1. Please name at least four advantages of rainwater infiltration as opposed to conveyance and discharge into waterways
2. Calculate the total runoff volume for a 15-minutes rainfall with an intensity of 20 l/(s*ha) on a total area of 800 m2 consisting of following partial areas with their respective runoff coefficients:
A1: 500 m2, C1= 0.2
A2: 200 m2, C2= 0.5
A3: 100 m2, C3= 0.35
3. The runoff from an area with a size of 5000 m2 is to be infiltrated in a swale. The infiltration surface should be 10 % of the impervious (or reduced) runoff area. The design storm should be a 5-year storm. Determine the required volume of the infiltration swale.
Additional information:
Runoff coefficient: C = 0.5
Hydraulic conductivity: k 0 1*10-4 m/s
Safety factor: fZ = 1.2
Rainfall intensity
Probability of occurrence = 1
Probability of occurrence = 0.2
Probability of occurrence = 0.1
Duration t [min]
IT [l/(sha)]
5
201,0
338,9
398,3
10
127,1
204,6
238,0
20
80,4
124,0
142,7
Exercises
Exercises