Reference no: EM132435772

1) Why might flood defenses increase damage during floods? How and where do flooding impacts occur when sea walls, levees or dikes are built?

2) Flood Recurrence Calculation Exercises

For given-size flood, recurrence interval is:

T=(n+1)/m

where T= recurrence interval

n= total number of years in record

m=rank of flood (largest= 1; second-largest= 2; etc.)

Example: If largest flood on river was in 1980-> m1980=1

And there are 70 years of records >n=70

Then recurrence interval for 1980 flood is___________________

If in 1990 a slightly larger flood occurs,

Corrected recurrence interval for 1980 flood is

T1980=(___+1)/2=________=_______ years(average)

If in 2012 another slightly larger flood occurs, m2o12= 1, m1s9o=2 and m1980=3

Corrected recurrence interval for 1980 flood is

T1980=_______________

T1990=_______________

How has the recurrence level of these floods changed with a longer flood record?