The time-area-concentration curve for an urban basin is given below. Also provided is
a table giving the rainfall hyetograph and losses.
a) What is the total area of the catchment?
b) What is the time of concentration of the overall catchment?
c) Compute and plot the hyetograph of rainfall excess as a bar chart.
d) Plot the time-area-concentration curve as a bar chart.
e) Use the time-area method to compute the runoff hydrograph, without any additional attenuation.
f) Provide additional attenuation by routing the runoff hydrograph through a linear reservoir with time constant K = 20 min. Use the Muskingum method (Chapter 4) to perform the routing, with routing parameter x - 0. When a time-area hydrograph is routed through a linear reservoir, this is known as a Clark model (1945).
g) Repeat part f for a time constant K = 15 min. Plot the inflow hydrograph from part e and the attenuated hydrographs from parts f and g on the same chart. Note the difference in attenuation for the two linear reservoirs.