plantselection (if non-native), use of fertilizer and withpesticides contaminated runoff (Getter andRowe, 2006). In some cases green roofs maycompete for space with other purposes such asphotovoltaic systems.

In the case of Toronto, literature research did notprovide evidence about widespread publiccomplaints about the city's bylaw to facilitate theinstallation of green roofs except of financialcosts (compare “Stakeholder Involvement“ p.7).This might be the result of clear communicationof economic, social and political benefits for thecommunity.

However, to decrease the potential for the mostcommon conflicts attached to green roofs, thecity offers information and advice on green roofsto prospective users and the affected community

as for example suggestions about native plantspecies for green roofs (City of Toronto, 2015a).

In 2011 another bylaw was issued which amendsthe City of Toronto Municipal Code Chapter 492on green roofs by providing an alternative to theGreen Roof requirement for industrial buildings.It enables industrial buildings to avoidinstallation of a green roof if a “cooling roof” isinstalled instead (City of Toronto Council, 2011).Private house owners can apply for an exemptionfrom the green roof bylaw which is mostcommonly coupled with the payment of a feewhich amounts to 200$/m² and can go up to100,000$ (City of Toronto, 2015a). Overall, thereis no evidence that major conflicts are attachedto the construction of green roofs. This might bethe result of clear communication of public andprivate benefits such as saving of energy costs aswell the general notion of green roofs as a “no-regret measure”.

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CONCLUSION AND RECOMMENDATIONS 3

DiscussionThis report set out with the aim to assess thecurrent green roof policy of the municipality ofthe city of Toronto in Ontario, Canada, andidentify its deficiencies and weaknesses in orderto formulate appropriate recommendation forfuture policy improvement. The assessment wasbased on a multidisciplinary approach includingaspects of water system knowledge, societalbenefits and demerits, authority, responsibilityand law, economics as well as technicalenforcement and feasibility. The “ten buildingblocks for sustainable water governance”assessment method provided a strongframework as a guidance through the mostrelevant aspects for policy assessment.

In summary, the city of Toronto has acomprehensive policy in place to facilitatewidespread implementation of green roofs. Thecity's decision to facilitate green roofimplementation was based on empiricalassessments about potential benefits for Toronto(Banting, 2005) and with respect to the expectedimpact of climate change in the future (City ofToronto, 2012).

The city of Toronto successfully communicatedthe benefits of green roofs among stakeholdersand thus minimised conflict. Most likely it wasfavourable that green roofs are commonlyregarded as a “no-regret” measure as nosignificant negative aspects, except of higherconstruction costs compared to normalbuildings, are known. This facilitated the creationof a shared vision of green roofs as a positivemeasure to improve the urban environment.

Since costs were the only major source ofpotential conflict, the city started a compre-hensive subsidy program for mandatory greenroof projects as well as an “Eco-Incentive”program for voluntary implementation of greenroofs. Most likely, the relatively effortlessreconciliation of stakeholders can additionally belinked to shared values among citizens, asToronto is known as a rather “green” city with asupposedly high rate of acceptance for greenroofs.

Toronto is also part of the “C40 Cities ClimateLeadership Group”, a fact that reflects, thatpublic awareness about environmental issues iscomparably high. It is also worth mentioning thatthe city of Toronto is relatively prosperous andcan financially afford the wide-spread subsidy ofgreen roofs.

Since 2010, green roofs are mandatory for newlyconstructed buildings with a floor size of 2000 m²or more. Mandatory implementation by law is anappropriate measure because the property rightsof the objects where green roofs areimplemented, often exclusively belong to house-owners. In order to avoid conflict, the installationof cooling roofs offers an alternative and servesas conflict prevention if stakeholders cannot ordo not want to install a green roof. Non-compliance with the bylaw (either green roof orcool roof if mandatory) is penalised with a fee.The engineering and monitoring of green roofs isclearly regulated by the “Toronto Green RoofConstruction Standard” and must comply withthe “Ontario Building Code”. Both documents arefreely accessible to any involved party.

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Policy EffectivenessNo official measurements about theeffectiveness of Toronto’s green roof policy arepublicly available. In fact, it is difficult to assesswhether the green roof policy has proven to besuccessful or not. One approach would be to lookat the economic benefits that are presently beinggenerated by the implementation of green roofs.

The city of Toronto disclosed that during a periodof roughly five years since the inception of thepolicy, 260 green roofs have been built. The areaof newly built green roofs amounts to 196,560 sqmetres and the total number of green roofswithin the municipality of Toronto is 444 (City ofToronto, 2015a). Assuming that the 260 newlybuilt roofs are representative for the averagegreen roof in Toronto, the average size of all 444green roofs would be 756 square metres.Multiplying the assumed average green roof sizewith the total number of green roofs results in atotal area of 335,532 square metres that arecovered with a green roof as of March 2015.

The “Report on the Environmental Benefits andCosts of Green Roof Technology for the City ofToronto” by the Ryerson University suggests that

green roofs hold potential for 313 million dollarsinitial- and 37 million dollars of annual costsavings. The underlying assumption of the reportwas that 50 million square metres of Toronto’sarea were covered with a green roof. If the costsavings are broken down to per square metresavings of green roofs, initial savings are 6.26$per square metre and annual savings amount to0.74$ per square metre. Scaling these values upwith respect to the area of green roofs coveringthe city today, the initial cost savings would be2,101,682$ and annual cost saving amount to248,441$.

The numbers are presentable assuming that thegreen roof initiative is still in its infancy andintended as a rather long-term measure for citydevelopment. They might even indicate that thegreen roof policy proofs to be effective.

However, it is arguable if the underlyingassumptions and values of the calculations aresufficiently based on empirical knowledge. Inaddition they assume that economic benefitsfollow a linear development which is most likelynot the case because of non-linear developmentand threshold levels within the water system.

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ConclusionWhether the green roof policy of the city ofToronto is a success or not is difficult to assessand depends on which indicator is consulted. Thetotal number of green roofs has almost doubledsince the enacting of the green roof bylaw. Still,the economic benefit of green roofs is (at leastpartly) difficult to measure and no detailedinformation about the number, size andperformance of green roofs is publicly available.

Overall the city of Toronto devised acomprehensive policy to facilitate the creation ofgreen roofs. All relevant aspects, such as

knowledge availability, stakeholderreconciliation, administrative organisation, legalarrangements, technical obligations andpossibilities for alternatives seem to have beensufficiently addressed during the policy-makingprocess.

Still, in order to further improve the policy,research must be conducted in order to assessthe performance of green roofs in Toronto andquantify their social, environmental andeconomic benefits. Based on this knowledge thegreen roof policy must be regularly subjected toenhancements.

Recommendations for Policy Improvement

Reco

mm

enda

tion

s for

Pol

icy

Impr

ovem

ent • Currently the implementation of green roofs is enforced by a rather simple set of

mandatory implementations and a subsidy program for green roof construction. A moresophisticated set of financial measures could involve reduction of taxes for example onwastewater treatment and/or energy prices for heating/air conditioning. A similar conceptis already being applied in Basel (Switzerland) and in Stuttgart, Germany (Mees et al.,2013). Reduction of taxes implies recurrent cost savings for green roof owners instead ofa one time subsidy and might pose an additional incentive for the construction of a greenroof.

• Joint efforts between private and public stakeholders of green roofs. This should includepublic authorities, public and private research institutes and roofing contractors in orderto maximise the performance of green roofs. Gained knowledge should be communicatedwith external partners such as C40 cities or other cities which have a large-scale green roofpolicy in place. Toronto will also be able to benefit from their experiences and knowledge.

• Green roofs potentially compete for space with solar energy. The city of Toronto shouldsupport construction of green roofs with solar panel integration for interestedstakeholders. This would reduce the potential for conflict and may even increase thewater retention capacity of green roof (GRT, 2015).

• Large scale subsidy programs can stimulate economy of scale processes and thusdecrease the costs of construction units and materials for green roofs. This would reducethe price margin between conventional roofs and green roofs and be supportive for theoverall share in installations. Additionally, the need for economic incentives will decreaseif the initial costs of green roof construction is reduced.

• More effort should be undertaken to quantify benefits of green roofs by monitoring andresearch. Reliable information about practical benefits of green roofs would help toimprove their performance and to make policy adjustments. Development of urbantemperatures for instance or combined sewage overflows might serve as appropriateindicators.

Water Governance Assessment of the Green Roof Policy in Toronto | Conclusion and Recommendations | 16

BIBLIOGRAPHY BAcks, 2003. A framework for cost-benefit analysis of green roofs: initial estimates.

Adelmann, M., 2014. City Failing to Harvest Potential of Green Roofs.

AMO, 2013. How Municipal Government Works.

Bale, G., 2014. Property Law [WWW Document]. Can. Encycl. URL http://www.thecanadianencyclopedia.ca/en/article/property-law/ (accessed 6.23.15).

Banting, D., 2005. Report on the Environmental Benefits and Costs of Green Roof Technology for the City of Toronto.

Barrett, T., 2009. 39:1 Bill 190, Property Rights and Responsibilities Act.

Benfield, K., 2010. Toronto’s leadership for green roofs | Kaid Benfield’s Blog | Switchboard, from NRDC [WWW Document]. URL http://switchboard.nrdc.org/blogs/kbenfield/torontos_leadership_for_green.html (accessed 5.18.15).

City of Toronto, 2015a. Green Roofs - Environment - City Planning | City of Toronto [WWW Document]. URL http://www1.toronto.ca/wps/portal/contentonly?vgnextoid=3a7a036318061410VgnVCM10000071d60f89RCRD(accessed 5.18.15).

City of Toronto, 2015b. Eco-Roof Incentive Program - Grants, Incentives & Tips - Programs for Residents | City of Toronto [WWW Document]. URL http://www1.toronto.ca/wps/portal/contentonly?vgnextoid=3a0b506ec20f7410VgnVCM10000071d60f89RCRD (accessed 5.26.15).

City of Toronto, 2012. TORONTO’S FUTURE WEATHER & CLIMATE DRIVER STUDY: OUTCOMES REPORT.

City of Toronto, 2009. STAFF REPORT ACTION REQUIRED By - law to Require and Govern the Construction of Green Roofs in Toronto.

City of Toronto, 2006. Making Green Roofs Happen.

City of Toronto Council, 2011. By-Law No. 1381-2011 - To amend City of Toronto Municipal Code Chapter 492, Green Roofs, by providing a cool roof alternative to the Green Roof requirement for industrial buildings.

Currie, 2010. Using Green Roofs to Enhance Biodiversity in the City of Toronto.

Esri Canada, n.d. EcoRoof Case Study.

Getter, K.L., Rowe, D.B., 2006. The Role of Extensive Green Roofs in Sustainable Development. HortScience 41, 1276–1285.

Greenroofs.org, 2007. How Your Community Will Benefit from Adopting.

GRT, 2015. Solar Energy and Green Roofs.

Harvey, I., 2009. When it comes to green roofs, there’s green and then there’s green. Tor. Star.

Hitesh, D., n.d. Toronto Green Roof Construction Standard - Supplementary Guidelines.

Mees, H.L.P., 2010. Climate Greening London, Rotterdam and Toronto A comparative analysis of the governance capacity ofadaptation to climate change in urban areas.

Mees, H.L.P., Driessen, P.P.J., 2011. Adaptation to climate change in urban areas: climate-greening London, Rotterdam, and Toronto. Clim. Law 2, 251–280.

Mees, H.L.P., Driessen, P.P.J., Runhaar, H.A.C., Stamatelos, J., 2013. Who governs climate adaptation? Getting green roofs

Water Governance Assessment of the Green Roof Policy in Toronto | Bibliography | 17

for stormwater retention off the ground. J. Environ. Plan. Manag. 56, 802–825. doi:10.1080/09640568.2012.706600

Toronto Municipal Code, 2015. TORONTO MUNICIPAL CODE CHAPTER 492, GREEN ROOFS.

Torrance, S., 2013. City of Toronto - Guidelines for Biodiverse Green Roofs.

TUCCN, 2009. TUCCN’s Mandate.

Van Rijswick, E., 2014. Ten building blocks for sustainable water governance: an integrated method to assess the governance of water. Water Int. 39. doi:10.1080/02508060.2014.951828

Van Rijswick, M., Edelenbos, J., Hellegers, P., Kok, M., Kuks, S., 2014. Ten building blocks for sustainable water governance: an integrated method to assess the governance of water. Water Int. 39, 725–742. doi:10.1080/02508060.2014.951828

Viola, D., 2013. Toronto a leader in green roof industry. REMINET.

White, T., 2010. Toronto’s Green Roof Policy - A Review of the Process and Product.

Wong, N.H., Tay, S.F., Wong, R., Ong, C.L., Sia, A., 2003. Life cycle cost analysis of rooftop gardens in Singapore. Build. Environ. 38, 499–509. doi:10.1016/S0360-1323(02)00131-2

Water Governance Assessment of the Green Roof Policy in Toronto | Bibliography | 18