Background to the Study
Land use are recognized as key drivers of environmental change (Shi et al, 2009) with significant implications for many international policy issues (Liu et al., 2010) and a central component in current strategies in managing natural resources and monitoring environmental changes (Minale and Rao, 2011).
In the context of urbanization, a large amount of agricultural land has been converted to built-up or urban land uses. Calabar has for the past 43 years experiencing a lot of land-use and land-cover changes due to both socioeconomic and natural factors. These include the increased spatial expansion arising from high rural-urban migration rates which has made the city one of the fastest growing cities in Nigeria (Rimal, 2011). It is therefore important to develop an explanatory model for understanding the rate, causes and consequences of the same which consequently aids in formulation of sustainable urban development strategies and in detecting environmental changes (Sultana and Weber, 2007).
Great efforts and methods have been done to understand the effect of urban structures but most of which are descriptive rather than quantitatively predictive. However, it is the quantitative predictive models which have a niche in aiding the development of sustainable urban development strategies. Technologies such as Geographical Information Systems (GIS) and remote sensing are currently presented as dynamic tools for monitoring land use and land cover changes and environmental quality which has continued to present challenge to sustainable urban development ((Mahmood et al., 2010; Minale and Rao, 2011).These technologies provide a cost
effective and accurate alternative to understanding landscape dynamics.
Urban Structures is a global change driver and has notable implications to many of the international policy issues (Vitousek and Field, 1999). Over the years, human activities have modified the environment with significant population increase, migration, and accelerated socioeconomic activities. The process of urbanization has been characterized not only by population growth but also by industrial expansion, increasing economic and social activities and intensified use of land resources (Karuga, 1993). The environment and social consequences of a growing population in a loosely planned urban/build area system could be dramatic especially when urban areas experience accelerated growth in a short period of time as is being witnessed in Calabar (Mundia and Murayama, 2010).
The interactive nature of urban structures is not fully understood, making it difficult, if not impossible, to develop effective adaptation strategies for urban development (Jiaguo et al., 2012, p.1). Most studies especially on urban land change dynamics done using such methods as (environmental) impact assessment or post project analysis have resulted in no quantifiable changes. Again, the urban land use and land cover dynamics have raised new challenges for urbanization theory.
In Nigeria, land use and land cover changes have been mostly planned and executed without appreciation of their implications, mainly due to absence of quantitative information which makes it difficult to anticipate the possible socio-economic and environmental consequences of such changes (Karuga, 1993). Unfortunately, efforts which have been formulated to postulate theoretical knowledge and explanations for its occurrence are often descriptive rather than quantitative thus leading to lack of comprehensive information. Karuga (1993) attributes the failure to anticipate the possible socio-economic and environmental consequences of such changes to lack of accurate predictive model. Rapid urbanization of the city has resulted in high development densities, environmental degradation, proliferation of slum and squatter settlements and general low productivity (Linn, 1983; Nzioki, 1988; Obudho, 1983). The Calabar’s environment is affected by the planning process
No study has been done to quantify the effects of urban structures on the environmental management in Calabar metropolis. Therefore there is need for a comprehensive methodological framework for quantifying the city’s land use and land cover changes and their environmental implications.
The Aim and Objectives of the Study
This study was occasioned by the need to understand the Effect Of Urban Structure On Environmental Management In Calabar Metropolis.
It was also occasioned by the need to establish factors that have influenced the land use in Urban city of Calabar, the nature of the changes as well as the environmental implications of those changes
In order to achieve the aim above, the study was guided by the following specific objectives:
- To establish the trend and nature of land use and land cover variations in Calabar
- To establish the factors that influence Urban structures and land cover dynamics within Calabar metropolis
- To assess Land Consumption Rate and Land Absorption Coefficient in Calabar.
- To establish the socio-economical and environmental implications of the land use and land cover changes.
The Research Questions
This study sought to answer the following research questions: –
- What is the trend and nature of urban structures in Calabar?
- What are the factors that influence land use and land cover dynamics within Calabar metropolis?
- How does the Land Consumption Rate correspond to Land Absorption Coefficient for the City between the years 1988 to 2010?
- What are the major socio-economical and environmental implications of the land use and land cover changes in Calabar City?
Null hypothesis (H0): The Urban structure decision making mechanism in the city as embodied by statutory legal and /or urban planning regulations as well as socio-cultural, economical, political and technological advancement in society does not determine the land use and land cover dynamism; hence the quality of urban environment.
Alternative hypothesis (H1): The Urban structure decision making mechanism in the city as embodied by statutory legal and /or urban planning regulations as well as socio-cultural, economical, political and technological advancement in society determine the land use and land cover dynamism; hence the quality of urban environment.
Justification of the Study
Over the years, the challenge to Nigeria’s sustainable urban development has remained achieving proper balance between land uses and the environmental quality. However, the ad-hoc manner in which the city’s development planning has been undertaken has not integrated land uses with controlled environmental quality consequently leading to environmental degradation. Consequently, it is clear that Nigeria needs a development strategy informed by the spatio- temporal analysis of the land use and land cover dynamics which provides the benchmark for projecting future land use and land cover differentiation rate, pattern, magnitude and trend (Devas, 1993). Over the years, Nigeria has continued to experience land use and land cover dynamics manifesting through the built up areas invading other land uses and land covers with the greatest casualties being forest resources, rangelands, shrubs and agricultural lands. This has consequently led to the loss of a significant amount of agricultural land and other natural resources which can only be mitigated through a comprehensive urban development strategy. However, this must begin with quantitative evaluation of land use and land cover dynamics which entails building of land use and land cover inventory and the assessment of the type, magnitude, pattern and trend of land use and land cover dynamics within the city. This was equally important in projecting future land development demand, environmental quality assessment as well as aiding in directing infrastructural facilities to the parts of the city where they are needed most to support development. Therefore, it was imperative that a better understanding of the rate, causes and consequences of land use and land cover change be modeled in a quantifiable manner towards aiding in the formulation of sustainable urban development strategies.
As earlier noted, urban land use and land cover dynamics have raised conceptual challenges to urban development theories and attempts to develop comprehensive explanatory model for understanding the same has mostly yielded descriptive rather than quantitative models, yet it is the quantitative models which have a niche in aiding land use decision-making (d’Aquino et al.,
Significance of the Study
State governments in Nigeria are charged with the responsibility of enacting and enforcing the development control measures. However in majority of the cases, the development controls are only based on human intuition rather than rational quantitative basis. This has always hampered developments of these urban centers as they hinder the aspirations of the developers to undertake investments due to what they view as punitive development control measures. It is in this regard that the study will inform development planning and processes, which creates a balance between land use and land cover as well as land use functionality. This was demonstrated by this study. The land use and land cover changes are often a reflection of urban developments which should be accompanied by infrastructural expansion. However, the regional governments are known to be expanding infrastructure in a way that sometimes is contrary to urban growth pattern and direction. A study of this nature, which uses satellite imageries, can form the basis of knowledge upon which proposals for the direction and patterns of infrastructure expansions as well as zoning requirements such as floor index, plot coverage, sky limit and plot size can be based. The infrastructure envisaged here included water reticulation, sewer and road network.
The study also provided a deductive basis for undertaking land suitability analysis which is imperative in protecting the fragile ecologies like the riparian vegetation and forests covers against encroachment by other urban anthropogenic activities and protection of human life and property (Liu et al., 2010). The use of high resolution imageries promotes object oriented land use and land cover dichotomy in a faster and accurate manner. It also enables direct segmentation of the objects as they appear on the ground as granted by their higher spatial
The major beneficiaries of this research will include two distinct groups: (1) estate managers at the state and national levels of government, and (2) regional as well as urban planners who want better urban planning in broader social and economic settings.
The Scope of the Study
This study was undertaken within what legally defines the area of the jurisdiction of Calabra metropolis.
Definition of Terms
Environment: This literally means surrounding and everything that affect an organism during its lifetime, collectively known as its environment. In other words, environment is sum total of water, air and land interrelationships among themselves and also with the human being, other living organisms and property. It includes all the physical and biological surrounding and their interactions (Ullah and Wee, 2009). In the context of this study, environment entails vegetations, air, water, and land/soil and temperature .
Environmental quality: This is a set of properties and characteristics of the environment, either generalized or local, as they impinge on human beings and other organisms. It is a measure of the condition of an environment relative to the requirements of one or more species and or to any human need or purpose. Environmental quality is a general term which can refer to varied characteristics that relate to the natural environment as well as the built environment, such as air and water purity or pollution, noise and the potential effects which such characteristics may have on physical and mental health caused by human activities (Johnson et al., 1997). Thus in the context of this study, environmental quality was limited to how the land use and land cover dynamics which manifests through spatial and temporal changes in the urban built-up and open lands, agriculture and riparian vegetation, rangeland and shrubs, forests and water bodies may have future implications on the urban surface runoff (flooding), loss of vegetation cover, water pollution, urban heat islands and a decline in air quality.
Built Environment: This refers to the human-made surrounding that provide the setting for human activity, ranging from individual dwelling and Building to neighborhoods and cities that can often include their supporting infrastructural services (Roof and Oleru, 2008)
Development: Pursuant to Section 3 (a) of the Physical Planning Act (Cap. 286-Laws of Kenya), development denotes making of material change, alteration of building density or land subdivision.