CHAPTER ONE
INTRODUCTION
- Background to the study
In recent times, flooding has been universally considered as one of the pronounced environmental hazards making most impacts on human lives and properties (Ouarda et al., 2009;Gaume, et al., 2010; Villarini, et al., 2009; Schmocker-Fackel & Naef, 2010; Greenbaum et al., 2010; Prudhomme et al., 2003; Kusumastuti et al., 2008). Smith (2001) stated that floods claimed over 20,000 lives and adversely affected around 75 million people worldwide annually. Existing flood defense structures are becoming too weak to withstand the increasing magnitude of flooding. This signifies that primary protection regarding flood is not sustainable anymore. The solution is moving to risk culture and finding the balance between the shape of land use and urbanization through adaptation, mitigation, prevention, and response and recovery strategies.
Morristown (2010) defined flood as an overflow of water onto normally dry land, the inundation of a normally dry area. In the same vein, Caldwell (2012) affirmed that flood is any high flow, overflow, or inundation by water which causes or threatens damage. Flooding can rise from overflowing rivers (river flooding), heavy rainfall over a short duration (flash flood) or an unusual inflow of sea water onto land (ocean flooding).
Olajuyigbe et al., (2012) defined flood as a natural hazard like drought and desertification which occurs as an extreme hydrological (runoff) event. Flooding according to geosciences Australia (2013) can be simply regarded as “water where it is not wanted”. It can be conceptualized as a situation that result when part of the earth surface that is usually dry is inundate ed and covered with water sue to high amount of rainfall or the overflowing of a water body.
Residential areas are more frequently exposed to natural hazards, in particular to flooding. Ebisemiju (2008) opines that human activities such as rapid industrialization and urbanization, population growth, exploitation of natural resources and location of infrastructures (dams, piers and lands) exacerbates the occurrence of floods in residential areas. Residential areas may deteriorate when flooded as a result of the impermeability of the rocks on the soil on which the buildings rests that leads to poor water penetration, increase in the height of water table as a result of cumulative rainfall, resulting into the inability of the soil supporting building to absorb water and obstruction of natural flow of water through drainage made to protect the buildings by debris and garbage disposed improperly by human beings. Flood is very problematic; its devastating effects in residential areas according to Adedeji and Salama (2011) can be categorized into three: structural, economic, and health related effects.
Flood occurring both in the developed or developing countries are always associated with heavy loses of life and property, misery, hardship, disease and at times famine in rural communities. In developing countries, people living in flood plain areas are poor people. As they cannot afford to buy legal land, they occupy vacant land along the riverside. Nevertheless, it does not always happen life that. Many planned residential areas are also built on lowland areas. This indicates the scarcity of suitable land in the urban area. However, when flooding occurs, not only people who live in the floodpain area, but also neighbouring areas may experience flooding since the flood plain areas have been expanded. Studies have shown that flooding is a common environmental hazard in Bangladesh, China, South Asia, United State, Australia, United Kingdom, and Europe (Ebusoeme, 2015)
Recently, in Northern Nigeria, flood displaced more than two million people as the flood gates on Challawa and Tiga dams were opened to release rising waters along the Niger River. Flooding has wreaked havoc across many other parts of Nigeria in recent years, including the following states: Anambra in the east, Sokoto in the northwest, Borno in the northeast, Plateau in the centre and Yobe in the north. Flooding is recorded every year in all the states along the Niger River and its tributaries, frequently causing disasters. Moreover, two-thirds of Bayelsa State and half of Delta State are inundated by devastating floods for at least a quarter of each year (Vincent and Paul 2012).
Cross river state is not left out of the scourge of flood hazard over the years. Flood occurrence has caused provocative havoc to several local government areas of the state of which calabar municipality stands as one count of such local government areas. Calabar south has recorded a countless occurrence of flooding which has caused destruction of buildings, lost of lives and properties.
