AN ASSESSMENT OF THE SOCIO-ECONOMIC IMPACTS (EFFECTS) OF AGULU-NANKA GULLY EROSION, ANAMBRA STATE, SOUTHEASTERN NIGERIA

Introduction

1.1 Background to the Study

Erosion is the process by which the agents of soil erosion wear away, eat into, loosen, or carry away soil material and transport it from one locality to another where it is eventually deposited (Egboka, 1991). Soil erosion is a complex process caused by wind, water and physical disturbances, encompassing detachment, transport and deposition of weathered rock. Soil erosion reduces land productivity, challenges agricultural sustainability and degrades environmental quality through contaminants attached to the sediments.

Soil erosion is caused and complexed by a variety of factors such as natural phenomena of neotectonics and paleotectonics, soil/rock features (pedology/geology), wind/water dynamics; and human phenomena such as population density, anthropogenic activities including engihanic effects (Egboka and Nwankwor, 1985). In the execution of colossal or small scale projects of Industrial or engineering nature, the textural, coherence and plasticity characteristics of the soil are not considered. Irrigation schemes, major road network, small and large dams, urbanization, deforestation, sand and laterite mining are carried out without cognizance of the warnings of environmental experts and/or professionals.

Similarly, sensitive drainage areas, wetlands and flood channels are encroached upon by hungry land developers. In view of these activities, sheet, rill and gully erosion are known to progressively develop over several years. All over the world man is a more important agent of environmental change than Nature (Press, 1990). Soil erosion problems are now endemic in many parts of southeastern Nigeria (Egboka, 1991). Increased awareness of erosion impacts on land, air, water quality and global climate, raises new challenges for erosion researchers. In some conditions, these impacts are so severe that they reduce the quality of life and economic well-being, and can threaten survival.

Chemical and physical deterioration of soil have major implication on agricultural productivity and housing development. In Nigeria agricultural production is the most important source of income to the people. Soil quality has a major impact on the capacity of the rural farmers to achieve food security. Soil erosion increment results in an unsustainable development of the living standard of the people. Sustainable development is the positive socio-economic change that does not undermine the ecological and social systems upon which communities and social systems are dependent. Land provides services to humans and other life forms as well as providing raw materials in production process. Land provides waste assimilation services as well as other ecosystem functions. Land provides utilities for recreation, health, cultural and ecological cycles and functions.

The quality of available land determines its production potential and real value. Land owned by families in Agulu-Nanka is mainly used for cultivation and housing development. Soil degradation resulting from gully erosion in the area, economically results in loss of its potentials (Values) for food production and housing development. This is because the eroded soil is not naturally replaced without costs. This process leads to material loss and reduction of economic base overtime and may have long term consequences on the living standard of the people affected. Agulu-Nanka erosion remain a local problem for a long time, which later gained attention on an isolated and adhoc basis from affected communities and relevant Government agencies, hence the silence on the documentation of losses sustained by the affected people: There is therefore, need for study on the social impact and economic losses sustained by affected people.

1.2 Statement of the Problem

Soil erosion is one of the most striking features on the land surface of southeastern Nigeria, especially in Anambra State. Several non-responsive human activities by both the Government and the inhabitants have culminated in the devastating gully erosion in this area. Some of these activities include, excavation of red earth (laterite) and sand in the process of sand/regolith mining, construction of roads without drainage channels, uncontrolled population growth and poor agricultural practices. Buildings are congested on top of groundwater recharge areas. The geology of the area (Nanka Sandstone) is composed of weak, friable soils which are poorly consolidated.

At Agulu-Nanka, each rainy season is associated with nightmares, particularly for inhabitants living at the proximity of erosion sites. Each gully incidence is accompanied by landslides and slumping, leaving at the end of each event inhabitants crying and mourning for loss of agricultural lands, ancestral lands, homes and economic trees. The cumulative effect is that the affected inhabitants are left homeless and/or jobless. The threats posed by gaping and daunting large gullies to farmlands, settlements, roads and human are enormous. Most communities in Anambra State have been ravaged by soil erosion of different dimensions. Sheet erosion is common and it has resulted in the reduction of soil fertility. Rill erosion is also common in many communities. However, in these areas they have graduated into gully erosion. The incidence of gully erosion is a common phenomenon in Agulu-Nanka communities. The inhabitants of gully ravaged sites have suffered mishaps ranging from psychological trauma to loss of property and life. Observations show that gullies in Agulu-Nanka are allowed to advance without adequate control efforts by Government, hence, the affected people watch helplessly while their farmland and homes are destroyed.

The incidence of gully erosion in Agulu-Nanka is not new, as it has formed a subject for research. Unfortunately, until now, most researchers are confined only to the factors causing gulling and control measures, keeping the losses sustained and other social and economic effects suffered by the affected people aside. It is of utmost importance to study and document the losses suffered by soil erosion victims in terms of social disruption, psychological effects and economic effects with a view to attracting Government, (State and Federal) to bring lasting solution to Agulu-Nanka erosion ravaged areas.

1.3 Research Questions

The following research questions inform the aim and objectives of the study:

1. What are the adverse social effects that are consequent on Agulu-Nanka gully erosion?
2. What are the adverse economic effects that resulted from gully erosion in Agulu-Nanka areas?
3. What percentage of the residents of various localities of Agulu-Nanka have suffered as a result of gully erosion?
4. What is the relationship between the social and economic effects that resulted from gully erosion in Agulu-Nanka areas?
5. How effective are the measures to contain the menace?

1.4 Aim and Objectives of the Study

The aim of this study is to assess the adverse social and economic implications of gully erosion hazards in Agulu-Nanka Communities of Anambra State, Southeastern Nigeria.

The specific-objectives of this study include:

1. To identify the adverse social effects that resulted from gully erosion in Agulu-Nanka.
2. To identify the adverse economic effects that is consequent o gully erosion in the Agulu-Nanka
3. To determine the size of residents in various localities of Agulu-Nanka that has suffered adverse social and economic effects resulting from gully erosion.
4. To determine the relationship between the social and economic effects of gully erosion in the area.
5. To determine the common adaptive measures and their sustainability

1.5 Research Hypotheses

The research questions and objectives translate to the following research hypotheses that are applied to this study.

1. H0: The adverse social effects of Agulu-Nanka Erosion on the Residents in the Erosion affected areas do not differ Significantly from the social situation in the unaffected Areas.
2. Ho: There is no significant difference between the economic effects of gully erosion in the various erosion ravaged localities of Agulu-Nanka and the other areas.
3. Ho: There is no significant relationship between the social And the economic effects of gully erosion in Agulu-Nanka areas.

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.1.6 Significance of the Study

The study is significant for two reasons. First, the study intends to identify the percentage of the residents according to localities that have suffered socially and economically from gully erosion incidence irrespective of the dimension of the gully occurrence. Adverse social effects include loss of ancestral home; loss of school building, loss of church buildings and loss of sources of water supply.

On the other hand, adverse economic effects include loss of farmland, loss of crops, loss of shop/business premises, loss of economic trees; palm trees, Ukwa trees (Bread fruit tree), Udara trees (African apple tree), kola trees, etc. Secondly, this study intends to determine the relationship the social and economic effects of gully erosion in the area. The study should enable decision makers, policy makers and environmental managers to evolve sustainable procedures for managing human activities like farming, road construction practices, stone and sand quarrying and harvesting in line with the characteristics of the lithology in the gully erosion prone areas.

Hitherto, the studies on gully erosion have established the general factors that cause gully erosion in the area. This study intends to move in another direction, it assesses the social and economic losses to the residents in Agulu-Nanka.

1.7 Scope of the study.

This section will be discussed under two categories, namely area coverage of the study and content. The coverage include erosion sites in Agulu-Nanka. Content of the research will include a study of the social and economic implications of gully erosion on the inhabitants of areas devastated by gully erosion.

Social characteristics that will be studied include, destruction of ancestral homeland resulting to forced relocation and hence refugee in Own-Land; loss of source of water supply, experience of trauma and frightful Scenic environment. On the other hand economic characteristics that form the crux of the study will include loss of building and furniture, farmland, planted crops, economic trees and monetary contributions to gully control works.

1.8 Theoretical framework

The Davison theory is the earliest cause and effect oriented theory on soil erosion. It holds that steep slopes are faster eroded than gentle slopes and that stream or runoff velocities are solely dependent on bed slopes, which got their derivation from this axiom. This law is tantamount to an obvious conclusion by Davis (1990) that the rate of change of landforms as well as other geometric impact magnitudes are functions of local relief. It therefore implies that the progressive changes on the terrain by the effects (impacts) of soil erosion are accepted to be universally associated with a progressive landscape evolution where the geometry of individual landforms and the rate of their erosion changes are both subject to sequential transformation through time.

The Ofomata’s (1987) Soil Erosion Model for humid tropics incorporates both the biophysical and human components in soil erosion cause and impact. The two major purposes that the Model addressed are firstly, the clarification of the relative importance of the numerous factors (causes) of soil erosion in southeastern Nigeria. Secondly, the advancing of a guide for uniformity of soil erosion research in all parts of the world in consonance with the second purpose. The Model explains comparative study and assessment of soil erosion in the entire humid tropical regions such that necessary variants in the major components of the Model can be introduced by specific local conditions. The model did not address the human impacts of erosion.

The 1969 passage of the National Environmental Policy Act in USA gave birth to the Environmental Impact Assessment. It was earlier known as cost-Benefit-Analysis (CBA). Its effect on human being or the human component of the environment was not at the centre focus. In other words, it has no human dimension.

Interaction Matrix Approach (IMA) has been earlier put forwards by Leopold, Clar, Hansaw and Ralsley (1971) as the first environmental impact assessment approach. It consist of ten (10) general categories of action on the abscissa or horizontal axis. This consist of about eight hundred and eighty eight (888) environmental factors or characteristic such as soil, flora and land uses. The vertical axis or ordinate has four (4) general categories with many impact characteristics. There are eight thousand eight hundred (8800) cells (that is 100 x 88) on a full matrix. It is denoted by (M/I) where M is the magnitude of interaction and I is the importance of Interaction. Burton, Kates and White (1978) Model, opines that natural

hazards are best viewed as ecological framework. This clearly explains that natural hazards occur from conflicts between what can be referred to as the natural event system and the human use system. The human (socio-economic environment) is given a central role from this interpretation of natural hazards. In the first place, through location. Secondly, through human perception.

Consequently, Kates (1971) concluded that hazard occurrences merely represent the extreme of natural processes and their distributions and in a slightly different context would often be regarded as natural resource. The study is based on this theory. Figure 1. shows the ecological framework of natural hazard.