Evaluation of Simulated Rainfall Patterns in Control Plot Subsections

Rainfall simulators have been used for many years in laboratory settings to simulate natural rainfall. This natural precipitation produced in a laboratory environment is particularly important for hydrological research in controlled laboratory environments where its natural variability can be examined in detail. This study examines the spatial variability of rainfall's fundamental parameters, intensity, uniformity, and drop diameter, in a nine-subarea arrangement within a single-channel rainfall simulator. To observe how the distribution patterns change depending on rainfall intensity within the simulator's operating range of 30-140 mmh⁻¹, we conducted simulations at four different intensities (40, 70, 80, and 100 mmh⁻¹). Within the channel area, I (rainfall intensity) showed local variations. Similarly, Christiansen's uniformity coefficients (CU) ranged from 69% to 95%. However, local CU values in some sub-regions were significantly lower than these averages. D50 (median drop diameter) varied between 1.32 and 1.77 mm for different densities and sub-areas. Generally, it was observed that homogeneity improved as rainfall intensity increased, but there were still significant differences within the area. The size of the raindrops varies depending on where they fall, with larger drops generally observed in the middle of the area (A3, A4, A5). These results contradict the common assumption of uniform rainfall intensity within the channel area and highlight the necessity of sub-area-based analysis for the accurate interpretation of simulated rainfall experiments.