Time (hr)             0          1          2          3          4

Area (km²)              148      252      318       189

Use onlinerouting06 (the time-area method) to calculate the flood hydrograph for the following effective storm pattern:

Time (hr)                                 0         1         2         3         4         5         6

Effective rainfall (cm/hr)               1          3         4         3          2         1

Time (hr)             0          1          2          3          4

Area (km²)              148      252      318       189

• Assume Δt = 1 hr, and K = 3 hr.

• Assume Δt = 1 hr, and K = 4 hr.

• Assume Δt = 1 hr, and K = 5 hr.

What happens to the peak flow of the unit hydrograph as K increases?

basin area A = 907 km²;

storage constant K = 2 hr;

number of reservoirs N = 2;

time interval = 1 hr;

number of increments of effective rainfall, 6;

increments of effective rainfall intensity (cm/hr): 1,3,4,3,2,1.

• Use ONLINE DIMENSIONLESS UH CASCADE to calculate the cascade-of-linear-reservoirs 1-hr unit hydrograph for the La Leche basin data of Prob. 3.

• Use ONLINE CONVOLUTION with the CLR 1-hr UH obtained in Prob. 4a and the data of Prob. 3 to calculate a flood hydrograph for the La Leche basin.

• Confirm that the method of cascade of linear reservoirs (Problem 3) and the unit hydrograph convolution (Prob. 4b) give the same answer when the cascade parameters are used to calculate the unit hydrograph used in the convolution.