A survey of erosion sites in Calabar Metropolis, southeastern Nigeria. – A. U. Ogogo, O. O.Egbai, F.A.Aya and O.E. Awala
Erosion is a common problem in Calabar metropolis. This has resulted in the loss of a large volume of soil, lives and destruction of property worth billions of naira. This study was undertaken to identify the erosion sites, determine the causes of the erosion and suggest solutions. Structured questionnaires and field measurements were used in the study. Stratified random sampling was used to administer the questionnaires. Four strata were established based on their topographic features and drainage pattern. Fifty questionnaires were administered in each stratum bringing the total number to 200. A 30m tape, 10m gunter’s chain, ranging poles, twine and anchor (weight) were used to measure the length, breath and depths of each erosion site. A global positioning system was used to take the co-ordinates and height above sea level of each erosion site sampled. A total of 42 erosion sites were identified out of which 11 were randomly selected for measurement. The eastern and western parts of the town with steeper slopes had more erosion sites than the middle low land area. The relationship between slope angle and erosion intensity was highly significant (r = 0.90). One hundred respondents(50%) agreed that lack of vegetation cover, poor drainage system, poor town planning, steep slopes and the sandy nature of the soil coupled with heavy rainfall (3,500mm per annum) were responsible for the erosion problem in Calabar metropolis. It was recommended that urban forestry projects should be embarked upon. There should also be provision of adequate drainage systems and development should conform to the approved plan of the town.