1.0 Introduction
African countries have been identified as amongst the most vulnerable places in the world due to climate change and climate variability, anthropogenic activities are a contributory cause to the extreme rise in global atmospheric temperature and the resulting climate change phenomena (IPCC{intergovernmental panel on climate change}, 2007). Flooding disaster is when a place that is normally dry becomes filled or covered with water (Oxford advanced learner dictionary). The main characteristics of these changes in climate are the increases in the average global temperature (global warming), changes in cloud cover and precipitation particularly over land; melting of ice caps and glaciers and reduced snow cover (United Nation Framework Convention on Climate Change - UNFCC, 2007).
In cities, these effects make communities vulnerable to climate change. In other words, climate change becomes a global threat to human survival. It is therefore imperative that, national and local governments take the necessary steps to ensure that the degree of vulnerability emanating from climate change and its associated risks are significantly reduced. Flooding has serious effects on the social, economic, environmental, physical and psychological wellbeing of people and even on the political and institutional levels of a country.
It is therefore, urgent that the vulnerability of developing countries to climate change is reduced and their capacity to adapt is increased at national, regional and community levels (UNFCCC, 2007). General climate changes (measured by temperature, precipitation, and number of rain days per year) show a positive and significant relationship with flooding and related extreme events.
Flooding is considered as a primary example of climate change related events in all parts of the world (IPCC, 2007). It is often argued that the more severe temperature levels vary, the higher the level of precipitation, and the more rain days per year the higher the risk of flooding.
Flooding is considered as one of the most hazardous, frequent and widespread natural disasters and yet, floods seem to be part of the lives of some communities in the world (Lawford et al, 1995; Dar and Nadargi, 2001; Schanze et al, 2006). Flooding mostly exacts adverse socio-economic impact on the wellbeing of flood prone communities. It does cause displacement of people, collapse of buildings, loss of lives, damage to valuable documents, unplanned migration, among others. Hence, significant information for people living in these flood prone areas is how often and how severe the flooding may be.
According to RICS 2009, “Surface water (pluvial) flooding, one form of flooding, is closely associated with intense, often localized, storms that overwhelm the capacity of local drains, causing flash floods. Pluvial flooding is a characteristic of urban areas where large areas of impervious ground exist and inadequate drainage systems abound. Impacts from climate change are understood to include water scarcity, drought, food shortages, malnutrition, increased disease vectors, increased storm surges and frequent flooding. For instance, droughts and floods, such as the African Sahel droughts and major floods in Mozambique, have caused ‘environmental refugees’ (Action Aid, 2006). The implications of these problems go far beyond the individual and sometimes threaten the fragile national economies (Rain et al, 2011).
It is imperative to note that, these new challenges will not only make achieving the Millennium Development Goals (MDGs) more difficult, but could also threaten some of the progress already made in eradicating extreme poverty and disease. Climate change is observed to be exacerbating and disturbing the delicate well-being of people. Water is critical to life but too much water or water that comes at an unexpected time or in unexpected places can be a big problem. As temperature and rainfall intensity increases, the frequency and occurrence of flooding may also increase (Afeku, 2005).
Flooding is described as a relatively high flow of water, which overflows the natural channel, provided for runoff. Floods are classifiable according to cause (high rainfall, tidal extremes, structural failure) and nature (e.g., regularity, speed of onset, velocity and depth of water, spatial and temporal scale) (Ahern, 2005).
Flooding can be divided into different categories according to their duration. Slow-Onset Floods usually last for a relatively longer period; it may last for one or more weeks, or even months. As this kind of flood last for a long period, it can lead to lose of stock, damage to agricultural products, roads and rail links. Rapid-Onset Floods last for a relatively shorter period; they usually last for one or two days only. Although this kind of flood lasts for a shorter period, it can cause more damages and pose a greater risk to life and property as people usually have less time to take preventative action during rapid-onset floods. Flash Floods may occur within minutes or a few hours after heavy rainfall, tropical storm, failure of dams or levees or releases of ice jams.
River Floods are the most common type of flooding. When the actual amount of river flow is larger than the amount that the channel can hold, river will overflow its banks and flood the areas alongside the river. The cause may be reasons like snow melt or heavy spring rain. Besides, flood risks may be further exacerbated by trends towards urbanization. Hollis (2003) as cited in RICS (2009) reveals that, more infrastructures such as roads and hard pavement surfaces increase the problem of urban run-off and thus, the resultant effect of flooding. These paved surfaces which are mostly seen in urban buildings prevent natural infiltration unless designed for this purpose, hence contributing to urban floods. The type of flooding of interest to this research is rain and over flowing damiver induced flooding.
Health Implication of Flood Disaster
Related to sanitation are the health implications. Flooding has a lot of health implications on the people. Stagnant water breeds insects and mosquitoes thus causing malaria. People who are directly exposed to flood waters suffer injuries and sicknesses like skin rashes and fever.
There is an outbreak of epidemics and diseases such as cold, flu, cholera, pneumonia and malaria during flooding. The flooding incident brings about an outbreak of diseases including malaria and diarrhea in the communities. The illnesses are an additional burden on household expenses; those who cannot afford the medical bills find themselves in trouble.
