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A Sustainable Way to Maintain Greenery within a City

Permanent Link: http://ufdc.ufl.edu/UFE0043851/00001

Material Information

Title: A Sustainable Way to Maintain Greenery within a City Using Rain Water Harvesting to Irrigate Vertical Gardens in Singapore
Physical Description: 1 online resource (71 p.)
Language: english
Creator: Pui Hoong, Wan
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2011

Subjects

Subjects / Keywords: rainwater -- sustainable
Architecture -- Dissertations, Academic -- UF
Genre: Architecture thesis, M.S.A.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: As urbanized cities move towards a more compact growth, and land is increasingly being used for building infrastructure and housing for an increasing population, there is a need to allow nature to manifest in urban buildings. Hence, it seems logical to have intensive greening on roofs and on intermediate floors of buildings, along with vertical gardens or living walls. Such green areas can provide food source and habitats for ecosystems such as birds, bees and butterflies, increasing biodiversity, and bringing nature up from the ground. This will also bring people nearer to nature in a city. Since vertical gardens or living walls are relatively new and can be provided as freestanding structures on land, as well as wall mounted on buildings, it would be an interesting topic to find out the extent of its use, policies that may encourage its use, ways of irrigating the plants, the appropriate plant selection, visual value added and the barriers to maintaining them. Case studies on projects completed in the United States and Singapore, as well as surveys done by practitioners, and the general public in Singapore will be used to provide information on the research. This study will focus on using rain water harvesting to irrigate vertical gardens as a sustainable way to maintain greenery within a city such as Singapore and in Florida since they have similar climates.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Wan Pui Hoong.
Thesis: Thesis (M.S.A.S.)--University of Florida, 2011.
Local: Adviser: Tilson, William L.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2011
System ID: UFE0043851:00001

Permanent Link: http://ufdc.ufl.edu/UFE0043851/00001

Material Information

Title: A Sustainable Way to Maintain Greenery within a City Using Rain Water Harvesting to Irrigate Vertical Gardens in Singapore
Physical Description: 1 online resource (71 p.)
Language: english
Creator: Pui Hoong, Wan
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2011

Subjects

Subjects / Keywords: rainwater -- sustainable
Architecture -- Dissertations, Academic -- UF
Genre: Architecture thesis, M.S.A.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: As urbanized cities move towards a more compact growth, and land is increasingly being used for building infrastructure and housing for an increasing population, there is a need to allow nature to manifest in urban buildings. Hence, it seems logical to have intensive greening on roofs and on intermediate floors of buildings, along with vertical gardens or living walls. Such green areas can provide food source and habitats for ecosystems such as birds, bees and butterflies, increasing biodiversity, and bringing nature up from the ground. This will also bring people nearer to nature in a city. Since vertical gardens or living walls are relatively new and can be provided as freestanding structures on land, as well as wall mounted on buildings, it would be an interesting topic to find out the extent of its use, policies that may encourage its use, ways of irrigating the plants, the appropriate plant selection, visual value added and the barriers to maintaining them. Case studies on projects completed in the United States and Singapore, as well as surveys done by practitioners, and the general public in Singapore will be used to provide information on the research. This study will focus on using rain water harvesting to irrigate vertical gardens as a sustainable way to maintain greenery within a city such as Singapore and in Florida since they have similar climates.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Wan Pui Hoong.
Thesis: Thesis (M.S.A.S.)--University of Florida, 2011.
Local: Adviser: Tilson, William L.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2011
System ID: UFE0043851:00001


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1 A SUSTAINABLE WAY TO MAINTAIN GREENERY WITHIN A CITY: USING RAIN WATER HARVESTING TO IRRIGATE VERTICAL GARDENS IN SINGAPORE By WAN PUI HOONG A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIA L FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN ARCHITECTURAL STUDIES UNIVERSITY OF FLORIDA 2011

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2 2011 Wan Pui Hoong

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3 To my parents friends and colleagues

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4 ACKNOWLEDGMENTS Firstly, I would like to thank my parent s for their guidance, support and hard work in bringing me up to be a good citizen of the world. Secondly, I would like to thank my committee members Professor William Tilson and Dr. Dawn Jourdan for their invaluable advice, encouragement and their tireless efforts made throughout th e writing of this thesis Additionally, I would also like to thank Mr Michael Kung for his help in resolving technical issues during the course. Next, I would like to thank my friends, fellow classmates and colleagues for thei r opinions and support throughout the course. Lastly, I would like to thank the University of Florida and the entire College of Design, Construction and Planning for the uniquely international experience in studying together with people living in different time zones.

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5 TABLE OF CONTENTS page ACKNOWLEDGMENTS .................................................................................................. 4 LIST OF TABLES ............................................................................................................ 7 LIST OF FIGURES .......................................................................................................... 8 LIST OF ABBREVIATIONS ............................................................................................. 9 ABSTRACT ................................................................................................................... 10 CHAPTER 1 INTRODUCTION .................................................................................................... 12 2 LITERATURE REVIEW .......................................................................................... 18 Policies, Legislatures and Formal Certification ....................................................... 18 Policies and Law for Water Management and Water Supply .................................. 18 Water Restrictions ............................................................................................ 18 Floridas Water Law .......................................................................................... 19 Water Supply and Water Resource Development in Florida ............................ 20 Water Supply and Alternate Sources of Water in highly urbanized Singapore ...................................................................................................... 21 Legislature on Water Conservation and Ways to Conserve Water ......................... 22 Landscaping ..................................................................................................... 22 Built Environment ............................................................................................. 23 On Water Use and Efficiency Requirements for Formal Certification ..................... 24 Wastewater Goals, Objectives and P olicies ............................................................ 26 Legislation on Environmental Sustainability for Buildings in Singapore .................. 27 Summary ................................................................................................................ 27 Case Studies .......................................................................................................... 29 Green Roofs and Brown Roofs ......................................................................... 29 Comparative environmental life cycle assessment o f green roofs .................... 31 Vertical Green .................................................................................................. 31 Green wall systems, living walls and vertical gardens ...................................... 32 Florida friendly Landscaping ............................................................................ 34 Summary ................................................................................................................ 35 3 METHODOLOGY ................................................................................................... 41 Research Approach ................................................................................................ 41 Survey in Singapore ............................................................................................... 41 Best Approaches for Creating Vertical Gardens ..................................................... 42

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6 Policies, Legislatures and Formal Certification ....................................................... 44 Summary ................................................................................................................ 45 4 DISCUSSION AND ANALYSIS .............................................................................. 46 Data from Surveys .................................................................................................. 46 Survey from general public in Singapore .......................................................... 46 Survey from irrigation specialists ...................................................................... 47 Data from Best Approaches for Creating Vertical Gardens ..................................... 48 Analysis .................................................................................................................. 52 Research Limitations .............................................................................................. 57 5 CONCLUSION ........................................................................................................ 58 APPENDIX A QUESTIONNAIRE FO R THE GENERAL PUBLIC IN SINGAPORE ....................... 64 B QUESTIONNAIRE FOR THE IRRIGATION SPECIALIST IN THE UNITED STATES OF AMERICA AND SINGAPORE ............................................................ 66 LIST OF REFERENCES ............................................................................................... 68 BIOGRAPHICAL SKETCH ............................................................................................ 71

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7 LIST OF TABLES Table page 4 1 Tabulation of survey results from the general public .......................................... 46 4 2 Tabulation of survey results from irrigation specialists ....................................... 47

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8 LIST OF FIGURES Figu re page 4 1 Column Chart of survey results from the general public ..................................... 46 4 2 Column Chart of survey results from irrigati on specialists .................................. 47 5 1 View of vertical garden near a collection pond ................................................... 62 5 2 Section of vertical garden showing proposed irrigati on system .......................... 63

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9 LIST OF ABBREVIATION S BCA Building and Construction Authority DEP Department of Environmental Protection IFAS Institute of Food and Agricultural Sciences LCA Life cycle assessment LEED Leadership in Energy and Environmental Design LID Low impact development LIUDD Low impact design and development MEWR Ministry of the Environment and Water Resources N EA National Environment Agency NParks National Parks Board Pte. Ltd. Private Limited PUB Public Utilit ies Board RO Reverse osmosis

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10 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science in Architectural Studies A SUSTAINABLE WAY TO MAINTAIN GREENERY WITHIN A CITY: USING RAIN WATER HARVESTING TO IRRIGATE VERTICAL GARDENS IN SINGAPORE By Wan Pui Hoong December 2011 Chair: William Tilson Major: Architecture As urbanized cities move towards a more compact growth, and land is increasingly being used f or building infrastructure and housing for an increasing population, there is a need to allow nature to manifest in urban buildings. Hence, it seems logical to hav e intensive greening on roofs and on intermediate floors of buildings, along with ver tical gardens or living walls Such green areas can provide food source and habitats for ecosystems such as birds, bees and butterflies, increasing biodiversity, and bri nging nature up from the ground. This will also bring people nearer to nature in a city Since vertical gardens or living walls are relatively new and can be provided as freestanding structures on land, as well as wall mounted on buildings, it would be an interesting topic to find out the extent of its use, policies that may encourage its use, ways of irrigating the plants, the appropriate plant selection, visual value added and the barriers to maintaining them. Case studies on projects completed in the United States and Singapore, as well as surveys done by practitioners and the general pu blic in Singapore will be used to provide information on the research. This study will focus on using rain water harvesting

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11 to irrigate vertical gardens as a sustainable way to maintain greenery within a city such as Singapore and in Florida since they hav e similar climates

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12 CHAPTER 1 INTRODUCTION Located along the equator, Singapore has a tropical climate where the temperature remains relatively constant. As for Florida, North and Central Florida has a humid subtropical climate, while South Florida has a tropical climate. Hence, i t seems appropriate to consider Florida and Singapore in this research since both have similar climate. As weather conditions are changing rapidly due to global warming, there is an urgent need to develop sustainable designs as m ean sea level rises, population increases, cities become denser and rainfall patterns change. Sharockman (2010) reported that a congressman from Bartow in Polk County, Adam Putnam said, The most important issue facing Florida long term is water -whether you want to plant an orange grove, build a sub division, save the Everglades ... it all boils down to water. He also added, "We've got to find 2 billion gallons (of water per day) between now and 2025" (Sharockman, 2010). Assuming that the population will reach 25 million by 2025, the state Department of Environmental Protection (DEP) projected that the state will require 8.7 billion gallons a day (Sharockman, 2010), which is an increase of 1.8 billion gallons per day, or 27 percent (Sharockman, 2010). This figure is close to Putnams 2 billion gallons a day. Measures are taken by the five water management districts to add reclaimed water and deminerali z e brackish water to ensure that there is sufficient water supply to maintain Floridas image of prist ine beaches, freshwater springs, and unique fishing opportunities. However, an increase in population is not the only issue that affects water supply, drought also affects water supply.

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13 The drought issue surfaced about four months after Putnams message. T his time it involved a drought resulting in low water levels in lakes that supply drinking water to communities, farming and plantations. Reid (2011) reported, Lake Okeechobee's declining water level once again threatens to generate water supply ripple ef fects throughout south Florida leaving less water for thirsty crops and lawns as well as an ecosystem trying to rebound from years of abuse. Apparently the water level was already two feet below average, and if it dropped to 10.5 feet above sea level, it would be too low for gravity to fill the drainage canals that send lake water south to suppl e ment irrigation for hundreds of thousands of acres of sugar cane and other crops in the Everglades Agricultural Area (Reid, 2011). However, the temporary pumps t hat will be used to keep the lake water flowing south do not transport enough water to meet the water needs of the crops. In order to prevent the water level from falling to the point where temporary pumps have to be used, water restrictions were imposed. Indeed, the urgency is evident, carbon dioxide emissions have to be reduced quickly to help slow down rapid changes in weather conditions, and water, as a natural resource, has to be conserved, recycled and reused. With an increasing population, urbanized cities need to curb urban sprawl and move towards a more compact growth so that with good mass trans it systems and walkable neighborhoods, there will be less reliance on vehicular travel and hence, less carbon emissions. Along with that, a good stormwater management will also help to replenish water aquifers and allow water to be reused for irrigation and washing purposes.

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14 In sustainable landscape designs, the focus seems to be on rain water harvesting, slowing down stormwater runoff, carbon sequestration, reducing heat island effect, maximizing land use within buildings and providing places for ecosystems to survive and thrive. As an alternative to traditional stormwater management, a low impact development (LID) allows cleaned water to go back to the ground. Landscape practices such as using pervious materials for pavements and footpaths, grassed swales for water conveyance, bioretention ponds or rainwater gardens and intensive green roofs are on the increase. The former allowed water to go back to the gr ound, while the latter actually helped to remove some metal pollutants from the polluted water before returning cleaned water to the ground. In colder climates, there seemed to be concerns of frosting in pervious pavements and bioretention ponds. However according to Dietz (2007), pervious pavements and bioretention have been found to work effectively in cold climates, with frost in the ground. Proper base design and installation are critical to this function. Hence, LID practices can be used almost ev erywhere except for places with high contaminants and brownfield areas. This may be more applicable to the occasional colder periods in cooler North Florida than in Central and South Florida. As with any planted areas, excessive use of fertilizers, pestic ides and herbicides can pollute the water systems, so great care has to be taken to ensure that only appropriate amount of such chemicals are applied when required. This can be done by providing training on maintenance to personnel and the public. In ot her parts of the world such as Australia and New Zealand, similar landscape practices known as low impact urban design and development (LIUDD) are used. The

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15 trend is to decentraliz e water treatment plants so that neighborhoods can easily use wastewater to irrigate planting areas and for industrial use. With reclaimed water from sewage effluent and storm water, there will be less demand on potable water for garden watering, public open space irrigation, car washing, firefighting and toilet flushing (Roon, 2007). By having onsite / localiz ed sewage treatment plants and using rain gardens, wetlands, rainwater collection tanks and ponds, better quality water can be put back to the ground, instead of discharging sewage effluent and stormwater straight to natural waters. Even if there is no water shortage, the management of water from rooftops, lawns, driveways, parking lots, and roads (known as nonpoint source pollutants), has become critical to the ecosystem health of rivers and oceans and to the industries t hat harvest fish and shellfish (Hill, 2009). Urban water pollution has become significant with an increasing population, and if untreated water goes straight to the natural waters, aquatic ecosystems will be affected. Rainwater runoff has to be dealt with through wetlands, rain gardens, green roofs and restored shoreline edge/water bodies. Basically, constructed urban landscapes should act as ecosystems to emulate the natural hydrologic process of water flow to downstream lakes/water bodies. As such, since more buildings occupy the land in cities as population increases, having intensive greening on roofs and on intermediate floors of buildings, along with vertical green walls or living walls seem to be in sync with the focus on stormwater management pract ices. After all, rainwater runoff on the roof will have an effect on downstream lakes/water bodies The natural process of plants taking in carbon dioxide and giving out oxygen not only reduces carbon dioxide but also allow all the ecosystems

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16 to breathe better. Besides, such planting areas may provide habitats and food sources for some ecosystems to survive and thrive above ground level. Facing similar issues, Singapore planned to ensure a sustainable water supply as she has limited natural water resources Due to rapid industrial, economic and social developments over the last few decades, demand for water has increased faster than the population growth. The Ministry of the Environment and Water Resources (MEWR) stated that Singapore's current per capita domestic water consumption is about 154 litres per day Our long term target is to bring down our daily per capita domesti c water consumption to 147 liters by 2020, and 140 liter s by 2030. According to the national water agency, the Public Utilities Board (PUB), the four sources of water are from local catchment s of seventeen reservoirs (covering about two thirds of land area by end 2011) imported water from two water agreements with Malaysia, NEWater which is reclaimed water, and desalinated water. As th e first water treat y with Malaysia expired in August 2011, and with the second one expiring in 2061, there is a need to rely more on reclaimed water and rainwater for water supply. Everyone is encouraged to reduce, reuse and recy cle water through installin g water efficient fittings using water efficient products for cooling systems, irrigation, swimming pools, and preventing leakages in plumbing systems. Unlike Florida, there are no water restrictions in Singapore for watering planting areas. Although ther e is no water shortage currently, nonpotable water is used extensively such as for watering planting areas, so that potable water can be saved for drinking Rainwater and used water are actually collected in separate systems. Surface

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17 runoff is collected from drains, canals, rivers and stormwater collection ponds and channeled into the reservoirs. With a land area of 712.4 square kilometers Singapore has a total population of approximately 5.2 million currently As she becomes more densely populated, land is infilled with buildings, and the authorities and developers are beginning to practice LID and stormwater management more extensively. Waterways were cleaned up so that they can also serve as recreational areas for water sports activities as land remains limited. Despite being a highly urbanized city state, Singapores vision is to be a City in a Garden ( Tan, Chiang, Chan, Wong, Chen, Tan, Wong, 2009) and pockets of open spaces can still be found. More roof gardens and sky terraces now sit on the roof s and intermediate levels of commercial buildings respectively, and recently on some residential buildings, such as The Pinnacle. Increasingly, vertical green walls are seen along Orchard Road and mounted on the walls of buildings. These help to mitigate t he urban heat island effect, provide more biodiversity and carbon sequestration, and improve the well being of people by bringing nature closer to their workplace and homes. Since green roofs and the relatively new vertical green walls or living walls can be established on buildings, it would be interesting to find out the extent of its use and the policies that may encourage its use. In the wake of water shortage due to higher demands and droughts, it would be important to find out ways of using rain water harvesting to irrigate the plants during dry seasons/droughts, the appropriate plants that require less water to survive, visual value added and the barriers to maintaining them.

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18 CHAPTER 2 LITERATURE REVIEW Policies, Legislatures and Formal Certification Most people always take the continuous supply of natural resources as given and indefinite. However, years of excessive use, increasing demands (due to an increasing population), pollution and more frequent droughts (due to changes in weather patterns) have shortened the supply of such resources like land, fossil fuel and water. It is imperative that water is managed properly and efficiently for the survival of all ecosystems. Policies and Law for Water Management and Water Supply Water Restrictions When w ater shortage occurs, water restrictions may be imposed in counties even for the watering of lawns. In certain places where potable water is used, watering of lawns is allowed once a week at designated times and days. However, some places within city limit s may use potable water to water their lawns twice a week at designated times and days. Perhaps lawn areas within the city are smaller compared to those outside the city, thus allowing them to water twice instead of once a week. The same applies to people who use reclaimed water. These are done using sprinkling cans, a handheld hose equipped with automatic shutoff nozzle, or a hose equipped with a portable sprinkler (Pasco Times, 2011). Other planting areas, however, are allowed to be handwatered anytime. These restrictions help to reduce the excessive use of water on planting areas, and can still be imposed even during times when there is sufficient water for everybody. However, water

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19 restrictions alone will not be able to curb excessive water use, other policies and laws are required for better water management. Floridas Water Law As part of a national movement, Florida went for a second wave of water reform in 1972 as one of the states that undertook a comprehensive reform, adopting detailed water codes that largely replace the common law (Klein, Angelo & Hamann, 2009). Historically, United States has the common law of water allocation systems for r i parianism and prior appropriation. The wetter eastern states followed the torts regime for riparianism, so land owners have equal right to use water within their own riparian land next to any water bodies such as a stream or a lake. In contrast, the dryer western states followed the traditional prior appropriation approach where the owner of a property can actually transport water from a natural watercourse elsewhere for beneficial use without waste. It worked on a system of priority rather than on equal share. Nevertheless, these two doctrines are the cornerstones for modernized water law. Traditionally fol lowing the common law of water allocation systems for r i parianism, the modernized Florida water law defined water as a public resource and permits have to be obtained for the right to use water. Permits are issued only if the applicants can show, among oth er things such as reasonablebeneficial use, evidence that their use is consistent with public interest. Permits last for twenty to twenty five years and have to be renewed for continued use of the natural resource. In times of emergency or water shortage, permit holders are not allowed to use up all their allotment of water in view of public interest. Moreover, permits can be revoked for a variety of reasons to safeguard public interest.

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20 The modernized Florida water law places great emphasis on the welfare of the community over individuals, and allows reviews of water management through the issuing of permits. Water Supply and Water Resource Development in Florida Florida gets her water supply from groundwater, surface water and desalination water. As thes e three sources of water need to be treated to potable water quality, costs incurred should be transferred to the people who benefit from using them. In line with the water management districts' core functions, and consistent with mee t ing the dual statutor y directives (Bilenky, 2009), such water supply development projects should be funded using local funding sources. Although it seems feasible to have local facilities to supply water and handle wastewater disposal due to their close proximity to users, is sues like having a low supply of groundwater and surface water in some areas, and stopping of discharges of treated effluent into water bodies as it has hit the maximum allowed under the law, cannot be resolved locally. It seems to indicate that using a regional supply authority for such utility services is more economically viable. Besides, for drought proof water supplies (Bilenky, 2009) that require alternative water supply such as desalination and treated wastewater, it may mean that water can be suppli ed at a cheaper rate due to the economies of scale that only the regional supply authority can offer. It will also be easier to justify for an increase in rate due to an increased cost of providing such a utility service. The water, although treated by a r egional supply authority, still belongs to the people of Florida. Despite the assurance on the quality of reverse osmosis ( RO ) treated water, Florida has not accepted the use of tertiary treated wastewater as an alternative potable

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21 water supply, although the cost of treating wastewater is only twothirds the cost of treating seawater or brackish water to potable water quality. However, Orange County has approved the construction of an RO facility in January 2008. Such facilities are also tested out in Texas, Australia and Singapore (Bilenky, 2009). Water treated this way can be used for commercial and industrializ ed needs. Increasingly, such water has been released in small quantities into reservoirs in Singapore for drinking. Water Supply and Alternate Sources of Water in highly urbanized Singapore In the small city state of Singapore, water supply comes from seventeen reservoirs that are water storages from urban stormwater runoff, imported water from neighboring Malaysia that will end in 2011 and 2061, r eclaimed water from treated used water purified to potable water quality, and desalinated water from treating seawater. The national water agency, Public Utilit ies Board (PUB) stipulates that water is for the community to use, and should be conserved and valued even as we use the reservoirs for recreational activities to maximize land use. To satisfy the needs of an increasing population, alternate sources of water will com e from rainwater harvesting, gre ywater recycling and seawater reuse (PUB, 2011). Ra inwater harvesting systems and underground tanks can be built by developers solely for their own nonpotable use such as toilet flushing and washing. They will have to pay a waterborne fee, just like the other domestic and industrial / commercial users, so that the used water can be treated and disposed properly. As rainwater collection systems are potential mosquito breeding sources (PUB, 2011), care has to be taken to abide by the National Environment Agencys (NEA) guidelines on mosquito prevention. Gre ywater from bathtubs, wash basins, showers and laundry can be treated for

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22 nonpotable use also. As for industries located near the sea or on offshore islands, PUB encourages the use of seawater for cooling and process use (PUB, 2011). As such, alternative sources of water can help reduce the reliance on potable water for washing, cooling and processing for industrial / construction purposes, leaving more potable water for consumption. Legislature on Water Conservation and Ways to Conserve Water Landscaping In Senate Bill 2080, Section 373.185, Florida statutes, stated that Floridafriendly landscaping involving principles such as planting the right plant in the right place, efficient watering, appropriate fertilization, mulching, attraction of wildlife, r esponsible management of yard pests, recycling yard waste, reduction of stormwater runoff, and waterfront protection (Senate Bill 2080, 2009) helps in water conservation and environmental protection. In view of publics interest in protecting water resourc es, each water management district has to encourage the county or municipality of the state to adopt Floridafriendly landscaping for development permit through incentive programs. In order for a development permit to be issued, the local ordinance must i nclude proper practices for landscape planning (that preserves natural vegetation), design, installation and maintenance that result in savings of water. This includes plant groupings that do not use exotic plant species, soil analysis, appropriate solid w aste compost, minimizing or efficient use of irrigation, and other practices that help to conserve water. There should also be a minimum use of appropriate turf and impervious surfaces. To ensure that this is complied, the development has to be monitored. As landscape irrigation requires quite a lot of water, Section 373.228, Florida statutes on landscape irrigation design, stated that the water management districts

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23 should work with the other stakeholders in the landscape industry to develop design standar ds for Floridafriendly landscaping and irrigation, including drip irrigation for plants, trees, sod and other landscaping (Senate Bill 2080, 2009). The irrigation codes should be in line with the Florida Building Code, Plumbing Volume, Appendix F. Such co des would have to be adhered to by public water suppliers when applying for water use permits. Furthermore, in Section 125.568, Florida statutes on conservation of water, it stated that Floridafriendly landscaping should be implemented as part of water conservation and water quality protection and restoration planning (Senate Bill 2080, 2009) to ensure sufficient water supply for the community. No law can prohibit anyone from implementing Floridafriendly principles of design. Built Environment Measures taken in the built environment to conserve water include more stringent plumbing fixtures, using water efficient appliances and using plants that require less water. Other possibilities include replacing potable water with nonpotable water for washing floors, flushing toilets and irrigation to reduce the demand for potable water. For wetter areas, rainwater harvesting, along with low impact development s such as using permeable materials, rain gardens and green roofs (Gonchar, 2009) can help to slow down rainwater runoff. Ponds with plants that can remove nitrogen and phosphates can help to clean the water before being channeled to water storage tanks for future use. As shown by Emory University in Atlanta in 2010, reclaimed water from greywater within a bui lding can also be recycled for nonpotable use (Gonchar, 2009). At the Omega Center for Holistic Studies, in Rhinebeck, New York, an Ecomachine that uses beneficial bacteria, plants, fish and other organisms (Gonchar, 2009)

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24 to treat wastewater and retur n the clean water to the aquifer and a lake nearby was built. Part of the treatment process is housed within a classroom and a small laboratory for students and guests to experience hands on study of the process. Other places such as Vancouvers waterfront convention center uses reclaimed water as well from grey water and desalination. In Atlantabased Eco Office, rainwater harvesting is used in a spray system to cool the ambient temperature. Conserving water is also a means of saving energy. On Water Use and Efficiency Requirements for Formal Certification The LEED for Neighborhood Development Rating System is the first system for neighbourhood design in the United States. It incorporates the principles of smart growth, urbanism and green building ( U.S. Gre en Building Council, 2011). In this rating system, the criteria are listed under five sections Smart Location and Linkage, Neighborhood Pattern and Design, Green Infrastructure and Buildings, Innovation and Design Process, and Regional Priority Credit. T here are four awards Certified, Silver, Gold, and Platinum. Criteria such as Building Water Efficiency, and Water Efficient Landscaping are under the Green Infrastructure and Buildings section that carries a maximum of 29 points. Both Building Water Effi ciency and Water Efficient Landscaping carry 1 point each. Under Building Water Efficiency for non residential buildings, mixeduse buildings, and multifamily residential buildings four stories or more ( U.S. Green Building Council, 2011), indoor water usag e in new buildings and those undergoing renovations have to be on average 40% less than in baseline buildings. The calculations are based on occupants who use fixtures such as toilets, urinals, lavatory and kitchen faucets, and

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25 showerheads. For Water Effic ient Landscaping, the emphasis is on not using or limited use of irrigation. Water consumption for landscape irrigation has to be reduced by 50% from a calculated midsummer baseline case ( U.S. Green Building Council, 2011). Under Singapores Building and C onstruction Authority (BCA) Green Mark scheme, the assessment criteria involved five sections Energy Efficiency, Water Efficiency, Environmental Protection, Indoor Environmental Quality, and Other Green Features and Innovation (BCA, 2011). Like LEED, there are four awards Certified, Gold, GoldPlus, and Platinum. The considerations for new nonresidential buildings under the section on Water Efficiency, are water efficient fittings, water usage and leak detection, irrigation system and landscaping, and w ater consumption of cooling towers. At a maximum score of 17 points, water efficient fittings carry 10 points, irrigation system and landscaping carries 3 points, while water usage and leak detection, and water consumption of cooling towers each carries 2 points. There are fewer considerations for new residential buildings under Water Efficiency. They are water efficient fittings, water usage monitoring, and irrigation system and landscaping. At a maximum score of 14 points, water efficient fittings carry 1 0 points, irrigation system and landscaping carries 3 points, while water usage monitoring carries 1 point. For both new nonresidential and residential buildings, water efficiency for irrigation system and landscaping requirements include using rainwater or recycled water for irrigation and use of plants that require less water. Out of a maximum of 3 points, 1 point is awarded for the use of nonpotable water (including rainwater) for

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26 irrigation, with the second point awarded for efficient use of irrigation system with rain sensor that covers at least 50% of landscape areas, and the last point is awarded for using drought tolerant plants that require minimal water covering at least 80% of landscape areas. Wastewater Goals, Objectives and Policies According to the City of Orlando Growth Management Plan Policy Document on Wastewater Element (2009), the two goals are to provide efficient and economic wastewater services in a safe manner at an affordable price, and to reduce the environmental impacts of the was tewater system on land and water resources. Several policies are set up to ensure that the following eight objectives are met: 1. R evenues and expenditures are monitored to maximize cost efficiency in wastewater management 2. C hecks on capacity of the systems being within limits are done through regular checks and maintenance of collection system 3. D uplication of services is reduced by adhering to the City of OrlandoOrange County Wastewater Service Territorial Agreement 4. Ensure that i nfrastructure of sewage and wastewater systems are in working condition through monitoring and maintenance. 5. D elineating wastewater system to allocate surpluses to encourage infill development 6. E valuate need to modify effluent utilization practices at existing facilities 7. E xtend the possibility of using existing water reuse programs to other urban areas 8. I ncrease public awareness on the importance of wastewater treatment and proper effluent utilization. As more people use treated wastewater for nonpotable water use, the stress on potable water supply can be reduced.

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27 Legislation on Environmental Sustainability for Buildings in Singapore The Building Control (Environmental Sustainability) Regulations not only apply to all new buildings with a gross floor area of 2000 square m eter s or more, but also apply to additions or extensions to existing buildings by a gross floor area of 2000 square m eters or more, and also apply to major retrofitting works to existing buildings with a gross floor area of 2000 square m eters or more (BCA, 201 0). For both new nonresidential and residential buildings, the minimum environmental sustainability standard involves five categories Energy Efficiency, Water Efficiency, Environmental Protection, Indoor Environmental Quality, and Other Green Features. The scoring system is similar to the BCA Green Mark Scheme. A maximum score of 190 points can be awarded for new nonresidential buildings, while a maximum score of 155 points can be awarded for new residential buildings. The Green Mark score has to be submitted as part of the requirement for Building Plan (BP) approval, before Temporary Occupation Permit (TOP) or Certificate of Statutory Completion (CSC) stage (if there is no TOP application). A minimum of 50 points has to be achieved to get BP approval. S ummary With more frequent droughts and water shortages, it is increasingly difficult to meet the increased demand for water. In most cases, water restrictions for landscape irrigation can be implemented even when there is sufficient water supply, while ot her measures such as using treated wastewater and grey water for nonpotable water use will help free up potable water for consumption and medical purposes. For activities near the sea, desalination and reusing seawater for industrial cooling and processing will help to reduce reliance on potable water. Having a water law that allocates permits

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28 with fixed renewal intervals to applicants based on public interest and needs will allow flexibility in assessing water needs periodically. Along with the use of wat er efficient fixtures and appliances, the use of rainwater harvesting, rain gardens, permeable materials, green roofs and drought resistant plants in an urban context also help to conserve water. The laws, policies and regulations implemented help to enfor ce that. Although roof gardens and vertical gardens can be implemented if desired, restrictions such as structural loading and budget for a development seem to pose some deterrence for their implementation. Since roof gardens are accessible for maintenance the plants can still be maintained and watered. For vertical gardens, there is a need to have access to them for as high as they go, so that dead plants can be replaced to maintain a healthy looking vertical garden. As such, there is a dire need to locat e platforms at each floor to access the vertical garden. Besides, an irrigation system has to be installed to water the plants as required, so some maintenance checks have to be done to ensure the normal functioning of the system. For aesthetics and safet y reasons, access to the vertical gardens should be designed as part of the building, and not as an afterthought. It is probably easier to implement roof gardens in new buildings than in existing buildings due to loading requirements. In Singapore, vertical gardens have been installed on the walls on an existing building such as the BCA Zero Energy Building. Hence, it seems feasible to install vertical gardens in both new and existing buildings. However, it remains to be seen if disturbances on the surface of the wall, onto which the vertical garden is mounted, will affect the growth of the plants. If the vertical garden uses a modular system for growing

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29 the plants, then those modules can be removed to allow repair for the wall. After which, new plants can b e replaced and the modules placed back at their original locations in the modular system. Case Studies As water becomes a scarce resource, everyone should find ways to conserve water. In order to bring nature to urban cities, greenery is placed on roofs and walls to provide a naturally greener environment and reduce ambient temperature, provide ecosystem services and carbon sequestration. Plants need water to grow and thrive, but just how much water do plants require and will there be sufficient water for urban cities to enjoy having greenery in their environment? Green Roofs and Brown Roofs Generally, green roofs are intentionally vegetated roofs. They can be classified primarily into extensive or intensive green roofs. However, some countries, such as the United Kingdom, have semi intensive (or semi extensive) green roofs as well (Livingroofs, 2011) With reference to the table on General Features of the Green Roof Type (Livingroofs, 2011) under Introduction to Types of Green Roof the soil depth for inte nsive green roofs is 150400mm, smaller trees requiring minimum soil depths of 1000mm can be planted on green roofs in Singapore. It all depends on the live load allowed for the building. Intensive green roofs tend to allow people to use the space designe d within green areas, and require maintenance and irrigation during dry seasons. In contrast, extensive green roofs are typically accessible only to maintenance staff, and require minimal maintenance and little or no irrigation due to its shallow substrate.

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30 Although green roofs are increasingly being built, barren roofs can also be used for brown roofs. These are vegetated roofs that have organic soil, commercial crushed brick or other porous type substrate, a nd plants that encourage biodiversity. In this case, the selection of plants is directed to specific vulnerable species that need to be protected from human or animal interference on the ground. They allow urbanized cities to make up for habitats lost during development and to use barren areas to incr ease biodiversity. The reused material that is part of the substrate should have known water storage and quality that will allow plants to survive. Both green and brown roofs help to improve air quality in congested cities. To provide decorative walls that have a softer facade, green walls or living walls are also getting popular. They are wall systems with media that allow plants to grow vertically with little or no maintenance, and can be freestanding structures. With suitable species selection, heights of up to 25m can be attained additionally if plants can be grown in large irrigated containers at height, then even greater heights can be reached (Livingroofs, 2011). Walls lined with climbers can have temperature fluctuations at the wall surface reduced from between 10/14F to 60C/140F to between 5C/41F and 30/86F (Peck et al 1999). They can protect the surfaces of buildings from heavy rainfall and hail, as well as temporarily intercept and hold rainwater. In temperate countries, evergreen c limbers can protect the building from wind chill by providing an air pocket between the plants and the wall, and also reduce the wind chill on wall surfaces, thus reducing energy consumption.

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31 Comparative environmental life cycle assessment of green roofs This case study involves a conventional ballasted roof, an intensive and an extensive green roof of an actual 1,115 square m eters (12,000 square feet ) green roof project on a retail store in Pittsburgh, PA, USA ( Kosareo & Ries, 2007). The life cycle assessment (LCA) will help determine the best environmentally preferable choice of roof for buildings. As for transportation, the materials for the conventional roof are found locally near the site, while the additional materials specific to the green roofs ar e acquired from Dayton, Ohio and Charlotte, North Carolina. Based on Figure 3 and Figure 4 in the journal the intensive green roof has the least impact among the three types of roofs. Figure 5 to Figure 7 in the journal indicated that the intensive green roof required the least additional en ergy of the three roof options. Hence, although intensive green roofs cost more to build due to loading requirements, they are the environmentally preferable choice when constructing a building due to the small reductio n in energy demand and the increased life of the roofing membrane ( Kosareo & Ries, 2007). Vertical Green When it comes to vertical green, Patrick Blanc comes to mind. Born in 1953, France, Patrick has been building vertical gardens on public and commerci al buildings, hotels, restaurants, lounges, museums, art exhibitions and private places since 1988. He is a botanist who gets his inspiration from nature and is known as the creator of vertical garden. His Vegetal Wall is copyrighted.

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32 The core innovation is to use the root ability to grow not only on a volume (of soil, of water, of sand, .....) but also on a surface (Blanc, 2011). Having plants that are selected based on the climatic conditions of the development, the vertical garden consists of a metal fr ame that is free standing or mounted onto a wall, a 1cm thick PVC layer riveted to the metal frame and acts as waterproofing, followed by a layer of felt made of polyamide. Seeds, cuttings or grown plants are installed on the rot proof felt layer with a de nsity of about thirty plants per square metre and left to grow on the felt. The felts high capillary action allows water to be distributed throughout the felt, providing water to the plants. Tap water supplemented with nutrients is automatically fed to the plants from the top. Fertilization is also automated. At a total weight of less than 30 kg per square metre, including plants and the metal frame, the vertical garden can be mounted on a wall without size or height limitations. Together with the metal f rame that provides an air layer that acts as a thermic and phonic isolation wall, the vertical garden allows greenery on a vertical plane just as land is being used in a horizontal plane for human activities. Similar to green roofs and brown roofs, vertical gardens also help to clean the air of pollutants, encourage biodiversity, lower ambient temperature and energy consumption, and provide carbon sequestration and ecosystem services. Green wall systems, living walls and vertical gardens Vertical green walls or gardens have traditionally been walls that are covered with suitable climbers. With the advance in technology, they have now become wall systems that are free standing structures or mounted onto walls of buildings. Many companies have developed such wall systems and one of them is BioTecture Ltd from United Kingdom. Their B&Q Garden and Principality of Monaco gardens have both won

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33 Royal Horticultural Society (RHS) Gold medals at the Chelsea Flower Show in May 2011. BioTecture Ltds patented BioWall allow plants to grow vertically in a unique, modular hydroponic system that can deliver precise, low water usage and low maintenance, proven over time to give superior performance (BioTecture Ltd, 2010). They can also incorporate cable or mesh support panel s if requi red. Their standard 600mm wide by 450mm high rainscreen modular panels have pre grown plants that can be installed anywhere, and customized to be placed even on convex and concave surfaces. When fully saturated, the BioWall system weighs approx imately 50 60 kg per square met e r about twice the weight of Patrick Blancs Vegetal Wall panel. The 50mm 200mm air cavity between the building and the back of panels stops the rain and irrigation water from penetrating through the building. By incorporating insulation boards to the wall system, it helps to reduce energy consumption. The main components of the BioWall are as follows (BioTecture Ltd, 2010): 1. C ladding rails any standard cladding system, or to our preference, timber rails. 2. Waterproof backing board marine ply or from 2010, ecosheet, an awardwinning sustainable backing material. 3. Drainage layer a void forming layer which accepts the drain down from each panel. 4. Irrigation line a horizontal baton which secures the pressure compens ated drippers. 5. Bio Panel plastic modular box/fascia containing the hydroponic growing medium 6. Vegetation plants of suitable species planted through fascia apertures 7. Drain channel for collection and disposal of surplus irrigation water (supplied by others).

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34 8. Surround fascia to finish off the wall and integrate into the building fabric, this element is supplied by others and typically specified by the architect involved. 9. Plant room for pumping and nutrient dosing equipment etc. Florida frien dly Landscaping For a landscape to be visually pleasant, the forms that shape the landscape and the materials used have to be aesthetically right. The selection of plants has to be correct also so that they will grow healthily in their natural conditions. In Florida where water is a scarce natural resource due to increasing demands and droughts, the Florida friendly principles are adhered to so that water can be conserved and cleaned for a sustainable development. According to the University of Florida IF AS Extension (2006), Florida friendly landscaping means quality landscapes that conserve water, protect the environment, are adaptable to local conditions, and are drought tolerant The nine principles of Florida friendly landscaping are (University of Florida IFAS Extension, 2006): 1. Right Plant, Right Place p lants selected to suit the specific site will require minimal amounts of water, fertilizer and pesticides. 2. Water Efficiently i rrigate only when your lawn and landscape need water as e fficient watering is the key to a healthy Florida yard and conservation of our limited water resources. 3. Fertilize Appropriately l ess is often best as o ver utilization of fertilizers can be hazardous to your yard and environment. 4. Mulch m aintaining a 3" layer of mulch will help retai n soil moisture, prevent erosion, and suppress weeds. 5. Attract Wildlife p lants in your yard that provide food, water and shelter can conserve Florida's diverse wildlife. 6. Control Yard Pests Responsibly u nwise use of pesticides can harm people, pets, beneficial organisms and the environment.

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35 7. Recycle g rass clippings, leaves and yard trimmings, if recycled on site, add nutrients to the soil and reduce waste disposal. 8. Reduce Stormwater Runoff keep rainwater and sprinkler water on the ground by directing rainwater downpipes into rain barrels to be used later for watering planting areas or washing, or into the planting areas, so that there is less water pollution from soil, fertilizer and debris. 9. Protect the Waterfront w aterfront property, whether on a ba y, river, stream, pond or beach, is very fragile and should be protected as a natural treasure. Most of these principles can be adapted for use in other states and countries to achieve a sustainable urban development. The principles such as using the appropriate drought tolerant plants particular to the climate, irrigating and fertilizing efficiently, and attracting wildlife such as birds and butterflies, are achievable in vertical gardens and intensive roof gardens. In addition, mulching and recycling organic matters can be used in intensive green roofs. Besides, intensive green roofs and vertical gardens also help to reduce stormwater runoff. Summary As land on ground is increasingly being developed for human activities, green space on ground is reduc ed and ecosystems are disturbed, hence reducing biodiversity. As greenery move upwards to roofs and links between buildings, and vertically on walls, extensive green roofs and intensive green roofs are being built. In places where developments have cleared out ecosystems, barren roofs could be used to provide brown fields for specific species that are then protected from ground activities by humans and predators. However, it was found that among conventional barren roof s, an extensive green roof and an intensive green roof, the intensive green roof seems to be the environmentally preferable choice when constructing a building since it indicated a small reduction in energy demand and an increased lifespan of the roofing membrane.

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36 On greening vertically, verti cal green walls or gardens have been developed from a traditionally simple cables and climbers system to vertical walls with panels of plants to be installed onto metal frames as freestanding structures or mounted on walls. In all cases, green roofs and vertical green walls or gardens help to provide ecosystem services, carbon sequestration, cleaner air quality, slow down rainwater runoff, reduce energy consumption and ambient temperature. However, there is not much information on getting sufficient water t o irrigate the plants. Hence, it seems that m any policies, legislatures and formal certifications that help to promote water conservation, environmental protection and use of reclaimed water are introduced in the United States. Particular attention is draw n to the water law in Florida. As cities are getting densely populated, references are made to Singapore as an example of a highly urbanized city state that faces similar issues. In the United States, the use of water restrictions for watering lawns and ot her planting areas seems effective in conserving water even when there is no water shortage. In Florida, issues like having a low supply of groundwater and surface water in some areas, and stopping of discharges of treated effluent into water bodies as it has hit the maximum allowed under the law, cannot be resolved locally. It seems to indicate that using a regional supply authority for such utility services is more economically viable due to economies of scale, and make it easier to raise the rate due to increased cost in providing utility services such as desalination and treated wastewater. The modernized Florida water law places great emphasis on the welfare of the community over individuals, and allows reviews of water management through the

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37 issuing of permits. Moreover, permits can be revoked for a variety of reasons to safeguard public interest. It seems a good mechanism for other states to implement. In Singapore, there is only one national water agency that takes charge of water issues. As a nation al agency, the Public Utility Board (PUB) stipulates that water is for the community to use, and should be conserved and valued even as we use the reservoirs for recreational activities to maximize land use. Similar to the United States, developers are enc ouraged to use rainwater harvesting for nonpotable use such as flushing toilets and washing, while industries on offshore islands and along the coastlines are encouraged to use seawater for cooling and process use. Greywater from bathtubs, wash basins, sh owers and laundry can be treated for nonpotable use also. Although planting areas are also fighting for limited water resources, they play an important role in providing ecosystem services, carbon sequestration, protection and habitats for biodiversity, f ood source for some ecosystems, shade to lower ambient temperature and better air quality. In Floridas Senate Bill 2080, Section 373.185, Florida statutes stated that Florida friendly landscaping involving principles such as planting the right plant in the right place, efficient watering, appropriate fertilization, mulching, attraction of wildlife, responsible management of yard pests, recycling yard waste, reduction of stormwater runoff, and waterfront protection (Senate Bill 2080, 2009) helps in water conservation and environmental protection. A development permit is issued only if the local ordinance must include proper practices for landscape planning (that preserves natural vegetation), design, installation and maintenance that result in savings of w ater. In

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38 Section 373.228, Florida statutes on landscape irrigation design, it stated that design standards for landscape irrigation should include irrigation codes that are in line with the Florida Building Code, Plumbing Volume, Appendix F. Such codes would have to be adhered to by public water suppliers when applying for water use permits. Furthermore, Section 125.568, Florida statutes on conservation of water, it stated that Floridafriendly landscaping should be implemented as part of water conservation and water quality protection and restoration planning (Senate Bill 2080, 2009) to ensure sufficient water supply for the community. As such, lush planting can still be seen in Florida today. For built environment in the United States, the emphasis is on using more stringent plumbing fixtures, water efficient appliances and plants that require less water, besides replacing potable water with nonpotable water for washing floors, flushing toilets and irrigation to reduce the demand for potable water. For wet ter areas, rainwater harvesting, along with low impact designs such as using permeable materials, rain gardens and green roofs are also used to help slow down rainwater runoff. In Singapore, the Building Control (Environmental Sustainability) Regulations u sing a scheme similar to the BCA Green Mark Scheme is used. The Green Mark score has to be submitted as part of the requirement for Building Plan (BP) approval, before Temporary Occupation Permit (TOP) or Certificate of Statutory Completion (CSC) stage (if there is no TOP application). BP is not approved if the score is less than 50 points. As for formal certification, both LEED for Neighborhood Development Rating System and Singapores BCA Green Mark Certification consider water efficiency, irrigation and green building features as part of their marking schemes. These encourage developers to help conserve water and protect the environment.

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39 In addition, the City of Orlando Growth Management Plan Policy Document on Wastewater Element aims to provide efficie nt and economic wastewater services in a safe manner at an affordable price, and to reduce the environmental impacts of the wastewater system on land and water resources. H ence, policies, legislatures and formal certifications are in place to promote wate r conservation, environmental protection and use of reclaimed water for nonpotable use in the United States and Singapore. The five case studies showed insights into green roofs, brown roofs and vertical gardens/walls in urban areas. As the ground is bei ng occupied for human activities, greenery is moving upwards to roofs and links between buildings, and vertically on walls. Depending on the loading capacity of the building, intensive, extensive and brown roofs can be built, with brown roofs specifically built for specific species that are then protected from ground activities by humans and predators, hence helping to improve biodiversity lost through rapid human development. The research done by Kosareo & Ries ( 2007) on the comparative environmental life cycle assessment of green roofs revealed that although intensive green roofs cost more to build due to loading requirements, they are the environmentally preferable choice when constructing a building, due to the small reduction in energy demand and the increased life of roofing membrane. Besides, intensive green roofs also maximize land use by allowing people to use the social spaces within the planting areas. As for vertical gardens/walls, there are many modular wall systems in the market that are freesta nding structures or can be mounted onto walls to provide greenery in a vertical plane. Drip irrigation is typically provided within the system from a piped source.

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40 In conclusion, the use of rainwater harvesting and reclaimed water is encouraged to reduce dependency on potable water for flushing toilet and washing. In the United States, non potable water is used for watering lawns and other planting areas at designated days and times, while in Singapore the public planting areas are watered using nonpotable water. As such, it seems plausible that rainwater harvesting can be used to irrigate drought resistant plants on roof gardens and vertical gardens/walls, thus providing a sustainable way to maintain greenery within a city.

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41 CHAPTER 3 METHODOLOGY This research investigates the feasibility of using rainwater harvesting to irrigate vertical gardens as a sustainable way to maintain greenery within a city. In the process of the investigation, it explores the extent of using vertical gardens in a city, the appro priate plants that require less water to survive, the visual and/or economic values added, the barriers to using vertical gardens, the need to maintain the wall systems / plants / irrigation systems, and the policies / incentives that may encourage their use. Research Approach The research will be done using data sources from nine vertical garden projects that were completed in parts of the United States and in Singapore. Information and opinions from the wall system and irrigation design specialists who w orked on these projects will be gathered. Together with the information gathered from a simple survey on visual and economic aspects, and by examining the policies on using rainwater in both the United States and Singapore, a conclusion may be drawn. Surve y in Singapore A simple survey was carried out to find out if people appreciate the visual aspects of vertical gardens, are acceptable to having food crops as vertical gardens, and if they find it useful in reducing ambient heat. Following that, sketches / drawings / diagrams were drawn based on current practice. Further sketches/drawings/diagrams on possible design guidelines for irrigation design using rainwater for watering the plant species used were produced.

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42 From the simple surveys, information can be gathered on peoples appreciation of the visual aspects of vertical gardens, peoples receptiveness to using food crops as vertical gardens, and peoples perception on vertical gardens being useful in reducing ambient heat through their comments on how they feel physically when standing or sitting near vertical gardens cool or hot Best Approaches for Creating Vertical Gardens Although vertical gardens can be found in many countries such as Australia, France, New Zealand, Singapore, United Kingdom and the United States, the focus for this research is just on cities in two countries Singapore and the United States since geographically they are far apart, have different climate conditions, size, building typology and plant species. The research is t hen applicable, to some extent, for both temperate and tropical climates but more so for tropical climates since the research is based more on Florida and Singapore. Bearing in mind that North and Central Florida has a humid subtropical climate where summ ers are hot and humid while winters are mild to cool South Florida and Singapore have a tropical climate where the temperature remains relatively constant. Besides, it is also easier to get information from these countries as language is not a barrier. T he following first seven projects in the United States were selected as they are located at different parts of the country with different climates and provide easily accessible information. The ones in Los Angeles and San Francisco have a Mediterranean cli mate that has moist mild winters and dry summers, while the project in Pittsburg has a humid continental climate with warm to hot (and often humid) summers and cold (sometimes severely cold) winters. The project in Atlanta has a humid subtropical climate c haracterized by hot, humid summers and mild to cool winters

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43 similar to North and Central Florida. The two projects in Singapore were selected as they provide more accessible information applicable for a tropical climate. They were all chosen also because they have been implemented for a few years so there is a possibility of finding if they are still performing well over time. The nine vertical gardens and their corresponding irrigation builders and suppliers on constructing and irrigating these vertical g ardens are as follows. 1. Urban Farming Food Chain Skid Row Housing Trust's 'The Rainbow' Green Wall (2008) Los Angeles, CA, USA Greenwall manufacturer Green Living Technologies (GLT) 2. Urban Farming Food Chain The Weingart Center Association Green Wall (2008) Los Angeles, CA, USA Greenwall manufacturer Green Living Technologies (GLT) 3. Urban Farming Food Chain Miguel Contreras Learning Complex Green Wall (2008) Los Angeles, CA, USA Greenwall manufacturer Green Living Technologies (GLT) 4. Urban Far ming Food Chain Los Angeles Regional Food Bank Green Wall (2008) Los Angeles, CA, USA Greenwall manufacturer Green Living Technologies (GLT) 5. San Francisco Residential Living Wall (2010) San Francisco, CA, USA Irrigation: Ewing Irrigation Products & The Urban Farmer Greenwall manufacturer Tournesol Siteworks' 6. PNC Bank Green Wall (2009) Pittsburg, PA, USA Greenwall manufacturer Green Living Technologies (GLT) 7. Atlanta Botanical Garden Edible Garden Green Wall (2010) Atlanta, GA, USA Green Wall System Manufacturer Tournesol Siteworks Green Wall System Supplier/Distributor Saul Horticultural Companies Green Wall Construction & Irrigation Valley Crest Landscape Development 8. 71 Robinson Road (2009) Singapore Irrigation Netatech Pte Ltd 9. Orc hard Central Mall Greenroofs (2009) Singapore Green Roof and Green Wall Specialist Elmich Pte Ltd Irrigation Netatech Pte Ltd

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44 For this research, the wall systems and irrigation design of these sources were studied by gathering information from their w ebsites and by contacting these specialists, and asking them about any maintenance barriers that they may face. Then comparisons are made of their systems to find out those that work best. From the nine data sources, information can be gathered about where vertical gardens are used, when they are used, how they are used (as a freestanding structure or mounted on walls), how tall they are, the type of plants used and hence the plants characteristics, the type of wall systems, the current irrigation system and water source, when the irrigation system is being used, barriers to the use of vertical gardens and need for maintenance of wall systems / plants / irrigation systems. Policies, Legislatures and Formal Certification Policies, Legislatures and Formal Cert ifications in the United States (particularly in Florida) and Singapore will be examined to find out if these are provided to encourage the use of rainwater to irrigate greenery, and if rainwater harvesting is currently recommended to be used for vertical gardens. The research will look into policies/incentives/design guidelines that may have to be introduced to promote the use of rainwater harvesting, and if there is a need to modify them to include their use on vertical gardens. From the policies, legisla tures and formal certification, information can be gathered about the policies/incentives that promote the use of rainwater harvesting currently and if there is a need to modify them to include their use on vertical gardens, perhaps only in Singapore.

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45 Summ ary Based on the analysis of the data sources, conclusions can be drawn on the feasibility of extensive use of vertical gardens in a city for their visual and/or their economic values, the feasibility of using rainwater harvesting as a sustainable way to maintain greenery within a city, and the need to provide policies/incentives to encourage using vertical gardens in a city.

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46 CHAPTER 4 DISCUSSION AND ANALY SIS Data from Surveys Survey from general public in Singapore A total of 30 people of various ages w ere requested to perform the survey, of which only 25 people replied based on the questions as shown in Appendix A The results from selected questions (Q1 to Q8) are as shown in Table 41 and Figure 4 1. Table 4 1. Tabulation of survey results fr om the g eneral public Figure 4 1. Column Chart of survey results fr om the general public

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47 Survey from irrigation specialists As there is a limited number of specialist companies that provide irrigation, only a total of seven companies that specialized in irrigation were requested to provide information based on the questions as shown in Appendix B Three of the companies are from the United States and four are from Singapore. Of the seven, only two from Singapore replied. The results from selected questions (Q1 to Q10) are as shown in Table 42 and Figure 4 2. Table 4 2. Tabulation of survey results f r om irrigation specialist s Figure 4 2. Column Chart of survey results fr om irrigation specialist s

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48 Data from Best Approaches for Creating Vertical Ga rdens Urban Farming Food Chain The Urban Farming Food Chain aims to provide vertical gardens using food crops for homeless people so that they can be self sufficient through skills training, tools and resources. Occupying an area of 750 square feet, t hese vertical gardens are known as Green Living Walls and are either mounted on buildings or on concrete walls. They can also be freestanding or in parking areas Located at four locations in and around downtown Los Angeles, inclusive of the Central City East (Skid Row) area, pesticides are not used on the fresh produce. The following four projects i n the United States of America (USA) were implemented in 2008 : Located in Los Angeles, C alifornia (CA), the project called Skid Row Housing Trust's 'The Rainbow' Gr een Wall (a permanent apartment for the homeless men and women) which is owned by Urban Farming is a Multi Family Residential building type. T he Living Wall in this project is a t est / r esearch project. At a size of 188 sq uare feet with each wall betw een 24 to 30 feet across and 6 feet high, it is made up of individual (2 f eet by 2 f ee t by 4 inches & 6 inches depths) interconnected recycled stainless steel panels Although privately owned, it is accessible to the residents The vegetable crops grown for the warm season are tomatoes, cucumbers (green and yellow), strawberries, bell peppers, hot peppers, tomatillos, spinach, parsley, leeks, edible lavender, eggplant, zucchini, Sugar Baby watermelon, and a variety of herbs For the cool season, lettuce v arieties, radish, and legumes are grown. 8mm drip lines 6" on center spacing that correlate to the 6" spacing of the Green Living Wall panels are used for irrigation. It is fully automatic complete with rain

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49 sensor set to provide minimal waste water wi th s tainless steel catch basins for recapture of excess irrigation and/or rain. Envisioned by Joyce Lapinski, the Director of Urban Farming the project's g uar dian wall was designed by architect Robin Osler of Emily Osler Architects (EOA) and manufactur ed and implemented by George Irwin of Green Living Technologies (GLT). Also owned by Urban Farming, t he following three projects have different building type and access from the Skid Row Housing Trust's Rainbow Apartment They are accessible and open to public: 1. Weingart Center Association Green Wall (a nonprofit building type) 2. Miguel Contreras Learning Complex Green Wall (a public high school) 3. Los Angeles Regional Food Bank Green Wall (largest food distribution centre for free food in Los Angeles area) San Francisco Residential Living Wall Located in San Francisco C alifornia (CA), the single family residential project was i mplemented in 2010. O ne of the three retaining walls of a remodeled house located at the foot of a hillside at Pacific Heights was covered by a vertical garden to encourage biodiversity and bring beauty and enjoyment to the owner. The wall is north facing at the hillside. At a size of 330 sq uare f eet it is 12 feet high and 27.5 feet wide ( 96 modules measuring 20 inches by 20 inches and 10 inches deep) Although privately owned, it is accessible to the residents. The wall consists of 75 varieties of subtropical shade loving plants (northwestern ferns and fern allies) For irrigation, it has a h orizontal main line with laterals along vertical rails, with multiport drip emitter at the top of each box

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50 The green wall is designed by owner Mic helle Bond of Thumbellina Gardens, and manufactured by Tournesol Siteworks T he plants are supplied by Sloat Garden Center, Flora Grubb Gardens, San Francisco Foliage and Pacific Nurseries while t he irrigation system is done by The Urban Farmer using Ewing Irrigation Products GYOSF INC is the supplier for the fertigation tanks and fertilizers and th e general contractor is Ral Dasco PNC Bank Green Wall As an innovative way to achieve energy efficiency as part of its dedicated effort to use technologies that contribute to the environment, the community and greening of urban areas the PNC Financial Services Group, Inc. commissioned a living art on the south facing wall of its headquarters. At 10 stories high, i t was co nsidered the largest commercial building in Pittsburg, Pennsylvania (PA) in 2009 and was estimated as being capable of cooling the building by 25% compared to ambient temperatures. At a total size of 2380 square feet, it is a living wall that can be accessed for maintenance and seen by the public. The plants used are carex variegated, heuchera purple varieties ferns euonymus lysimachia sedum ajuga black scallop, and brass button. The y are irrigated at 9 zones with more than 2,000 micro drip emitters at r oughly 15 minutes per week (warmer months) and r oughly at 15 minutes per month (colder months) The modular green wall system is manufactured by Green Living Technologies (GLT), and designed and installed by Philly Green Wall. The design consultants are Kari Katzander of Mingo Design and BD&E Strategic Branding and Design, while Cenkner

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51 Engineering Associates is the engineer for the project. Atlanta Botanical Garden Edible Garden Green Wall Located within an abandoned parking lot in Atlanta Georgia (GA), the Edible Garden Green Wall is part of Atlanta Botanical Gardens Edible Garden Green Wall and Outdoor Kitchen It is implemented in 2010, and is a living wall filled with herbs that showcases the concept of growing and consuming local produce in a sustainable manner using food crops as plants for the landscape. Having a size of 416 s quare feet ( 52 feet long by 8 feet high ) it is accessible and open to the public. The crops grown are s age, dianthus, dwarf, phlox, and boxwoods The T ournesol VGM system for irrigation has a m ain lateral pipe that runs horizontally along the top of each row of boxes with e ach box having 4 irrigation emitters The green wall is designed by Tres Fromme of MESA Design Group, and manufactured by Tournesol Siteworks It is supplied by Saul Horticultural Companies While the green wall construction and irrigation is done by Valley Crest Landscape Development the plants are sourced, grown and planted by Sau l Nurseries 71 Robinson Road Vertical Green Wall The office building owner for this project in Singapore is Kajima Lehman (Robinson) Development Pte. Ltd. Implemented in 2009, t he vertical greenery located at the car park provides shade and helps to scre en air pollutants. Rainwater harvesting is used here, and with a combination of soil moisture sensors and irrigation controller from Acclima, helps to provide additional water savings on irrigation.

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52 At 190 m eters in length by 4 m eters high the curtain wa ll is accessible and open to the public. Creepers are planted in the facade planters so that they can climb up the support spanning each floor, and inline drip with embedded drip emitters placed in the facade planters are used to irrigate these creepers. The c urtain w all construction and i rrigat ion are done by Netatech Pte. Ltd. Orchard Central Mall Greenroofs and Greenwalls V ertical greenery for th is mall in Singapore helps to soften three high walls and part of a corridor on the 11th floor and two lower walls on the 12th floor roof terrace Owned by Far East Organization, the green walls and intensive green roofs are implemented in 2009. They are accessible and open to public. Having a total size of 6493 sq uare feet. It consists of 3 high walls on the 11th floor totaling 160 sq uare m eters, and a section of a 11th floor corridor and 2 lower walls at 12th floor totaling 45 sq uare m eters. the plats used for the green walls are Ophiopogon japonica, Russelia equisfolia, and various fern species A utomated dr ip irrigation and fertilization system (timed release of water and nutrients to the plants) are used, with c ollection trays positioned at ground level to allow overflow or excess water to be discharged or recycled. the modular green wall system is manufact ured and supplied by Elmich Pte Ltd Analysis As greenery moves from the ground up, roof and walls of buildings are being green increasingly in cities. From the case study on green roofs and brown roofs (Livingroofs, 2011) vulnerable species can surviv e and thrive if barren roofs can be used for brown roofs

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53 where plants selected are food sources for these species. This has yet to be extensively done in Singapore and may be worth exploring. The comparison of intensive, extensive green roofs and bare roof s in the case study on comparative environmental life cycle assessment of green roofs in Pittsburg (Kosareo & Ries, 2007) with warm to hot (and often humid) summers and cold (sometimes severely cold) winters, indicated that intensive green roofs performed the best in terms of the three. They require the least additional energy to increase the lifespan for the roofing membrane. Besides, intensive green roofs also allow social interaction as recreational spaces within buildings since they are accessible to t he occupants. Such green roofs are seen extensively in Singapore. Moving greenery onto a vertical plane, Patrick Blancs vertical green Vegetal Wall (Blanc, 2011) has led to m any other similar installations. His indoor installation in CapitaLand at 6 Battery Road in Singapore presented an impressive piece of art. It probably inspired another similar indoor installation here by another developer in 158, Cecil Street, although it spanned vertically in contrast to Patrick Blancs horizontal display here. Verti cal green seems to be getting more popular in Singapore. Based on the results of the survey done by the general public in Singapore, most of the people have seen vertical gardens that are outdoors and mounted on walls of buildings rather than freestanding or indoor vertical gardens. Looking similar to BioTecture Ltds BioWall in the case study on green wall systems, living walls and vertical gardens (BioTecture Ltd, 2010) the vertical gardens with modular systems of pre grown plants can be installed to create green walls of any height and width as required. Perhaps there are more outdoor vertical gardens that can be seen more

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54 prominently than indoor ones that are located at more obscure places within buildings at the time the survey was done. There is also a possibility that, like the freestanding green totems along Orchard Road (Singapores shopping belt), people tend to take home the beautiful orchids or the hardy and less beautiful bromeliads planted on the totems as souvenirs As a result, the authority has since removed the freestanding totems altogether as the bare totems are eyesores as the plants cannot be replaced fast enough and are costly to replace (Tan, 2011) M ost of the public in Singapore are also receptive to living near a vertical garden and having food crops as plants on a vertical garden. They also find vertical gardens pleasant looking, if the plants are growing well. From their comments, t hose who find vertical gardens unpleasant are those who find dead plants unacceptable and felt that t he maintenance of plants could be costly and unsustainable. The results seem to reflect that people in Singapore are receptive to having more vertical gardens that have plants that are growing well and they can be planted with landscape plants or food crops Being aware of food scarcity, some people are also willing to grow their own vegetables. From the results of the survey done by the irrigation specialists, most of the vertical gardens in Singapore are mounted on the walls of buildings and use precisi on drip irrigation. Although the water source for irrigation used are either potable water or harvested rainwater or treated grey water, harvested rainwater as the water source is used more often. The water source can be located on ground or at the top of the vertical garden. The barriers to having vertical gardens included budget for the project and structural loading. Maintenance is required for both the plants and the irrigation system.

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55 Pruning of overgrown plan ts and replacing of dead plants need to be done monthly, and filters have to be cleaned along with the checking of the emitters and batteries of control sensors every three to six months. Hence, access to vertical gardens is necessary and should be considered during the design process of new buildi ngs. I t cannot be determined if all these are applicable to the United States as there were no replies for the same survey fr om the irrigation specialists but it may be similar in Florida as the principles in Floridafriendly Landscaping case study stipu lates measures to conserve water that are applicable to vertical gardens Nevertheless, the data collected from the seven best approaches for creating vertical gardens at various locations in the United States offer some insights. It was observed that vert ical gardens are mostly found in cities which are naturally more populated than rural areas and hence may need to use vertical planes for green areas The vertical gardens can be freestanding, but are mostly mounted on walls either on the ground or at a h igher level For instance, the vertical gardens in projects such as the U rban F ood C hain and Atlanta Botanical Garden are located on the ground. At a height of six feet to eight feet high, herbs and vegetables are within reach for harvesting when required. These vertical gardens can be as long as desired. For vertical gardens that use landscape plants suitable for the climate at that location, they can be as long and as tall as desired. In all cases, modular wall systems are used with automatic precision dr ip irrigation system. Using micro tubings and drip arrows to deliver water from a horizontal main line precisely to the root zone with minimum over watering seems to be the best method of irrigation. To provide minimal waste water, the fully automatic irri gation system should

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56 make use of rain sensors to determine when to irrigate. By placing stainless steel catch basins at the bottom of the modules, excess irrigation and/or rain can be recaptured and reused. It seems that fertigation is also incorporated i nto the irrigation system for the San Francisco Residential Living Wall project. In Singapore, modular wall systems are also used with automatic precision drip irrigation and fertilization system in the Orchard Central Mall project. Similarly, collection t rays are also located at ground level to allow overflow or excess water to be discharged or recycled. In this project, it seem s like treated grey water is the water source for irrigation. In contrast, the curtain wall at 71 Robinson Road is known as a vert ical greenery support system ( Tan, Chiang, Chan, Wong, Chen, Tan, Wong, 2009) where creepers are grown in planters located at the faade of the levels where the car parks are located, with support for climbers to climb. It helps to screen polluted air and cool the ambient temperature. In this case, harvested rainwater is used as the water source in its i nline drip irrigation system With limited land to collect rainwater and no natural aquifers or lakes, Singapore has created estuarine reservoirs by damm ing up major rivers instead of tapping into groundwater supplies And as she stops importing water from M alaysia, that will put a strain on water resources. For a sustainable supply of water, Singapore will have to rely on local water catchment areas that will cover two thirds of land area by end 2011, NEWater that will supply fifty percent and desalination that will meet the needs of about thirty percent of future water needs by 2060 respectively. Hence, there is no risk in not letting rainwater or reuse w ater re enter the surface and recharg e the groundwater

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57 As the demand for drinking water increases, nonpotable water is used for irrigation. From the survey, it seems that grey water used for irrigation is minimal currently Perhaps it is more expensive to use as it has to be treated and any harmful chemicals have to be removed before it can be used for irrigation. To encourage people to conserve water, there are two components in the pricing of water water tariff and water conservation tax. The former is aimed at covering the full cost of production and supply of water while the latter is applied to the water tariff to reflect the real cost of water that is the higher cost of additional sources of water. In the Blue Paper and Solutions launched during the Singapore International Water Week ( 2011) Singapores Prime Minister noted that Over the long term desalination and water reuse technologies have tremendous potential to tackle water challenges It seems that Singapore is heading in this direction t o address our future water demands. Perhaps when the cost of reusing water goes down with improved technologies, treated grey water will be the more popular water source for irrigating vertical gardens in future. Research Limitations Although great care has been taken to gather the information required for the research, l imitations may include a lack of good information on irrigation for vertical gardens, and proprietary knowledge that cannot be divulged by specialists and companies providing vertical garden and irrigation systems. Another limitation could be that the survey on visual aspects and food crop vertical walls is skewed towards tropical climate as it will be done in Singapore. Lastly, the duration for the research and the sample size for surveys may limit the extent and depth of the research.

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58 CHAPTER 5 CONCLUSION It can be seen from the literature review on policies, legislatures and formal certifications that water conservation, environmental protection and use of reclaimed water for nonpotable use in the United States and Singapore are highly encouraged. In both countries, the use of nonpotable water (either rainwater or recycled water) for i rrigati ng green areas and the use of appropriate drought tolerant plants are the main concerns. They contribute points to both the LEED Green Building Rating Systems in the United States and the BCA Green Mar k Scheme in Singapore that are formal certification systems. As land is increasingly being used for housing and infrastructure in urbanized cities ever ywhere, greening vertical planes is becoming more popular in an attempt to bring nature closer to urbanites and to provide habitats and food sources for ecosystems that lost their space to urbanization. In fact, v ertical gardens can help to provide visual relief from hard building faade, screen and isolate unsightly views, protect building faade, reduce urban heat island effect, improve air quality by absorption of pollution and dust, reduce greenhouse effect by reducing carbon dioxide, enhance biodiversi ty, improve rainwater retention, and reduce cooling loads through better insulation and shading of building faade. With scarcity in food crops as farmers grow crops on their land for biofuel which is deemed to bring in more money, herbs and vegetables may replace landscape plants on vertical planes Due to the scarcity of land, people are now more receptive to the functional aspects of landscape and not just the aesthetic aspects of it

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59 The data collected from the studies on best approaches for creating v ertical gardens in the United States revealed that vertical gardens using vegetable crops can be located at places where the community needs it most or at places near kitchens so the fresh produce can be easily harvested and is sustainable. For those verti cal gardens that use landscape plants, it seems appropriate to use plants that are suitable for the climate where they are placed, and that they should be pruned monthly. Care should be taken to use plants that can survive and thrive in the light and wind conditions at the project site. According to Tan, Chiang, Chan, Wong, Chen, Tan, Wong (2009) in Singapore, plants that employ the Crassulacean Acid Metabolism (CAM) mode of photosynthesis have high water use efficiency since they close their stomata in t he day and open them at night. They are represented in thirty three plant families and provide a huge variety of plants to choose from. In a bid to conserve water, irrigation specialist s in Singapore use harvested rainwater or treated grey water to irrigat e green areas. As in normal green areas, rainwater falls onto the plants and goes into the ground. Hence, i t seems logical to use rainwater to irrigate the vertical gardens as it is more economical since no treatment is required before it can be used, unl ike grey water (PUB, 2011) The studies seem to indicate that the preferred irrigation system is the precision drip method that uses micro tubings and drip arrows to deliver water from a horizontal main line precisely to the root zone with minimum over wat ering seems. It should be a fully automatic irrigation system that make s use of rain sensors (if it is a living wall of plants grown in modules) or moisture sensors (if it is a green faade of climbers grown

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60 on planters with supports for the climbers to cl imb up) to determine when to irrigate. This will provide minimal waste water. And by placing stainless steel catch basins at the bottom of the modules, excess irrigation and/or rain can be re captured and reused. It would be better if fertigation is includ ed in the irrigation system so that water soluble fertilizers can be dispensed at specific times automatically. A possible efficient irrigation system would dispense about 2.5 liter s twice a day to irrigate 1m2 of plants on a vertical surface, which is si milar to a normal landsc aping usage rate of 4 to 5 liter s/ m2 (Tan, Chiang, Chan, Wong, Chen, Tan, Wong, 2009) At 66 square meter s of green space per person (Lim, 2 011), we will be using 330 liter s of water per person per day. This shows a substantial sav ings in potable water, more so in a city that does not have many natural water resources, and we hope to achieve a water usage rate of 140 liter s per person per day by 2030. Although rainwater can be harvested and stored in a storage tank either at the to p or bottom of a vertical garden, energy can be saved by keeping the storage tank, and hence the water source, at the top so that irrigation can be done by gravity. Excess rainwater collected on trays /catch basins at the base can then be pumped up for reus e. The following serves as possible design guidelines for vertical gardens in Singapore. 1. L ocate a large and shallow or small and deep collection pond as part of the rooftop garden or intermediate garden. 2. Locate the vertical garden mounted on a wall beside the collection pond so that the rainwater can be tapped to irrigate the vertical garden. 3. N onpotable water will still need to be tapped into the collection pond so that water make up for the collection pond can be done during dry seasons 4. T he collection pond can be aerated to prevent mosquito breeding

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61 5. Prevent debris from getting into the horizontal main pipe for irrigation by putting a w ire mesh / gauze as a filter for the harvested rainwater, and placing it at the mouth of the pipe that allows water to flow down to the horizontal main pipe. 6. F ully automate the irrigation system that makes use of rain sensors (if it is a living wall of plants grown in modules) or moi sture sensors (if it is a green faade of climbers grown on planters with supports for th e climbers to climb up) to determine when to irrigate In the event that the building does not have an intensive rooftop garden, storage tanks can still be placed at the roof to collect rainwater for use to irrigate the vertical garden as per normal pract ice.

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62 Figure 5 1. View of vertical garden near a collection pond

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63 Figure 5 2. Section of vertical garden showing proposed irrigation system In conclusion, rainwater harvesting can be used to irrigate vertical gardens as a sustainable way to maintain greenery in a city. Although most vertical gardens are found in commercial buildings that have more funds allocated for going green, perhaps as technology improves and the cost of installing and maintaining vertical gardens becomes more economical, resi dential building will have their walls don with vertical gardens. More research can to be done on the possibility of using grey water or desalinated water to irrigate vertical gardens if Singapore is to rely more on these sources for future water demands.

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64 APPENDIX A QUESTIONNAIRE FOR THE GENERAL PUBLIC IN SINGAPORE

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65

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66 APPENDIX B QUESTIONNAIRE FOR THE IRRIGATION SPECIAL IST IN THE UNITED ST ATES OF AMERICA AND SINGAPORE

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67

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68 LIST OF REFERENCES BCA Building and Construction Authority ( 2011, May 3). BCA Green Mark Assessment Criteria and Application Forms Retrieved from http://www.bca.gov.sg/GreenMark/green_mark_criteria.html BCA Building and Construction Authorit y (2010, December 10). Legislation on Environmental Sustainability for Buildings Retrieved from http://www.bca.gov.sg/EnvSusLegislation/Environmental_Sustainability_Legisl ation.html BCA Building and Construction Authority (2010, August). Code for Environmental Sustainability of Buildings Retrieved from http://www.bca.gov.s g/EnvSusLegislation/others/Env_Sus_Code2010.pdf Bilenky, W.S. (2009). An alternative strategy for water supply and water resource development in Florida. Florida State University Journal of Land Use & Environmental Law BioTecture Ltd. (2010). Green wall systems, living walls and vertical gardens Retrieved from http://www.biotecture.uk.com/ Blanc, P. (2011). Vertical Garden. Retrieved from http://www.verticalgardenpatrickblanc.com/#/en/projects/typological/commercia lbuildings/484 Blanc, P. (2011). The Vertical Garden, from nature to cities: A Botanical and Artistic approach by Patrick Blanc Retr ieved from http://www.murvegetalpatrickblanc.com/upload/pdf/Vertical_Garden__from_nat ure_to_cities_1.pdf BrownRoofs. (2011). Brown Roofs and Biodiversity Retrieved from http://www.brownroofs.co.uk/brownroof biodiversity.php City of Orlando (2009, June 8). Growth Management Plan: Policy Document on Wastewater Element. Retriev ed from http://www.cityoforlando.net/planning/cityplanning/ GMP.htm Dietz, M.E. (2007). Low Impact Development Practices: A Review of Current Research and Recommendations for Futur e Directions. Water Air Soil Pollution 186, 351 363. doi: 10.1007/s11270 007 9484 z Gonchar, J (2009, October 1). Quenching the built environments thirst for water Architectural Record Hill, K. (2009). Urban Design and Urban Water Ecosystems. The Water Environment of Cities 141 170 doi : 10.1007/978 0 387 84891 4_8

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69 Klein C.A., Angelo M.J., & Hamann R. (2009). Mod ernizing Water Law: The Example of Florida. Florida Law Review Kosareo L., Ries R. ( 2007, July). Comparative environmental life cycle assessment of green roofs Building and Environment, Volume 42, Issue 7, Pages 2606 2613 Lim, J. (2011, February). Singapore, Asias greenest city. AsiaNews.it. Retrieved from http://www.asianews.it/news en/Singapore, Asia%E2%80%99s %E2%80%9Cgreenest%E2 %80%9D city 20825.html Livingroofs. (2011). On Green Roofs and Brown Roofs Retrieved from http://livingroofs.org/ Livingroofs. (2011). Introduction to types of Green Roofs Retrieved from http://livingroofs.org/2010022858/greenroof types/greenrooftypes.html Livingroofs. (2011). Extensive Green Roofs Retrieved from http://livingroofs.org/2010030162/greenroof types/extens.html Livingroofs. (2011). Green Walls Retrieved from http://livingroofs.org/2010030363/greenroof types/grwalls.html Ministry of the Environment and Water Resources. (2011, October 17). Top 5 Most Popular FAQs Retrieved from http://www.ifaq.gov.sg/mewr/apps/fcd_faqmain.aspx Pasco Tim es. (2011, May 1). Watering Restrictions; Pg. 14. St. Petersburg Times (Florida) Public Utilities Board (n.d.) Water Efficient Building Design Guide Book. PUB. Public Utilities Board (2010). Water for all Retrieved from http://www.pub.gov.sg/LongTermWaterPlans/cve_love.html Public Utilities Board (2011, July 6). Alternate Source of Water Retrieved from http://www.pub.gov.sg/conserve/CommercialOperatorsAndOther/Pages/Alterna teSourceofWater.aspx Reid, A. (2011, January 16). The Nation; Drought stirs water worries Los Angeles Times Roon, M ( 2007, June). Water locali sation and reclamation: Steps towards low impact urban design and development Journal of Environmental Management, Volume 83, Issue 4, Pages 437 447

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70 Senate Bill 2080. (2009, July 1). Retrieved from http://archive.flsenate.gov/data/session/2009/Senate/bills/billtext/pdf/s2080er.p df Sharockman, A. (2010, September 13). Adam Putnam sounds alarm on looming water crisis. St. Petersburg Times (Florida) Si ngapore International Water Week. (2011). Water Solutions for Liveable and Sustainable Cities. Retrieved from http://www.siww.com.sg/media/sing aporeinternational water week launches bluepaper andsolutions Tan, A. (2011, September 15). Blooming shame. The Straits Times Tan, P.Y.,Chiang, K., Chan, D., Wong, N.H., Chen, Y., Tan, A., Wong, N.C. (2009). Vertical Greenery for the tropics. NParks 2009, NUS 2009 and BCA 2009. University of Florida IFAS Extension. (2006). What is FloridaFriendly landscaping. Retrieved from http://pasco.ifas.ufl.edu/ffl/FL Friendly_Landscap ing.shtml U.S. Green Building Council. (2011). LEED for Neighbourhood Development Retrieved from http://www.usgbc.org/DisplayPage.aspx?CMSPageID=148 Wastewater Element Goals, Objec tives, and Policies. ( Approved 1991, August 12; Amended 2009, June 8). City of Orlando Policy Document Retrieved from http://www.ci tyoforlando.net/planning/cityplanning/Policy%20Document/GMP% 2009/12%20%20Wastewater%20GOPs.pdf

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71 BIOGRAPHICAL SKETCH Wan Pui Hoong has worked for more than twenty years in both the public and private sectors in industries such as the built environment, computer software design and development, landscape architecture and education. Based mostly in Singapore, she has also spent a few years working in Kuala Lumpur, Malaysia, while working in a landscape architecture firm. Believing in continuous learning and work experience, Pui Hoong has earned two diplomas through part time studies before embarking on the Bachelor of Science in Computer Science from the Open University (United Kingdom), and graduated in 1999. In 2004, she ha d the opportunity to pursue a bachelor degree in landscape architecture and graduated in 2008 from Lincoln University of Christchurch, New Zealand with the Bachelor of Landscape Architecture with Second Class Honours Division 1. With a keen interest in sustainable design, Pui Hoong is currently pursuing her graduate degree in Master of Science in Architectural Studies, with an expected date of completion in f all 2011. She hopes to inspire her students to incorporate sustainable design thinking when desig ning landscapes in an urban setting