Unit Hydrograph

in class exercise

$($a$)$ What is the area of each catchment?

$($b$)$ Catchments A and $B$ are similar, except that one contains a town. Which is more likely to contain

a town and why

$($c$)$ Net rainfall of $10mm$ in the first hour, $20mm$ in the second hour and $15mm$ in the third hour

falls on catchment A$.$ Calculate the resulting run$-$off as a function of time.

$($d$)$ Net rainfall of $10mm$ in the first hour, $20mm$ in the second hour and $15mm$ in the third hour

falls on catchment B$.$ Calculate the resulting runoff as a function of time.

$($e$)$ The rivers flowing out from catchments A and $B$ meet shortly after they leave the catchments. $A$

storm with the net rainfall given above moves across the two catchments, with the rainfall starting

an hour later on catchment B than catchment A$.$ Calculate the resulting combined run$-$off as a

function of time.

$($f$)$ The simple triangular $1-$hr unit Hydrograph $\text{'}$UH A$\text{'}$ from above was actually generated using the

data below. Use the data to generate a $2hr$ hydrograph. Plot your hydrograph and fit a simple

triangular UH to it$.$ What's the peak flow of your $2-$hr UH$?$ And the time to peak flow? Check that

that volume implied by your UH is appropriate.