ABSTRACT
Flood estimation is one of the major tasks that Civil/Water engineers deal with. Rainfall amount and pattern are the main focuses for hydrologists and meteorologists. Flood frequency analysis is basically a statistical analysis of observed/measured flood discharges from at least several years. It determines the relationship between Average Recurrence Interval/Annual Exceedance Probability (AEP) and flood magnitudes. Floodwater overflowing the bridge deck during a flood event, this can be termed as hydraulic failure of the bridge, however the bridge might be intact. The graphical method method is basically to draw a relationship graph between AEPs and flood discharges based on the given historical flood data. The analytical method method is basically used to derive an equation representing the relationship between AEPs and flood magnitudes, with drawing/using the graph/plot. Similar to the ‘graphical method’ of the ‘Annual Maximum Series Analysis’, this method draws a relationship graph between Average Recurrence Intervals and flood discharges based on the given historical flood data.
