Experimental Study of Rainfall-Runoff Process Through Calibrated Simulator; A Case Study of Auchi Polytechnic, Auchi, Edo State, Nigeria

Abstract

The relationship between rainfall-runoff is a complex hydrological process that requires technical-based approaches to investigate and understand the interaction of the hydrological variables. A calibrated rainfall simulator was developed to produce storms at seven (7) predetermined rainfall intensities (RIs) over two (2) runoff plots (RPs). The runoff plot (RP) is 0.72 m2 and RPB is 0.5 m2 was inserted 0.3 m into the bare sandy loam. The results of the experimentation showed the first rainfall simulation attempt (RSA) of RI of 10.8mm/hr was completely lost to infiltration from the two runoff catchment plots. Subsequently, the RSA generated surface runoff intensities (SRI) and RPB produced higher SRI and volume compared to catchment plots (RPA). Conversely, the relationship of rainfall-runoff showed co-linearity between the simulated rainfall (SR) and generated surface flow RPA and RPB with the determinant of coefficients of 0.9926 and 0.9942 at P < 0.05. Therefore, the study’s finding is useful to develop a rainfall-runoff model under different runoff catchment areas for developing integrated water management schemes, hydraulic structures, and irrigation scheduling.