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)