THE PLACE OF SOIL CHARACTERISTICS IN THE PREVALENCE OF FLOODING
CHAPTER ONE
INTRODUCTION
1.1 Background of the Study
Nigeria has experienced flooding attacks in diverse places and levels within the last two decades. In 2001, for instance, Abia, Adamawa and Akwa-Ibom States witnessed heavy downpour and rainstorm which affected about 5,000 people. In the same year, about 12,300 persons were displaced by torrential rain that resulted to flooding that destroyed farmlands, damaged properties and submerged buildings in Zamfara State. In 1988 and 2001, Kano witnessed windstorm and flood that affected 300,000. What with the 2011 Lagos and Ibadan floods that wreaked extensive havoc? (Ajayi, Ola 2012)
Similarly, in 1999 and 2001, Bayelsa and Delta States experienced heavy floods that rendered hundreds of people homeless. In 2005, it affected Taraba State as massive flood displaced over 50,000 persons. And then, in August and early September 2007, heavy rainfall led to severe flooding in several West African countries such as Nigeria, Ghana, Burkina Faso, Mali, Kenya Togo, killing 353 and affecting over 600,000 persons. It becomes clear that the flood menace is not strange to Nigeria after all. (Punch 2015)
Soil is defined as the thin layer of the earth surface that can hold anything on its surface and also have the ability to support. In a very broad sense, soil refers to all unconsolidated materials at the earth’s surface that is capable of supporting life (Ogundimu, 2005)
Soil is a mixture of minerals, organic matter, gases, liquids, and countless organisms that work together to support life on Earth. Soil is a natural body called the pedosphere which has four important functions: it is a medium for plant growth; it is a means of water storage, transport, supply and purification; it is a modifier of Earth’s atmosphere; it is a habitat for organisms; all of which, in turn, modify the soil. Soil is called the “Skin of the Earth” and interfaces with its lithosphere, hydrosphere, atmosphere, and biosphere (Montgomery 2003).
The physical properties of soil are texture, structure, density, porosity, consistency, temperature, colour and resistivity. Of all the factors influencing the evolution of soil, water is the most powerful due to its involvement in the solution, erosion, transportation, and deposition of the materials of which a soil is composed. (Strahler, 1971).
Flood is defined as extremely high flow of river, whereby water inundates flood plains or terrains outside the water confinement of major river channels. Flood hazard is measured by possibility of occurrence of their damaging consequences, conceived generally as flood risk or by their impact on society conceived usually as the loss of lives and material damage to society. Flood is a natural occurrence, yet, its impact can be controlled by man. It becomes a problem when people are not prepared for it and early warning prognosis are flagrantly ignored while mitigation measures are not put in place to attenuate its impact on the economy. (Oriola, 2000) Floods occur when water particularly from rainfalls accumulates across an impermeable surface and cannot rapidly dissipate or evaporate. Floods can also be caused by a series of storms moving over the same area. Even dams can flood low-lying areas, often causing significant damages.
Nationally Anambra State is aflood prone zone which includes Awka excluding few parts. The flood hazard of year 2012 was unprecedented in Nigeria and was seen as a national disaster. 94% of states of the Federation including Anambra State suffered great losses in the flood. 38% of local government areas in Anambra State including Awka south local government area were adversely affected. Houses and other public and private properties, infrastructure and facilities were submerged and destroyed while many residents were displaced (SEMA, 2012). The essence of this study is to ascertain the place of soil characteristics in the incessant flooding in Awka.
1.2 Statement of Problem
Flooding has been a threat in Awka the capital of Anambra State. The area has been experiencing flood disasters as a result of so many factors which help to aggravate rate of flooding during rainy seasons in Awka. (Nwilo2011). Statistic have it that more than 28 buildings, including schools, churches, hospitals and residential homes, have been submerged by flooding in Awka, Anambra State following torrential rain which lasted for about three hours in July 2012, three churches, two primary/ nursery schools and two hospitals were badly affected while no fewer than 90 families living within Owurah, Ezioka, Court Road, Amikwo, Umubelu, Iyiagu, Kwata, etc were rendered homeless, as their homes were taken over by flood water. Motorist always find it difficult to pass through the area during the rainy season. This is evident along zik’s Avenue where any motorists are always trapped in the flood. In these areas many lives, properties worth billions of naira have been damaged, accidents, congestion and loss of aesthetics values and beauty of the environment become the other of the day, overcrowding, spread of communicable diseases and water-borne diseases like cholera, typhoid fever have become prevalent in the area, lives have been lost by car accidents as a result of damaged roads, rate of crime and conflict increased as people resort to all kind of social vice in order to stay alive. (Ebuzoeme and Ogechukwu 2015).
The problem of flooding has led to the pollution of water bodies in Awka and the main source of portable water supply in the flood prone area which is hand dug well always become contaminated with silt, sand and debris during rainy season because the flood water flow into them and this has contributed immensely to the problem of scarcity of portable water supply in the flood prone areas during rainy season (NEMA 2012), they also reported that it always leaves behind a large quantity of debris and dirt’s lying around on the road and sidewalks thereby littering and causing environmental deterioration.
Despite all the efforts, resources and manpower that have been dedicated to finding the root cause of this incessant flooding, the problem still persists. The answer to this is not far-fetched, considering that most researchers concentrate only on things like climate, topography, land use, and other anthropogenic activities without attempting to take a closer look at the soil characteristics which is a key determinant in the fate of flood water.
It is to this effect that this project seeks to study the place of soil characteristics in the prevalence of flooding in Awka, because there is need to approach the problem from another perspective other than what has been done already, with a view to proffering solution to the menace.