Comparison of Manning and Chezy Discharge Analysis Methods on the Primary Irrigation Channel of Lanangga Reservoir, Dompu Regency

Abstract

Irrigation is the addition of artificial soil water deficiencies by channeling water needed for plant growth to cultivated land and distributing it systematically. Therefore, it is important to conduct a comparative analysis between the Manning and Chezy methods in the context of the Lanangga primary irrigation channel to determine the most appropriate method. The results of the second analysis showed differences in flow rate (Q) and velocity (V) for Manning Q = 0.572 m3/s and velocity V = 0.487 m/s while Chezy flow rate Q = 0.546 m3/s and velocity V = 0.465 m/s. Factors that cause differences in results where Manning's main parameter is the roughness coefficient (n) while Chezy's main parameter (C) is calculated from n. Roughness Coefficient n and C where Manning's formula directly uses the value of n which is very sensitive to channel surface conditions, vegetation, and shape, while Chezy's formula uses the coefficient C which also depends on R and n, but the form of the relationship is more indirect