DEGRADATION OF THE NASIA RIVER BASIN IN NORTHERN GHANA

Abstract

The Nasia River is located with the Guinea Savanna Ecological Zone in the Northern Region of Ghana. It is the drainage basin of the left bank tributary of the White Volta along and on which several domestic and commercial activities take place. Activities such as farming very close to water bodies lead to environmental degradation with its associated effects. The study was aimed at assessing the effect of land degradation of the flow pattern of the Nasia River. To achieve this, rainfall data, information of Nasia soils and a semi-structured questionnaire was used in the study. results of the study revealed that within the time interval of 10 years, there was an area loss of 10% closed savannah and 3.2% of open savannah woodland and a percentage change increase of - 4.1% dense herbaceous plants and 0.6% for grasses and herbs. Burnt area increased from 0.5% to 0.7% indicating high level of burning. Built-up and bare land also increased from 2.7% to 11.4% while water bodies consisting of dugouts, dams, wetlands, streams and rivers reduced by and area of 24.61 km2. variation from the mean annual rainfall of 1045.18 mm (for a 33 year period) ranged from + 13.82 mm to +534.82 mm above annual mean and - 10.18 mm to - 382.78 mm below annual mean. rainfall intensities of 100 to 200 mm/h and infiltration rates of 43.0 to 61.9 mm/h suggested that overland flow and water erosion occurs.