Victim’s Perception of Gully Erosion in Edo State, Nigeria
Department of Geography and Environmental Management, University of Abuja, Nigeria
This research is on victim’s perception of gully erosion in Edo State, Nigeria. The primary objective was to evaluate how victims understand causes, effects of gully erosion and effectiveness of erosion control measures in the study area. The research used questionnaire as a tool to examined victims perception of gully erosion in the area. Out 480 questionnaire administered, 454 were returned and they were use for the analyses. Based on the findings of this study, victims of gully erosion in the area attributed causes to poor construction of culverts, deforestation and termination of drainages in sloppy topography. They agree that gully erosion in the area has resulted to losses of human lives, losses of buildings, displacement of people and losses of productive land. Victims also confirmed damages of infrastructures such as roads, bridges, buildings and altering of transportation corridors. Their responses revealed that gully erosion has resulted to decreased species richness, slowed succession and declining agricultural productivity which means less vegetation cover to soil, less return of organic matter and less biological and nutrient activity.
Key words: gully, erosion, perception, control, measures, causes, effect, effectiveness
Soil is an important land resource and human communities depend on it’s for agriculture, construction and even as a habitat. Research on soil erosion has a long scientific history and the underlying fundamentals of soil erosion processes have been investigated for many decades. But research is still ongoing and increasingly focuses on very detailed topics of gully erosion processes, causes and control measures. Mashi, Yaro and Jenkwe (2015), suggested that studies are also lacking that examine people’s perception of the environmental and socio-economic consequences of gully erosion problem. According to Areola (1999), in the past people’s reaction to the problem of soil erosion was to abandon the devastated area and migrate to new area. This is because they regarded soil erosion control as responsibility of government. There is need for attitudinal re-orientation of the public especially those affected by soil erosion problem. Although Areola (1999) recognized some active reaction like dumping of animal waste, ash and other household refuse materials as control measures, they have little influence as they are not used in large scale.
According to Musa, Ahmed, Muhammed and Abdul (2016), the community should be encouraged and advised to contribute their quota in addressing the problem of gully erosion through traditional means and other cultural practices such as agro-forestry system, planting of cover crops in their farms, planting trees along the streets as well as other local factors that can mitigate the gully erosion. Local communities have important roles to play in ensuring effective erosion control measures are put in place. Communities should be encouraged to form local committee to handle control of soil erosion problem. There is need for people to respond to their difficult environmental challenges by evolving highly specialized and cost effective control measures. Due to the fact that gully erosion control measures have not yielded positive result especially in study area, there is need to study the erosion control measures applied in the area and the level of community participation in application of these soil erosion control measures to reveal the most suitable gully erosion control measures and environmental conservation techniques appropriate in mitigating this problem.
STUDY AREA DESCRIPTION
Edo State is located in the South-South Zone of Nigeria. Its capital town is Benin-city. The State was created in 1991 out of the old Bendel state and its geographical coordinates are Latitudes 05° 44′ to 07° 34′ N and longitude 05° 04′ and 06° 45′ E. It has a land mass of 19,794km square and it is bordered by Kogi State to the north, Delta State to the East and South and Ondo State to the West.
The geology of the study area reveals that the entire area is underlain by sedimentary rocks. It consists of the crystalline basement rocks in the hilly and dissected zone in the north followed southwards by residual lateritic soils of the well drained dry lands at Auchi, Agbede and Afuze. Aderemi and Iyamu (2013) observed the area is underlain by sedentary rock of the Pleistocene age often referred to as the Benin formations. The sedimentary rock contains about 90 percent of sandstone and shale intercalation. It consists of over 90% sandstone, clay, shale and lignite coarse fine grained in some areas. The nature of the underlying geology contributes significantly to the origin and spread of gullies Afegbua, Uwazuruonye and Jafaru (2016). The relief of the area is mainly characterized by swamping creeks and dissected plateau such as the Esan Plateau, Orle valley and the dissected uplands of Akoko-Edo Local Government Area. According to Adediji and Felix (2013), there are six types of physical features which constitute the landscape of the area. Sandy coastal plain and alluvium clay are found in the Benin lowlands area with some hills in the east. Slopes are tilled in the southwest direction. River Osse, River Orihionmwon and lkpoba are the major drain in the area.
With the exception of River Osse that has a wide flood plain, Eseigbe and Ojeifo (2012), observed that other rivers in the area are characterised by steeply incised valleys in their upper courses and they become broad as they enter River Ethiope in Delta State. According to Eseigbe and Ojeifo (2012), the state has land mass that is relatively flat terrain in the southern part with an average height above the sea level of about 500metres except towards the northern axis where the Northern and Esan plateaus range from 183 metres at the Kukuruku Hills and 672 metres at the Somorika Hills.
The climate of the study area is humid sub-tropical indicating that it is basically within the tropical rain forest zone dominated by broadleaved trees that form dense layered stands which usually are above 50m (165 ft) in height. It is typically tropical with two major seasons- the wet and the dry seasons. Ikhile (2015), highlight that the seasons correspond to the periods of dominance of the wet tropical continental air masses and the seasonal distribution of rainfall follows the direction of the Inter-Tropical Divergence (ITD) which varies almost proportionally with distance from the coast.
The temperatures across the state is relatively high with a very narrow varies in seasonal and diurnal ranges 22-36 range with an average annual rainfall of about between 2000mm-2500mm. The wet season comes between April and November and the dry season between December and March. According to Onakerhoraye (1995), there is a marked dry season, with duration of increases from three months in south, northwards, while the rainy period decreases inland from nine months in the south to five months in the northeast.
The vegetation zones of Edo State coincide with the political zones in the state. Edo South is in the moist rainforest, Edo Central in the dry rainforest and derived savanna and Edo North is characterized with derived savanna and southern guinea savanna. The area is also characterized by few scattered rainforests, wooded shrub lands and farmlands. Adekunle, Olagoke and Ogundare (2013), observe that the trees could be seen to be green throughout the year because they retain their leaves all through the year. This is because the temperature and precipitation are sufficiently high for continuous growth. The state is blessed with abundant natural resources. Virtually all species of hardwood can be found – high quality timber is produced from most local government areas of the State.
The state consists of eighteen Local Government Areas which include Akoko-Edo, Egor, Esan Central, Esan North-East, Esan South-East, Esan West, Etsako Central, Etsako East, Etsako West, Igueben, Ikpoba-Okha, Oredo, Orhionmwon, Ovia North-West, Ovia South-West, Owan East, Owan West and Uhunmwonde.
Major towns in the State include Benin City (the State Capital), Abudu, Ekpoma, Uromi, Auchi, and Sabongida-Ora. Generally, Edo State is traditionally known for agriculture, trade and deep historical virtues. The residents are traders and farmers whose activities are closely tied to the land. A lot of residential structures are within the gully strip, Edo State Strategic Health Development Plan (2010-2015). Due to their proximity to the gully, some of these structures have been marked as danger zones by the Edo State Ministry of Land, Housing and Survey. According to the State Strategic Health Development Plan (2010-2015) 70% of the landmass is cultivated for agricultural production as a means of livelihood with an average of about 2.345 million persons in the State directly or indirectly engage in agricultural activities. Major ethnic groups in the state are the Binis, the Esan, Ora, Etsakos, Owans, Akoko, Igarra and Afemai. The Binis occupy the southern part of the state, Esan and Ora occupy the central part and Afemai, Igarra and Akoko in the northern area. According to National Population Commission (2006) Edo State has a total population of 3,233,366. The demographic features of the area are typical of states in Southern part of Nigeria, growing rapidly with the population overstretching the weak social services. With the figure of 2006 Population and Housing Census, the state has population of 3,233,366 and an average population density for the state is about109 persons per sq. km, which is above the national average of about 96 persons per sq. km. According to the State Strategic Health Development Plan (2010-2015), the total population figures have been projected to over 3.4 million people. Most people in the area engaged in food crops cultivation. The main food crops cultivated include yam, cassava, maize and rice in the Benin lowlands and on the Esan plateau. There is also rice cultivation in the flood plains of the River Niger at Agenebode and Illushi. Tree crops such as rubber and oil palm are also cultivated in the Benin lowlands and Esan Plateau and cocoa in Owan, Etsako and Akoko Edo. The major environmental and ecological problems associated with Edo State are waste management, pollution and sanitation, forest depletion, flooding and erosion of the surface of the soil. Land degradation due to flooding and erosion ranked first and second in the objective ranking of environmental problems in the state. (Edo State Strategic Health Development Plan 2010-2015).
The magnitude of devastation as a result of flooding and erosion has resulted in loss of lives and properties, destruction of arable lands and wastage of large areas of usable lands. The State Strategic Health Development Plan also suggested need for re-afforestation, regulated construction and provision of drainage facilities in urban areas as well as attitudinal change on the part of the people.
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Figure 1.1: Local Government Areas in Edo State Source: Edo State Ministry of Lands and Surveys
The research used questionnaire to examined victims perception of gully erosion in the study area. From the 480 questionnaire administered, 454 were returned and they were use for the analyses. The questionnaire was designed to collect educational characteristic of the respondent, information on causes of gully erosion and control measures in the study area. It was also used to collect information on people’s perception of effectiveness of erosion control measures applied in the area and the level of community’s participation in erosion control measures in the area.
In administering the questionnaire, the purposive sampling technique was used. This system was chosen because gully erosion affects some specific areas of the state and not all the people in the study area are affected by gully erosion. The questionnaire was administered to people who are directly affected by gully erosion within 5km radius of the chosen gullies. This is to ensure that the respondents are those affected by gully erosion problem. Due to the nature of the study, considering time, cost and for convenient, a copy of the questionnaire was administered to 30 respondents at the chosen 16 gully sites making a total of 480 respondents considered in the course of this research.