PROBLEMS IN THE DESIGN AND IMPLEMENTATION OF A GIS FOR URBAN
GREEN DEVELOPMENT IN GHANA
A thesis presented to
the faculty of
the College of Arts and Sciences of Ohio University
In partial fulfillment
of the requirements for the degree
Master of Science
ALEX B. OWUSU
June 2005
PROBLEMS IN THE DESIGN AND IMPLEMENTATION OF A GIS FOR URBAN
GREEN DEVELOPMENT IN GHANA
BY ALEX B. OWUSU
has been approved for
the Program of Environmental Studies and
the College of Arts and Sciences by
James K. Lein
Associate Professor of Geography
Leslie A. Flemming
Dean, College of Arts and Science
ABSTRACT
OWUSU, ALEX B. MS. June 2005. Environmental Studies.
Problems in the Design and Implementation of a GIS for Urban Green Development in Ghana ( p. 103)
Director of Thesis: James K Lein
Olembo and Rham (1987) demonstrated the age-old belief by urban dwellers that urban greens make cities livable although few solid scientific data are available on the measurable benefits of greens on the urban environment. With the advent of
GIS and remote sensing technologies, the American Forests Organization has measured the role of urban greens in dollar terms in some selected American Cities.
This is seen in terms of physical or tangible benefits, environmental and health benefits, stormwater control, air quality control, energy conservation, social and other non-quantifiable benefits. Similarly the idea of green development in urban areas of developing countries, including Ghana, has come of age, with the call for identification of suitable sites for green development through capture, storage, integration, manipulation, analysis, querying and displaying of data that are spatially referenced. It is in this view that this study analysis problems that are likely to be encountered in the design and implementation of a GIS for urban green development in Ghana.
While GIS and remote sensing technologies have the capacity to be utilized in the urban green development, its application in cities of Ghana may not be without problems. Some of the possible problems identified in this study, include data availability, data currency, accuracy and precision. Other data problems relate to data standardization, data merging and the database design and management. In addition to data problems, there are other problems such as personnel, financial and other
resources, political and bureaucratic procedures involved and other socio-cultural barriers such as the traditional land tenure system, perception of development and attitudinal factors.
In spite of these problems, a journey of a thousand miles begins with a step; it is against this study suggested that a successful GIS development project begins on a pilot basis, involving situational assessment, needs of the end users, software and hardware requirements, requirements of the GIS (implementation plan), education and training, database design, implementation and system maintenance requirements.
Approved:
James K. Lein
Professor of Geography
D E D I C A T I O N
Dedicated to Nana B. Osei-Owusu and Kwaku Jr. Owusu-Barimah
ACKNOWLEDGMENTS
My utmost appreciation goes to the Almighty God for bringing me this far. I would like to thank all friends and loved ones who contributed in diverse ways to the success of this work. Mention must be made, however, of the following people for their distinctive contributions: Dr. James K. Lein, my primary advisor, (Jim, God
Bless you). Also to my committee members, Dr. Christopher Boone and Dr. Stephen
Howard. I also appreciate the contributions of the rest of the lecturers at Ohio
University and most especially Dr. Gene Mapes (Director of Environmental Studies) for her concern and encouragement.
Also my heartfelt appreciation goes to Mr. Daniel Amponsah Opoku, Eric
Gavua, Kwaku Owusu-Banahene, all of Ohio University and my good friend Mr.
Kwadwo Afriyie of Kwame Nkruma University of Science and Technology.
Finally, I am grateful to my parents, brothers and sisters, more especially, Rev.
Fr. Cssp. John Osei Yaw and Fred Agyemang for their immeasurable love, encouragement and support throughout my schooling. To you I say a very big thank you.
However, I must emphasize, that I am solely responsible for any shortcomings, marginal or substantial, which may be found in this text.
7 TABLE OF CONTENTS
Title Page
Abstract ……..…………………………………………………………….………….iii
Dedication .……….…………………………………………………………………...v
Acknowledgements..………..………………………………………………………..vi
List of Tables……………………………………………………..……………...... 9
List of Figures…………………………….………………………………….………10
CHAPTER ONE : DESTRUCTION OF NATURE IN THE CITY …..……………11
1.0 Introduction ……..………..…….…………………………………...... 11
1.1. Thinking Green .. ...……….…….………………….………...…………11
1.2. The Question of Green Development …..……………….………….…..13
1.3. Research Objectives …………………………….……...... 15
1.4. Research Methodology …………………………….………..………….16
CHAPTER TWO: DEVELOPMENT, URBANIZATION AND THE
ENVIRONMENT NEXUS ………………...……………………………….….… ..18
2.0 Introduction …………………………………..………………………….18
2.1. Sustainable Development and Urban Environment……………...……. .18
2.2. Urbanization and Environment..…………………..…….…………..…..21
CHAPTER THREE: THE COMCEPT OF URBAN GREEN DEVELOPMENT:
BENEFITS AND CHALLENGES ...……………………..………..………………..29
3.0 Introduction ……………………………………………………………..29
3.1 Urban Green Defined ....………..….…….……………...…..…………...29
3.2 Benefits of Urban Green ….…………..………………..………...………30
3.3. Challenges of Urban Green…………….…….………….…………...... 41
8 CHAPTER FOUR: THE ROLE OF REMOTE SENSING AND GIS
TECHNOLOGIES IN URBAN GREEN..…………………………………...………46
4.0. Introduction …...………………….…………………………..…………46
4.1. GIS and Remote Sensing as a Planning Tool ..………………...……….46
4.2. Linking GIS to Urban Green Development .………………………...…50
CHAPTER FIVE: MODEL OF GIS APPLICATION IN URBAN GREEN
DEVELOPMENT IN GHANA ……………………..…………….………..…..…...53
5.0. Introduction ……………………………………….……………..….…..53
5.1. Requirements for Creating an Urban Green GIS .………..……..….…...53
5.2. Urban Green Area Modeling …...……………………………….….…...64
5.3. Problems of Applying GIS Technique for Urban Green Development in
Ghana ………………………………………………………………………..72
CHAPTER SIX: CONCLUSON ...…………….……….………………..…………83
6.0. Introduction ………………………..………………..…….……..……..83
6.1. Recommendations ….…………………………..……….……..………..83
6.2. Future Research …………………………………………………………86
References ………………………………………………….…….………..………...87
Appendix: Photo Gallery ...…………………………………………….….…...……98
9 LIST OF TABLES
Table Page
1. Environmental Problems Facing Major Cities in Ghana …………………...……15
2. Distinct Food Crops (species and distinct varieties) Found Present in Surveys of
Urban Agroforestry Systems ..…………………………………………………...32
3. Pollutants Removal by Trees in Selected Cities of US Measured in Pounds and in
Dollars ……………………………..…………..…………………………….….38
4. Required Data for GIS and Urban Green Modeling ...…..……..…..…………....66
5. Factors and Constraints for GIS Modeling of Urban Green Area ………………..67
10 LIST OF FIGURES
1. World Regional Population Living in Urban Centers (1950-2015) ….………….22
2. Regional Rural and Urban Population Distribution of Ghana (1972-1984) ……...24
3. Regional Population Distribution for Ghana …………………………………….24
4. Urban Heat Island Profile – Late Afternoon Temperature …….……………….....39
5. Modeled Selection Process of Area for Urban Green Development ……...……...69
6. Modeled Structure of GIS and Remote Sensing Application for Urban Green
Development …..………………………………………………..…………….…..72
7. Modeled Structure of the Asante Land Ownership System.………..…………...79
11
CHAPTER ONE DESTRUCTION OF NATURE IN THE CITY 1.0 Introduction
Development plans in Ghana, like other developing countries have aimed at utilizing natural resources to generate economic growth with “how the country or a community could be converted from being a 5% saver of GDP to a 12% saver with all the changes in attitudes, institutions and techniques which accompany its conversion”
(Todaro 1992 p. 90-109), as the central theme. The net effect is the emergence of
bizarre economic and cultural landscape in cities devoid of natural (green) areas.
These cities are characterized by heat islands, excessive runoff and shortage of ground water, lack of natural areas, with a large gap between urban dwellers and nature.
Realizing how we have become captives of technology, as in the case of developed world, is the first step in bringing people back to nature. It is therefore our duty to
rethink green and also explore the benefits of greening our world through the
application of modern technologies such as Remote Sensing and Geographic
Information Systems (GIS).
1.1 Thinking Green
The Habitat Agenda, adopted globally in 1996, clearly recognizes the
urbanization challenge and the need for all governments and international agencies to
prepare and implement plans of action to support sustainable urban development,
which is essential in achieving economic growth, social development and
environmental protection (Wekwete 2001). The US Congress first recognized the
12 importance of urban forests in 1978 with the Cooperative Forestry Assistance Act, which provided funds to promote the maintenance, expansion and preservation of urban tree cover while encouraging research and development of related technical skills at the local level. The legislation also called for tree planting to complement existing urban forest and open space maintenance programs. The Urban and
Community Forestry Assistance Program of 1990 expanded aid to state foresters and nonprofit organizations working to promote and expand urban forest parklands (Baker
2000). Recently President Bush has pushed to increase annual appropriations under the program by more than $31 million per year (Scheer 2001). The question then is what is the motivation to create or embark on sustainable urban development; economic, environmental, aesthetic, population and housing or personal interest?
Frederick Law Olmsted, the grand-daddy of American landscape architecture, said jokingly to the City of New York in 1872 that the midtown Manhattan Park he was busily creating would serve as the “lungs of the city” (Scheer 2001 P. 1). Today, he is the hero; hardly did he know how prescient he was when he made the statement.
His posthumous victory stems from the fact that urban forests found within city parks across the United States and other developed countries today, serve not only as recreational and social centers, but also as organic sponges for various forms of pollution and as storehouses of carbon dioxide to help offset global warming. Indeed, recent experiences in several U.S. cities have shown Olmsted's metaphor for what is now Central Park to be far more literal than figurative. Each year in Chicago, for example, the urban tree canopy removes 15 metric tons of carbon monoxide, 84 metric tons of sulfur dioxide, 89 metric tons of nitrogen dioxide, 191 metric tons of ozone and 212 metric tons of particulates, according to David Nowak, project leader
13 of the U.S. Forest Service's Urban Forest Ecosystem Research Unit. Trees absorb
these gaseous pollutants via their leaf stomata and break them down into less-harmful
molecules during photosynthesis (Nowak 1995). Though scattered, individual trees
can absorb pollution, urban forests provide the most booms for a city's buck.
Chicago's urban forest canopy, which covers roughly 11 percent of the city's total
land, saves the municipal government more than $1 million every year, according to
Nowak (1995), in what would otherwise be spent on traditional pollution mitigation
efforts.
Urban forests also play an important role in sequestering carbon dioxide, the potent greenhouse gas that is primarily blamed for global warming. It also maintains the energy budget, promote rainfall and reduce run-off (Sundaram 2001).
1.2 The Question of Green Development
Although developed countries like United States and other Western European
countries have realized the incalculable benefits derived from keeping cities
vegetated, the situations found in the cities of developing countries, including Ghana
are right opposite. The rapid growth of cities in Ghana has focused on the cities’ role
for economic development, with their huge population-base, pushing these cities to an
unprecedented size. These processes have modified the urban environment from its
natural state through the following processes:
• The conversion of land to urban uses;
• The extraction and depletion of natural resources;
• The disposal of waste in urban and sub-urban areas;
14 As the cities expand through spatial spread or urban sprawl and conurbation
processes, prime agricultural lands and habitats such as wetlands and forests, in and around the cities, are transformed into paved surfaces, land for housing, roads, industrial and other uses (Corubolo and Mattingly 1999). According to Olembo and
Rham (1987), many colonial towns in the developing world, previously well-endowed
with trees and greeneries, have deteriorated in this respect as standards of living have
declined.
Today cities in Ghana have grown to an unprecedented size with Accra
Metropolitan Area leading with population of about 5 million people. The second city
Kumasi, which was popularly known as ‘The Garden City’ because of its low density residential areas, many beautiful species of flowers, trees and green plants, has a population of about 2.5 million. Other cities like Tamale, Sekondi-Takoradi, Cape
Coast, Tema and Sunyani have all received their fair share of the urbanization spree in
Ghana with significant environmental consequences as shown in table 1: below. The crux of the matter is that city and development planning has not only ignored green
area development but has converted existing green areas into paved surfaces,
residential land use, industrial land use and waste dumping grounds.
Given these consequences, future development planning must consider among
other things:
• How to create more friendly natural environment in the city so as to reduce air
pollution, run-off, diurnal temperature range, loss of biodiversity and make the
city more livable than today?
• How GIS can be used to guide Green Development in cities of Ghana?
• What are the likely problems when trying to apply GIS in Green Development
in Ghana?
15 Table 1: Environmental Problems Facing Major Cities in Ghana
Major Cities Common Environmental Problems
1. Accra Perennial flooding as a result of excessive run-off, soil erosion 2. Kumasi and the associated destruction of properties 3. Tamale Air pollution, especially from vehicle exhausts, manufacturing 4. Tema plants, dust, household energy consumption and improper and 5. Sekondi- limited capacity for waste disposal Takoradi Depletion of the green areas and loss of biodiversity 6. Cape Water scarcity and alteration of basic cyclic pattern of the local Coast ecosystem – including hydrological cycle and nutrient cycle
Microclimatic change Monotonous in the visual environment Creation of an unfriendly man-made environment and increasing variation in the diurnal temperatures
1.3 Research Objectives
Urban green initiative seeks to manage urban trees and related vegetation to
meet the environmental health, economic, social and psychological needs of urban
dwellers. The inability of many resource poor cities, especially in Ghana to meet these
basic needs of its dwellers, stems from the complexity, unavailability of data,
financial and human resources requirement and laborious nature of the designing and
implementation of such a noble idea. It is the aim of this study to demonstrate how the cities in Ghana can integrate urban green with other urban land uses through the application of GIS and Remote Sensing technologies to ensure a livable city for the
people.
To this end, the main objectives of this study are:
1) Understanding the importance of urban green development in the urban milieu
2) Develop an urban green implementation model for Ghanaian cities
16 3) Highlight and caution potential developers of some of the possible problems
they are likely to encounter
1.4 Research Methodology
Data Source:
Originally this work was meant to create urban green design for Kumasi
Metropolitan Area. Unfortunately, this project was hampered by lack of area-specific
data which are current and accurate, time and financial constraints. It was against
these constraints that this new research topic emerged as a way of exploring and highlighting the nature and extent of the actual problems that are likely to emerge when developing and implementing GIS and remote sensing application for urban green development in Ghana. The study sought to review the literature and models
about urban green development worldwide to ascertain the methodologies, data type
and data sources and to use these to explore what is available in Ghana, in order to
conclude on what the likely problems and opportunities may be. Some of the critical
questions answered in this study include: the what, where and how of data for urban
green development in Ghana, the human resource, hard and software requirement and
institutional setting for successful GIS for urban development in Ghanaian cities. The
study therefore drew mainly on secondary data that were both published and
unpublished, internet sources and also on personal experiences, as far as the culture
and institutions that are likely to promote or hinder urban green development program
in Ghana is concerned.
Data Analysis:
Most cities in Ghana are far older than the country itself. For example Kumasi
and Cape Coast are some of the earliest cities in Ghana and it is described in many
17 official circles as the hub of Ghanaian culture. From its historical background, the
design and build-up of these cities epitomizes the culture and the entire history of
Ghana. In this way, planning to integrate green areas to the old cities’ landscape and land use involve rezoning of an existing land use zones, although these cities, for their historical settings, lack a well-defined land use zones. Rezoning of the cities’ spatial organization might affect the historic and cultural significance of these cities. In order not to disturb these cities and their spatial organization, this project drew from experiences from some ancient cities on how they were able to integrate green areas consisting of trees, flowers and other green plants into the existing city plans without any dramatic transformation of the existing spatial arrangement of these cities and the way of life of the people. Data gathered were used to develop models and build spatial relationships to take care of the nature of urban green in old cities. Some of the data were also developed into graphical presentation to show spatial interactions and connectivity, as a way of highlighting the likely land use conflict. For example the absence of sidewalks in Ghanaian cities was identified as one of the key problems likely to emerge when developing urban green system in Ghana.
Although the methodological approach of this study might defy the strict jack research methodology of Environmental Studies, it proves very beneficial because it shows the spatial relationships, which in turn reveals the data and other resources required and also highlights the actual problems that are likely to occur when developing and implementing GIS and remote sensing applications for urban green development.
18 CHAPTER TWO DEVELOPMENT, URBANIZATION AND THE ENVIRONMENT NEXUS
2.0 Introduction
Balanced interplay between economy, society and ecology is regarded as a prerequisite for sustainable development in the modern world, either in the developed or the developing world (Cartalis 1997). Unfortunately, past development approaches have focused on societal economic development goals with the urban centers as the catalyst to the neglect of the natural environment (ecology). Oakley (1991) has argued that no matter the development approach in question, it operates within certain environmental conditions and deterioration of such environment has an adverse effect on the sustainability of the development. Owusu (2001) in a study argued that,
“Development must not only enlarge people’s choices rather enlarge people’s choices in a manner that is economically, socially and ecologically sustainable” (Owusu 2001 pp 25). The chapter looks at the linkages between development, urbanization and the natural environment, which past development efforts have relegated the environment to the background.
2.1: Sustainable Development and Urban Environment
Sustainable Development (SD) is a term that has been overused in recent times
(Kamete 2002). This, perhaps, is due to the fact that “there is much confusion on the meaning of the concept” (Atkinson 1999). As a concept, SD was defined as
“development that meets the needs of the present without compromising the ability of future generations to meet their own needs” (WCED 1987). World Conservation
Union, United Nations (UN) Environment Program and World Wide Fund for Nature
(1991) also gave a complementary definition to sustainable development as:
19 “improving the quality of life while living within the carrying capacity of supporting ecosystems”. Various academic disciplines have given different definitions to the concept from their own perspective. To the economist, sustainable development implies achieving economic sustainability, while sociologists also think about social implications of development with poverty and social structure as critical indicators.
Similarly, the ecologist understands the concept in terms of ecological stability and its implications on biodiversity. To us, the environmentalists, the concern is how production and consumption impacts the natural system and how we can protect the
natural environment.
In practice sustainable development is a much broader concept than
environmental protection. It implies a concern for present and future generations
(inter and intra generational equity) and for the long-term health and integrity of the
environment. That is, it embraces concern for the quality of life (not just income or
economic growth), for equity between people in the present (including access to
resources), for inter-generational equity (people in the future deserve an environment
which is at least as good as the one we currently enjoy, if not better), and for the
social, health and ethical dimensions of human welfare (Kamete 2002; UNDP 1997).
It also implies that further development should only take place as long as it is within
the carrying capacity of natural and human systems. Sustainable Development is seen
in many circles as a paradigm shift, which challenges the status quo. It poses new
challenges to the concept of development, especially in developing countries where
development is see as urban bazaar economy with mass production and consumption,
acquisition of 4 to 5 cars, L’cartesian, paved surfaces, sky scrapers, with no
semblance of nature, while local cultures are deemed outdated.
20 Clearly, addressing the sustainable development agenda provides new
challenges for traditional urban planning. In planning the natural environment
conveys many different meanings. From one perspective the environment supplies the
land required to accommodate growth and development of urban bazaar economy. By
contrast environment defines a series of natural functions to be maintained, hazards to
be avoided and opportunities to be exploited (Lein 2002). The concept of sustainable
development looks at the environment not only from its utilitarian point but also from
the point of the environment as an all-encompassing entity that simply exists not as a
passive feature there to serve human needs but as a set of active processes that define
behavior and establish patterns that interact with and redirect human trajectories (Lein
2002). The traditional planning ideas have focused on the utilitarian view of the
environment and therefore utilized it to satisfy human wants such that urban centers
are devoid of natural areas. The net effect is the creation of unsustainable cities across
the globe.
The situation assumes an alarming dimension when considered in the context
of developing countries. The development drive perused by third world countries
including Ghana have focused on GDP growth, with urban economy as the catalyst. It
is therefore not surprising that developing countries are experiencing an
unprecedented urbanization with another Shanghai developing every 10 years
(Kuchelmeister 1999) with limited concern for the natural environment, hence fear for
their sustainability.
21 2.2: Urbanization and Environment
Human habitat is rapidly urbanizing. By 2030, the urban population globally
would be twice as large as the rural population (World Bank n.d.). By 1850, Britain
was the only country considered urbanized with half of its population in cities; today
all developed countries are urbanized with at least 75% of its population living in
urban centers (United Nations 1998). Most of the developing countries, which are not
yet urbanized societies, would also become urbanized by 2030 (United Nations 1998).
Between 1990 and 1995, some 260 million people were added to the cities of the
developing world - the equivalent of another Shanghai forming every ten years
(Kuchelmeister 1999). Population increase in urban areas in developing countries will
be the distinguishing demographic trend of the next century, accounting for nearly 90
percent of the 2.7 billion people due to be added to world population between 1995
and 2030. By the year 2030, almost 85 percent of Latin Americans would be living in
cities, as would over one-half of all Africans and Asians. Asia would have the largest
urban population in the world, almost twice as many people in cities as in Africa and
Latin America combined, and Africa would have more urban residents than Latin
America (United Nations 1998). Some 73 percent of Latin Americans now live in
cities, making the region roughly as urbanized as Europe and North America. Thus,
the most explosive growth in the future is expected in Africa and Asia. Figure 1 below
shows percentage of regional population living in urban center.
Africa is said to be the last continent to become urbanized. At the start of 20th
Century, 95 percent of Africa’s population lived in rural areas. Up to 1960s, Africa
remained the least urbanized region in the world with an urban population of 18.8%
as shown on figure 1: below.
22 Figure 1. World Regional Population Living in Urban Centers (1950-2015)
90% 80% 70% 60% 50% 40% 30% Urban Population 20% 10% 0% 1950 Africa Asia Latin Industrial World 1975 America Countries 1995 Region 2015 Source: United Nations 1998 Adapted
1) Asia Excluding Japan 2) Industrial Countries include Europe, Japan, Australia, New Zealand, and North America but excluding Mexico
By 1996, African urban population had more than doubled, with over 43% living in cities by 2010 (UNPD 1997).
The average annual urban growth rate of Africa 1970-2000 was estimated to be the highest in the world, at more than 4% (GEO 2000). According to UN (1998),
Africa will have more urban residents than Latin America by the year 2030 although
Latin America has about 75% of its current population living in cities. By implication
Africa has to more than double its current urbanization rate in order to achieve the predicted level of urbanization. Within Africa the extent of urbanization differs widely. Whereas over 50% of the population lives in urban centers in North Africa, east Africa has only 23% of the sub-region’s population in urban centers. Southern,
Central and West Africa has between 33-37% of their population in urban centers
(UNPD 1997). The differences in urbanization in African assume a wider dimension
23 when it is narrowed down to country levels. In countries like Algeria, Djibouti, Libya,
Mauritania, to mention but few, over 50% of the population live in cities while
Rwanda and Burundi are the least urbanized with only between 6-8% of its population in urban centers (UNPD 1997).
Ghana’s urbanization experience is not very different from the general African picture painted above. It is classified among the rapidly urbanizing countries of the
African region. Since 1960, localities in Ghana of 5,000 persons and above are classified as urbanized. On this basis, the 1960 urban population totaled 1,551,174 persons, or 23.1 percent of the total population. By 1970, the percentage of the country's population residing in urban centers had increase to 28 percent. That percentage rose to 32 in 1984 and was estimated at 33 percent in 1992. Currently the total urban population of Ghana is estimated to be around 45% with Accra forming a primate city with a total population of over 3 million and Kumasi, the second city with 1,170,270 (GSS 2002). Like other regions of the world, the rate of urbanization in Ghana varied from one administrative region to another. While the Greater Accra
Region showed an 83-percent urban residency, the Ashanti Region, which is the second populous region of the country, matched the national average of 32 percent in
1984 and 51.3% in 2000 (GSS 2002). The figure 2 and 3 below shows the regional rural-urban population distribution of Ghana from 1972-1984. The three northern regions are the least urbanized. Upper West Region of the country, which is the least urban, recorded only 10 percent of its population in urban centers in 1984, which reflected internal migration to the south and the pattern of development that favored the south, with its minerals and forest resources, over the north, a pattern established by British colonial administration. Urban areas in Ghana have customarily been supplied with more amenities than rural locations.
24 Figure 2: Regional Rural and Urban Population Distribution of Ghana (1972-1984)
10 0
90
80
70 n o
i 60 t a 50
opul 40 P
% 30
20
10
0 Ashanti Brong- Central Eastern Greater Northern Upper Upper Volt a We st e rn GHARuNA ral Aha fo Accra Regions Ea st We s t Urban
Source: Ghana Statistical Service (1991).
Figure 3: Regional Population Distribution for Ghana
Upper East
Upper West
Northern
Brong Ahafo
Ashanti
Volta Eastern
Western GT Accra Central
Source: GSS 2000
25 Consequently, Accra, Kumasi, Tema, Koforidua and many towns within the southern economic belt attracted more people than the savanna regions of the north; only
Tamale in the north has been an exception. The linkage of the national electricity grid to the northern areas of the country in the late 1980s and early 1990s may help to stabilize the north-to-south flow of internal migration. The growth of urban population notwithstanding, Ghana continued to be a nation of rural communities.
The 1984 enumeration showed that six of the country's ten regions had rural populations of 5 percent or more above the national average of 68 percent. Rural residency was estimated to be 67 percent of the population in 1992. These figures, though reflecting a trend toward urban residency, are not very different from the
1970s when about 72 percent of the nation's population lived in rural areas (GSS
2002; Corubolo and Mattingly 1999).
In an attempt to perpetuate this pattern of rural-urban residency, thereby lessening the consequent socioeconomic impact on urban development, the "Rural
Manifesto," which assessed the causes of rural underdevelopment, was introduced in
April 1984. Development strategies were evaluated, and some were implemented to make rural residency more attractive. As a result, the Bank of Ghana established more than 120 rural banks to support rural entrepreneurs, and the rural electrification program was intensified in the late 1980s. The government, moreover, presented its plans for district assemblies as a component of its strategy for rural improvement through decentralized administration, a program designed to allow local people to become more involved in planning and implementation of development programs to meet local needs. Unfortunately, this program ended up creating more urban centers, as areas with growth impulse and district capitals attracted government workers and
26 other service providers. Also life in those centers became attractive and people moved from nearby villages to settle in those towns.
As centers of population and human activities, cities consume natural resources from both far and near and also generate waste that is disposed of, both inside and outside the city. In the process, cities generate environmental problems over a range of scales, the household, workplace, the neighborhood, the city, the wider region and the globe. Urban environmental problems also create a range of socio-economic impacts that may impair human health, cause economic and other welfare losses, or damage to the ecosystems on which both urban and rural areas depend. Most urban environmental problems entail all these impacts, either directly or indirectly. Increasingly urban air pollution has direct impact on human health, especially incidence of respiratory diseases. The impact on the economy is indirect, through loss of productivity due to ill health (World Resources Institute 1996).
According to World Resources Institute (1996), these problems vary from city to city and region to region and are influenced by such factors as a city’s size and rate of growth, income, local geography, climate and institutional capacity. For these reasons poor and fast growing cities in Ghana such as Accra, Kumasi, Tema and Sekondi-
Takoradi are more likely to face sustainability crisis.
Currently urban centers like Accra and Kumasi are saddled with problems related to the conversion of natural areas to urban uses, the extraction and depletion of natural resources, and the disposal of wastes in the urban areas. As these cities expand, through conurbation process, prime agricultural land and habitats such as wetlands and forests (in and around the city) are transformed into land for housing, roads, industry etc. (Corubolo and Mattingly 1999) (Appendix Plate 2 and 4). Other problems in these cities include air pollution, depletion of the green areas and loss of
27 biodiversity, water scarcity and alteration of basic cyclic pattern of the local ecosystem – including hydrological cycle and nutrient cycle, microclimatic change, excessive run-off, soil erosion and frequent flooding and associated destruction of properties, monotonous in the visual environment, creation of an unfriendly man- made environment and increasing variation in the diurnal temperatures (Corubolo and
Mattingly 1999).
Over the last few decades there have been many discussions on the decline of the tropical forests in developing countries. Until recently the loss of trees in and around the places where people live has hardly received international attention. In
Kuchelmeister’s view, nearly all major donor agencies have restricted their forestry mandate to the rural area, despite the rapid process of urbanization in developing countries (Kuchelmeister 1999). He argued that, due to the social and environmental problems associated with rapid and uncontrolled urbanization in the developing world, resource-poorer city dwellers have to be a focal development issue for many years to come. The dramatic increase in urban population in developing countries and the corresponding increased demand for food, fuel and shelter and for improved quality of life in the cities, call for the design of strategies in which forestry and other green plants can play a more important role. In an interview with hundreds of individuals in 43 cities, including national governments and research organizations,
Green Urbanism indicates that European city policies aim to increase sustainability through space planning, alternatives to automobiles, energy efficiency and renewable energy, passive solar design, water conservation, green-roofs and green walls, preservation of green space, education of citizens, and the encouragement of businesses to adopt sustainable practices (Newcomb 2000). The research clearly
28 illustrates the importance of supportive political and public values and the importance of planning for the future. Similarly poor cities in developing countries can develop an appropriate low cost green area development plan and adopt appropriate political, social and economic strategies to attract political and public support.
29 CHAPTER THREE THE CONCEPT OF URBAN GREEN DEVELOPMENT:BENEFITS AND CHALLENGES
3.0 Introduction
The term ‘urban green’ has been used frequently and loosely by many people
and in different contexts. Perhaps the greatest concern is the changing meaning of the
term, as people often used it to mean different things depending on their background.
One interesting observation is the fact that most of these definitions share common
goal of introducing greeneries into the urban setting for economical, environmental,
social, and psychological benefits to the people.
In spite of the changing meaning and the diversity in the definition of the term
urban green, there is a unanimity in its benefits and the challenges, in terms of what it
poses to the urban people and environment and what it faces from the urban dwellers
and the general urban environment. This chapter discusses the definition, benefits and
challenges of urban green in the urban centers of developing countries with emphasis
on Ghana.
3.1 Urban green defined
Sundaram (2000) used the term urban green to imply all attempts at increasing
green spaces in the urban landscape such as; urban forestry, silviculture, afforestation social forestry etc. Thaman, writing about urban agroforestry also defined it as the planting, protection or preservation of trees for their economic, social and ecological value as part of agricultural and horticultural systems in urban areas, not only adjacent to houses and other buildings but also on undeveloped land within urban areas
(Thaman 1987). Similarly, Kuchelmeister (1997) and Miller (1997), use the term
30 ‘urban greening’ interchangeably with urban forestry. Kuchelmeister (1998) defines
urban forestry as, planning, management and conservation of trees, forests and related
vegetation to create or add value to the local community in an urban area.
In general, urban green development is a modern approach to urban (including
peri-urban) vegetation management, encompassing long-term planning,
interdisciplinary professional coordination, and local participation. It aims at securing
the environmental and psychological health, economical and sociological well-being
of society. Urban green development is said to be a young science that originated from the developed countries in the 1970s, focusing on how natural and open green space can be integrated to the existing urban environment (Kuchelmeister 1999).
Today the idea has spread to the developing countries with a wider focus than just integrating greens and open spaces into the urban spatial plan and environment. It is believe by many urban geographers, ecologists, environmentalists and arborists that urban green can play a wider role by providing benefits ranging from economical
through ecological, social to psychological health of the urban people. Some of the
benefits of urban green development are discussed below.
3.2 Benefits of Urban Green
According to Olembo and Rham (1987) few solid scientific data seem available on the measurable benefits of trees on the urban environment. This probably results in part from the attitude of the general public, especially in developed countries, which regards trees, forests and green areas as unquestionably having such positive effects and therefore being very desirable assets for the community. The large parks of London and Manhattan for example, have been called the ‘lungs’ of the city for a long time without anyone really knowing much about how this beneficial
31 functions work. Therefore the incentives to measure such benefits have not been very
great. The public's energy has instead, and probably well-focused, on how to save the
trees and other green areas of the city. The very strict laws protecting trees in many
western cities indicate how much effort have often been placed, though successfully,
on urban green.
Urban green development seeks to improve the well-being of urban and peri
urban dweller in many different ways. These benefits have been classified simply by
Kuchelmeister (1997) to include physical or tangible benefits (economic),
environmental and health benefits, social and numerous other non-quantifiable benefits.
• Physical or tangible benefits
Urban green provides physical or tangible benefits that are mainly consumables.
These include food, woodfuel, fodder, fencing materials, timber and poles
(Kuchelmeister 1999). In the developed part of the world urban green development has focused mainly on amenities and environmental benefits, the approach in poor countries must pay attention to assisting in the fulfillment of basic necessities first, by contributing significantly to the food and other material requirements of the urban poor, both on daily basis and in times of crisis (Lanly 1997). Evidence from Sahel
regions of Africa shows that baobab leaf, tamarind and processed parkia seeds are
very popular in large towns as source of food to poor people. Fruit bearing trees like
mangoes, oranges, avocado pea, to mention but few, are noted for their contribution to
the nutritional status of street children and children in poor cities of the tropical
regions.
In a study of Pacific Islands, Thaman (1987) observed that trees are perhaps as
important to urban people as they are to rural people. The preservation, promotion,
32 and improvement of urban agroforestry could be one of the most direct and
economically, socially, ecologically and nutritionally appropriate means of bringing
about sustainable development in the Pacific Islands. He established that, even in
areas not known for agricultural diversity, such as Kiribati and Nauru, urban gardens
contain a wide range of food trees, non-tree staple and supplementary food plants and
countless non-food plants. He estimated the contributions of agroforestry into the food
needs of urban dwellers in Pacific Islands. Summary of his findings are presented on
the table below.
Table 2: Distinct Food Crops (species and distinct varieties) Found Present in Surveys of Urban Agroforestry Systems
Crop types Port Suva, Nuku'alofa, South Nauru Location Moresby, Fiji Tonga Tarawa, Papua New Kiribati Guinea Food trees 30 39 27 20 14 16 Non-tree 7 10 8 6 5 8 staples Non-tree 48 65 44 35 14 41 supplementary Total 85 114 79 61 33 65
Source: Thaman 1987
Among the plants cultivated are a great variety of food trees including Musa
clones, coconuts, breadfruit, pandanus, citrus trees, papaya, guava, avocado, Annona,
Ficus and Syzygium spp., and the beach almond (Terminalia catappa). Also staple
root crops such as taro, cassava, tannia, sweet potato, yams, giant taro and giant
swamp taro; and a great range of supplementary non-tree food plants, including
onions, amaranths, pineapple, peanuts, cabbages, a wide variety of legumes and
spinaches, cucurbits, okra, tomatoes, passion-fruit, sugar cane, eggplant and maize.
33 Others include spices such as chilies, ginger, coriander, and mint; and beverage,
stimulant and depressant plants such as betel nut, betel pepper, kava (Piper
methysticum), tobacco and lemon grass. Many of these plants were found present in a majority of home gardens in Pacific Islands.
Sene (1993) has noted the exploitation of local trees for their medicinal values in some poor cities of Asia. Similarly tropical trees like neem tree and its medicinal value of curing malaria has been utilized in many cities of Ghana. Carter (1993) has documented the tremendous benefits derived in arid regions from urban trees. He singled out the role trees play in meeting the fodder requirements in arid zones, to the extent that even amenity trees are exploited during the dry seasons.
Also the role urban trees play in meeting the fuelwood needs of poor people in cities of developing countries have been well documented. According to Hague
(1987), some 13 cities including Kampala, Debre Birhan have organized urban fuelwood plantations by planting trees which have other uses besides fuelwood, such as fodder and electric pole production. In his view urban forestry can make an important contribution to solving the fuelwood crisis in developing countries, and he recommend that more urban fuelwood tree planting programs need to be developed.
• Environmental and health
Trees are said to be the oldest and largest living things on the earth and they are a good measure of the health and quality of the environment. It is therefore not surprising that founders of Kumasi, with their wisdom and vision of building a green city planted a locally endowed tree to test the health and quality of the environment.
According to American Forests (2000), as city expands and population grows, trees become important in terms of their ecological values and conservation roles. It is argued that, until recently, it was extremely difficult if not impossible to quantify how
34 vegetations improve our environment. The application of GIS and Remote Sensing
techniques has helped in no small way in quantifying the benefits of urban trees.
In the view of Olembo and Rham (1987), trees have a proven beneficial effect.
First, let us consider the city environment as it differs from the countryside
environment. Cities are characterized by a predominance of cluster of houses, stones,
concrete, asphalt and metal, all materials which accumulate and radiate heat and
which have a high reflective power for light and sound. Metabolic and economic
activities heating, cooling, transport, heavy industry, etc; produce great amounts of
heat. The air becomes filled with carbon dioxide (CO2), carbon monoxide (CO),
sulphur dioxide (SO2) and many other pollutants including dusts. As a result the
climate of large cities, especially in badly ventilated areas, differs considerably from
that of their surroundings. The median temperature is higher, the air is drier and the
sunlight is often partially blocked by haze or even fog induced by emissions. Rainfall,
however, can be higher and tends to be more torrential. Trees beneficial effects
include dust reduction, fixation of some toxic substances, reduction of high
temperatures and increasing relative humidity. In a study of 20 cities in the USA,
American Forests has documented the loss of trees and open areas, and calculated the
value of trees not only in terms of ecological benefits but also in dollars terms. They
argued that trees are nature’s public utility and they perform this function in terms of
stormwater management, air quality improvement and energy conservation.
Noise reduction by trees, although widely believed in, is difficult to prove. It is
possible that trees, rather than directly blocking sound emissions, reduce the vibration,
reflectibility and resonance of sounds produced in the immediate environment. In addition, vegetation, and especially trees, can be used in urban areas as excellent
35 indicators of the quality of the environment and health since they react by integrating
external factors, both positive and negative (Olembo and Rham 1987).
• Stormwater drainage:
According to Keating (2002), stormwater managers face two main challenges.
1) Channel the water so that it does not flood homes, properties, or city streets
2) Making sure that the water is reasonably clean before it flows into natural
streams, rivers and lakes.
The solution to these two challenges in most cities lies in the construction of large and
expensive storm drains, sewers, concrete drainage ditches and the like. The efficiency
of the drainage system in poor cities of the developing world, including Ghana, has
come under question. This is because most of these drainage ditches were built
several years ago, when these cities were two to three times less than their current
sizes. They are also narrow and uncovered (shown by plate 4 and 11).
It is therefore not surprising to see these ditches filled with garbage and other wind-blown litters which block drains to cause the perennial flooding associated with
Ghanaian cities. Another factor that brings the efficiency of these ditches under questioning is the increase in stormwater due to increased in paved and concrete surfaces in the city over the years.
Keating (2002) has argued that before humans changed the landscape, nature had
its own way of dealing with stormwater. It either soaked into the soil nurturing the
plant life or overflowed in the form of runoff in floodplains or wetlands. This process,
in the past, worked very well, however, modern development drive and the resultant
impervious surfaces have made the natural drainage system inefficient and
problematic. For this reason, some scholars and researchers are taking a fresh look at the role open areas and trees play in natural stormwater diversion and treatment.
36 According to American Forest Organization (www.americanforests.org), a healthy tree canopy can reduce stormwater runoff dramatically, thereby saving its host city millions of dollars in infrastructural cost. Using CITYgreen software, American
Forests Organization (2000) calculated that the tree canopy of Garland City, TX, was saving the city $5.3 million dollars a year. This includes residential energy savings, runoff reduction and air pollution removal. In another study, a Horticulturalist has noted that trees’ weekly water needs equal 5 gallons per caliper inch. That is, a 2- caliper-inch tree needs 15 gallons {5+(5x2)=15} weekly (Keating 2002). This calculation represents minimum water absorption by trees. For example, it is believed that a matured bald cypress can absorb 880 gallons per day depending on soil type and level of saturation. However, it is worth mentioning here that the level of efficiency with which trees can absorb and control stormwater depends on the type of tree and the green design.
3) Air quality:
Urban areas account for only 2% of earth's land surface; they produce 78% of greenhouse gases, thus contributing to global climate change. Cities also play a central role in alteration of global biogeochemical cycles, changes in biodiversity due to habitat fragmentation and exotic species, and changes in land use and cover far beyond the city's boundaries (Grimm et al 2000; Barradas 2000). It is estimated that globally, 1.1 billion people live in urban areas with unhealthy air, exposed to pollutants released from industrial, energy and vehicular sources. World Bank has also estimated that if particulate matter levels alone were to be reduced to the World
Health Organization (WHO) guidelines, between 300,000 and 700,000 premature deaths per year could be avoided (World Resources Institute 1996). WHO estimates
37 that in Mexico City, suspended particulate matters from vehicles and other sources accounts for 6,400 deaths each year.
The situation in Ghanaian cities might not be as notable as that of Mexico City due to size and activity concentration differences; it may not be far from reality, to envisage a city located in tropical environment and urbanizing at a rate of about 4.5 % p.a. with a current population of between 2- 5milion while devoid of trees and other green open spaces. It would not be unthinkable to imagine that pollution and poor air quality related diseases and deaths might be closed to the situation in Mexico City of
6,400 people per annum.
Gary Moll asserts that trees are the ‘ultimate urban multitaskers’, performing the functions of air filter, sponge, humidifier, heat shield, wind block, and carbon sink
(Scheer 2001). It is estimated that each year in Chicago, the urban tree canopy removes 15 metric tons of carbon monoxide, 84 metric tons of sulfur dioxide, 89 metric tons of nitrogen dioxide, 191 metric tons of ozone, and 212 metric tons of particulate matters. According Nowak (1992), green plants absorb these gaseous pollutants via their leaf stomata (the tiny pores on leaves) and break them down into less-harmful molecules during photosynthesis. Trees also reduce wind speed so that large particles settle out before it could cause any meaningful damage to life and property.
In 2001, American Forests in a research to determine the work trees do to clean the air using CITYgreen software—a desktop GIS program, which calculated the value of trees to urban environments. The table 3: below shows the value of trees in terms of cleaning the air, measured in pounds and in dollars.
38 Table 3: Pollutants Removal by Trees in Selected Cities of US Measured in Pounds and in Dollars
City Pounds of pollutants Annual value of trees with removed annually by trees respect to air pollution Washington, DC 878,000 $2.1 million Atlanta, GA Metro Area 19,000,000 $47 million Portland, OR Metro Area 2,000,000 $4.8 million Denver, CO Metro Area 1,100,000 $2.6 million
Source: American Forests 2001
4) Energy conservation
Analysis of temperature changes using general circulation models suggest that
by the end of the century, the world would be presented with a warmer climate than
has been experienced during the last 100,000 years. Models of climate change have
predicted an increase in the mean global temperature of about 1.5-4.50 Celsius in the next century. This rising temperature is due to increasing concentration of enhanced greenhouse gases (mostly carbon dioxide) due to human activities. Trees remove carbon dioxide from the air through leaves and store carbon in their biomass.
Approximately half of a tree’s dry weight is carbon. For this reason, large-scale tree
planting projects are recognized as a legitimate tool in many national enhanced
greenhouse gases-reduction programs.
Furthermore, trees provide a secondary carbon-related benefit that can be
much more valuable, particularly in urban areas. Research by the USDA Forest
Service and others has shown that trees, strategically planted to shade homes, can
reduce air conditioning bills significantly. As a result, local power plants are not
required to produce as much electricity and thus emit less pollution, including carbon.
In certain areas (urban and suburban areas with high cooling costs) these indirect
39 carbon benefits can be significantly higher than the direct effects of carbon
sequestration.
In 2001, American Forests found that tree cover in the metro Atlanta area
saved residents approximately $2.8 million annually in reduced energy costs. In 1999,
a 3.2 million acre area around Houston was found to benefit by $26 million annually
as a result of the cooling effects of its vegetation (tree) cover. Similar trends have
been found throughout the United States (American Forests 2001).
Figure 4: Urban Heat Island Profile – Late Afternoon Temperature
Source: American Forests 2001
However, it should be noted here that the age, geographical location (based on
aspect) and closeness of the trees to houses and residential areas play an important role by influencing the effectiveness of trees to reduce energy consumption and cost.
5) Aesthetic and recreational values
There is little doubt also that it is the aesthetic and recreational values of green areas and forests which are best perceived by the public, especially the urban public.
The more alienated from nature human beings become and the less directly their
40 living depends upon biological processes, the more they wish to re-establish some
links with a previous environment (Thaman 1987; Uasylva editorial 1987). Trees,
because of their size, shape, color, seasonal changes and importance in the landscape,
are the natural living element most visible and therefore the most cared for. It is
argued that, green is the color most restful for our eyes, presumably because we
evolved in a predominantly green environment. Greens bring back a certain harmony
with nature to the urban environment and therefore play a very important social role
in easing urban tensions.
Street forestry can and has undoubtedly been a very efficient tool when used in
conjunction with other measures to rehabilitate old city centers. However, because of the great amount of land involved, it is in the new suburbs that the greatest challenges
for urban greeneries are to be found.
6) Social benefits
The social benefits of urban green are manifold. These include: the maintenance
of social ties through the sharing of garden produce and provision of food for hungry
people in the community; the recreational and physical exercise value; and the
educational importance to urban dwellers and their children, who often have limited
knowledge or appreciation of agriculture, tree and its culturally important in general.
The spiritual importance of urban agroforestry and trees in particular, to the Hindu community of Fiji was observed and documented by Thaman in 1987. According to
Thaman (1987), Hindus attach great religious significance to trees such as the coconut, tamarind, mango and neem (Azadirachta indica), which are common in home gardens in both urban and rural areas. Moreover, religious shrines, known as
‘sthan’, are often found in gardens, with the garden itself having considerable sacred values.
41 Similarly, Melanesian societies are also said to be renowned for garden ritual, and
it can be assumed that there is widespread magico-religious significance attached to
urban forestry and gardening in Melanesian towns. Sacred plants are also said to be
common throughout the rest of the Pacific. For example Thaman estimated that there
are over 35 species of sacred plants (akau kakala) in urban home gardens in Tonga.
Finally, urban green provides other social benefits such as center for social
activities, food for the landless, experimental environmental education, a meeting
ground for improving community spirit and lessening alienation among different
social, ethnic or racial groups and above all bringing urban dwellers closer to nature
(Thaman 1987).
3.3 Challenges of Urban Ggreen
Challenges of urban greens can be understood in two ways, those posed by the
urban green, especially trees to the urban environment and people and those posed by
the urban environment and people to the greens, particularly trees as they grow
maturity with increase in height and size. Some of these challenges include
1) Poor growing conditions
Firstly urban soils are mostly compacted, they contain few air spaces and
consequently cannot provide oxygen and water to tree roots. Secondly they contain
few essential mineral nutrients (e.g. potassium, calcium and phosphorus). This
generally means that urban soils do not provide an ideal medium for growth of new
urban vegetation, particularly trees as compared to its rural counterparts. This is
aggravated by the fact that above average air temperatures, created by long wave radiation emitted from tarmac surfaces, paved surfaces, glasses and buildings, cause
42 already stressed urban vegetation to lose even more water. In this sense, some writers
have strongly argued that urban vegetation needs regular care, including manuring and watering. A renowned urban forester has expressed his fears succinctly about the high likelihood of urban greens suffer from neglect. This he attributed to lack of irrigation, weed infestation, constricting ties on standard trees that restricts the flow of water and sap, trimmer and mower damage that damages and removes the tree bark, overdosing and misuse of herbicide. This fear may be very high in Ghanaian cities where fieldworks such as caring and treatment of greens are mostly regarded as a menial job basically for people with little or no high formal education.
Mowing and watering of greens can help them to survive especially in this
tropical environment where diurnal temperatures and evapo-transpiration is extremely
high. Slackening tree ties ensures that the stakes do not cause health problems to the
tree.
2) Accidents
Vehicles which reverse or drive into trees and open areas damage tree barks, break
stems, snipe roots and destroy greens. Guards, fencing and posts can help trees to avoid vehicle damage.
3) Utility lines:
Modern city life runs on availability of utility service including drains, sewers,
water, electricity, gas, telephone and Television (TV) cables, which are often laid via
open trenching into the footways of our towns and cities. In the case of developing
country like Ghana, utility services run as both overhead cables and dugout and
43 covered trenches that form part of the soil. This can cause serious disruption to existing and new trees by damaging or severing roots. Installation, maintenance and renewal of these utilities may also damage greens and woody roots which serve to stabilize the tree, thereby making the affected tree unstable and subject to uprooting by rainstorm and winds.
Similarly engineering works such as soil surface installation and maintenance of the footway surfaces (e.g. paving slabs and tarmac), including new curbs and the creation of car driveways to homes may cause the severance of or damage to both woody and fibrous roots. Such damaged roots may easily become infected with disease and decay leading to the early demise of the affected tree.
4) People pressure
Greens belts located in certain urban areas (e.g. streets and housing estates) may be a source of conflict with the public, as the city increases in size and land becomes scarce. Green areas are often encroached for want of land for residential and other industrial purposes. Public officials are frequently petitioned for the release of open and green areas for housing and industrial purposes.
Also trees in some locations may be a source of conflict as tree increase in size and height. Frequently, requests are made to repeatedly or severely prune these trees, or remove them because they entangle utility cables, block light or for fear that they may fall over and damage people or property. Brernhardt and Swiecki (1989) have noted in their California urban survey that damages caused by tree roots to sidewalks and other hardscapes was cited for removal of tree from some California cities. In addition, seasonal problems associated with some plants such as shedding of leaves,
44 flowering and fruiting may also bring them into disfavor with the public. In the case
of Ghana, this problem is likely to be common with fruit bearing trees like mangoes
and oranges, which young boys harvest by throwing stones, which fall on roofs and
vandalizes properties. This situation can only be rectified with increased public
awareness of the value of trees.
5) Opportunistic and premeditated vandalism
One critical problem facing urban greens is vandalism. Tree vandalism can occur
in two main forms, namely opportunistic and premeditated. Opportunistic vandalism
include snapping side branches, breaking off crowns, uprooting and pulling whole
trees out of the ground. Premeditated vandalism also include ring barking (knives &
chisels), drilling, sawing off branches/crowns of young trees and poisoning roots.
Tree vandalism is a social problem, not a tree problem. Despite the fact that it is
illegal to damage a public protected tree, this often fails to prevent or deter people
from vandalizing trees. Similarly trespassing on open lawns has been a common
phenomenon in Ghanaian cities due to the general absence of pedestrian sidewalks
along major roads and streets. It is believed that the only long-term solution is
education to raising awareness and appreciation towards trees while efforts are made to provide sidewalks.
Secondly, problems posed by urban green:
6) The cost of growing and management of urban trees
As trees grow and increase in size they may require a commitment of
resources in order to keep them in harmony with their surroundings. Inherently this
management - via tree surgery - can be expensive (if carried out to the correct
45 professional standard), and therefore it may be neglected. As a result drastic action is
often taken (eg lopping/topping, heavy crown reduction or removal) as this provides
an immediate quick fix solution, even though these options are not good for the tree and the safety of people around it.
The long-term implications of neglect can be serious. A tree growing in an
urban area, especially when it is not properly managed, becomes a source of constant
nuisance. People who live with, near to or pass by this tree may begin to regard trees
in general as troublesome, when in fact the fault lies less with the tree than with the
neglect demonstrated by its owners and managers. In certain circumstances an
unmanaged urban tree may pose a tangible hazard to those who pass by or live near it:
e.g. low branches hanging at face level or deadwood in the crown. In US one common
problem for the urban green development in cities is the creeping crisis that sets in as
city trees grow and mature while budgets and programs shrink. Moll and Gangloff
(1987) have noted that in 1984 the delegates at the national meeting of the directors of
parks and recreation identified trees as their biggest maintenance problem, a problem
they have yet to communicate effectively to the public or their political leaders. An
appreciation of the values and needs of city greens by citizens and decision-makers is
what ultimately determines the size and success of local urban forestry programs and
their budgets.
46 CHAPTER FOUR THE ROLE OF REMOTE SENSING AND GIS TECHNOLOGIES IN URBAN GREEN DEVELOPMENT 4.0 Introduction
Remote Sensing and GIS Technologies have been described as the cutting-
edge tools for planning. They provide the medium for data gathering, data storage, data display, analysis and interpretation and the display of the results of an analysis.
In addition they provide planners with the means to observe beyond human natural observation limits. GIS is a dynamic field meant to assist in problem solving process and it is left with planners and decision makers, especially urban planner to take advantage of it in the process of solving urban environmental problems. This chapter explores the potentials of GIS and Remote Sensing technologies in terms of the actual usage and untapped potentials in urban green development.
4.1 GIS and Remote Sensing as a Planning Tool
The dawn of humans on the earth has been the idea of spatial interaction
between humans and the natural environment; population growth, rapid pace of
agricultural growth, urbanization and industrial development (Parker et. al 2000).
Unfortunately, these interactions have adversely affected the natural environment.
This environmental degradation has in turn affected humans such that some writers
have argued on the basis of a symbiotic relationship between humans and the natural
environment while others believe that humans and the environment are inextricably
intertwined, there is therefore the need for humans to learn to live their lives with the
environment. Whereas others have argued for the need to exploit the environment for
human betterment, the bottom line is that the environment belongs to the living,
unborn and the dead, hence the need for inter and intra generational equity, that is,
47 sustainable development (WCED 1987; Kamete 2002). The search for sustainable
development has renewed the idea of conservation and preservation, which has been
defined simply as use without consummation.
In spite of the tremendous benefits derived from conservation and preservation
of the environment, local people have not been able to plan and conserve their
environment in a way that would ensure sustainable development. The destruction of
forest, conversion of forest into paved and urban land uses, loss of biodiversity and natural areas, damping of waste and endangering and extinction of biodiversity in its entire dimensions has become the order of the days. Previous attempts at preserving the environment have focused on protection of areas of exceptional beauty or unique scenic features (Dasmann 1970). Unfortunately these approaches have not been successful enough as biodiversity loss has accelerated now than before. It is against this background that Parker et al (2000 p. 2) have argued, “in order to manage and mitigate our environment … we require tools and methods of analysis, which helps us to collate, analyze, model and monitor diverse data on our environment in a rapid and flexible manner”. They further argued that these tools should allow the environmental scientists to communicate readily to decision makers the analysis made and their implications.
Keyworth and Healey (2002) have also argued that good environmental
management requires careful collection and monitoring of an immense amount of
data. One way to meet this data management challenge is to tie together data sources
in the form of text, tables, aerial photographs, remotely sensed image and maps
through a computerized Geographic Information Systems (GIS). Similarly the idea of
green development in urban areas of developing countries, including Ghana, has come
of age, with the call for identification of suitable sites for green development through
48 capture, storage, integration, manipulation, analysis, querying and displaying of data
that are spatially referenced. It is in this view that Remote Sensing (RS) and
Geographic Information Systems (GIS) are seen as the greatest tool of our time to
accomplish this odious but all-important task.
Remote Sensing is defined as technique for acquiring data without physical
contact. Anyamba (1992) has clearly articulated the unique perspective of remote
sensing technique, especially the multispectral capabilities in observing and
measuring biophysical characteristics of the landscape. He also demonstrated the
usefulness of applying remote sensing data analysis using Normalized Difference
Vegetation Index (NDVI) method for monitoring vegetation change.
Similarly, GIS describes an information system capable of capturing, storing,
updating, manipulating analyzing and displaying data identified according to their
locations on the earth. The use of queries such as ‘display all wetlands within 100-
mile radius of Monday Creek Watershed’, or ‘show all areas of acid drainage in
Monday creek watershed’, are easily answered by a GIS because it is geo-referenced
or it uses geography as a data link. Because of its flexibility, GIS also captures data at
different formats and can output the information using various display plotting, printing and transfer functions.
As a tool for environmental management, GIS has been employed in different
places and different contexts. For instance the Army Reserve, as a pilot program in
New England, conceived the Geographic Army Reserve Information System
(GARIS), with the potential for nationwide implementation. This GIS program
provides instant access to comprehensive environmental and facility information.
Users can retrieve, query, analyze and print facility-specific data for: compliance with
environmental regulations, relocating personnel and equipment, prioritizing facilities
49 for wastewater system upgrades, planning pollution prevention projects, and managing facility maintenance or construction contracts.
GIS has also been applied in Ghana and Zimbabwe for monitoring of land
degradation due to population growth, unsustainable agricultural practices and the
system of land ownership. These two projects analyzed time-series aerial photos and
supported it with field interviews and predicted the pattern that would follow if
population growth, land tenure system and farming practices were to remain
unchanged (Elliott and Campbell 2001). Again GIS has been used in environmental
conservation/biodiversity conservation planning and management and two of these,
GAP project in USA and the Arabian Orxy Sanctuary.
Perhaps one of the key areas where GIS application has been very successful
and very prominent with up-to-date information is urban landuse planning and
management. The world over, cities in both developed and developing countries have
designed their own GIS database for planning and management purposes. For
example in Ottawa, Canada the NRTEE Sustainable Cities Initiative has focused on
one of the greatest environmental and economic challenges of the 21st century,
specifically on the ballooning population of the world's urban regions in the next 25
years (NRTEE 1998). Coiner has documented recent experiences in the
implementation of GIS for urban planning and management in Ho Chi Minh City and
Hanoi, Vietnam, Bhutan, Jamaica, and Qatar (Coiner 2002).
Similarly researchers and other specialists are working seriously on new
models of GIS application in urban environment and landuse planning. For instance in
the University of Zimbabwe, Harare – Zimbabwe, researchers are working on a GIS
model for urban management applications (Semwayo et al 2001). They focused on
50 developing techniques for and expertise in the use of GIS in the development of urban
environment at two levels: the strategic or planning level and the operational
management level. The main objective was to apply GIS-based techniques to the
problem of optimizing the development and manage of urban sprawl.
Another area of interest in the progress of GIS field is Enterprise GIS in Urban
Planning and Management (Coiner 2002). Enterprise GIS, according to Coiner, is
meant to solve the problems of data integration, that is planning and management of
urban areas generally occur by agency, with each agency designing its GIS
applications from its own limited databases and perspectives. By focusing only on
selected features of the overall urban environment, such individual applications, i.e.,
project-based approach to database development has created significant problems in
broadening the scope of GIS. For instance, when decision-making elements of the
urban government want to use multi-agency, GIS-derived information, it is often
difficult to integrate data meant for urban land use by local authorities (Coiner 2002).
He cited recent experiences in the implementation of GIS for urban planning and
management in Ho Chi Minh City and Hanoi, Vietnam, Bhutan, Jamaica, and Qatar to
illustrate the problems and argued as a basis for the emergence of enterprise GIS.
4.2 Linking GIS to Urban Green Development
Sundaram (2002) has argued that the selection of an appropriate city green system involves a number of selection criteria and different disciplines, which are tedious jobs for a planner / designer to do manually. Handling all these criteria and
data types from the different discipline demands a sophisticated tool. The emergence
51 of Remote Sensing (RS), Geographic Information System (GIS) and Global
Positioning System (GPS) would enable urban planners and designers to acquire and analysis different data in variety of fashions.
In the development of urban green system, RS technique would assist in data gathering in the form maps and images; such as soil map, climatic maps, topographic maps, vegetation maps, land use maps, land cover maps, etc. i.e. either aerial photographs or satellite images gathered on the regional scale. It will also assist in the city inventory as well as analyzing and monitoring greeneries in the city. Remote
Sensing also has a post implementation role by monitoring changes in greeneries, monitoring diseases, fire, unlawful encroachment and any other damages that might affect the urban green system.
Perhaps one factor relating to GIS, which is also of importance, is Global
Positioning Systems (GPS). GPS measures the exact location of a tree or the coordinates of a polygon designated for green development. It is also important in referencing such that monitoring and evaluation would not be successful without knowing ‘what is where’.
GIS assist us in handling all the data simultaneously as we desire and it is easy to find alternatives. GIS handles a number of spatial attributes, their properties, and their interrelationships to each other. This would enable us to store, process and visualize current and old information, update and manage the data desirably. The stored digital map information of the GIS database can be plotted in the required format to produce a map, retrieval, manipulation and display of all the data through set of GIS tools. For example the allocation of particular location for certain green
52 type to meet certain aesthetic quality can be accomplished easily through multiple criteria and multilevel queries of the spatial and attribute data.
GIS might also contain information for management and monitoring, such as
soil moisture content of the soil, green types and conditions, including climatic
requirements, risks and management (care) needs. In a study, American Forests
(1999) applied GIS technology to analyze urban ecosystems of the District of
Columbia. Some of the GIS uses include measuring the structure of the landscape,
with emphasis on tree cover, landcover changes and economic value of urban forests.
Similarly the post implementation role of GIS may include the changes in the urban
greeneries, changes in the ecosystems and the economic impact of urban greening.
53 CHAPTER FIVE DEVELOPING A MODEL OF GIS APPLICATION IN URBAN GREEN DEVELOPMENT FOR GHANA 5.0 Introduction
Implementation of a GIS for the purpose of collecting and analyzing data on
individual trees and other vegetation within an urban green program is a daunting and
time consuming task. This is especially true for poor cities in Ghana, which vary
greatly in space and time and also in terms of financial and human resources. The
crux of the matter is that such a program requires volumes of up-to-date data, which is
well managed, with no doubt in its accuracy and precision. It also requires a good leadership, personnel, and a system of software and hardware capable of handling geospatial information in a manner that allows quick and continuous operations.
5.1: Requirements for Creating an Urban Green GIS
The process of creating an urban green GIS, according to Franke (1997) is
essentially the same as creating GIS for any other uses, whether for a military
installation, large city, or small municipality. Franke identifies five main criteria,
while Pacific Meridian Resources (PMR), a GIS consultancy company, suggested
nine basic steps. The most important steps among these diverse views include:
• Situational Assessment / Needs/Requirements of the end user
• Software and Hardware Requirements
• Requirements of the GIS (Implementation Plan)
• Education and Training
• Database Design/ implementation Requirements
• System Maintenance/Updating Requirements
54 According to PMR (2002), a typical situational assessment is undertaken to review existing organizational operations and to align the GIS to the existing operations. It is also meant to clarify to management and answer their concerns related to the cost effectiveness of implementing GIS. Due to the high cost involved in GIS technology, it is important to clarify all issues prior to commitment of any investment. This situational analysis is perhaps the most important step on the road to
GIS; failure to do a good assessment might lead to a total failure.
The needs and requirements of the end user are usually the first criteria to be examined when creating an urban green GIS. It is important to outline and understand exactly what type of information the user of the system wants to put into the system and utilize on a regular basis. Often these needs can be determined by asking a few simple questions about the type of information needed, what is available and what is not available; how much information can be accurately maintained; and possibility of other people need to use or share this information.
Experts believe that the specific conditions of the urban green design play a role in shaping the GIS. For example if large numbers of one tree species are planted as wind breaks or food trees are planted, different methods for capturing and storing this information would be implemented into the GIS design.
Software and hardware requirements play an important role in the development of an urban GIS. In many cases people move in for hardware without knowing the software to be used only to realize that the system is not suitable for the software. It is therefore suggested that software considerations be made before the hardware specifications are acquired. Software requirements for an urban green GIS utilizing
ArcView 3.2 at the minimum, might include the following software being properly installed and configured.
55 Microsoft Windows 98, Windows 2000, or Windows NT
• ArcView 3.2 Desktop
• Microsoft Office 2000
• Others (optional)
The minimum system requirements of the above software must be met. These
requirements include:
• 64 MB of RAM
• Intel Pentium II,
• 10 GB hard disk space
• 10 GB backup hard disk
• CD-ROM drive
• Floppy drive
• Zip drive
Based on the software and hardware requirements, the GIS requirement, which is the next step, can be formulated. Franke (1997) in a review observed that the easiest and quickest way to determine the GIS requirements is to formulate a series of questions meant to be answered. He suggested questions relating to:
• Nature of the city: structure, build up, population
• Climatic conditions
• Type of land use and cover
• Type of green design
• The species composition of the urban green
• Quantity of species within the urban green
• Number of trees located near some type of utility and vital installations
56 • The number of trees making up the urban forest
• Maintenance requirement
• The number of trees within the urban forest need more than routine
maintenance
• Cost of maintenance; such as cost of trim, take off, watering, manuring and
pest control.
Issues related to mapping include determining what scale of map is most often
needed, the level of precision and accuracy and what information should be shown in addition to the urban green data. Scales and areas of interest should be determined in
order to accommodate the necessary requirements in the GIS.
Another milestone down the lane is education and training to both management
and workers who are going to work on the project. This could be a series of
workshops and programs organized to fill the knowledge gap of management and
other employees. PMR (2002) has suggested the following themes:
• Introduction to GIS
• GIS awareness for management and operational staff
• GIS implementation issues and strategies (data management)
• GIS for urban green management
• Application development methodologies (ArcView – the software you are
using)
• Strategies for deploying GIS to the desktop
• Principles and procedures in GIS modeling
• Linking external models
• Enterprise GIS Procedure
57 GIS database design requirements for urban green development is more likely to be the most demanding and time-consuming due to the nature and type of information to be built into the system. This requires a considerable time for planning and experimentation before a coherent and consistent design would be achieved. It is suggested that simple database structure is often a good rule to follow when designing a database. Using a minimum number of tables helps reduce the amount of potential maintenance, aids systems performance, and makes understanding the system much easier. At a minimum, tables should be created which store attribute information about individual plants. Additionally, tables, which store information about maintenance requirements, risk factor, medicinal value, local uses, spiritual and social values, local names or other relevant information, can be added. Below is an example of typical attribute data structure for individual trees at various United States Air
Force Installations. This provides us with an example of data structure that can be followed in urban green GIS data preparation. Database structure adapted from
Franke (1997)
Species Identification:
Every species recorded in the database is given a number so that a list could be created in which each species with its associated attributes may be readily identified.
This system also provided an accounting system for the identification of the total number of trees included in the area.
Block Identification:
In this study the first one or two digits of building numbers generally correspond to area identification. In the study of trees on military installations similar approach was adopted to identify the facilities within that area. In the case of Ghana the first two digits approach would be appropriate since they clearly identify the location e.g. KO
58 80; OT 457C; where KO represents an area in Asante Newtown and OT represents
Old Tafo. These blocks would be designated on a map before data collection begins, as a means of simplifying green location and structuring the database.
Road or street name:
The name of the closest street was included for each tree. This association aided in the quick location of a specific tree or group of trees for ongoing inspection and maintenance. The use of road names seems very appropriate especially in areas where roads are clearly named. Unfortunately this may not be as smooth as it seems in the case of some cities in Ghana. For example, the majority of roads in Tamale and
Kumasi are not named.
Similarly downtown Accra has no well-defined streets and road network to facilitate this kind of exercise. It is therefore the task of the concerned department to find a way of utilizing major roads rather than minor residential streets in downtown areas. In the case of newly developed suburban areas, the situation is different and the approach would be viable since there are defined streets with most of them, named. It would not be beyond this project if it becomes necessary to rename streets in these areas.
Building Number:
The real property building number or address of the nearest building would be recorded for each green area. This information would serve as an aide in locating individual trees and greens, especially in areas where the block or street names did not provide enough specific information for locating the greens.
Plant Type:
All trees can be designated as either Deciduous or Evergreen. These terms are defined below. The term ‘deciduous’ generally describes a tree that loses its leaves
59 annually, usually in the dry season. The deciduous category included trees that are
semi-deciduous, retaining most of their leaves throughout the year. In fact, these trees lose leaves as new leaves appear, so they may be classified as deciduous trees.
"Evergreen" are trees that remain green throughout the year without loss of leaves in
any part of the year, but more particularly in the dry season.
Tree Name:
Trees are typically identified by the common name generally associated with the
tree and by their botanical name, which is a Latin derivative specific to the species.
Because of possible variations in common names from locality to locality, botanical
names would be the important identification and communication device. Surveys
should include the recording of both the common and botanical name.
• Plant Name (local name):
This is the common name for the tree, as it is normally called.
• Botanical (Latin) Name:
This is the scientific or Latin name of the tree. This name is composed of two parts,
with the first word being the genus name, followed by the species.
• Cultivar:
This is the specific name given to a cultivated variety of tree.
Growing Environment:
Growing environment describes the general spatial characteristics of the area in which
the greens are found. This may include about five growing environment designations,
which may be included in the survey data:
• 1 - Open:
Open Lawn areas, spaces between buildings, athletic fields, and residential lawns
• 2 - Wells:
60 Tree wells, planters, or tree grates
• 3 - Median:
Roadway islands or medians
• 4 - Parking:
Lot islands and surrounding plantings associated with parking lots.
• 5 - Parkway:
Growing areas which are between roadways and parallel pedestrian walkways
immediately adjacent to the roadways
Stem Diameter:
The overall height and size of deciduous trees and evergreen would be recorded as a
measurement of the diameter of the trunk.
Condition:
International Society of Arboriculture has adopted a guide for appraisal and some of
the important indicators of tree conditions include Roots, Trunk, Branches, Smaller
Branches and Twigs and Foliage. Evaluation with this system would be based on the
percentage of these components observed to be alive and in a healthy condition. This evaluation would then be ranked into one of the following categories: Excellent,
Good, Fair, Poor, and Very Poor.
Maintenance:
The maintenance requirements of each green area can be document and addressed into category of priority of maintenance needed.
• Routine:
Greens with this designation are generally in a healthy condition and required the same maintenance as they have been receiving, which is considered normal for that particular species or area. Routine practices generally required some degree of
61 pruning, as well as other standard practices such as fertilizing, watering, and insect
control.
• Training:
This designation identified green areas with correctable structural problems such as
irregular growth patterns or some damages. This designation also included trees
requiring greater attention such as pruning because they were growing near a structure
or a utility. It may also be an area with frequent predation or interference.
• High:
Areas requiring a high degree of maintenance or observation including individuals damaged from storms or other extreme conditions, suffering from drought or nutrient deficiency, or located in a precarious situation, or located in sensitive and areas of higher priority such as ministries, high official buildings, academic institutions and or under a utility cable. These green areas are determined to be manageable in their location for the present and long-term, avoiding removal, but will require a higher degree of maintenance which may include pruning, watering, fertilizing, and/or other actions necessary to create or maintain a "Good" plant condition rating and also for aesthetic purpose.
• Removal:
This assessment recommends immediate removal of the identified trees. These trees
may be generally dead, although it may also be applicable to living material as well.
In either case, the individual may be or have the potential to become, hazardous to
humans, automobiles, and building structures, or aesthetically displeasing.
Maintenance needs may be considered in conjunction with the Risk Potential (see
Risk Potential) assigned to a tree. A high risk potential, for example, may necessitate immediate or constant maintenance consideration.
62 Other Required Maintenance:
This data category can be captured to report any unique or specific maintenance requirements not included in the maintenance category. Specific items that may be included in this category are:
F: Fertilizer application
I: Insect treatment
FU: Fungus and/or bacteria treatment
B: Cabling and bracing
C: Cavity work
G: Girdling root removed
V: V-Shaped Crotch
Risk Potential:
The risk potential is the potential for injury or damage to persons or property likely to occur from the tree because of its condition or location. This potential can be assessed using a range of 0 to 6. This range is defined as:
0 -No risk potential and no action required
1 -Annual evaluation recommended
2 -Potential safety hazard
3 -Safety hazard or damage likely
4 -Imminent property damage
5 -High risk that is life threatening
6 -Immediate action required
Utilities Present:
Existing utilities have to be noted especially when they are or likely to conflicted with green areas or trees. Trees that conflicted with buildings must be noted in this
63 category. These conflicts usually affected the risk potential and the maintenance
requirements of the tree. Conflicts can be recorded using the following abbreviations:
EC -Overhead Electric, or other cables present
UE -Underground Electric or other cables present
UT -Underground Telephone
G -Gas lines present
W -Water lines present
S -Storm and Sanitary Sewer lines present
B -Building conflict
VC -Vehicular conflict (i.e. Tree blocking the view of a stop sign.)
PC -Pedestrian conflict
SW -Open Storm way / Flooding
Comments:
Any additional comments necessary during the field visit and necessary to be put into
the database. Examples of these included trees planted in memory of a person or
events, trees of historical significance and trees of state champion size. Others may include green areas for special groups, philanthropic trees, sponsored greens etc. The maintenance and updating of the information contained within the GIS database is equally as important as the design of the system itself. Because an urban area is a dynamic community, which is always changing, maintenance and updating of GIS information is of prime importance. Strategies for maintenance and updating should be addressed during the design of the GIS in order for these activities to occur in a systematic fashion. At the barest minimum, an urban green GIS should be updated one time every year. This will vary depending upon the location, size, and staff responsible for the urban information gathering. Finally, database development must
64 also be guided by ethics and security, which defines which data can be put into public
domain in terms of public right to know and personal safety and privacy issues.
5.2 Green Area Modeling
Cities in Ghana have certain socio-cultural patterns that describe the history,
culture and the changes that have occurred over the years of their existence. Kumasi
for example, is one of the earliest cities in Ghana and it is described in many official
circles as the hub of Ghanaian culture. It is against this background that it serves as the appropriate location for the Center for National Culture. From its historical background, the design and build-up, Kumasi epitomizes the culture and the entire history of Ghana and the Asantes in particular. In this way planning to integrate green areas into the city build-up and land use involves rezoning of an existing land use zones, although the city, for its historical setting, lacks well-defined land use zones.
Rezoning of the city’s spatial organization might affect the historical and cultural significance.
Other cities like Accra, Sekondi-Takoradi, Cape Coast, Bolgatanga and
Tamale have similar spatial arrangements that depict the cultural setting of the people.
It is therefore the task of the urban green implementation agency to explore GIS
capabilities and apply specific data processing algorithms that do not destroy the
city’s spatial structure but rather preserve the existing structure and make way for
successful integration of greens zones. In order not to disturb the entire city and its
spatial organization, this model seeks to integrate green areas consisting of trees,
flowers and other green plants into the existing city plan without any dramatic
transformation of the existing spatial arrangement of the city and the way of life of the
people.
65 McHarg (1968) introduced a systematic land use planning by using the concept of compatibility of multiple land uses. He mentioned that the factors affecting land and its relative values are different and therefore, it is difficult to think of optimizing them for a single use. It can be optimized for multiple compatible uses. He introduced simple matrix system for determining the degree of compatibility. The idea of multi-criteria decision-making was based on this concept. Recent developments in
Geographical Information Systems have drawn upon concepts of the multi-criteria methodology. It follows the idea that we have some set of objectives to be achieved and that achieving these have some enhancing factors and constraints. If we plug in these objectives, factors and constraints, we can select specific locations that satisfy these criteria. In this approach, there would be multi-levels of multi-criteria decision- making.
1) Selecting which location would be suitable for greens development
2) Selecting which plant would be suitable for which location to meet certain environmental, economical, socio-cultural, psychological and aesthetical requirements. Table four and five (4 and 5) below summarizes the data requirements and factors and constraints for this modeling process.
The selection of locations for green zone and the selection of particular greens for particular location involve multilevel queries of the spatial and attribute data. GIS multi-criteria decision-making algorithm has the capacity to handle all the data, constraints and factors simultaneously as we desire. It is easy to find alternatives or different locations suitable for green area development. GIS handles a number of spatial objects, their properties, and their interrelationships to each other, and enable us to store, process and visualize current and old information. The stored digital map
66 information of the GIS database can be plotted in the required format, to produce a map of green areas.
Table 4: Required Data for GIS and Urban Green Modeling
Factors Data type Level of Precision Geophysical Data Soil Soil types, depth, physical properties, Chemical properties, boundary and other major limitations Slope/ aspect Percentage of the slope, exposures, (DEM) orientation Topography Contours, elevation, landforms, streams. Geology Bedrock types, morphology and chemistry. Climate Rainfall, temperature, humidity, wind speed and any other local factors of important consideration Physical Latitude and altitude. location Hydrology Surface water sources, ground water sources and their properties Vegetation Nature of the vegetation occurring in that area, forest type, exotic species, and their social, commercial and religious values, physical features (height, crown type, speed of the growth, flowering, resistance to pest and management needs etc.) Socio-political Land use/ Land Present and proposed use pattern of the factors cover land; Land cover type such as forest, built up area, agriculture land, etc. Ownership The ownership of the land: Spatial pattern Built versus open spaces in the city. of the city Demographic Population and density of the city. Political Government policy, environmental laws, reservation, Administrative boundaries. Ethnicity Location of tribal group in the city Environmental Air Air quality, level of particulate maters etc. factors Water Water availability, water quality, level of pollution Land Land quality, contaminations, Microclimate Microclimate and its variability
67 Table 5: Factors and Constraints for GIS Modeling of Urban Green Area
Design Factors Details Aesthetic / Functional Scale and maturity, structure of crown. Density of Criteria the foliage Growth rate Seasonal attributes. Relation to the surroundings. Texture Special properties Cultural criteria City tolerance Hardness Local habit characteristics Resistance to pest Operational criteria Transplanting limitation. Maintenance requirements Cost of plantation /transplantation. Availability of species. Spatial availability Socio-economic criteria Life pattern of the people. Growth pattern of the city. Economic base of the city. Population and density. Land use pattern. Ownership of the land.
Steps involved:
Step 1: Regional vegetation map
The project involves building data on local vegetation, which will help us to query the type of plant cover to be allocated in specific areas to form the vegetation map; information on soil, climate, hydrology, geology, topography and vegetation would be combined in a database that would be modeled to produce the regional vegetation map for the area. This regional vegetation map would be the basis for determining which vegetation type is suitable for the area after considering other factors including the area specific design, beautification needs and other cultural arrangements.
68 Step 2: Potential land area
Land use, land cover, administrative and land ownership maps would also be
modeled to identify the potential areas for green development. This is land area that
can be used for green development based on the fact that it is within the
administrative area, it has appropriate land use/cover and the ownership makes it
reasonably inexpensive to acquire.
Step 3: design factors
Factors such as aesthetic, cultural, geophysical and socioeconomic would also be
considered as the design factor needed to minimize the negative socio-cultural,
economic and other physical impact of the project. These factors are considered as constraints in the modeling process and where necessary, they have to be avoided.
They are very necessary because they determine to a large extent the success of the green development project. In order to reduce the negative effects, these factors would be weighed and ranked in terms of their likely impact from a scale of 1- 100.
Step 4: Environmental factors
Environmental factors such as air, water, land and microclimate are considered
enhancing factors that would be integrated after being weighed on the scale of 1-100 based on their desire properties.
In multicriteria decision making step 3 and 4 are important factors in modeling step 2.
Figure figure 5 below, is a flow chart designed to assist in the data organization in order to arrive at an appropriate green area selection.
69 Figure 5: modeled selection process of area for urban green development
Soil map
Climate map
Geological map
Regional Vegetation map vegetation map
Topographic map
Hydrological map
Landuse map/ Landcover map Potential land area Green Landownership map Area
Administrative area
Aesthetic criteria Selection criteria Functional criteria
Operational criteria Design factor
Cultural criteria
Geophysical criteria
Socio-economic criteria
Air Environmental Water factors
Land
Microclimate
They are constraints and factors that would be considered in addressing the issue of potential land area which becomes the selection criteria. Finally the selection criteria
70 would be used as cookie-cutter with the regional vegetation map generated from the
earlier modeling and quarried to produce specific locations suitable for green area
development.
The spatial analysis capabilities of GIS would help to retrieve, manipulate and
display map and locate related attribute data to show spatial interrelationships from
the final output. This database management would help us in handling variety of
attribute data both for present and future use. GIS is therefore a vital tool in planning
and implementation of appropriate city green strategy, through the application of
spatial quarry tools. The new information in the digitized maps can be merged with
satellite images, in layer form, using the common database. Through this merging
technique we can identify potential area to improve the green systems and set of plant
list for that particular area.
The post implementation structure of this project is displayed in figure five above. In figure five the structure of GIS and Remote Sensing applications for urban green development displays different levels of information in a database that keeps changing or updated through the help of GIS Remote Sensing and GPS data. It displays information on City Green (green area) and their easing conditions.
It also contains information on the urban area and the regional information
acquired through Remote Sensing and GPS technologies. This information includes
natural factors, cultural factors, and environmental factors. They also include other
critical urban information such as population, social and economic factors. This data
is combined with need assessment, spatial attribute data, regional plant list, design
factors, selection criteria in a GIS database. This database is continuously update and
queried to generate new information for urban green monitoring and expansion
71 Figure 6: Modeled structure of GIS and Remote Sensing applications for urban green development
City Green
Assessment of easing conditions
Remote Sensing Urban areas Regional
Natural Factors Population/Socio Environmental Factors Cultural factors Polygons Features economic Factors
Need Spatial & Assessment Attribute Data Geographic Regional Information Plant list System
Design Factors Selection Criteria
GPS Data
Spatial Search (Land, soil, Vegetation for Particular vegetation, water) location
Model adapted from Sandaram (2002)
72 5.3 Problems of Applying GIS Technique for Urban Green Development in Ghana
• Need for awareness and management support:
Experience from the developed world indicates that successful implementation and use of spatial information infrastructures in developing countries is dependent on political and institutional support. In the case of poor cities of Ghana, leadership support is a necessary and sufficient condition in an attempt to mobilize resources to building the infrastructure, understanding the limitations and providing the necessary flow of information to support GIS application in urban green development. This is particularly important in Ghanaian cities like Accra and Kumasi where in the past leadership crisis has led to paucity of data of all kinds. Over the past 20 years these cities have suffered from mal-administration and poor planning due to the general lack of well-informed leadership, who have the vision and commitment to plan and manage the city.
Lack of independence and manipulation of city managers by politicians has been eating into the city’s financial resources, management and the general direction of the cities’ development. In most cases city mayors are political favorites who dance to the tune of politicians and have no plan of their own for the city. It is therefore the first hurdle in an effort to build a GIS for city management, to get support from city managers that are knowledgeable, independent and have vision of what GIS can do to make the city livable. Lessons from a Bangkok city GIS project indicates that the project only received the necessary political support after a Professor of Surveying was seconded from a University to the Bangkok Metropolitan Assembly as a Deputy
Governor.
Also, problems of getting members of the Metropolitan Assembly aboard the GIS train are critical to the development of GIS for urban green development in Ghanaian
73 cities. Most metropolitan assemblies are composed of people with little or no
knowledge of GIS and its potential. It is therefore an uphill task to convince these
people to vote for the huge sum of money (investment) need to get the project to start.
• Data availability:
GIS is a data driven project that depends on availability of data. The successful
development of spatial information infrastructures in developed countries has partly been due to much of the data being available in digital form or the existing political will and financial backing to build the required data sets. However, in Ghana the situation is very different. Data is generally not available, either in digital form or paper-base maps. Even where spatial data exist, they are paper maps, which are often too generalized such that they are unsuitable for use.
Additionally, existing maps were made in 1960s, (1962 survey maps), for different purposes. This means that they are either not applicable or might have changed to the extent that their applicability and relevance to our times is in doubt. In order to have smooth and efficient GIS operations in Ghanaian cities, it is important to start with basic data collection. This requires time, human and financial resources, which only few cities and their city managers have or are willing to commit, as
associated benefits are either not known or not immediate.
Experience from other developing countries have shown that even where there is
political will from city administrators, it often appears to be a political urgency that
negates long term planning and database development and management procedures
required for a successful GIS development. Man and Gerland (1998) have argued that
in most cases, politicians put a timeline of say two years for the GIS project to be
operational, which is virtually impossible. For this reason, an appropriate strategy for
successful GIS is often not implemented thereby resulting in little progress after a
74 maximum of say ten years. On the other hand, developed countries built their digital systems from well-established manual map systems, which have often evolved over decades and sometimes centuries.
Ghana stands to gain by learning from developed countries experience of gradual and systematic GIS development based on careful accumulation and standardization of data over the years. Some experts believe that such a project works pretty well if it starts on pilot basis and that a minimum of eight years is required to study, train, implement, evaluate and re-implement a successful city GIS project.
• Personnel:
There is an acute shortage of trained professional GIS personnel capable of introducing spatial information technologies in Ghanaian cities, even where they appear to be aware of the technology; they only know GIS in theory. This is due to the fact that in most universities of Ghana GIS classes are theoretical-based rather than application based. The GIS laboratory of the Department of Geography and Resource
Development, University of Ghana, for example, is closed to students. It exists only to serve departmental needs. The few GIS professionals trained outside Ghana are not willing to work in Ghana for lack of adequate and commensurate remuneration as compared to their level of qualification, cost of living and the standards in other parts of the world.
In this case setting GIS for Ghanaian cities may require the acquisition of the services of an expatriate GIS professional at a cost well beyond the means of these cities. The second option would be sending people for training well in advance before the project can take place. Perhaps the third option would be cooperation between the
Department of Geography and Resource Development, University of Ghana - Accra and the Department of Natural Resources Management, Kwame Nkruma University
75 of Science and Technology – Kumasi, who have recently established GIS labs for their own purpose to train people to serve this project.
Although these appear to offer good solutions to the personnel need for starting a GIS project for urban green development, a new problem in the form of worker turn over arises. That is, retaining worker, this to a large extent depends on remuneration and conditions of service. It is therefore a question of how we reward workers such that their take-home pay does really take them to their houses and not just in front of their offices. The salary structure is so low that most professionals are compelled to travel outside the country to seek better remuneration for their services.
It is also worth noting that the shortage of personnel for this kind of project may not only relate to GIS applications but also arborists and other workers to manage the greens. At best, the workers that may be attracted by this kind of job would be people with very low education due to the social stigma attached to this kind of job.
The solution to the problem lies in paying adequate remuneration to make the job attractive enough to the people. It also hinges on availability of appropriate tools and infrastructure that improves the condition of services of the worker.
• Resources:
Because of the current practices of decentralization and local government administration in Ghana, it is often difficult to get budgets approved for the purchase of new technology. It is particularly difficult in the case of Ghanaian cities where administrators do not get enough funds to match the urbanization challenges from the district assembly common fund and regional development funds.
76 Another factor compounding the problem is the fact that senior administration and Assembly members have little or no experience with the new technology and therefore see no need for committing any financial resources to it. GIS requires investment in hardware, software, data collection, data maintenance and education and training, and it is very difficult to get support for such projects from senior management without the awareness of the potential of the new technology.
In recent years, United Nations Development Project (UNDP) has assisted many poor cities in developing countries to acquire GIS technology for urban management.
There are other funding agencies helping poor cities to acquire this much-needed technology. There are also low cost desk top GIS software packages, with some of them being available through the internet at very low cost, which central government can assist poor cities to acquire.
• Data standards:
Urban green development requires multiplicity of departments and agencies involved in one way or the other in urban management and these departments require different data at different scales. That is, they require data in the form of map with varying scales, precision, graphic elements, accuracy and currency. This makes data harmonization very difficult for the city. Adoption of a common data standard accepted by all potential users will reduce duplication of data and data redundancies.
This will also reduce cost and conserve resources. It will also be helpful if enterprise
GIS system can be adopted so as to facilitate exchange of information and ensure cost sharing. According to (Bishop et al 2000), in Bangkok, utility agencies require larger scale maps than planning agencies. A map scale of 1:4000 or smaller scale is sufficient for strategic urban planning and urban monitoring but a scale of 1:1,000 or
77 larger is required by the utility agencies. An agreement was made about the map scale
at the very beginning of spatial infrastructure development and that made urban GIS
development efficient and effective. In practice it is very difficult to gain agreement
due to different institutional needs. Ghana stands to gain from US experience where
US Geological Survey (USGS) has established data standardization for others to
follow. Similarly Ghana Geological Services, the official governmental agency
responsible for mapping can establish data standards, fixed scales and determine the level of precision and accuracy required for all agencies and organizations involved in data acquisition and management.
• Procedures:
The bureaucratic procedures for approval and procurement of technology in
Ghana are often very slow and cumbersome. It requires a great deal of travel, lobby,
cost and energy in order to find a way through the political system to obtain support
and approval, prepare tenders, evaluate tenders, award contracts and take delivery of the system.
In most cases the time lapse is so long that by the time the contract is awarded, either the technology intended for use is already outdated or the person promoting such projects is transferred or both. As a result many project remains on paper or often delayed. It is frequently not uncommon to see such projects abandoned due to political change. Where the person muting the idea is either changed or loss power because the ruling government has loss election, the new government tends to abandon the entire idea because it was established by an opposition party, without weighing costs and benefits the project, irrespective of the committed investments.
Such delays also breed corruption among public officials.
78 • Other socio-cultural barriers:
Problems that GIS for urban green development in Ghanaian cities may face include social and cultural factors such as land tenure system, nature of the city built and attitudes and perception towards green areas.
Land tenure system is defined to include the system of land ownership, acquisition and used. In Ghana land ownership is of three types. These include state lands, i.e., lands belonging to government of Ghana; private or individual lands, consisting of lands owned by private individuals or organizations either through purchase or inheritance; and stool and clan lands.
Historically, Ghana Government has acquired certain parcels of land by paying compensation to the original owners or in the form of seizure. This constitutes only a very small portion of urban lands. In Accra government lands are basically parcels acquired for educational institutions, recreational activities, ministries and other government services. Others include lands for conservation and other protected sites
Private lands are also very infinitesimal part of lands in Ghana. Before 1972 individuals could acquire land and register with land title registration department.
After 1972 no individuals can sell or purchase a parcel of land. Land parcels are leased with a maximum of 99 years. Greater part of Ghanaian lands belongs to the category classified as stool and clan lands. The percentage may differ from region to region but in places like Ashanti, Eastern and Northern regions about 98% of the land are clan and stool lands. Under the stool (tribal) and clan lands, it is believe that land is communally owned. It belongs to the dead, the living and unborn, and that every member of the tribe has user right and therefore has no right to sell. This means that
79 any member of the tribe or the clan or any stranger who wants a parcel of land can acquire it through the chiefs and clan heads.
The figure 7: below explains the hierarchy of authority in land ownership in
Ashanti region of Ghana. In a typical case of Ashanti, the Asantehene, King of
Asantes, is the overall owner of the entire Asante land and this land is divided among divisional chiefs and sub-chiefs and among various clans within the chiefdom.
Figure 7: Modeled Structure of the Asante Land Ownership System, Ghana
Asantehene (Overall owner)
Divisional Chiefs
Sub-Chiefs
Strangers Clan / Family lands: Stool lands: Dead, living Handed from Generation to generation and held in and unborn trust by family head members of society
Chiefdom boundary
Chain of interaction between tribal members and other levels of authority
Interactions between strangers (non tribal members) and tribal members
including leaders
80 The acquisition of land in Asante and many other tribes of Ghana follows the above
model where all lands are owned by the tribal chief who is the overall owner
(Asantehene) in the above model who holds land in trust for the people. This tribal
land is then divided among Divisional Chiefs, who also subdivide them among sub-
chiefs. Under sub-chiefs are stool lands, clans and family lands with their leaders
controlling portions of land. It worth noting that each leader holds land in trust or
serves as custodian and that each member of society has user right which is
sanctioned by the leader.
Perhaps the good side of the system is that it gives everybody in the
community access to land at a reasonably low cost (usually a token of drink) paid to
any of the positions on the command chain but in most cases the bottom chain (clan /
family chiefs and stool land heads), except lands in Kumasi city itself and also when it
involves large tracks of land to strangers. The disadvantage side of the land tenure system is the fact that it has led to land fragmentation, with an average parcel size of less than two acres. Also land acquisition is cumbersome and time consuming as it sometimes involves going through the command chain.
In addition, the problem of indeterminate land boundaries has led to long- standing land litigations among sub-chiefs, clans and tribes. This is particularly serious in the case of Accra where a single land can have as many as five people claiming ownership. It therefore scares people as you can lose your investment on land so easily due to litigation and lack of defined land boundary. Although land tenure seems to be an important discouraging factor, the good side is that in the case of urban green development, we may be operating within an area of jurisdiction of only one traditional authority. That is, in the case of Kumasi, we may be operating within the area where Asantehene’s influence is supreme and so it would be easy to
81 acquire the land through Asantehene with minimal compensation to the divisional chief whose land is being taken. The situation might be different in Accra due to the absence of single overall head like Asantehene. While Teishe lands belong to Teishe
Mantkse, Abrekuma lands have different supreme head (Chief of Abrekuma). Perhaps the good thing is that we can go through the political system where a parcel of land can be acquired through the regional and metropolitan assembly or through the national government.
Cities in Ghana are basically old cities built before 1900. For example, Yendi
was built around 13th Century while Kumasi was built around 1700. Similarly Cape
Coast, Accra, Sekondi-Takoradi and Elmina were all built during the early days of trade with European merchants i.e. before colonialism. Like all ancient cities, they are characterized by narrow streets, absence of sidewalks and crowded interior without open spaces (plates 8 and 10). This means that greens along streets would experience land use conflict with human traffic (pedestrians) due to the absence of sidewalks.
Also green areas may not be possible especially in downtowns due to the
general absence of open spaces but rather in suburban areas where abundant land
exist. This, in effect, may lead to higher rent, higher cost of living in suburban areas
and general inequalities between the poor in downtown and the rich who can afford
the higher rent in suburban areas. This is also a challenge to the principles of
sustainable development, which implies inter and intra generational equity and which also forms the main philosophy of urban green development.
Lastly, one critical problem to be solved in urban green development in
Ghanaian cities is the attitudes and perceptions of the people. Ghana is a tropical environment with abundant green plants that grow almost everywhere. Due to this, people take greens for granted and do not put much value on it, particularly in the
82 urban milieu. The general perception is that urban areas must look different from rural environments. This general perception of the urban area as an epitome of
‘development’, which most people perceive as a build of skyscrapers, paved surfaces with infrastructure of all kinds and are of high-density population with human and vehicular traffic. This means that urban green development would be successful if the perception of what development might look like is changed. This will only happen through education about the importance of urban green development in the promotion of sustainable urban living.
83 CHAPTER SIX
CONCLUSON
6.0 Introduction
The quest for survival, in human history has negatively impacted the natural environment. Human history is predominantly an interaction between humans and the natural environment with human life depending on the natural environment. For example prehistoric man depended on hunting and gathering while modern man depends on agriculture with natural environment providing the medium for satisfaction of human wants. Unfortunately, this interaction has adversely affected this life-supporting medium such that places where humans live (cities) are no more satisfying (livable). It is against this background that new approaches are being sought to make cities livable and perhaps the most recent approach is urban green development.
6.1 Recommendations
It is an uphill task for any individual seeking to develop GIS and urban green system for poor cities in Ghana. Like Olmsted, the victory would be the lungs of
Ghanaians and the increased life expectancy that would be experienced over the years. Currently, there is no known study that relates absence of vegetation in cities to human health in Ghanaian cities, although it is believed, based on studies from the rest of the world, that the effects of the destruction of the natural environment is just beyond imagination. It is therefore recommended that GIS and urban green development must be taken as a matter or urgency. It would also be helpful if an initial study of the need for urban green development and for that matter GIS can be conducted by the cities themselves. This study can be presented to the politicians and
84 other development partners in order to mobilize the necessary support for immediate
take-off of GIS and urban green project. One quick and perhaps cost reduction way of
accomplishing this task is to support a student from any of the Universities
(University of Ghana, Kwame Nkrumah University of Science and Technology etc.)
to do this study as thesis for the award of his/her final degree.
Secondly the results of this study can be made available to the numerous local
radio stations, which would be broadcast to conscientise the general public on the
need for greens in the cities and also the role that they need to play in the green
development. For example, the public needs to know why they have to develop green
belts and backyard gardens around their houses instead of concrete and tiled floors.
Although good GIS plan and design for urban green development is important, the
implementation is very important. It is one thing to plan and another to implement.
Experience from other countries has shown that legislative support and civil society
participation is as equally important to the success of green area development as it’s
planning.
In terms of legislative support, local government Act, or bylaws would be the
most appropriate law that would make it flexible for people of different cities to adopt different strategies suitable to their local conditions. It is also possible to adopt green open spaces as building design requirements for the country. Perhaps this would be the easiest way to spread the green concept with limited cost. In Ghana it is mandatory that the department of Town and Country Planning approves the building design, to be in conformity with the specifications for the area concerned. It would therefore not require any new or meaningful change to the existing laws. It would only be an additional requirement that housing surroundings are left green instead of concrete or specify the green component requirement of any new housing design.
85 While ensuring that people adopt the green design concept, it is necessary for the
Department of Roads and Highways, Urban Roads and Municipal Authorities to adopt
the concept as part of their design so that city roads and streets would have greens
(trees) and sidewalks.
Community groups of all kinds may participate in the planning and
development of these greens, including schools, local governments, market women, social groups, nongovernmental organizations and churches. The activities of civil society marked the beginning of the American people's involvement with their forest resources. Also it is recommended that the Department of Parks and Gardens be charged with the development of tree and other vegetation (grass) nurseries that would be made available either free or at a minimal cost to individuals, organizations and groups that would be ready to plant and care for them. Perhaps it would be more helpful if people would be encouraged to plant food trees and food supplement plants,
including backyard gardens.
Furthermore, urban green development fund may be created where individuals
and groups can make donations. It would also be a good idea to create philanthropic
tree sites where individuals can sponsor trees by making contributions to the tree
while the trees are labeled with their names. For example, if I decide to sponsor a
baobab tree by contributing $50 monthly to the upkeep of the tree, it would be labeled
“Owusu Barimah Baobab”. Organizations and individuals can adopt sites, which
would be named after them. For example, an area can be labeled ‘Guinness Ghana
Limited park’ while Guinness Ghana Limited makes annual contributions to the
upkeep of the greens. A site can be created in the city where you can pay an instant
fee and plant a prescribed tree. That is, you pay and plant once and write you name in book of honors for that particular site. Also brochures describing trees, sites, their
86 medicinal values, spiritual significance and their age (including other information from the database about that particular site or tree), can be distributed to visitors and tourists for a token. It is hoped that this green marketing would make a valuable financial contribution for the success of the GIS for urban green project. Lastly, voluntary contributions, both in cash and kind may be solicited. For example FM radio stations can be approached for public education towards urban green while annual fund raising activities may be conducted.
6.2 Future Research
This work focused mainly on benefits urban green and problems of developing GIS for urban green development in Ghanaian cities. The usefulness of this project has been demonstrated in this work, there is therefore the urgent need for such system in fasting growing cities in Ghana like Accra, Kumasi, Tema and Tamale to mention but a few. It is therefore recommended that future efforts should be focused on:
1) Undertaking a feasibility studies to align GIS for urban green development
objectives with city plan and developmental needs, identify major users, data
requirements and educate major stakeholders in this project.
2) Develop and implement a plot project to set the project on course. This can be
evaluated and re-implemented.
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98 Appendix: Photo Gallery
1: Thinking Green in Ghanaian cities
2. The emergence of bizarre economy in Ghanaian cities
99 3: Destroying nature for residential land use
4: narrow streets and open drains
100 5: Open and paved surfaces causing excessive heat
6: Open and paved surfaces causing excessive heat with little of no greens
101 7: Green development to reduce pollution
8: Absence of sidewalks and crowded interior
102 9: Narrow and dusty streets of Kumasi with no sidewalks
10: Lack of open space for green development in downtown
103 11: Narrow streets and uncovered gutters (drains)
12: Land-use conflict in Ghanaian cities