DEVELOPMENT OF A PORTABLE RAINFALL SIMULATOR INFILTROMETER FOR INFILTRATION, RUNOFF AND EROSION STUDIES

Field measurements of infiltration rates are frequently used to index environmental conditions, soil hydrology, and the potential of rainstorm response for judicious and efficient water management. Since the commonly adopted method of infiltration measurement using double-ring infiltrometer tends to give higher values of infiltration, and most of the rainfall simulator infiltrometers developed in the past have higher cost and low transportability, making investigations expensive and limited to specialized studies, this study aims at the development of a low-cost, highly portable rainfall simulator infiltrometer (RSI). In this RSI, raindrops are produced at the end of capillary holes drilled through a 10 mm thick circular perspex sheet. The RSI is calibrated for various rainfall intensities. The characteristics of the simulated rainfall are evaluated for intensities of 100 mm/h and 200 mm/h. Field tests are conducted to evaluate the infiltration, runoff and soil-cover conditions. Infiltration is also measured simultaneously with the double-ring infiltrometer (RI), and values are found to be 2 to 3 times higher than those measured with the developed RSI. The effect of rainfall intensity and type of soil cover on runoff and soil erosion is also studied.