Question 4 a) \"SuDS are designed to mirnic the natural rnovementof water and slow down the process of the water getting into thewatercourse. They can channel the flow of water above ground andreduce the burden on the piped sewerage system- The Pitt Review2007. This extraction from the Pitt Review surnmarised theapplication of Sustainable Drainage Systerns of which there arernany designs. Briefly explain each of the different types of SuDSnoted below. i. Green Roofs ii. Balancing Ponds iii. Infiltrationtrenches iv. Swales v. Permeable pavements (10) b) The floods for aparticular river conform to an Extreme Value Type I (i.e. Gumbel)distribution. If the 100-year flood has a magnitude of 260 ri,/sand the 10-year flood has a rnagnitude of 170 rnsVs. what is theprobability of having a flood as great as or greater than 240 rn-,and what is the return period of that event. c) Give 3 examples ofHuman flood causes (12) (3)
