A water resources project with an expected life of 25 years has to be designed for an acceptable risk of $5 \%$ against a design flood. The return period for the design flood (in years) is __________ (rounded off to the nearest integer).
The mean rainfall over a catchment has to be estimated. The data for four rain gauges located in and around the catchment is listed in the table. Which one of the following statements is correct:
$$ \begin{array}{|l|c|c|c|c|} \hline \text { Rain gauge station } & \text { P } & \text { Q } & \text { R } & \text { S } \\ \hline \text { Whether located inside the catchment } & \text { Yes } & \text { Yes } & \text { Yes } & \text { No } \\ \hline \text { Thiessen weightage factor } & 0.25 & 0.50 & 0.10 & 0.15 \\ \hline \text { Rainfall (mm) } & 100 & 110 & 100 & 125 \\ \hline \end{array} $$A symmetrical trapezoidal canal is 100 km long. The bottom width is 10 m and the side slope is 1 Horizontal : 1 Vertical. The average flow depth in the canal is 2.5 m throughout the month of April. The measurement from a Class-A evaporimeter in the vicinity of the canal indicated an average evaporation rate of $0.5 \mathrm{~cm} /$ day in April.
The volume of water evaporated from the canal (in $\mathrm{m}^3$ ) in the month of April is close to __________ $\times 10^3$ (rounded off to 1 decimal place).