Considering Problems 14 and 17, determine the return period for the diversion capacity with maximum expected annual benefit.

Data from problem 14 The frequency–discharge–storage–damage data for existing conditions at a particular area along a river is given in Table 13. 17. The storage–discharge data make up the rating curve, the discharge–frequency data compose the frequency curve, and the storage–damage data make up the storage–damage curve. Plot these three relationships.

Data from problem 17 If channel modification is used for the situation in Problem 14 to increase the conveyance capacity of the river up to 15 m3/s, develop the damage frequency curve for this alternative.

Q (m/s) 339.84 TABLE 13.17 Frequency-Discharge-Storage-Damage Data in Problem 14 Exceedance Probability 20 Stage (m) Damage ($10%) 103.7 0 10 396.48 120.9 6 752- 424.8 129.6 10 452.8 138.1 13 509.4 155.4 22 566.4 172.8 30 0.5 623.04 190.0 40 0.2 708 215.9 50 0.1 736.32 224.6 54 0.05 792.96 241.9 57