What is the probability (as %) that a 220 year flood will occur in any given year?

If the flood stage occurs at a discharge of 3000 m³/sec, how often has the house been flooded in the last 30 years?

If the flood stage (bankfull stage) occurs at a discharge of 1000 m³/sec, what is the recurrence interval of such a discharge according to your graph? 

Determine the peak discharge expected in a flood with a recurrence interval of 90 years?

All other factors being equal, the risk of stream flooding is probably greatest

                   X = 4 km

If aquifer hydraulic gradient, hydraulic conductivity and effective porosity are found to be 0.4, 0.4 m/day and 0.1 respectively, determine how long the contaminants have been in the aquifer (in years)? 1 year = 365 days