In a basin of 120 km2, which has a main channel of 12 km with a slope of 2.5%, an urban development will be carried out.
Originally, the basin is made up of 50% forest with C=0.10 and 50% submontane scrub with C=0.20. The development contemplates substituting the scrub zone with a commercial zone (C=0.95) in 50% and a residential zone (C=0.70) in the other 50%.
The forest part would remain untouched.
From studies in the region, the intensity-duration-return period curves are available given by i = 220T^0.62 / d^0.58 with i in mm/h , T in years and d in minutes.
The payback period for the design is T=10 years.
Determine:
a. Flow rate in initial conditions (m3/s)
b. Expenditure in urbanized conditions (m3/s)
You can consider that the rainfall is uniform and covers the entire basin.