Abstract

Dune sand was subjected to varying rainfall intensities in order to generate runoff under laboratory conditions on slopes of 20 and 30°. Soil moisture probes were inserted into the soil at varying depths to investigate the movement of water through the profile. Results indicate that in spite of continuous simulated rainfall administered for over 4,000 min, no runoff could be generated over the sand surfaces and across the different slopes. It was deduced that for this to occur, rainfall intensities in excess of 6,000 mmh^-1 would be required. The results also indicated that to generate runoff from such sandy soils, treatment of the upper 0 to 10 cm of the soil profile would be required to reduce significantly the infiltration rate of the soil profile, which then will translate into runoff generation.

Key words: Ghana, rainwater harvest, overland flow, deep percolation losses, soil amelioration, sand