Hydraulic Efficiency
Hydrologic analysis involves the estimation of a design flow rate based on climatological and watershed characteristics. This analysis is one of the most important aspects of drainage design. Unfortunately, the statistical uncertainties, such as rainfall intensity and runoff, inherent in hydrologic analysis give less accurate results than the hydraulic analysis of a drainage system. To achieve this hydraulic analysis accuracy, however, it is imperative
that the designer has the correct design information. The hydraulic design of a drainage system always includes an economic evaluation. A wide spectrum of flood flows with associated probabilities will occur at the site during its service life. The benefits of constructing a large capacity system to accommodate all of these events with no detrimental flooding effects are normally outweighed by the initial construction costs. Thus, an economic analysis of the trade-offs is performed with varying degrees of effort and thoroughness.
