EFFECTIVENESS OF DRAINAGE NETWORKS ON FLOODS
The study examined the effects of drainage networks on floods in Calabar metropolis, Nigeria. The rapid increase in urbanization without corresponding infrastructures in the city of Calabar has led to increased incidences of flood as the available drainage channels cannot contend with the volume of storm water. In view of this, the study established gauging stations for the measurement of drainage run off using measuring steel tape. And the volume of flood water was measured using stop watch method (Velocity of flow) and copies of questionnaire were administered to 400 households proportionally to the seven sample units. In view of the study objectives, it determine the relationship between drainage width and depth and floods. In addition, varied descriptive statistics tools were used to give a spot on assessment and understanding of the variables of interest. In view of the response of the gauging and physical measurement, it was established that Calabar experience heavy rainfall due to poor drainage facilities The result revealed that about 47% of the respondents said flood occur every year in their zone and 41.75% said it occurred most parts of the year. The frequency of flood is compounded with it’s intensity as over 59% of the sampled population agreed that flood of the sampled population agreed that flood intensity is very high in Calabar. The result further showed that the factors of flood occurrence in the study area is linked to heavy rainfall (26.3%), inadequate drainage channel (22%) poor physical planning (15.5%) among others. On the perceived causes of inadequate drainage channel, the result indicated that abuse of land use plans (28.7%) was a major factor followed by poor monitoring and evaluation of project (21.5%). the study also revealed that the drainage were very narrow and shallows as shown in frequent floods in the city. The incessant flood often leads to water inundating compounds (64.5%), preventing people from going out (11.25%), distortion of the scenic beauty of the environment (6.25%), landslide (4.75%). Based on these findings, the study recommended that since Calabar is located in a tropical zone characterized by heavy rainfall the government should take proactive measure to mitigate storm water. The present drainage systems should be cleared with shovel by the people on a regular basis to allow for a free flow of storm water. State department of town planning should live up to their bidding by ensuring total compliance to urban ordinance to forestall incessant floods and destruction of properties in the city of Calabar.
1.1 BACKGROUND TO THE STUDY
Cities the world over are the dominating forces in the organization of human population. As the world most crowded places, cities continue to show increase in urban population. This increase leads to a growing urbanization trend. Duru and Nnaji (2008) defined urbanization as the increase in the population of cities in proportion to the region‟s rural population.
Urbanization is the outcome of social, economic and political developments that lead to concentration and growth of large cities, changes in land use and transformation from rural to metropolitan pattern of organization and governance. Rapid growth of towns and cities has been common feature of the developing world (Aderamo, 2008).
Although urbanization is the driving force for modernization, economic growth and development, there is increasing concern about the effects of expanding cities, principally on human health, livelihoods and the environment. The implications of rapid urbanization and demographic trends for employment, food security, water supply, shelter and sanitation, especially the disposal of wastes (solid and liquid) that the cities produce are staggering (United Nations Conference on Environment and Development, 1992).
The process of urbanization is believed to be connected with levels of development and some assert that, for a country to develop there is the need for an increased level of industrialization as it is generally accepted that there cannot be urbanization without rapid economic growth (Tettey, 2005). The pattern of urbanization in developing countries, particularly Africa, however, is creating some concern that it may be generating a lot of development problems in the process of its growth.