Annual flood data of the river Narmada as Garudeshwar covering the period 1948 to 1979 yielding for the annual flood discharges a mean of 29,600 m²/sec and a standard deviation of 14,860 m³/sec. For a proposed bridge on this river near this site it is decided to have an acceptable risk of 10% in its expected life of 50 years. (1) Estimate the flood discharge by Gumbel's method for use in the design of this structure. (II) If the actual flood value adopted in the design is 125000 m³/sec, what are the safety factor and safety margin relating to maximum flood discharge? (Consider to y₁=0.5380 and 1.1193)

It gives a framework that is financially critical for finding the exceptional designs of hydrological systems with a reduced cost in total inclusive of the project cost and the disaster mitigation cost. But there would be hardly any assessment of a decen…