In developing land management plans to minimize erosion problem, it is imperative to provide quantitative information on aggressiveness of storms for identifying areas in the landscape which are sensitive to disturbances. The study established that rainfall erosivity (R) indices over Southeastern Nigeria range from very low to very high erosivity. Periods of very low erosivity coincided with the dry season months in the region while the very high R coincided with the rainy season peak periods (June-September). Calabar Owerri and Port-Harcourt recorded the highest erosive storms/ more months of very high erosivity index. The deterministic relationship between kinetic energy of rains and erosivity pattern observed for the different stations showed that erosive rains contribute significantly to detachment of soil materials in the study area. The need for proper land use management and maintenance of surface vegetal covers cannot be overemphasized with increased weather variability. Monitoring of hydrologic regime and climate -related factors in the region as well as defining areas most vulnerable to erosion would help in erosion disaster management.

This article examines the geomorphometry of Ikpa River as a major determinant of the planning pattern for fluvial hazards in the Northeast of Akwa Ibom State. Geomorphometric parameters were computed for the entire area and the seven sub-basins sampled within the main watershed. A descriptive analysis of the parameters indicates that the dendritic Ikpa Watershed is a natural river with homogenous geologic formation and possesses high degree of integration of the smaller rivers. Sixteen geomorphometric parameters were measured for the seven sub-basins. Using Principal Component Analysis, four major geomorphometric parameters were identified and they Original Research Article

ABSTRACT:The study attempts to estimate the stream discharge of the Aboine river basin, southeast Nigeria, using modified climatic water balance approach. Moisture deficit in the basin generally begins from January and lasts up to April while utilization begins from October up to December. The basin attains a field capacity from August to September and decreases in moisture storage from October when more water is removed from the basin to meet plant water needs. The value of the circularity ratio of 0.29 showed that the Aboine Basin will produce little surface runoff. Results of bifurcation ratio, compactness coefficient, stream length and modeling of inter-basin parameters showed that the Aboine drainage basin is basically a flat surface. This will affect both the amount of water available from the basin for any water resources projects. Such information also provides the basis for demonstrating the effects of environmental control on the fluvial system and also for predicting the basin output variables. Surface runoff contribution to discharge was computed as a residual of our modified climatic water balance equation while groundwater flow contribution to discharge was determined from the separation of water stage hydrograph available for the study area from 1984 to 1987, using the hydrograph separation technique. Comparison of calculated discharge values using modified THWB climatic water balance with stream discharge determined from water-stage showed significant difference between computed stream discharge from water stage and discharge estimated from our water balance model at 0.05 level of confidence. This suggests that our modified water balance model if further improved maybe suitable for generating information on all the aspects of the moisture relationship in the basin in the absent of measured stream flow data. © JASEM

This paper examined the physical characteristics of floods and management adaptations to flood hazards in the Imo River basin. From the study, it was determined that the pre and post flood disaster management is a yearly event. The extent and time of commencement usually differs in each flood season, being between July, August and September when rainfall is at its peak. From the study, it was observed that flood duration in the sampled communities last for as much as three to four months. The velocity of the floodwaters under peak discharge usually between August and September was observed to be sluggish, while being faster during recession in mid-October. An investigation of human adaptation to flooding in affected communities indicated that up to 70% of the inhabitants have derived ways of managing their flood disasters on short term basis. These adaptation methods include emergency evacuation and rescheduling of activities, bearing flood losses and land use changes. It is recommended flood forecasting and warming systems be introduced. Engineering control of the major tributaries of the Imo River system is required to reduce impact of flooding on the settlements, while land use zoning will serve as an effective adaptation and disaster management option in the study area.

Discharge data for most basins in developing countries are lacking or inadequate where available. An alternative is to find other ways of appraising the natural water potential of basins without stream discharge records. This study attempts an appraisal of the water resource potential of the Eze-Aku basin in Ebonyi State of Nigeria using morphometric indices alone. From its morphometry the basin is essentially a low land and erosional surface. This affects both the quantity and quality of water for use by inhabitants of the basin. The analysis of results show the Eze-Aku basin is not suitable for water resources development projects demanding large monthly and annual discharge volume such as hydropower and navigation. Other morphometric parameters investigated in the study include bifurcation, shape, stream and drainage densities. Analyses of these parameters provide the basis for demonstrating the effects of environmental controls on both the basin stream network system and for predicting the basin's output variables. Such information are essential and provide framework for improving agricultural activities, flood control and management measures and potable water supply in the study area for increased standard of living in the agricultural dominated area.