Question 6: Impact of urbanisation A catchment near Adelaide Kent Town is considering some development scenarios. Compute the percentage increase in Q20 at the following three development scenarios (shown below). The development area (Yellow) is 30% of the total catchment area (A₁-3ha). Runoff coefficients of the development and un-development areas are 0.7 and 0.15, respectively. Travel time of the catchment before the development is 40 minutes. Three possible development scenarios are. (a) Patchy development (tc after the development = 40 minutes) (b) Upstream development (tc after the development = 30 minutes) (c) Directly connected development ((tc for the developed area = 20 minutes) (a) Figure 5 for question 6 (b) (c)

Fig: 1