ABSTRACT
This chapter examines some basic techniques for estimating runoff volume and peak discharge, and for analyzing flood hydrographs. The two methods for estimating peak discharge discussed are the rational method and flood frequency analysis. Flood frequency analysis determines the exceedence probability of an annual maximum peak discharge using historic streamflow data. This chapter examines five theoretical probability distributions. These distributions fit to the data in using a combination of graphical, parametric, and frequency-factor techniques. A The unit hydrograph is a method for deriving the complete runoff hydrograph - rising limb, falling limb, peak discharge, and the time base. It is one of the most popular methods for flood analysis. The chapter has introduced some basic concepts and techniques used to analyze stream flows and flood discharges. It qualitatively describes how hydrographs suffer a reduction in peak and a lengthening of the time base due to storage as the flood wave passes through a reservoir or a channel reach.
