Grag final report - rough draft

GREEN ROOF ADVISORY GROUP

Report to Council

August ��

“Green Roofs represent

an elegant opportunity

to simultaneously

mitigate environmental

problems and

create immediate

life-enhancing value.”

~Leslie Hoffman

Executive Director,

Earth Pledge

Executive Summary Charge and Process Advisory Group Efforts Key Findings and Conclusions Existing Green Roof Efforts Green Roofs in Austin’s Code Research and Monitoring Design and Performance Considerations Water Conservation and Green Roofs Green Roof Density Bonus Green Roofs on City Buildings Outreach and Education Next Steps Five-Year Policy Implementation Plan Request for GRAG Extension

I: The Case for Green Roofs

II. Advisory Group Charge and Process Overview Charge from City Council Green Roof Advisory Group Process Membership Committees Decision-Making Public Review Review by Boards and Commissions

III: The State of Green Roofs in Austin City of Austin Green Roof Monitoring Efforts Project Profiles Austin City Hall Austonian Condominiums

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III: The State of Green Roofs in Austin Project Profiles continued Dell Children’s Medical Center of Central Texas Escarpment Village Hill Country Residence Stanley Studio

IV. Design Considerations

V: GRAG Accomplishments

VI. Findings and Recommendations Policy and Incentives Zoning Energy Conservation, Air Quality & Climate Protection Watershed Protection Financial Incentives

Alignment With Water Conservation 2020 Strategic Recommendations Strategies Meriting Further Analysis Data collection Target Areas of Austin to Focus Green Roof Efforts Inventory Green Roofs in the Region Evaluate Green Roof Opportunities for Residential and Retrofit Projects Investigate the Potential to Implement Green Roofs on City Buildings Take Advantage of City Hall as a Green Roof Educational Model

VII: Next Steps Outreach and Education Design Considerations Existing Development Options Potential Development Options

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VII: Next Steps Energy Impacts Innovative Stormwater Management Green Roofs for City Buildings Financial Incentives Green Roofs Five-Year Policy Implementation Plan Proposed Extension of Advisory Group Timeframe

VIII. Appendices

A. Excerpt from Green Roofs: A Resource Manual for Municipal Policy Makers B. Five-Year Policy Implementation Plan Flow Chart C. Interim Report Comments D. Policy and Incentives Matrix E. Letter to City Council Advocating Addition of Green Roofs to Density Bonus Program Public Benefit Options F. Boards and Commissions Comments G. Green Roof Map and Inventory H. City of Austin Green Roof Monitoring Efforts I. Brief Overview of Green Roof Credits and Incentives in North America J. Recommended Marketing Proposal for Green Roof Educational Initiative and Website K. Watershed Protection Ordinance Summary Table L. GRAG Members and Meeting Attendees M. GRAG Committees N. Outreach Presentation, June 3, 2010 O. Design Considerations Discussion Summary P. City of Austin Departmental and Staff Perspective White Paper, Growing Austin’s Living Roofs, December 2008

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GREEN ROOF ADVISORY GROUP Report to City Council

Executive Summary

Charge and Process

On August 27, 2009, Austin City Council charged the Green Roof Advisory Group (GRAG) to work with City staff to explore

the feasibility of offering energy and stormwater credits and other incentives, based on performance, to encourage the

creation of green roofs in the City. GRAG produced a policy document that included recommendations regarding those

credits and incentives that would be appropriate for promoting green roofs in Austin. The stakeholder group was drawn

from the fields of design, development, and green building and includes input from local green roof organizations and the

Lady Bird Johnson Wildflower Center.

In order to accomplish these goals, GRAG established monthly meetings to occur from August 2009 to October 2010,

formed separate committees to focus on specific green roof topics, and assisted staff in formulating a framework for inter-

departmental review. We worked extensively with staff from the Watershed Protection Department; Austin Energy Green

Building; and the Austin Climate Protection Program. The staff engaged other departments such as Planning and Develop-

ment Review, Parks and Recreation Department, Public Works, and the Austin Water Utility. Through joint, collaborative

efforts of staff and the stakeholder group, GRAG was able to assess the value green roofs within City of Austin policy, initi-

ate discussions on best practices for green roofs in Austin, and develop a Five-Year Policy Implementation Plan.

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Advisory Group Efforts

GRAG stakeholders and staff have engaged in and accomplished the following:

Developed consensus on the public and private benefits of green roofs as a component of green infrastructure, including improved air quality, stormwater abatement, urban heat island mitigation, open space, wildlife habitat, and others.

Completed a review of green roof incentive and credit policies of other cities in North America.

Established a database of green roofs in Austin.

Documented existing City of Austin policies and incentives which encourage green roofs.

Analyzed potential policies that could be developed to encourage green roofs.

Developed proposals to integrate green roofs into departmental program efforts.

Advocated for green roofs as a Public Benefit Option during the public hearings on the Down-town Density Bonus Plan..

Supported the inclusion of green roof policy and benefit education on a City of Austin website.

Developed a proposal for green roof monitoring research.

Advocated for an increase in Austin Energy green roof rebates.

Developed Five-Year Policy Implementation Plan.

Initiated a framework for green roof design considerations.

Organized a public seminar by a green roof industry leader on green roof water retention mod-eling.

Provided an outreach seminar to present GRAG’s efforts and solicit public feedback.

Integrated principles from Water Conservation 2020: Strategic Recommendations into green roof recommendations.

Developed and presented the interim and final reports to selected Boards and Commissions and the City Council.

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Key Findings and Conclusions

Existing Green Roof Efforts

Since the Green Roof Advisory Group was the first combined stakeholder and staff body sponsored by the Council to re-

view the status of green roof policy in the City and to bring together various diverse green roof initiatives, there is no sur-

prise that there is not a unified green roof policy across City departments. Many of our key findings and recommendations

have sought to bridge this gap.

In 2007, Austin Energy and the Watershed Protection Department compiled a thorough white paper discussing the multi-

tude of benefits of green roofs which is provided in Appendix P. Prior to GRAG, there was no documentation of other cities’

policies and programs, no overall Austin policy in support of green roofs, and no database of successfully implemented

green roofs in the City.

Through our joint deliberations, we have further established within GRAG that the multiple benefits of green roofs in Aus-

tin far exceed any one benefit. Multiple benefits include urban heat island mitigation, reduction of energy demand, im-

provement of air quality, creation of green space for social and recreational use, wildlife habitat, local food productions,

and stormwater attenuation. We have also acknowledged that these benefits can be difficult to quantify. Different City de-

partments may only address a specific benefit, making it a challenge to calculate the cumulative positive impacts of green

roofs.

Review of other cities’ green roof policies for incentives and credits, such as Portland, Chicago, and Toronto, have shown

that those municipalities are far ahead of Austin in development of a robust framework to support green roofs. Through

research, GRAG discovered that green roof policy development tends to follow a six phase time line:

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Phase 1: Introduction and Awareness

Phase 2: Community Engagement

Phase 3: Action Plan Development and Implementation

Phase 4: Technical Research

Phase 5: Program and Policy Development

Phase 6: Continuous Improvement.

(Source: Green Roofs: A Resource Manual for Municipal Policy Makers, excerpted in Appendix A.)

GRAG assert that Austin is in Phase 3 of policy development with the establishment of the Green Roof Advisory Group. By

bringing together professionals with knowledge of green roofs all over Austin, GRAG has begun to synthesize the knowl-

edge base. As a result, staff in the Watershed Protection Department and at Austin Energy have initiated an inventory of

existing green roofs, documenting their location and various attributes.

Green Roofs in Austin’s Code

Review of existing City code uncovered several existing open space credits and requirements referring to open space which

may be able to be accomplished by the use of green roofs. Some of these requirements refer to Planned Unit Development

(PUD) requirements, multi-family, parkland dedication, etc. Minor effort would be required to educate staff and the devel-

opment community about the availability of green roofs to satisfy these requirements.

During this extensive review of code, it was determined that although green roofs are mentioned in different areas of the

code, there is not one central location where a citizen can go to retrieve the information. GRAG acknowledged the need

for education and advocated for a green roof web page on the City’s website as a repository for all green roof information.

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Austin Energy’s Climate Protection Program has agreed to develop the web page. Add Leah’s sentences here.

Research and Monitoring

The Watershed Protection Department (WPD) determined the need for monitoring research, a Phase 4 activity, to docu-

ment the performance of green roofs for stormwater detention prior to giving credit for green roofs. Two efforts have

been initiated to close this gap. First was the review of existing water retention modeling data specific to Austin provided

by a leading green roof manufacturer. Second was the funding of monitoring research at the Lady Bird Johnson Wildflower

Center. In addition, results of ongoing monitoring of an Austin green roof by WPD staff will be summarized for the record.

Design and Performance Considerations

Watershed Protection Department and Austin Energy (AE) underscored the need for development of design considerations

for green roofs. GRAG has embarked upon the effort of creating baseline standards, but will require more time to flesh out

and finalize the design considerations discussed in this report into tangible performance standards that can be published

for use by staff and the development community.

Water Conservation and Green Roofs

During the timeframe of GRAG’s efforts, the Citizens Water Conservation Implementation Task Force Report to City Coun-

cil, Water Conservation 2020: Strategic Recommendations, was published. Many of the water conservation policies pre-

sented were in alignment with policies that GRAG supports, such as use of water conserving landscape and irrigation tech-

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nologies, use of non-potable water, use of graywater, and more. (See section VI, Alignment with Water Conservation 2020

Strategic Recommendations, for details.)

Green Roof Density Bonus

Also during the timeframe of GRAG’s efforts, the draft Downtown Density Bonus Plan was presented to Council. Through

GRAG’s research into different cities’ green roof policies, it was revealed that density bonus incentives are the green roof

incentive most often implemented. Similarly, the green roof density bonus option was one of the benefits most often se-

lected by the private sector in exchange for increasing entitlements. This, coupled with the fact that the hottest area of th e

urban heat island and the area with the most impervious cover and stormwater runoff is the downtown core, led GRAG to

recommend that green roofs be one of the individual Public Benefit Options in the Density Bonus Plan. While one position

is that green roofs are optional in the Gatekeeper Sustainability requirement, GRAG believes that there is not enough in-

centive present unless green roofs are a separate, standalone option for selection.

Green Roofs on City Buildings

While reviewing the charge of the GRAG with various City departments, many City personnel were unaware the Austin City

Hall had a green roof that was designed as an environmental education model and had been nationally recognized as an

exemplary green roof project. It was clear that more green roof education should be provided to City staff, the City Hall

green roof performance should be monitored and documented, and the City Hall green roof should be used as a model to

educate the public about the benefits of green roofs.

With the success of the City Hall project, the Public Works Department (PW) is investigating the potential of green roofs for

any new City building projects. In particular, GRAG supports the inclusion of one additional green roof to the City’s portfo-

lio in the next five years.

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Outreach and Education

As GRAG assessed the state of green roofs in Austin, it became evident that continued outreach and education were im-

portant to the progress of promoting and implementing green roofs. While the website will move green roofs forward,

there is need to provide a more focused outreach effort to various organizations and entities. This effort is not the charge

of GRAG, but individuals and organizations represented by its members could certainly continue to provide seminars,

green roof tours, and other forms of publicity.

Next Steps

Five-Year Policy Implementation Plan

Once GRAG identified the need for various green roof activities which obviously could not be accomplished in one year,

GRAG set out to develop a Five-Year Policy Implementation Plan. Staff worked with various City departments to create rea-

sonable goals for each year which cumulatively ensure that green roofs would remain on the policy and program agenda

and budget. (See section VII. Next Steps for the Five-Year Policy Implementation Plan, also represented graphically in Ap-

pendix B.)

The Five-Year Policy Implementation Plan was developed to systematically support the increased use of green roofs in Aus-

tin. The primary basis for the Five-Year Plan was the Policy and Incentives Matrix (see section VII. Next Steps), developed

by staff, which reviewed a wide range of options to offer credits, incentives, and other measures to encourage the use of

green roofs in Austin. These options ranged from potential changes specific to Austin’s regulatory system to measures

used by other cities across the world. The GRAG and staff worked to identify the most feasible and productive of these op-

tions. Staff also met with targeted City departments to solicit staff input and recommendations for measure. The GRAG

and support staff then developed a Five-Year Plan to carry out the most important measures, with the five-year period be-

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ginning in October 2010. Policy options were prioritized in years one though five according to their ease of execution and

their critical-path nature for the development of future program elements.

Request for GRAG Extension

The Green Roof Advisory Group requests a one year extension to initiate the implementation of the group’s recommenda-

tions outlined in the Five-Year Plan and to provide a solid basis for ongoing policy development. The existing, mutually sup-

portive relationship between city staff and GRAG stakeholder members is an important key to assisting the City in imple-

mentation of green roof policy goals.

All parties recognize the need for continued GRAG and other green roof stakeholder activities to complement future staff

efforts and most effectively promote green roofs in the City. The critical need for the establishment of green roof design

considerations—performance based criteria for successful green roofs—was identified. The development of the design

considerations, however, is a substantial undertaking and was not possible to accomplish within the one-year timeframe

allotted by Council for GRAG activity. Therefore, the task was pushed forward into Year 1 of the Implementation Plan. Ad-

ditional Year 1 stakeholder tasks include support for staff educational activities, continued advocacy for green roofs as a

density bonus public benefit option, assessment of green roof monitoring research, and progress review of policy recom-

mendations for incentives and credits.

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I: The Case for Green Roofs

Why are green roofs proliferating throughout the world as well as in Austin? Use of “green infrastructure” to help mitigate

the environmental impact of the built environment has become increasingly important as our world continues to urbanize.

Rooftops are one of the few available areas within the “concrete jungle” to reintroduce vegetation. Green roofs have the

potential to be an important tool and powerful symbol in fulfilling the City of Austin’s vision as leader among sustainable

cities. Not only can a green roof provide aesthetic views when seen from adjacent buildings, the technology can offer

many potential environmental, cultural, and economical public and private benefits,. Because some of a green roof’s at-

tributes may be enhanced with irrigation to keep the roof’s vegetation alive during dry weather, water stewardship is an

important consideration in green roof design, implementation and maintenance.

The benefits of green roofs align well with Austin’s environmental and cultural priorities. They include:

Vegetation cleans and cools the air, improving air quality and reducing the urban heat island effect.

Rooftop vegetation cools a building’s roof, reducing cooling season energy use, which in turn reduces greenhouse gas emissions.

The life expectancy for cooler roof membranes under green roofs can be over twice that ex-pected for other roofs. Long-lasting roofs are more sustainable and reduce landfill use. Waste from standard roofing accounts for 10 million tons/year in the US according to the EPA report Building-Related Construction and Demolition Materials Amounts, March 2009.

Green roof systems can prevent sound from both entering and leaving a building, potentially helping reduce inner city noise pollution.

Stormwater runoff from conventional roofs flows directly into drains. A green roof can be de-signed to detain and retain stormwater, potentially reducing flood events and serving as an in-tegral component to protect water quality.

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Many urban dwellers have poor access to green space. Accessible green roofs can improve qual-ity of life by providing an urban oasis. Property values can also increase with a green roof prop-erly integrated into a building’s use.

Green roofs can help provide habitat for wildlife such as birds and butterflies, particularly in areas where at-grade habitat

is scarce.

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II. Advisory Group Charge and Process Overview

Charge from City Council

Per Council Resolution Number 20090827-057 passed and approved by the City Council on August 27, 2009, the Green

Roof Advisory Group was convened and directed to explore the feasibility of offering energy and stormwater credits and

other incentives, based on performance, to encourage the creation of green roofs in the City.

Specifically, the resolution charged the Advisory Group as follows:

1. The stakeholder group shall produce a policy report that includes recommendations regarding credits and other incentives to promote green roofs in the City.

2. The stakeholder group shall work with City staff.

3. The stakeholder group shall provide Council with an interim progress report on or before February 25, 2010 and shall present a final report to Council on or before August 26, 2010. The deadline was extended to Octo-ber 28, 2010.

4. The stakeholder group shall be drawn from the fields of design, development, and green building, and in-clude input from local green roof organizations and the University of Texas at Austin’s Lady Bird Johnson Wildflower Center.

Green Roof Advisory Group Process

Membership

As the Council sponsor of the resolution, Council Member Chris Riley invited individuals representing the various groups

and organizations with a stakeholder interest in green roofs to be members of GRAG. The intent was to provide a balanced

perspective among design professionals, green building advocates, developers, and academics. A policy was set that any

interested parties would be given an opportunity to review the Interim Report for direct feedback prior to production of

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the final report. Members and other meeting attendees are listed in Appendix L.

Throughout the duration of GRAG, various interested citizens have attended individual meetings and offered comment for

consideration.

Staff members from Watershed Protection, Austin Energy, Austin Water Utility, and Public Works have provided extensive

support to GRAG in its initiatives. In particular, GRAG would like to thank Matt Hollon, Watershed Protection, Maureen

Scanlon, Austin Energy Green Building, and Leah Haynie, Austin Energy Urban Heat Island for their diligent pursuit of our

charge. The robust allocation of staff resources to the promotion of green roofs in the City is appreciated.

Committees

To facilitate more focused research, discussion, and analysis, GRAG members formed smaller committees in the first and

second halves of the group’s activity period. (A complete list of committee members is found in Appendix M.) The group

felt strongly that the committee structure allowed a measure of efficiency important to achieve results in a short time. The

activities of the committees were as follows:

Executive Committee

The Executive Committee (Excom) was made up of the Chair and Co-chair and two primary staff members.

The Excom met as needed to determine direction and focus for GRAG. The development of the work prod-

uct was a creative process which necessitated continual regrouping to ensure an agreed upon path to pro-

duce the best result was followed. Since there had been no green roof policy prior to the formation of

GRAG, the Excom sought to assess the progress and determine the most advantageous approach to accom-

modate both stakeholder and staff concerns.

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Site Committee

The Site Committee met to discuss five topics in detail to explore potential incentives and credits at the site

level of development:

Flood detention (existing and potential options)

Watershed impervious cover (green roofs vs. pervious cover)

Zoning (zoning impervious cover, building height, open space, and other density and community considerations)

Water quality (retention-irrigation systems, biofiltration, treatment trains, green roofs as standalone water quality controls, and sizing of water quality volume)

Water conservation considerations (including soil depth)

The findings of these meetings are compiled in the Policy and Incentives Matrix located in Appendix D.

Building Committee

The Building Committee identified the public and private benefits associated with green roofs. The focus

was vertical build-out rather than site. The committee gathered research on what effects green roofs have

on energy consumption and peak summer energy, roof longevity and landfill issues, urban heat island, air

quality, aesthetics, habitat creation, interior and exterior sound attenuation, increased tax base, and public

and private amenity space. The building committee further considered green roof initiatives and synergies

with existing City of Austin initiatives such as Zero Waste, Climate Protection Plan, Energy Efficiency, Urban

Heat Island Mitigation, Watershed Protection, Water Conservation, Green Building, Green Garden Initiative,

Great Streets, and others.

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Density Bonus Incentives Committee

The Density Bonus Incentives committee researched green roof density bonus incentives in other cities,

such as Portland and Chicago, and reviewed the proposed Downtown Density Bonus Program. (See Appen-

dix E.) GRAG determined that downtown Austin would benefit the most from a standalone Green Roof Pub-

lic Benefit Option. A letter was sent to City Council outlining a proposal to add a Green Roof Public Benefit

Option. Subsequently, Council authorized a stakeholder group led by the Planning Commission to review the

proposed Density Bonus Program. The consensus of the stakeholder group was that green roofs were a wor-

thy Public Benefit Option. The Planning Commission recommended that green roofs be added to the Density

Bonus Program. Currently, the entire Downtown Plan is being prepared for Council approval later this year.

Community Outreach Committee

The Community Outreach Committee was formed to educate the community about the efforts of GRAG

through comment solicitation and an outreach seminar. Multiple stakeholder groups were identified and

contacted via email by GRAG for feedback on the interim report. The 17 stakeholder groups contacted are

listed in Appendix C; the outreach seminar slideshow are found in Appendix N. See “Public Review” below

for more detail on specific outreach activities.

Design Considerations Committee

The Design Considerations Committee began determining what performance standards for green roof de-

sign should be considered. Multiple meetings were held where the complexities of soil depth, mulch, and

other possible factors were discussed in detail. Several topics were identified and are discussed in section IV

of this report. The considerations include green roof size, soil media depth, plant cover and variety, water

use, visibility, access, and maintenance requirements.

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Policy and Incentives Matrix Committee

Staff from Watershed Protection, Planning and Development Review, Austin Energy, Public Works, Eco-

nomic Growth and Redevelopment Services, and Parks and Recreation collaborated in their review of exist-

ing City code and national and international green roof strategies to identify potential credits, incentives,

and other measures to encourage the creation of green roofs in Austin. A summary table (see Appendix D)

was developed which described the potential optional codes, description of current status and concerns,

potential improvement, advantages and disadvantages of anticipated impacts, and staff recommendations.

The main headings are: Zoning, Energy Conservation, Air Quality & Climate Protection, Watershed Protec-

tion, and Financial Incentives. The overall findings and the options with the most promise are included in

the Five-Year Policy Implementation Plan (see section VII).

Five-Year Policy Implementation Plan Committee

The leaders of the Five-Year Plan committee were the Chair and staff lead from Watershed Protection. Input

to the plan was given by additional staff and stakeholder members. The basis for the Five-Year Plan was the

Policy and Incentives Matrix. Specific policy options were prioritized for staff development in years one,

two, three, etc. according to their ease of execution and their critical path nature for the development of

future program elements. Potential GRAG tasks were added with stakeholder review.

Interim and Final Report Committee

The report committee convened to facilitate the development of the written interim and final reports to

City Council detailing GRAG activities and recommendations. The process of creating each of the reports be-

gan with group consensus as to the structure of the document, delegation of writing and editing tasks to

appropriate Advisory Group members, and final editing and design.

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Decision-Making

As much as feasible, the method of decision making was consensus. However, due to the fast paced nature of the process,

bimonthly updates of staff progress, and the separate efforts of the various committees, some of the final elements within

the work product are a compilation of committee reports. Opportunity was given for member feedback if some portions of

work product did not have full support. In these cases, the outline of the product was approved within the Council -

approved timeframe.

Public Review

The outreach committee notified stakeholder groups via email of the interim report and solicited comments. Comments

were received by email and are compiled in Appendix C. The interim report was also posted on Council Member Chris Ri-

ley’s website with a link for submitting comments.

Stakeholder groups were also invited to a seminar on green roofs held on June 3, 2010 at the Carver Branch library. The

seminar included an introduction by Council Member Riley on a vision of Austin made more livable through green roof in-

frastructure. GRAG members continued the presentation by defining the components of a green roof, discussed the multi-

tude of benefits and presented green roof incentive programs of other cities. A question and answer session was held at

the end of the presentation. Written comments were also collected and are included in Appendix C.

Review by Boards and Commissions

GRAG is charged with presenting its results to selected Boards and Commissions, including but not limited to the following:

Resource Management Commission, Environmental Board, Design Commission, Parks Board, and Planning Commission.

(See Appendix F for individual comments of Board and Commission members.)

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III: The State of Green Roofs in Austin

Austin’s green roof community has learned that green roofs can succeed. A broad spectrum of intensive and extensive in-

stalled systems have demonstrated attributes critical to their successful application in Austin’s climate. A wide variety of

heat and drought hardy native plant species have proven themselves on local green roofs. The engineered soil depth and

associated components can be selected to support rooftop vegetation through the most severe environmental conditions.

After a green roof’s components are carefully selected, determining the roof’s water needs and sources is critical to roof-

top vegetation performance, particularly in our climate. Access to sufficient water for plants is the central factor in main-

taining a green roof’s optimal performance.

The green roof design considerations evaluated by GRAG are based on those roofs in the local portfolio that can be learned

from and observed. Public interest in Austin green roofs has outpaced implementation, and while interest and momentum

continues to build for installing green roofs, examples of their application are limited. Based on lessons learned in other

American cities as well as abroad, local incentives would spur more green roof construction.

City of Austin Green Roof Monitoring Efforts

In the summer of 2006 the Water Quality Monitoring Section of the City of Austin’s Watershed Protection Department be-

gan monitoring runoff quantity and quality from a green roof installed in a shopping center. Monitoring began on a green

roof installed at a private residence the following summer. Please see Appendix H for a summary of the results of those

monitoring efforts. GRAG recommends that the City of Austin engage in further monitoring and design experimentation so

that conclusions may be drawn that support the effective and sustainable design of green roofs as the technology matures,

as well as potential incentives.

Project Profiles

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The following project profiles are included to provide detail about a select few of the growing number of green roofs al-

ready established and contributing to the development of best practices and lessons learned in Austin. The roofs repre-

sented here span multiple diverse building and owner types, soil depths, plant palettes, water use profiles, and other de-

sign considerations. See Appendix G for a map and table that inventories Austin’s green roofs. The City, along with input

from GRAG members, will maintain and expand the list as Austin’s green roofs proliferate and data becomes more robust.

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IV. Design Considerations

Incentives and credits offered by the City of Austin for green roof construction relate to the community and environmental

benefits the City will receive in return. As a result, it is important that a green roof function successfully. A living, healthy

green roof is well-positioned to mitigate against the urban heat island, cut cooling season energy use, reduce stormwater

runoff, lengthen the life of roof membranes, and provide valuable urban green space and habitat for wildlife. But this need

for water also means that water conservation techniques need to be considered throughout a green roof’s design, to in-

clude not only irrigation methodology and prudent selection of water sources including nonpotable water, but plant selec-

tion and optimization of the moisture-retention ability of the soil and other system layers. A green roof must be designed

with water conservation in mind system-wide. Green roof soil media and plants can also be designed to minimize the use

of fertilizers, which helps preserve downstream water quality. GRAG is charged with determining the performance-based

criteria for successful green roofs in Austin.

There are multiple applications for green roofs: residential, multifamily, commercial and retrofit. Depending on the appli-

cation and the profile of the green roof, the benefit level can vary. For example, roof profiles may range from four-inch to

six-inch soil depth planted with native grasses on a residential project to a deeper 24-inch soil profile on a commercial

building which allows for a larger variety of plants, such as trees and understory. Both roofs reduce building energy con-

sumption, mitigate urban heat island, and attenuate small storm events. The deeper roof with a wider variety of plant spe-

cies can achieve a higher level of environmental benefit by providing additional wildlife habitat, increased biodiversity, an d

greater soil-moisture holding capacity.

The unique characteristics of the Central Texas climate require careful landscape design of the green roof to ensure viabil-

ity. The periods of drought and punishing heat contrast with heavy rainfalls, requiring vegetation that can withstand a mul-

titude of tough conditions. Therefore, it is important to establish minimum design standards for a green roof to ensure that

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a minimum level of community benefit is attained.

The intended function of the green roof would also affect performance expectations. Some will be designed as public-

space amenity requiring some level of public and/or private access, others for environmental protection such as reduction

in runoff or habitat creation, and others for enhanced landscaping. A performance standard system will need to take into

account some factors which extend across all installations such as water use and maintenance access while also consider-

ing that standards for some specialized uses will not be applicable for others.

GRAG advocates the development of design considerations to identify the minimum requirements of a green roof. Discus-

sions included consideration of baseline versus higher credit green roofs and how best to create varying requirements.

Higher credit roofs would attain a higher level of environmental function and receive a higher level of incentive. Several

design considerations were identified to ensure adequate function of the green roof, including: size, soil depth, plant cover

and variety, water use, stormwater retention, pollutant removal, pest management, fertilization, mulch, visibility, access,

and maintenance requirements. Refer to Appendix O for a summary of the discussion that has occurred to date on these

potential criteria.

GRAG will need additional time to relate the design considerations to various environmental goals, develop the design

considerations into performance standards, and align the performance criteria with specific incentives and credits offered

by the City of Austin. The goals may depend on which City department is giving credit. For example, a credit from Planning

and Development Review (PDR) to satisfy the open space requirement may need a greater percentage of the green roof

area for gathering space for those accessing the roof, whereas a greater percentage of roof area for vegetation and a

deeper soil depth might be required for stormwater retention credits.

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V: GRAG Accomplishments

Developed consensus on the public and private benefits of green roofs as a component of green infrastruc-

ture, including improved air quality, stormwater detention, urban heat island mitigation, open space,

wildlife habitat, and others.

In Phase 1 of its activity period, GRAG engaged in discussion and evaluation within Site and Building commit-

tees to develop consensus on the public and private benefits of green roofs. The GRAG Interim Report to

City Council dated March 25, 2010 details these findings.

Completed a review of green roof incentive and credit policies of other cities in North America.

Staff and stakeholders completed a review of U.S. and international green roof incentive and credit policies

in Phase 1 of the GRAG activity period, evaluating potential confluences between those initiatives and exist-

ing and potential Austin incentives and credits. For details, please see Appendix I, Brief Overview of Green

Roof Credits and Incentives in North America.

Established a database of green roofs in Austin

Staff from Watershed Protection compiled an inventory of existing green roofs in Austin using input from

GRAG members and City staff as well as a list of projects from the GRoWERS website. The inventory was

mapped using GIS software and attributes including project name, address, and land use category (e.g.,

commercial, single-family residential, institutional) were populated. To date, 23 existing green roofs have

been included in the inventory (see Appendix G).

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Analyzed potential policies that could be developed to encourage green roofs.

Staff met with and obtained input from the following City of Austin Departments: Watershed Protection,

Planning and Development Review, Austin Energy, Public Works, Economic Growth and Redevelopment Ser-

vices, and Parks and Recreation. Each considered potential incentive measures relevant to their mission and

their potential inclusion in the Five-Year Policy Implementation Plan.

Developed proposals to integrate green roofs into departmental program efforts. Documented existing

City of Austin policies and incentives which encourage green roofs.

Staff reviewed and compiled all existing and potential policies and incentives to encourage green roofs. The

measures identified ranged from options specific to Austin’s regulatory system to measures used by other

cities across the world. The compilation forms the Policy and Incentives Matrix presented in Appendix D.

Supported the inclusion of green roof policy and benefit education on a City of Austin website.

GRAG proposed the creation of a green roof educational campaign that will serve the larger Austin commu-

nity including policy makers, residents, academia, and developers. It is envisioned as a resource for local

Austin citizens and people doing business in the Central Texas region. Currently the City of Austin’s Urban

Heat Island Mitigation (UHIM) program exists primarily as an education and tree planting program, which

provides a strong foundation for an expanded green roof program. The goal of the campaign is to increase

square feet of green roof space in Austin by a percent to be determined, and the local Central Texas green

roof industry by a percent to be determined. (See Appendix J for details on the proposed educational initia-

tives and website.)

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Advocated for an increase in Austin Energy green roof rebates.

The newly adopted 2009 energy code requires R-20 insulation and reflective roofs in new construction and

retrofits, which is very efficient. Therefore, no commercial energy efficiency rebates are provided for green

roofs or reflective roofs at this time. However, green roofs are recognized for reducing energy use by seven

to twenty-five percent more than reflective roofs.

Advocated for Green Roofs as a Downtown Density Bonus Public Benefit Option.

As part of the Downtown Austin Plan a draft of the Downtown Density Bonus Program was presented to

Council by the consultant team and staff at Planning and Development Review. The program offered Public

Benefit options for selection by the private sector in exchange for increased entitlements. Gatekeeper Re-

quirements set a baseline for participation in the program. Out of the options, the first 50 percent of

“bonused floor area” would go to affordable housing and the second 50 percent would go to such benefits

as family-friendly housing, child and elder care, cultural uses, historic preservation, and open space.

Through GRAG’s research of different cities’ green roof policies, such as Portland, Chicago, and Toronto, a

density bonus program was their number one policy tool to incentivize green roofs. In Portland, the green

roof floor to area ratio (FAR) bonus is offered on a graduated scale as follows:

Summary of Portland’s Green Roof Density Bonus Program

Green Roof Size Density Bonus

10 – 30% of building footprint 1 square foot of building area per square foot of green roof

30 – 60% of building footprint 2 square foot of building area per square foot of green roof

> 60% of building footprint 3 square foot of building area per square foot of green roof

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In an independent evaluation of Portland’s density bonus program, the green roof option was discovered to

be one of the public benefits most frequently selected by the private sector in exchange for increasing enti-

tlements.

In assessing areas in Austin which could benefit the most from the mitigation characteristics of green roofs,

GRAG reviewed urban heat island diagrams and areas with the most impervious cover and stormwater run-

off. The Downtown core was found to be the epicenter of the urban heat island and the greatest percentage

of impervious cover. Current regulations have no impervious cover limitation for downtown development

and have no requirements for landscaping, other than street trees. (See Appendix K, Watershed Protection

Ordinance Summary Table).

The review of other cities green roof policies and the discovery of Downtown Austin as the area that could

benefit the most from green roofs, led GRAG to recommend that green roofs be added as one of the individ-

ual Public Benefit Options in the Density Bonus plan. While one position is that green roofs are optional in

the Gatekeeper Sustainability requirement, GRAG believes there is not enough incentive present unless

green roofs are a separate standalone option for selection.

As a result, GRAG members participated in stakeholder discussions led by the Planning Commission to re-

view the draft Downtown Density Bonus Program. The group consensus was that green roofs were a worthy

Density Bonus Option to be included in the program.

While not a part of a specific “Density Bonus Program”, the City has seen interest from the downtown de-

velopment community to offer green roofs in exchange for increased entitlements. On May 26, 2010 a Re-

strictive Covenant for the Shoal Creek Walk project agreed to provide the following:

25

“Green Roofs. At least 20,000 square feet of green roof design shall be provided as a means to improve the

quality of the air, reduce stormwater runoff and improve energy efficiency of the structure beneath. The

green roof system shall be designed according to City approved requirements and standards.”

Developed a proposal for green roof monitoring research.

Staff evaluated the potential for green roof monitoring project to better understand if green roofs can be

used in Austin to mimic natural hydrologic regimes and reduce the impacts of urbanization. On June 24,

2010, the Austin City Council approved $10,000 for the Lady Bird Johnson Wildflower Center to study the

amount of rainfall runoff that two different green roof systems can retain and/or delay in comparison with a

conventional impervious conventional roof. This information will be used by City of Austin Watershed Pro-

tection Department staff to calibrate hydrologic models to estimate the quantity of rainfall that green roofs

can retain and/or delay on an average annual basis. The Wildflower Center expects to complete the study in

2011.

Organized a public seminar by a green roof industry leader on water retention modeling.

April 2010, GRAG sponsored a Water Retention Modeling seminar by American Hydrotech, a well-known

green roof manufacturer and installer. The central objective was to explore the use and quantification of

green roofs to meet City of Austin water quality and flood detention requirements. American Hydrotech

presented a hydrologic model for their proprietary green roof system to the Capital Area Erosion Control

Network (CAECN). The tool calculates how their systems retain stormwater runoff in its soil media and

drainage layer, slow the rate of rainfall runoff, and provide long-term benefits over “bare” conventional

roofs. These calculations have been used to confirm the use of green roof components to comply with LEED

requirements.

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Several green roof projects in the Austin area have used American Hydrotech’s products, such as Austin City

Hall, Ronald McDonald House, and Dell Children’s Center. These projects did not seek or receive stormwater

detention credit for their green roofs. (Where required, detention was provided using conventional storm-

water ponds.) However, in the future, American Hydrotech and other companies designing green roof sys-

tems can submit proprietary engineering models to the Watershed Protection Department for evaluation

and potential use for flood detention credit. (Future site-specific applications using such models might also

require additional review.) Green roofs using systems designed using approved models would be able to

provide this additional benefit to their projects.

Provided an outreach seminar to present GRAG’s efforts and solicit public feedback.

The outreach committee sought to educate the community on the benefits of green roof infrastructure. Al-

though the response was mostly positive, additional community education through continued outreach ef-

fort is important to reach a wider audience.

Developed Five-Year Policy Implementation Plan.

The Green Roof Five-Year Policy Implementation Plan was conceived to set in motion a long-range program

which recognized the increasing viability of green roofs as a component of green infrastructure for Austin.

The primary basis for the Five-Year Plan was the Policy and Incentives Matrix developed by staff which re-

viewed various aspects of City code that might target green roofs. Staff worked with various City depart-

ments to create reasonable goals for each year which cumulatively ensure that green roofs would remain on

the policy and program agenda and budget. Specific policy options were prioritized for staff development in

years one, two, three, etc. according to their ease of execution and their critical path nature for the devel-

opment of future program elements.

27

Additional attention was given to potential GRAG stakeholder activities that could underscore staff efforts

as well as promote green roofs in the City. The critical need for green roof performance standards was iden-

tified. The development of the standards was not able to be accomplished within the Council-approved

GRAG time frame. Therefore, the task was pushed forward into year one of the implementation plan. An

additional year-one stakeholder task was outreach to key design and sustainability organizations.

Initiated a framework for green roof design considerations.

The design considerations matrix will be an important tool for identifying the components of a green roof.

As green roof credits and incentives become a part of City policy, City staff can use the matrix during the

permit processes to determine if a project qualifies for credits and incentives. GRAG has identified a range

of potential credits, but some credits, such as parkland dedication, may only be suitable for a higher per-

forming roof that is publicly accessible. Not only is continued development of the minimum requirements of

a green roof important, but GRAG should identify the medium and higher credit green roof so that a correla-

tion between the constructed green roof and particular incentives and credits exists.

Integrated Water Conservation 2020 principles into green roof recommendations.

A potential increase in green roofs in Austin raises the specter of a proportional increase in potable water

use for irrigation. While not all green roofs require potable water irrigation—and in dense multi-family con-

struction a green roof would require less water per capita than large lawn areas in single-family subdivi-

sions—any possible additional stress on water resources merits thoughtful consideration. The Green Roof

Advisory Group has made a concerted effort to explicitly align green roof design considerations and policy

recommendations with the Water Conservation 2020: Strategic Recommendations report released in March

2010. These efforts included meeting with Susan Butler, Citizens Water Conservation Implementation Task

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VI. Findings and Recommendations

Policy and Incentives

A major focus of the Council resolution and thus of the GRAG and staff support was to identify a comprehensive set of op-

tions to incentivize and otherwise encourage the creation of green roofs in Austin. Staff from Watershed Protection, Plan-

ning and Development Review, Austin Energy, Public Works, Austin Water, Economic Growth and Redevelopment Services,

and Parks and Recreation collaborated in their review of existing City code and national and international green roof

strategies to identify potential credits, incentives, and other measures to encourage the creation of green roofs in Austin. A

summary table, presented in Appendix D, was developed to describe the potential optional codes, description of current

status and concerns, potential improvement, advantages and disadvantages of anticipated impacts , and staff recommen-

dations. This section discusses the high points of this research, but the table in Appendix D should be consulted to better

understand each option considered.

For completeness, a wide an array of options are included in the Policy and Incentives Matrix. Not all items in the Matrix

are expected to be implemented, or even considered, in the short term. Some options will be more suitable and feasible

than others. Those with the most promise were included in this report’s Five-Year Policy Implementation Plan. Some

strategies used by other communities with more mature green roof programs, such as direct or indirect financial incen-

tives, may become appropriate for Austin in the future once green roof initiatives gain more experience and momentum.

The four main headings in the Policy and Incentives Matrix in Appendix D are: (1) Zoning; (2) Energy Conservation, Air Qual-

ity & Climate Protection; (3) Watershed Protection; and (4) Financial Incentives. The most promising options in each cate-

gory were included in the Five-Year Plan and are discussed below. Also discussed are several high-profile options that were

studied but not ultimately included in the Five-Year Plan.

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Zoning

Austin’s existing Land Development Code already enables green roofs to count towards key zoning credits and require-

ments. Since, in most cases, these possibilities are poorly known and/or understood by either City staff or the design and

development communities, a great opportunity exists to educate City staff and the public about them. Improved publicity

of these options may help encourage the construction of green roofs and would not require significant resources or any

additional action by Council. All of the following items are included for early implementation in the Five-Year Plan:

Green roofs for PUDs.

Green roofs are a natural fit to help PUDs (Planned Unit Developments) meet minimum requirements for open

space & landscaping.

Green roofs for PUD Green Building.

Green roofs have the capacity to single-handedly contribute multiple points towards a project’s Green Building

rating, which is a standard PUD requirement.

Green roofs for creative/innovative environmental PUDs.

The PUD system includes a “Tier 2” system to enhance their acceptance, of which environmental innovation is a

component; green roofs would logically contribute.

Open Space for Multifamily Projects and Commercial Projects.

All multifamily residential developments (apartments and condominiums) and commercial developments over 5

acres in size are required by code to include minimum open space provisions. This mandate can be met using

roofs.

Green roofs over subsurface parking garages.

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A creative use of green roofs is already allowed in that subsurface parking garages covered with 4-foot soil

count as “pervious” cover within the urban roadway boundary (area served by the Commercial Design Stan-

dards).

Green roof parks.

Green roofs may potentially be used to meet parkland dedication requirements under certain circumstances,

which is an innovative approach in dense areas with few open space opportunities.

Several zoning-related options were identified that will require Council or City Department action to bring them about.

These options include:

Downtown Density Bonus.

This option, discussed earlier in this report in more detail, is a cornerstone request of the GRAG. The benefits of

their inclusion in a density bonus program would be enormous for green roofs in Austin, not the least of which

is the momentum-shifting push that this would provide to make them more common and accessible to the de-

sign and development community.

Other density bonus options.

Green roofs might also be used to attain density bonus entitlements in other areas, such as North Burnet-

Gateway Planning Area, Airport Blvd near Highland Mall, East Riverside Corridor, and the Transit Oriented De-

velopment (TOD) districts. All of these areas would greatly benefit from more green open space, lower ambient

temperatures, and increased aesthetic appeal.

Increased building cover.

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Green roofs could be used to potentially increase maximum allowable building cover for projects. Maximum

building cover requirements were instituted to limit the built environment from overwhelming adjacent land

uses; green roofs serve to soften and counter these negative impacts and a system could be devised to produce

a favorable ratio of new building added to increased green roof.

Green roofs on all new Central Business District buildings.

An idea needing further research, this Chicago-inspired option would see the systematic greening of Austin’s

downtown skyline. It is included for consideration for discussion purposes in the Five-Year Plan.

Energy Conservation, Air Quality & Climate Protection

Urban Heat Island Mitigation.

The greatest energy conservation benefits for green roofs may come in their ability to assist with urban heat

island mitigation. GRAG and AE staff recommends the incorporation of green roofs into this program for educa-

tion, outreach, and incentives and included this measure in the Five-Year Plan.

Energy Rebates.

Future consideration of rebates for green roofs will be given; at present, however, such rebates were judged by

AE to not be warranted.

Green roofs in lieu of cool roofs.

The Austin Energy Code allows the use of a green roof instead of a high reflectivity roof. But there is no defini-

tion of what a green roof is, and AE staff asked for GRAG help in defining green roofs. The proposed GRAG work

on the design considerations will help toward this goal.

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Watershed Protection

Green roofs for flood control.

Methods exist today to incorporate flood control into green roof design (though some options will likely be fi-

nancially impractical for many applications). A project engineer would have to demonstrate to City staff how

such a system would work and be maintained. In the meantime, a study by the Lady Bird Johnson Wildflower

Center will seek to better understand the potential flood detention capabilities of several green roof systems.

Water quality control research needed.

The benefits of green roofs to improve water quality and flood control over conventional impervious roofs is

the subject of much discussion internationally. As cited above, several studies and monitoring efforts have

shown promise in reducing the total volume of runoff from green roofs versus those of standard roofs. At this

time, water quality credit is not given to green roofs in Austin’s Environmental Criteria Manual. (The quantifica-

tion and assurance of benefits is hampered by the wide variety of proprietary and custom green roof systems

and the relative lack of data showing their performance.) More research needs to be done to prove this to be a

viable approach in Central Texas. One option, however, is that a private entity could bring forward data and

modeling information to demonstrate the function of a particular green roof system. The Environmental Criteria

Manual includes provisions for designers to bring forward new concepts and controls for approval for water

quality credit. A second approach recommended by this report is the further study of the ability of green roofs

to control site hydrology. This recommendation has led to Council approval of funds to have the Lady Bird John-

son Wildflower Center research this issue. The data hereby collected and possible follow-up studies may lead to

future design criteria for water quality controls using green roofs.

Existing green roof options for water quality.

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In addition, Appendix D documents that several water quality systems are possible now using green roofs,

where the green roof serves as a component of a larger, integrated treatment system. Examples include the use

of green roofs for re-irrigation of captured stormwater and direct incorporation of existing stormwater controls,

such as biofiltration and rain gardens, into a green roof system.

Not ready to count green roofs as “pervious” cover.

GRAG and staff considered the possibility of granting partial or complete credit for green roof systems to count

as “pervious” rather than “impervious,” as they are currently counted. Impervious cover limits and control are

one of the cornerstones of watershed protection and a deviation to the use of engineered pervious cover, in

this case in the form of a green roof, is a major step. WPD staff judged the City is not at a point where this con-

clusion is justified.

Less runoff allowing smaller water quality controls.

While a green roof might not be reliably considered “pervious,” a reasonable middle step would be to acknowl-

edge that they can, if demonstrated, reduce rainfall runoff and therefore be potentially given credit toward re-

ducing the size of downstream water quality controls required for a site. As such, they function (as anticipated

by the 2009 EPA report) as integral components in overall “green infrastructure” solutions for environmental

protection.

Drainage Fee Reduction.

Some communities have used drainage fee reductions to incentivize green roofs. Austin already gives a fee re-

duction for properly maintained stormwater controls. A green roof, if designed and approved as a stormwater

control, would qualify for the drainage fee reduction.

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Financial Incentives

Four major categories of financial incentives for green roofs were considered and included in Appendix D. They are as fol-

lows:

Subsidies, Grants, Low-Interest Loans

Development Process Incentives (Fee Rebates, Expedited Process, Design Support)

Local Improvement Credits

Property Tax Credit

All were taken from other US and/or international examples. All have potential and are recommended for exploration in

the Five-Year Plan. See Appendix D for more detailed discussion of each.

Alignment with Water Conservation 2020: Strategic Recommendations

The Water Conservation 2020: Strategic Recommendations report details how conservation can reduce the demand placed

on water suppliers and thereby increase supply of a limited resource for a growing population. The report specifies a num-

ber of water conservation principles, which GRAG supports.

GRAG expresses a strong commitment to aligning green roof design with the following principles of water conservation in

Austin:

Year-round “no more than twice a week” watering schedule

Use of air conditioning condensate for irrigation

Use of reclaimed water and other non-potable water sources

efficient irrigation systems

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Promotion of native and drought-tolerant plant materials

Development of water budgets where possible, and working toward water budgeting as an industry standard

Partnering with City departments that focus on sustainability to create cohesive knowledge base

Strategies Meriting Further Analysis

Data collection

Data collection needs and strategies were thoroughly considered by GRAG and City staff. At the present time, efforts have

been concentrated on understanding and better quantifying the potential benefits of green roofs on controlling the quan-

tity of runoff emanating from buildings using these systems. GRAG recommended funding for a study by the Lady Bird

Johnson Wildflower Center on green roof impacts on hydrology (see description above); Council has approved funding for

the project, which is expected to be completed in 2011. Ongoing and past efforts by the Watershed Protection Department

have also resulted in the monitoring of two green roof systems in Austin and will be made available in the near future. Ad-

ditional, future studies will likely include research of water quality (e.g., control of nutrients) using green roofs.

Green roof performance data for energy conservation and heat island mitigation already exists from US and international

studies. This data needs to be further reviewed for its applicability to green roofs in Austin. Central Texas studies of this

topic may or may not be required.

Target Areas of Austin to Focus Green Roof Efforts

Staff has conducted preliminary studies of areas within Austin most suitable for targeting for green roof implementation.

The results confirm what is intuitively obvious; green roofs will likely deliver the greatest net benefit to areas dispropor-

tionately devoid of vegetation, open space, and natural areas. Such areas include intensely impervious hotspots such as

downtown, the North Burnet-Gateway Neighborhood Plan area, the East Riverside Corridor, and the Airport Boulevard

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Corridor near Highland Mall. All three of these areas are potential locations for incentives bonus for green roofs and are

included in the Five-Year Policy Implementation Plan. However, many other areas of town, such as commercial and office

areas along major roadways and Transit-Oriented Districts (TODs), might also benefit from the introduction of green roofs.

Policies encouraging green roofs in these additional areas are a logical extension of pilot efforts in these three target areas.

Inventory Green Roofs in the Region

City staff, using site plan submittals as well as ongoing input from GRAG members, will continue to add green roof projects

to the green roof projects inventory. The map will be incorporated into the new green roof website for education and out-

reach similar to the “Austin’s Green Map” showing Austin Energy Green Building-rated and LEED-certified projects.

Evaluate Green Roof Opportunities for Residential and Retrofit Projects

Single-family residential green roofs represent about five percent of known green roofs in Austin. (See Appendix G for

Green Roof Inventory and Map.) Few existing areas of code evaluated by GRAG include significant single-family residential

opportunities for green roofs. Retrofits make up a smaller proportion of Austin’s green roofs. Further evaluation and re-

search is needed to identify barriers and opportunities to increase green roof proliferation in both areas where appropri-

ate.

GRoWERS, a four-year-old Austin green roof organization represented on GRAG, began the pilot phase of their Green

Roofs Over (GRO) Austin project in 2009 to facilitate the construction of small, privately owned residential and retrofit

green roofs across the Austin area, observing and learning from them in various settings. The goal is to continue to close

gaps in the local knowledge of green roofs, primarily in the residential context, and to develop best practices. GRAG may

evaluate opportunities to partner with GRoWERS in later phases of work.

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Investigate the Potential to Implement Green Roofs on City Buildings

The justification for a green roof on a city building requires comparison of maximized public benefit against the additional

investment required. Opportunities for green roofs on the City’s inventory of buildings may be limited by utilitarian func-

tion, but Capital Improvement Programs and operating expenditures include replacement of existing roofs at end of life,

renovations involving roofs, and new buildings. Consideration occurs currently through City Resolutions requiring projects

over $2 million construction cost to be certified under the LEED Green Building Rating System. Also, Baseline Sustainability

Criteria for smaller projects include consideration of a green roof.

A proactive effort for the City would be to categorize all city-owned roofs with the intent to study, select and seek addi-

tional funds for appropriate green roof locations. In addition, the green roof at City Hall should be monitored and analyzed

to form milestone reports. A forecast by a representative of the Department of Public Works estimates that the City has

the potential to add at one additional green roof to the City’s portfolio in the next five years.

Take Advantage of City Hall as a Green Roof Educational Model

The City Hall Green Roof was designed to be an environmental educational model for the citizens of Austin and out of town

visitors. With its two types of green roofs over the parking garage and over occupied space, the layout offers a green roof

educational opportunity. Flyers could be developed which explain the components of the different types of green roof and

the type of soil, irrigation, and plant palette. The flyers could be available at the reception desk in the City Hall lobby to ac-

company other handouts. Biannual tours in the spring and fall could be advertized and offered to the public. The tours

could focus on the green roof challenges and opportunities through design, construction, and on-going maintenance.

While for this City of Austin building these activities would likely be led by the City of Austin, similar initiatives could be

considered for other green roofs in Austin under other auspices.

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VII: Next Steps

In order to accomplish the policy goals determined by the Green Roof Advisory Group, the following Five-Year Policy Imple-

mentation Plan is proposed. Staff has identified tasks that could be executed to further promote green roofs within various

City departments. Some tasks will be easier to accomplish within Year 1, while others may take a more concerted effort to

bring forward. Those tasks that may require more review and coordination have been distributed throughout Years 2-5

accordingly. While some first year tasks are clearly defined, the long range plan is meant to be a dynamic, evolving docu-

ment which takes into account new information, resources, and priorities.

The goals for policy implementation fall into eight broad categories: Outreach and Education, Design Considerations, Exist-

ing Development Options with Green Roofs, Potential Development Options with Green Roofs, Energy Impacts, Innovative

Stormwater Management, Green Roofs for City Buildings, and Financial Incentives.


Outreach and education is critical to encourage the implementation of green roofs in the city. Educational activities need

to focus on the public and private benefits of green roofs, the availability of city departments to facilitate green roof imple-

mentation, and existing Austin green roofs as educational models. Green roof outreach and education should target inter-

departmental staff activities, the design and development community, and professional organizations. In particular, GRAG

recommends a green roof web page be developed as the central clearing house for all green roof activities in the city.

Design Considerations

In order for the city to offer green roof incentives and credits, some design considerations need to be reviewed to establish

baseline performance criteria. GRAG request for a one year extension includes effort to create these minimum standards.

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Existing Development Options

In some existing development regulations, green roofs already qualify to meet the code. GRAG recommends these options

be highlighted to City staff and to the development community.

Potential Development Incentives

Existing and proposed development regulations could be modified to include green roofs. GRAG recommends that green

roofs be considered as density bonus options and to offset potential building cover increases.

Energy Impacts

Green roofs provide energy reductions for individual buildings. GRAG recommends that these impacts be evaluated and

that green roofs be considered for rebates.

Innovative Stormwater Management

Green roofs provide retention and run-off control for stormwater management. GRAG recommends City staff work with

green roof manufacturers to verify proposed hydrological models for the Austin area. GRAG also recommends technologi-

cal research be conducted to collected field data in our climate.

Green Roofs for New Buildings

Many cities leading the way in green roof infrastructure require green roofs on new institutional and commercial buildings.

Although not a requirement in 1995, a green roof was implemented on the Austin City Hall, with the intent of the green

roof being used as an educational model. In the first year of the Five-Year Plan, GRAG recommends the City consider green

roofs for any new city building projects. Also, we recommend that at least one new green roof be implemented on a new

40

city building in the next five years. GRAG also suggests, during the second year, to evaluate the feasibility of requiring

green roofs on new commercial buildings in the Central Business District.

Financial Incentives

Financial incentives have been shown to be effective in other cities. GRAG recommends that these be evaluated for imple-

mentation in years four and five of the plan.

Green Roofs Five-Year Policy Implementation Plan

(Key to acronyms follows.)

Year One (FY 2010-11)

Year One (FY 2010-11)

Activity Lead Discussion


Green Roof Web page & support materials AE Develop; includes items below w/ asterisk (*)

Green Roof program tracking & report* AE/WPD/PDRD Track GR initiatives/5-Year Plan progress

Staff education and coordination* Multiple Done for each initiative; internal web page

Urban Heat Island integration* AE Integrate GR into program

Green Roof database* AE/PDRD Track projects in City maintained database

City Hall educational model* AE Develop educational flyer and tours

Outreach to focus areas GRAG Meet with professional organizations

Green Roof Design Considerations Baseline Performance Criteria GRAG/AE/ Define minimum standards for City-incentivized

projects; extend GRAG to accomplish task Existing Development Options with Green Roofs PUD Open space & landscaping* PDRD Show can meet requirements with GRs

PUD Green Building requirements* AEGB Show GRs can contribute to score

PUD use of GR in Tier 2* PDRD/AE Show GRs can be "other creative or innovative [environmental] measures"

Multifamily open space* PDRD Show can meet requirements with GRs

Subsurface parking garage* PDRD Show GRs over subsurface garages do not count as impervious

Parkland dedication using GRs* PARD Show can use privately owned/maintained GRs to meet requirements

Potential Development Incentives (require code change & Council approval)

GR Density Bonus: Downtown PDRD Add green roofs to program

Building cover increase PDRD Allow more building cover if offset with GR

Energy Impacts Austin Energy rebates AE Evaluate energy impacts & potential rebate incentives

Innovative Stormwater Management GR hydrologic study WPD/WFC Research of detention & runoff control by LBJ

Wildflower Center

GR industry water quality control Industry/WPD Coordinate with staff to verify hydrologic model for WQ credit (option exists throughout 5-year period)


GR on City Buildings PWD Evaluate feasibility & funding of green roofs for all

new City buildings per Council resolutions 20071129-045 & 20071129-046

Year Two (FY 2011-12)


Outreach and Education Green Roof Web page & support materials AE Continue funding allocation

Green Roof program tracking & report* AE/WPD/PDRD Track GR initiatives to show progress

Green Roof project database* AE Track projects to show progress

Incentives for Green Roofs

Austin Energy rebates AE Implement rebate if warranted, pending evaluation results from Year 1

North Burnet/Gateway GR density bonus PDRD Needs Council approval; follows Downtown density bonus

Innovative Stormwater Management

Water quality sizing credit WPD Allow limited number or pilot projects in DDZ

Watersheds to receive partial WQ credit on condition of monitoring

Plan for GR/LID design competition WPD/GRAG Follow City of Houston example

Planning for Green Roof for City Building

Collect, evaluate data on buildings PWD

Create inventory of existing & proposed COA buildings/roofs, select subset for further GR

consideration per Council resolutions 20071129-045 & 20071129-046


GR on New Commercial Buildings GRAG/PDRD Evaluate feasibility of green roofs for all new buildings within the Central Business District

Year Three (FY 2012-13)


Outreach and Education Green Roof program tracking & report* AE/WPD/PDRD Track GR initiatives to show progress


Incentives for Green Roofs

Airport Blvd. Corridor GR density bonus PDRD Needs Council approval; follows Downtown & N. Burnet/Gateway density bonuses

Innovative Stormwater Management Flood detention and/or WQ sizing credit WPD Pending Wildflower Center results & possible other

follow-up studies Hold GR/LID design competition WPD/GRAG Follow City of Houston example

Year Four (FY 2013-14)


Outreach and Education Green Roof program tracking & report* AE/WPD/PDRD Track GR initiatives to show progress


Innovative Water Quality Controls

Green Roof as WQ control WPD Evaluate feasibility to add ECM Criteria for green

roofs; pending Wildflower Center results & additional follow-up studies

Subsidies, Grants, Low-Interest Loans Funding Allocation EGRSO Develop criteria pending staff review

Year Five (FY 2014-15)



Green Roof program tracking & report* AE/WPD/PDRD Track GR initiatives to show progress


Development Process Incentives

Fee Rebates, Expedited Process & PDRD

Develop Incentive Program Design Support

47

Proposed Extension of Advisory Group Timeframe

GRAG developed a proposed Five-Year Policy Implementation Plan which outlined efforts and initiatives that would be rea-

sonable to achieve within the timeframe of the Implementation Plan. In particular, GRAG identified critical path tasks for

the first year that were not able to be addressed within the timeframe approved by Council for GRAG, but would be neces-

sary to achieve in order to provide a solid basis for further policy development. To this end, GRAG requests to continue its

efforts for one year after presentation of the final report to Council to accomplish the following:

Key to Acronyms

AE Austin Energy

COA City of Austin

DDZ Desired Development Zone (Urban & Suburban watersheds) EGRSO Economic Growth & Redevelopment Services Office

FY Fiscal Year

GR Green Roof GRAG Green Roof Advisory Group

LID Low Impact Development (design strategy to limit environmental impact)

PDRD Planning and Development Review Department

PWD Public Works Department

WFC Lady Bird Johnson Wildflower Center

WPD Watershed Protection Department

WQ Water Quality

48

Develop of green roof design considerations for commercial building projects

Support for the development of green roof web page and other educational initiatives

Advocate for green roofs as a public benefit option for the Downtown Density Bonus Plan

Assess City funded green roof monitoring research

Provide progress review of staff implemented year one policy incentive and credit initiatives.

During this time staff could continue to flesh out the proposals of the Policy and Incentives Matrix and provide feedback on

the viability of the Design Considerations within individual departments, as well as consider the feedback of local profes-

sional organizations and additional stakeholders. If ordinance changes to encourage green roofs are able to be proposed,

then, with Council direction, staff could take them through the Legal Department and subsequently send to the Codes and

Ordinances sub-committee of the Planning Commission for feedback and review prior to presenting back to Council for ap-

proval.

GRAG believes that without continuation, the momentum currently achieved could go for naught and the potential within

the final report never realized. However, with the continuation of GRAG, the group can assist staff in providing a baseline

level of green roof policy support that will solidly secure its position within City programs and codes.

49

VIII. Appendices

A. Excerpt from Green Roofs: A Resource Manual for Municipal Policy Makers

There are six phases in establishing a green roof policy. This Manual discusses jurisdictions that represent each phase in

more detail in later sections. The policy phases this Manual describes are not rigid classifications. Jurisdictions may be at

different phases at the same time and they may return to an earlier phase if they need to.

Phase 1: Introduction and awareness

In this phase, a jurisdiction looks at the merits and environmental benefits of green roofs. The municipality may hold a

green roof workshop, send delegates to a green roof conference or visit a jurisdiction with existing green roofs or a green

roof policy.

Green Roofs for Healthy Cities (green roofs.org3) has been key in helping North American municipalities organize green

roof workshops to bring local stakeholders together. In this phase, a local champion is usually declared who may act as a

spokesperson for the jurisdiction. Winnipeg and Ottawa are examples of municipalities in this phase. (www.Green

roofs.com4 has a comprehensive overview of green roof technology).

Phase 2: Community engagement

A local champion or a green roof committee may seek any number of creative methods to raise the profile of green roofs.

There may be meetings with community leaders, mayors, architects, landscaping professionals, building owners and envi-

ronmental groups to gain support for green roofs. Funding sources, such as government programs, utilities or green roof

manufacturers, will be explored and negotiated.

The champion or committee will outline the opportunities, threats, strengths and weaknesses of green roof development

50

in the municipality. An extremely harsh climate is a potential threat; a large number of flat roofs are an opportunity. Hali-

fax and Calgary are in phase 2 and are nearing phase 3, with plans for green roof demonstration sites and research.

Phase 3: Action plan development and implementation

The municipality or the community may establish a green roof advisory or working committee made up of key community

leaders. A green roof demonstration project may be launched with or without scientific monitoring equipment, depending

on the need for local research data. Green roof tours and ongoing planning meetings often include site visits to buildings

with different types and designs of green roofs, leading to the establishment of a green roof database or inventory. A re-

view of existing policy options and tools may be explored in this phase and various programs and policy opportunities iden-

tified. Minneapolis-St.Paul, in Minnesota, is an example of a municipality in this phase.

Phase 4: Technical research

The local green roof advisory committee or the local champion(s), or both, along with a possible consortium of public-

private partnerships set up a research site. In some cases, the technical research is demonstration projects or green roof

installations on prominent site, such as the green roofs on the Toronto and Chicago city halls. A jurisdiction exploring gree n

roofs as a step in setting green roof policy needs local research data with outcomes that can be applied to any or all of the

key motivators prioritized in the jurisdiction. The National Research Council of Canada (NRC) has provided technical assis-

tance to many research projects.

In the technical phase, researchers investigate and quantify the benefits of green roofs, which will become part of green

roof policy and design guidelines. Research typically involves assessing the ability of green roofs to manage stormwater,

mitigate the urban heat island, or provide other necessary environmental benefits. Typically, jurisdictions with monitored

demonstration sites collect and prepare findings for conference proceedings, which are shared at international green roof

conferences. Sharing data and research findings is an important part of the technical research phase. Toronto, Waterloo,

51

Vancouver, Montréal and New York are examples of municipalities in this phase.

Phase 5: Program and policy development

The green roof advisory committee may expand to include more professionals, such as landscape designers, horticultural-

ists, designers and municipal urban planners. This phase translates local and regional research into policy options and

tools. This involves establishing ways of offering incentives to contractors, developers and building owners to retrofit or

plan new buildings with green roofs. This can include financial incentives, tax credits or density bonuses. Chicago, Portland

and Singapore are in this phase.

Phase 6: Continuous improvement

At this phase, a jurisdiction has achieved maturity and familiarity with green roof technology. Now, the jurisdiction as-

sesses the effectiveness of policies and programs and decides whether to continue on the same path or explore other pol-

icy options. To gather information and assess program success, there must be a mechanism to collect and analyze con-

structive feedback from users, professionals and the building community. Phase 6 typically involves exploring other policy

options or further research to fine-tune existing programs. One German jurisdiction had to include policy language requir-

ing maintenance of green roofs for a specified period, as some owners neglected their green roofs and the roofs did not

achieve their expected environmental goals. The German cities of Stuttgart, Münster and Berlin and the state of North

Rhine Westphalia are in this phase.

Source: Canada Mortgage and Housing Corporation, May 2006

Green R

oofs Policy Implem

entation 5-Year Plan

YEAR O

NE


Green R

oof web page &

support materials

Austin E

nergy

Green R

oof program and

project tracking

track projects to show progress

AE

/WP

D/P

DR

D

Staff education and

coordination

done for each initiative; internal web page

Multiple stakeholders

Urban H

eat Island Integration

integrate GR

s intoprogram

Austin E

nergy

Innovative Stormw

aterM

anagement

Green R

oof Dem

onstration

GR

pilot for city building

City H

all likely candidate

Plan G

R/LID

designcom

petition

WP

D/G

RA

G

follow C

ity of Houston exam

ple

Hydrologic study

LBJ W

ildflower C

enterresearch of detention &

runoffcontrol

WP

D/W

FC

Green roof industry

demonstration

coordinate with

WP

D/P

DR

D staff for

input

WP

D/G

RA

G

Incentives for Green R

oofs

Austin E

nergy rebates

evaluate energy impacts &

potential rebate incentives

AE

Zoning Incentives

GR

Density B

onus: Dow

ntown

Code A

mendm

ent/Council A

pproval

PD

RD

Building cover increase

Code A

mendm

ent/Council A

pproval

PD

RD

Subsurface parking garage

with 4 ft of soil

qualifies now as pervious &

is GR

Green R

oof Performance M

atrix

Baseline P

erformance

Requirem

ents

Define m

inimum

standards forC

ity-incentived projects

GR

AG

/AE

/WP

D

Planned Unit D

evelopment (PU

D)

Open space &

landscapingrequirem

ents

PD

RD

Green B

uildling requirements

AE

GB

Use of G

reen Roofs in Tier 2

needs staff review

PD

RD

/AE

Multifam

ily Residential

Developm

ents

Open space requirem

ents

PD

RD

Parkland Dedication

Privately ow

ned/maintained G

R

Allow

GR

as parkland

requires 3 neighborhood amenities

PA

RD

YEAR TW

O

Outreach &

Education

Green R

oof web page &

support materials

continue funding allocation

AE

Green R

oof program and

project tracking

track projects to showcontinued progress

AE

/WP

D/P

DR

D

Innovative Stormw

aterM

anagement

GR

industry demonstration

continue to seek projects

WP

D/G

RA

G

Announce G

R/LID

designcom

petition

follow C

ity ofH

ouston example

WP

D/G

RA

G


oofs

Austin E

nergy Rebates

WP

D/G

RA

G

North B

urnet/Gatew

ay GR

density bonus

Requires C

ouncil Approval

follows D

owntow

n density bonus

WP

D/G

RA

G

YEAR TH

REE

Innovative Stormw

aterM

anagement

Flood Detention and/or W

Qsizing credit

Pending W

ildflower C

enterresults &

possible otherfollow

-up studies

WP

D


oofs

Airport B

lvd. Corridor G

Rdensity bonus

requires Council approval

follows D

owntow

n & N.

Burnet/G

ateway density

bonuses

PD

RD

YEAR FO

UR

Innovative Water quality C

ontrols

Green R

oof as WQ

control

evaluate to add EC

M C

riteriafor G

Rs: pending W

ildflower

Center results &

additionalfollow

-up studies

WP

D

Subsidies, Grants,

Low-Interest Loans

Funding Allocation

develop criteria

EG

RS

O

YEAR FIVE

Green R

oofs for City

Buildings

Evaluate feasibility &

funding

consider green roofs for City buildings

Council approval required

PW

D

INTROD

UCTIO

N:In order to accom

plish the policy goals determined by the G

reen Roof A

dvisory Group, the follow

ing 5-year implem

entation plan is proposed. Staff has identified tasks that could be executed to further the prom

otion of Green R

oofs within various city

departments. S

ome tasks w

ill be easier to accomplish w

ithin Year 1, while others m

ay take a more concerted effort to bring forw

ard. Those tasks that may require m

ore review and coordination have been distributed throughout Years 2-5 accordingly. O

ngoingm

onitoring of activities on a yearly basis is recomm

ended with end-of-year reports evaluating and adjusting for upcom

ing year.

Green R

oofs Policy Im

plementation 5-Year P

lan .mm

ap - 7/14/2010 - Mindjet

53

Stakeholder groups contacted for their feedback on the interim report:

Associated Builders & Contractors, ABC

Associated General Contractors, AGC

American Institute of Architects Committee on the Environment, AIA COTE

American Society of Professional Engineers, ASCE

American Society of Landscape Architects, ASLA

Austin Contractors and Engineers Association, ACEA

Austin Econetwork

Building Owners & Managers Associates, BOMA

Capital Area Erosion Control Network, CAECN

Congress for New Urbanism, CNU

International Facilities Management Association, IFMA

Real Estate Council of Austin, RECA

Save Barton Creek Association, SBCA

Sierra Club

Save Our Springs (SOS) Alliance

Texas Society of Professional Engineers, TSPE

U.S. Green Building Council, USGBC

54

D. Policy and Incentives Matrix

TO BE ADDED IN XLS

E. Letter to City Council Advocating Addition of Green Roofs to Density Bonus Program Public Benefit Options

TO BE ADDED IN PDF FORMAT

F. Boards and Commissions Comments

Upon receipt, Boards and Commissions comments will be recorded in this section.

G. Green Roof Map and Inventory

TO BE ADDED IN PDF

The C

ity of Austin is com

mitted to com

pliance with the A

mericans w

ith Disabilities A

ct. Reasonable m

odifications and equal access to communications w

ill be provided upon request.

O

cto

ber 1

4, 2

009

Fro

m: G

reen

Ro

of A

dv

iso

ry G

rou

p

To

: M

ayo

r Lee L

effin

gw

ell

M

ayo

r Pro

Tem

Mik

e M

artin

ez

Council M

em

ber L

aura

Morris

on

C

ouncil M

em

ber S

hery

l Cole

C

ouncil M

em

ber R

and

i Sha

de

C

ouncil M

em

ber B

ill Spe

lman

C

ouncil M

em

ber C

hris

Rile

y

Re:

Do

wn

tow

n A

ustin

Pla

n –

Den

sity

Bo

nu

s P

rog

ram

Ad

ditio

n o

f Gre

en

Ro

ofs

to D

en

sity

Bo

nu

s P

rog

ram

Pu

blic

Ben

efit O

ptio

ns

Dear M

ayor a

nd M

em

bers

of th

e C

ity C

ou

ncil:

The G

reen R

oof A

dvis

ory

Gro

up (G

RA

G) re

quests

that C

ouncil a

dd

Gre

en

Ro

ofs

to th

e D

AP

Den

sity

B

on

us P

rog

ram

Pu

blic

Ben

efit O

ptio

ns, a

s a

se

para

te o

ptio

n w

ith its

ow

n c

riteria

. This

requ

est is

the

outc

om

e o

f the in

itial e

fforts

of G

RA

G to

rese

arc

h a

nd

develo

p a

po

licy re

port th

at in

clu

des

recom

mendatio

ns re

gard

ing c

redits

and in

ce

ntiv

es to

pro

mote

gre

en ro

ofs

in th

e c

ity. T

he g

roup is

w

ork

ing w

ith W

ate

rshed P

rote

ctio

n a

nd A

ustin

Energ

y to

de

ve

lop p

erfo

rmance b

ased s

tand

ard

s fo

r gre

en ro

ofs

that w

ould

esta

blis

h b

ase lin

es fo

r consid

era

tion

. G

reen R

oofs

addre

ss a

bro

ad ra

nge o

f issues a

cro

ss a

bre

adth

of s

cale

, from

build

ing to

site

to u

rban

desig

n, a

nd a

s s

uch, o

ffer a

un

iqu

e c

om

bin

ed P

ublic

Ben

efit in

a s

ing

le te

chno

log

y. A

s d

ow

nto

wn

Austin

becom

es d

enser, g

reen ro

ofs

mitig

ate

the

com

bin

ed n

ega

tive e

ffects

of th

e b

uilt e

nviro

nm

ent.

Effe

ctiv

ely

reconstitu

ting o

pen g

reen s

pace w

ithin

the b

uild

ing fo

otp

rint, p

lante

d ro

ofs

augm

ent th

e

City

’s g

reen in

frastru

ctu

re, m

itigate

sto

rmw

ate

r runoff, c

ool a

mbie

nt te

mpera

ture

s to

coun

tera

ct th

e

urb

an h

ea

t isla

nd

effe

ct, in

cre

ase e

nerg

y c

onserv

atio

n, s

equeste

r carb

on, o

ffer a

esth

etic

am

enity

, pro

vid

e w

ildlife

ha

bita

t and a

n o

pportu

nity

to c

on

nect w

ith n

atu

re in

the h

eart o

f the

City

. The

cum

ula

tive

impact o

f gre

en ro

ofs

in d

ow

nto

wn A

ustin

, especia

lly a

s e

ncoura

ged a

nd a

pplie

d in

gre

ate

r num

bers

with

ap

pro

pria

te lo

cal te

chno

log

y, s

tands to

be fa

r-reachin

g.

The D

ensity

Bonus P

rogra

m fo

r the C

entra

l City

of P

ortla

nd

inclu

des o

ptio

ns th

at in

centiv

ize G

reen

Roofs

for th

e b

en

efit o

f pub

licly

accessib

le o

n-s

ite o

pe

n s

pace a

nd fo

r sto

rmw

ate

r managem

ent. In

C

hic

ag

o’s

Density

Bon

us P

rogra

m, G

reen R

oofs

are

pro

mote

d to

mitig

ate

the

effe

ct o

f the u

rba

n h

eat

isla

nd a

nd a

ir quality

. GR

AG

is lo

okin

g to

these a

nd o

ther e

sta

blis

hed d

ensity

bo

nus p

rogra

ms fo

r crite

ria a

nd s

tand

ard

s re

latin

g to

gre

en ro

of d

esig

n a

nd

constru

ctio

n.

At th

is p

oin

t, we p

rop

ose th

e fo

llow

ing B

on

us P

rovis

ion

s fo

r Gre

en R

oofs

in th

e D

AP

Density

Bo

nus

Pro

gra

m c

om

para

ble

to P

ortla

nd

an

d C

hic

ag

o:

• 3-5

s.f. o

f bonused flo

or a

rea fo

r each s

.f. of g

reen ro

of (p

lan

ted ro

of is

a m

in. o

f 50%

of

build

ing fo

otp

rint)

The c

urre

nt D

AP

De

nsity

Bonus P

rogra

m p

roposes P

ublic

ly A

ccessib

le O

pe

n S

pa

ce a

s a

Pub

lic B

en

efit

Optio

n w

ith 5

s.f. o

f Bonuse

d F

loor A

rea fo

r each 1

s.f. o

f elig

ible

ope

n s

pace w

ith a

12

00 s

.f. min

imum

. H

ow

ever, n

on-p

ub

licly

acce

ssib

le g

reen

roofs

that w

ou

ld m

itigate

the u

rba

n h

eat is

lan

d a

nd p

rovid

e

sto

rmw

ate

r managem

ent w

ould

no

t fit un

der th

is o

ptio

n.

Founded by C

ongress, R

epublic o

f Texas, 1

839

P.O

. Box 1088, A

ustin

, Texas 7

8767

dylan

Text Box

20

The C

ity of Austin is com

mitted to com

pliance with the A

mericans w

ith Disabilities A

ct. Reasonable m

odifications and equal access to communications w

ill be provided upon request. T

he A

ustin

En

erg

y G

reen

Build

ing (A

EG

B) o

ne-s

tar ra

ting s

yste

m h

as b

een p

ropo

sed a

s a

gate

keeper

require

ment a

nd a

dd

itiona

l density

ma

y b

e o

bta

ined

thro

ugh p

roje

cts

achie

vin

g a

two a

nd th

ree-s

tar

AE

GB

ratin

g. W

hile

the A

EG

B c

urre

ntly

offe

rs p

oin

ts fo

r ve

geta

ted ro

ofs

, costs

associa

ted w

ith th

is

optio

n (w

ith n

o a

dd

ed in

cen

tives) in

com

paris

on to

a re

flectiv

e ro

of o

r oth

er g

ree

n b

uild

ing m

easure

s

effe

ctiv

ely

mean th

at th

e v

egeta

ted ro

of o

ptio

n is

rare

ly c

hosen.

There

fore

, we b

elie

ve

tha

t a s

epara

te G

ree

n R

oof P

ub

lic B

enefit O

ptio

n is

necessary

to p

rom

ote

Gre

en

Roofs

in th

e D

ow

nto

wn a

rea fo

r all o

f the re

asons d

escrib

ed a

bo

ve. T

hank yo

u fo

r consid

era

tion o

f this

re

quest. W

e a

re w

illing to

assis

t you in

whate

ver m

anner is

de

em

ed a

ppro

pria

te to

add G

reen R

oofs

as

a P

ublic

Benefit in

the D

AP

Density

Bon

us P

rogra

m.

Sin

cere

ly,

E

lean

or M

cK

inn

ey, C

hair

Bria

n G

ard

iner, C

o-C

ha

ir

cc:

City

Ma

na

ge

r Ma

rc O

tt A

sst. C

ity M

an

ag

er S

ue

Ed

wa

rds

A

sst. C

ity M

an

ag

er R

ud

y G

arz

a

City

Cle

rk, S

hirle

y G

en

try

dylan

Text Box

21

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ÔÕ

IH-35

Mo-Pac

Lamar

Airport

Cong

ress

Brod

ie

Slaughter

Us Hwy 290

F M 2244

Ben White

5th

William Cannon

Oltorf

12th6th

Southwest

51st45th

Manc

haca

F M 18

26

State Hwy 71

Manor

Sh 45

Capital Of Texas

Cesar Chavez

Bee Caves

Stassney

Enfield

15th

26th

Monto

polis

35th

Riverside

24th

Red R

iver

West

Gate

Koenig

Pleas

ant V

alley

Burne

t

1st

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ÔÕ

Green Roof LocationsFinal Report Case StudiesCity Monitoring Sites

Zarsky Roof

EscarpmentVillage

Wildflower CenterTest Plots

Dell Children'sHospital

StanleyStudio

AustonianCity Hall

Known Existing Known Existing Green Roof LocationsGreen Roof LocationsIn Austin, TexasIn Austin, Texas

°0 2 41 Miles

Known Existing Green Roof Locations in Austin, Texas

Name Address Type Case Study Monitoring

Austin City Hall 301 W. Second St. Institutional Yes

Boyter Bunk House 5125 Bruning Ave. SF Residential

Crescent Riverside Apartments 127 E Riverside Dr MF Residential

Dell Children's Hospital 4900 Mueller Blvd. Institutional Yes

Escarpment Village Starbucks 9600 Escarpment Blvd. Commercial Yes Yes

Great Outdoors Nursery 2810 S. Congress Ave. Commercial

Jefferson 26 600 W. 26th St. MF Residential

Palisades West 6408 Bee Caves Rd. Commercial

Residential Project (approximate location) Barton Springs Rd. and Dawson Rd. SF Residential

Residential Project (approximate location) Mt. Bonnell Rd. and RM 2222 SF Residential

Residential Project (approximate location) Westlake Dr. and Redbud Tr. SF Residential

Ronald McDonald House 1315 Barbara Jordan Blvd. Institutional

Shore Condominiums 603 Davis St. MF Residential

Spring Condominium 300 Bowie St. Mixed Use

Stanley Studio 1901 E M Franklin Ave. SF Residential Yes

The Austonian 200 Congress Ave. Mixed Use Yes

Welch Hall Plaza 2400 Speedway Institutional

West Campus Housing (Cameron House) 2707 Rio Grande St. Mixed Use

West Campus Housing (Montgomery House) 2700 Nueces St. Mixed Use

West Campus Housing (Sterling House) 709 W. 22nd St. Mixed Use

Whole Foods 525 N. Lamar Blvd. Commercial

Wildflower Center Research Plots 4801 La Crosse Ave. Institutional Yes

Zarsky House 9524 Circle Dr. SF Residential Yes Yes

Green Roof Inventory 8/2/2010

55

H. City of Austin Green Roof Monitoring Efforts

In the summer of 2006 the Water Quality Monitoring Section (WQM) of the City of Austin’s (COA) Watershed Protection

Department (WPD) began monitoring runoff quantity and quality from a green roof installed in a shopping center (GRE).

Monitoring began on a green roof installed at a private residence (KZE) the following summer.

Runoff

Runoff measurements from the GRE roof were unsuccessful because the drainage area was ill defined. Runoff ra-

tios (Rv), the ratio of runoff depth to rainfall depth, was often greater than 1, which is not possible. After several

attempts to revive the data, they were determined to be unusable. (This did not affect the runoff concentration

data for the site.)

The runoff measurements at KZE were successful. The average annual runoff ratio from this roof is approximately

0.45, meaning about 45 percent of the rain falling on the roof ends up running off. This is significantly lower—by

about one-half—than the runoff from a conventional roof (which would have a runoff ratio of 0.8-1.0).

Studies at the Lady Bird Johnson Wildflower Center (WFC) indicate the design of a green roof plays a significant

role in the amount of runoff generated from a roof. The KZE event runoff data indicate that the moisture condi-

tions of the roof also play a critical role. As expected, if the rain event is larger than the storage capacity of the

roof, the runoff ratio is increased. This is often the case during rainy periods because the media is at or near its

water holding capacity at the start of rainfall. This may also occur if additional water is applied to the media to

maintain plant growth. Further study of this aspect of green roofs is being started by WFC and WPD.

Water Quality

The other aspect of green roof runoff is the impact on water quality. WPD collected and analyzed runoff samples

for total suspended solids (TSS), volatile suspended solids (VSS), total organic carbon (TOC), chemical oxygen de-

mand (COD), nitrate plus nitrite (NO3 + NO2), ammonia (NH3), dissolved phosphorus (DP), total phosphorus (TP),

cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn). Please see Appendix H for a table detailing the mean runoff

56

concentrations from the two green roofs (assuming lognormal distribution). Concentrations from developed and

undeveloped areas are included for reference only.

The solids concentrations (TSS and VSS) are generally lower than those seen elsewhere, however the proportion

of non-mineral solids (VSS) to the total is higher. This taken with the measured organics in the runoff (TOC and

COD) indicates that there is higher level of organic material (both solid and dissolved) in the runoff from green

roofs.

Nitrogen concentrations in the runoff from green roofs were similar to those observed in runoff from developed

areas with the exception of ammonia, which was low. The DP and TP concentrations for the KZE roof were near

that of runoff from undeveloped areas while the concentrations at GRE were much higher. This difference could

be due to fertilizer applications or the roof medium. In both cases the proportion of DP was higher coming off of

the green roofs.

The concentration of metals (Cd, Cu, Pb, Zn) in the green roof runoff was unremarkable, but it should be noted

that roofing materials will have an impact on the metals concentrations. The following table details total levels of

pollutants on both green roofs as compared to developed and undeveloped areas.

Total Levels of Pollutants on Monitored Green Roofs KZE and GRE

as Compared to Developed and Undeveloped Areas

57

Elevated concentrations of nutrients (defined as chemical elements and compounds found in the environment

used in the growth and survival of plants and animals, such as nitrogen and phosphorus) in runoff from green

roofs has been noted in the past and it has been hypothesized that there is an initial flush of nutrients from the

roof but that it will decrease over time as the roof matures. Please see below for graphs that show the event

Pollutant KZE GRE Developed Undeveloped

TSS (mg/l) 23.9 6 178.8 125.6

VSS (mg/l) 12.4 3.4 34.9 16.5

TOC (mg/l) 19.9 40.9 13.4 10.8

COD (mg/l) 61.6 98.2 80 39.9

NO3+NO2 (mg/l) 0.96 0.58 0.62 0.41

NH3 (mg/l) 0.07 0.08 0.32 0.06

TKN (mg/l) 1.6 1.57 1.7 0.81

TN (mg/l) 2.16 2.05 2.27 1.2

DP (mg/l) 0.09 0.4 0.17 0.04

TP (mg/l) 0.18 0.47 0.4 0.12

Cd (μg/l) 0.07 0.07 0.56 0.54

Cu (μg/l) 8.13 5.9 15.3 5.18

Pb (μg/l) 17 0.23 23.9 3.87

Zn (μg/l) 50 28.5 106.8 20.4

58

mean concentrations of phosphorus (total and dissolved), nitrogen (total and nitrate + nitrite) and TSS over time

as measured at the KZE roof.

There is quite a bit of variability in concentrations from storm to storm and there may be a slight downward trend

in nutrient concentrations. However, there was an increase in 2008. TP appears to have more scatter than the

other parameters. The decrease in concentrations is most notable in the latter part of 2009 and the first part of

2010 in the dissolved parameters (DP and NO2+NO3). This period coincides with the end of a drought and the re-

duction may be due to increased rainfall flushing the media; it is unknown at this time if the concentrations will

return to the previous level with more normal rainfall patterns.

The KZE results appear to parallel those encountered in a green roof study by Penn State University for the US En-

vironmental Protection Agency (EPA). The authors of this work concluded that green roofs could significantly re-

duce the average annual stormwater runoff as compared with conventional roofs (with results very similar to the

KZE roof) and that the runoff could contain high levels of nutrients such that additional polishing by vegetation (in

ground-level landscaping, rain gardens, etc.) was recommended. The authors summarize the water quality find-

ings as follows:

Runoff from green roofs had higher concentrations of most of the nutrients and ions evaluated. From the five pre-

cipitation events monitored, green roof runoff appears similar to what might be expected as leaching from any

other planted system in the landscape…. Results indicate that a green roof will contribute more nutrients (except

nitrate), hardness, salts, and other ions to the roof runoff, due mostly to the use of media and initial composting to

provide nutrients for plants…. Increased loadings of some water quality constituents does not necessarily indicate

that green roofs would increase loadings to receiving waters; however, this would suggest that the green roof as a

stormwater BMP [Best Management Practice] should probably be integrated with other treatment techniques. Ap-

propriate additional treatment, such as routing through a centralized BMP or more appropriately discharging from

the downspout to LID [Low Impact Development] type BMPs, (e.g., swale, bioretention system, rain gardens) could

be recommended for green roof runoff as a part of an overall stormwater system. Green roof runoff could also be

collected and used for ornamental landscape purposes (p. 4-16).

59

Event Mean Concentrations of Phosphorus (Total And Dissolved),

Nitrogen (Total And Nitrate + Nitrite) and TSS Over Time as Measured at Green Roof KZE

0

0.1

0.2

0.3

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28-Apr-07 14-Nov-07 01-Jun-08 18-Dec-08 06-Jul-09 22-Jan-10 10-Aug-10

To

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60

I. Brief Overview of Green Roof Credits and Incen-tives in North America

Boston

Rebate of $5.00/sf up to $100,000

Chicago

0

1

2

3

4

5

6

7

8

9

10


To

tal

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en

(m

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)

0

20

40

60

80

100

120

140

160


To

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So

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s (

mg

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0

0.5

1

1.5

2

2.5

3

3.5

4


Nit

rate

+ N

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te (

mg

/l)

61

Climate Action Plan for 6,000 green roofs by 2020. Over 2.5 million square feet of green roofs installed to date in institutional / commercial arena.

Green Roof Grant Program – up to $5000 to residential and small commercial projects

Density Bonus

Cincinnati

Low interest loans for green roofs

Washington, D.C.

Rebate of $5.00/square feet up to $20,000

Minneapolis

50% stormwater credit for strategies that increase quality of runoff

50% to 100% credit for strategies that decrease quantity of runoff

New York

Tax Credit Incentives

Philadelphia

Tax credit of 50% discount on stormwater charges for residences and businesses

Portland, OR

All new City-owned buildings must have a green roof that covers at least 70% of the roof.

Density Bonus

100% discount of site fee or 35% of total stormwater discharge fee based in management of roof runoff

Tempe, AZ

Green vegetated desert roof counted toward LEED. (While this is not a city program, the green roof was installed on a city building.)

Toledo, OH

Maximum credit of 50% for non-residential

Toronto

62

Eco-Roof Incentive Program provides funding for qualifying green roof projects of $50 per square meter, up to a maximum of $100,000.

Green Roof By-law requires all new institutional and commercial buildings to have green roofs. Graduated cov-erage chart applies.

Vancouver

Density Bonus

Credit for reduction of stormwater if integrated into Stormwater Management Plans

Sewer System Fee Reduction

Mandated requirement on 25% of roof areas in new sustainable development area

Virginia

Reduction in permit fees

Rate incentive based on stormwater reduction

Prepared by Eleanor McKinney, RLA, GRP

J. Recommended Marketing Proposal for Green Roof Educational Initiative and Website

We propose the creation of a green roof educational campaign that will serve the larger Austin community

including policy makers, residents, academia, and developers. It will be a resource for local Austin citizens

and people doing business in the Central Texas region. Currently the City of Austin’s Urban Heat Island Miti-

gation (UHIM) program exists primarily as an education and tree planting program, but this limited scope is

the perfect foundation for an expanded green roof program. With Austin’s progressive policies and pro-

grams in relation to mitigating the urban heat island effect through tree plantings, cool roofs, and eventually

green roofs, Austin could once again be pushing the envelope and setting the bar for other cities to reach

for.

63

Goal

Increase square feet of green roof space in Austin by a percent to be determined, and the local Central

Texas green roof industry by a percent to be determined.

Value to The City of Austin and its Citizens

The value that The City of Austin and its Citizens will derive from the successful development of a green roof

marketing plan will include, but are not limited to:

Educating City staff, policy makers, residents, developers and business owners about the benefits of green roofs in Austin

Providing an easily accessible source of information about existing incentives and policies available for green roofs

Reducing the UHI effect, energy use, carbon foot print, providing space for wildlife, improving air qual-ity, and reducing storm related runoff.

Encouraging the development of a green roof industry in Austin, and supporting the City as “the most livable city in the world” which will help to attract people and business to Austin’s unique, and beau-tiful community.

Objectives

Support the City of Austin’s goal as an environmentally progressive community.

Support the City of Austin’s vision as “the most livable city in the country.”

Educate public and private entities on the benefits of green roofs, and the challenges particular to Aus-tin.

Develop educational/marketing tools such as:

a comprehensive long term marketing plan;

a new Urban Heat Island Mitigation programmatic logo that is inclusive of the re-vegetation programs such as tree planting, and green roofs;

improved UHIM website and development of green roof specific web pages featured within the website;

64

Current UHIM website can be found at: www.cityofaustin.org/urbanheatisland

Outreach materials including a quarter sheet informational insert and an appropriate green roof themed outreach item

Strategies & Deliverables

Create a long term comprehensive educational/marketing plan for the Urban Heat Island Mitigation program with an emphasis on green roofs;

Re-design the existing Urban Heat Island Mitigation website to feature re-vegetation programs cur-rently happening in Austin, and to highlight an expanded section dedicated to green roof resources, Austin-centric green roof information, and the benefits and challenges of green roofs in Austin;

Create a new inclusive UHI programmatic logo

Educational Component:

Educational resource oriented towards policy and decision makers, City staff, and architects, engineers, and developers working

in Austin and the surrounding area.

Website

Brochure or insert

Presentations to the public, City staff, and interested parties.

Outreach Campaign:

The outreach component will promote existing incentives, best practices and green roof benefits specific to Austin.

Create outreach materials like a quarter sheet informational insert;

Production of an appropriate outreach item.

Events:

Austin’s Green Roof of the Year Awards @ the Environmental Awards event

Green Roof Challenge 2010 for residents

UHIM symposium for Central Texas

Advertising:

Mailing Campaign to real estate, architect, policy makers, developers, engineers. Send letter, brochure and magnet. In-

vite to a speakers event and free luncheon.

http://www.cityofaustin.org/urbanheatisland

65

Word of mouth

UHI – Green Roof Logo button on synergistic websites

Articles in local newspaper

Articles in ACPP and Green Building e-newsletter

Austin Energy’s citywide distribution utility newsletter

Partner with weather reporters

Local advertising before movies featuring Urban Heat Island commercial.

Timeline

Year 1 (2011) Year 2 (2012) Ongoing

New green roof web compo-nent to the existing City of

Austin Urban Heat Island web-site.

Austin Green Roof Awards in conjunction with the Environmental Awards Program

Evaluation of goals and strategies of Urban Heat Island re-vegetation of

Austin campaign.

Create comprehensive mar-keting program - strategies for education and outreach, col-

lateral, and partnerships.

Coordinated effort between City departments to develop technical requirements for

website.

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67

L. GRAG Members and Meeting Attendees

Eleanor McKinney, Landscape Architect, Chair

Brian Gardiner, Roofing Consultant, Co-chair

Kathy Zarsky, Sustainability Consultant, Secretary

Fayez Kazi, Civil Engineer

Terry Mitchell, Developer

Dylan Siegler, Sustainability Consultant, Center for Maxi-mum Potential Building Systems

Dr. Mark Simmons, Lady Bird Johnson Wildflower Center

Lauren Woodward Stanley, Architect, Founding Member GRoWERS (Green roof advocacy group)

Blayne Stansberry, Civil Engineer

Dr. Steve Windhager, Lady Bird Johnson Wildflower Center

Staff

Matt Hollon, Watershed Protection, Chair Site Committee

Roger Glick, Watershed Protection

Erin Wood, Watershed Protection

Maureen Scanlon, Austin Energy Green Building, Chair Building Committee

Leah Haynie, Austin Energy, Urban Heat Island

Norman Muraya, Austin Energy

David Greene, Austin Water

Abigail Webster, Austin Water

Peter Davis, Public Works

Council Policy Aides

Marisa Ballas, Council Member Chris Riley, GRAG Sponsor

Andy Moore, Mayor Pro-Tem Mike Martinez, GRAG Co-Sponsor

Glen Coleman, Council Member Randi Shade, GRAG Co-Sponsor

Citizen Attendees

Casey Boyter, Casey Boyter Landscapes + Green Roofs

Drew Sloat, Landscape Architect

Emily Levings, Design for Place/Bercy Chen

Jon Kinder, Prairie Designs

Dave Williams, Prairie Designs

68

M. GRAG Committees

Executive Eleanor McKinney, Brian Gardiner, Matt Hollon, Maureen Scanlon

Site Matt Hollon, Erin Woods, Abigail Webster, Kathy Zarsky, Blayne Stansberry, Eleanor

McKinney, Fayez Kazi, Mark Simmons, Steve Windhager

Building Maureen Scanlon, Norman Muraya, Leah Haynie, Lauren Woodward Stanley, Brian Gar-

diner, Dylan Siegler

Density Bonus Incentives Brian Gardiner, Eleanor McKinney, Blayne Stansberry

Policy and Incentives Matrix Matt Hollon, Maureen Scanlon, Eleanor McKinney, Blayne Stansberry, Dylan Siegler

Performance Matrix Blayne Stansberry, Mark Simmons, Kathy Zarsky, Lauren Woodward Stanley, Peter

Davis, Matt Hollon, Dylan Siegler

Community Outreach Blayne Stansberry, Kathy Zarsky, Brian Gardiner

Five-Year Plan Eleanor McKinney, Matt Hollon, Maureen Scanlon, Kathy Zarsky, Blayne Stansberry

Interim and Final Report/Editing/Graphics

Dylan Siegler, Leah Haynie, Maureen Scanlon, Eleanor McKinney, Blayne Stansberry

1

Exploring Austin G

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June 3, 2010

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70

O. Design Considerations Discussion Summary

Size

For a project to receive incentives and credits from the City of Austin, a certain percentage of the building foot-

print shall be designated as a green or vegetative roof. Higher percentages will correspond to higher credit green

roofs. Further discussion and analysis is needed to determine the minimum percentages and whether percentages

will impact construction costs for certain types of commercial developments that require minimum structural sup-

port, such as large indoor multipurpose spaces. It should be noted that the LEED Rating System offers credit for

green roofs in Sustainable Sites Credit 7.2: “Install a vegetated roof that covers at least 50% of the roof area.”

Soil Depth

There has been significant discussion regarding whether soil depth should be included in the design considera-

tions or inherent in the design of the roof. Varying plant species require differing amounts of soil. For example,

succulents may only need a few inches of soil where as a tree may require a few feet. Specifying a minimum depth

may limit design creativity, especially on roofs where soil weight is problematic. In contrast, specifying a minimum

soil depth will ensure plants have access to a minimum amount of water provided in the moisture holding capac-

ity of the soil. It also provides the developer with a target early in the project design phase for conceptual analysis

of the structural requirements and green roof components.

Plant Cover

Hardscape areas for pedestrian access typically accompany green roof design, particularly where the roof is util-

ized as amenity space. However, the amount of hardscape should not be excessive leaving minimal vegetation.

Therefore, a minimum size or percentage of planting area should be specified. The planting area is the cumulative

total of green roof areas suitable for plant growth, i.e., soil areas.

Plant Variety

The plants on a green roof should be drought tolerant and suitable for growth in the Central Texas climate. At a

minimum, the plant varieties shall not include any species known to be invasive. The group identified the City of

72

Austin Grow Green list of native and adapted species as a comprehensive list of suitable plants for green roof

vegetation. A higher credit roof may strive to achieve restored native habitat by utilizing only native plant species.

Water Use

Supplemental irrigation will be needed for plant survival on a green roof during periods of drought. The irrigation

requirements of a green roof are consistent with the irrigation goals of the Water Conservation 2020: Strategic

Recommendations report dated March 2010. Furthermore, potable water use should, at a minimum, meet the

irrigation requirements of LEED Water Efficiency Credit 1.1 or Austin Energy Green Building Rating Water Point 1a,

both require fifty percent less potable water compared to a baseline system. A higher credit roof may explore

ways to achieve irrigation exclusive of potable water such as rainwater harvesting, HVAC condensate, or gray-

water.

Pest Management and Fertilization

A green roof should follow the typical standards set forth in an Integrated Pest Management Plan (IPM) for a tra-

ditional landscape. The IPM plan may be expanded to become an education tool for maintenance staff on the care

requirements of a green roof. It would strictly control and minimize the use of pesticides, herbicides, and chemical

fertilizers.

Stormwater Retention and Pollutant Removal

A green roof may potentially help meet City of Austin water quality or flood detention requirements. An engineer

would need to demonstrate a reduced a curve number to indicate improved control of peak storm flows during

flooding events. A green roof might be used to address water quality by serving as a component of a larger system

to reduce runoff and pollutant export. For example, if an engineer could show the hydrologic response of the

green roof is similar to 50 percent impervious cover rather than 100 percent impervious roof, credit might be con-

sidered to reduce the size of stormwater controls needed on the site. Additional analysis of the hydrologic re-

sponse of green roofs is currently underway by the Lady Bird Johnson Wildflower Center.

Mulch

73

Mulch is an important component of the landscape design to minimize evaporation of water from the soil. Mulch-

ing on a green roof may include hard wood mulch or a lighter weight lava rock, among other options. Further dis-

cussion is needed to determine if a minimum depth of mulch should be specified in the design considerations to

implement water conservation and plant health.

Visibility and Access

There are varying degrees of green roof access and visibility based on the use and function of the roof. A green

roof may be visible from only a few windows within a building, visible from taller surrounding buildings, or visible

to citizens on the street. Access varies similarly and a green roof can be privately or publicly accessible. A green

roof may be accessible only by maintenance personnel. Access as a private amenity space may be provided only

to tenants within a building. A green roof may also be used a public open space and accessible to the general pub-

lic.

Maintenance Requirements

Access to a green roof for maintenance of plants, soil, and other rooftop equipment is critical. If a project receives

credits or incentives from the City of Austin for a green roof, the project may be required to demonstrate mainte-

nance responsibility, such as an operations and maintenance manual, landscape warranty, or restrictive covenant.

Restrictive covenants may be required for projects where a green roof satisfies parkland or open space require-

ments.

74

P. City of Austin Departmental and Staff Perspective White Paper, Growing Austin’s Living Roofs, December 2008

TO BE ADDED IN DOC FORMAT

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