ABSTRACT

 Rainfall simulator is an important instrument for producing artificial rainfall for the determination of soil loss from a catchment over a given period of time. The instrument is rarely available in most Nigerian Universities for practical demonstration for students and research in Soil and Water Conservation Engineering. This is due to high cost of the rainfall simulator and materials that are commonly used for the construction of rainfall simulator are not readily available or expensive in developing countries. In this study, a pressurized rainfall simulator was designed and constructed using locally available materials mainly PVC pipe, shower rose and a pump for supplying water to the simulator for its operation. The main-pipe receives water from the pump and supplies it to the laterals. The laterals supply water to the sub-lateral pipe which passes it to the shower rose. Sixteen shower roses on four laterals spray water to the ground surface through 2 mm openings. The simulator measures 2.1 by 1.7 m and all the components are detachable for portability. The simulator rests on an adjustable frame made of bamboo 2.20m height. The coefficient of uniformity and drop velocity from the simulator during the performance test were 84.03 % and 1.59 m/s, respectively. The results of Coefficient of Uniformity (CU) is within the range because the recommended minimum value of CU is 81 %. The intensity of water dropping from the simulator depends on the inflow rate of water which could be regulated by the control tap fixed to the inlet main-pipe.