ABSTRACT A portable low-cost field rainfall simulator was designed to provide rainfall intensities in the range of 14 to 80 mm h⁻¹. The designed simulator is easy to assemble, transport and its portability and flexibility enable the necessary experimental replicates in remote locations. The simulator was tested in terms of Christiansen Uniformity coefficients that ranged from 89 to 94% for the three Full-jet nozzles used in this study, with median diameters ranged from 0.836 to 2.113 mm, showing an appropriate degree of accuracy. The terminal velocities of the raindrops was also examined and ranged from 3.35 to 6.83 m s⁻¹. Furthermore, kinetic energy values ranged from 12.7 to 18.9 J m⁻² mm⁻¹, showing similarity to the natural rainfall occurs in the Mediterranean regions under conditions of low rainfall intensity. The applicability of the rainfall simulator in the dynamic processes of erosion characteristics was investigated in the northwestern coastal zone of Egypt, where erosion is an important threat of sustainability. Five rainfall intensities (14, 21, 30, 36, and 45 mm h⁻¹) were evaluated in three repetitions at three uncultivated sites having slope gradients of 5, 9 and 12 %, forming 45 simulated rainfall. The changes of sediment yield, sediment concentration, runoff rate and runoff coefficient for the 45 simulated rainfall were quantified. Altogether, the results indicated that runoff and sediment yield rates were substantially different between the rainfall intensities of 14 and 45 mm h⁻¹than those obtained between any other pairs of intensities under all soil gradients. Summing up the results, the designed portable rainfall simulator can be effectively used in studying the dynamic processes of soil erosion in field scale, specifically quantifying these processes in the presence of variability in rainfall intensity and soil slope.