Design, manufacture and calibration of the SARI portable rainfall simulator for field and laboratory experiments

The Simulator of Artificial RaInfall (SARI) rainfall simulator (RS) is a newly designed, constructed and calibrated, portable, two-nozzle RS with low water consumption, accurate measurement, easy management and low cost. The raindrop size distribution and velocity and mean rainfall intensity were measured. The best rainfall spatial distribution was achieved with nozzles separated by 50, 60 and 70 cm, and with oscillation angles of 30, 45 and 60 degrees, at a pressure of 60 kPa. The uniformity coefficient varied from 57 to 61% and rainfall intensity from 48 to 101 mm h(-1). The raindrop diameter varied from 0.2 to 9.9 mm. The raindrop velocity at the optimum pressure of 60 kPa, which was measured with high-speed photography, ranged from 1.1 to 7.1 m s(-1). Comparison with other RSs shows that the SARI simulator is a suitable apparatus to research soil erosion and runoff generation under laboratory and field conditions.