1. Supervised by: _Pr Cedo Maksimovic (UWRG, Imperial College) _Pr David Balmforth (Technical Director, MWH)

2. Motivations (1) Pluvial floods are a natural phenomenon and a component of the hydrological cycle. However, many recent factors have made human lives more exposed to stronger floods: urbanisation and its effects on storm hydrograph increased run-off volume increased peak flow shorter time to peak increased urban population number and density climate change (which can decrease return period of storms)

3. Motivations (2) Urban storm water is typically carried away through storm sewers and eventually discharged into a large water body (river, lake, ocean etc.) However, and owing to the above factors, urban storm sewers are more and more overwhelmed during flood events. The resulting flooding has many adverse consequences on human lives: injuries and casualties physical damage health issues (e.g. water born diseases ) economic repercussions

4. Objectives (1) Consider the urban storm sewers as part of a bigger system: the urban drainage system that would be composed of: storm sewers (either separate or combined) water courses (natural/artificial, covered/uncovered) surface run-off (through streets, highways, open spaces) source control (local disposal, inlet control and on-site storage) The traditional approach to floods management is to focus investments on the first component. However, water courses, planned surface run-off and source control can be very efficient in disposing of storm flow.

5. Objectives (2) The main objective is to estimate the maximum conceivable flow each component can possibly carry and to propose a strategy for flood management combining them. The strategy must be: sustainable, which includes being: Environmentally suitable Socially acceptable Affordable cost-effective adapted to the impacts of climate change Strategies focusing on suitable construction solutions could also be considered to reduce physical and human damage (receptor protection).

6. Method Based on the use of Infoworks CS, urban drainage simulation software The strategy will be developed and tested using three modelled catchments: a steep-sloped catchment a mild-sloped catchment a flat catchment The software (with training) and the data for each case will be provided by MWH.

7. Conclusions Subject of significant importance globally. Very interesting and challenging question. Offers the opportunity of a collaboration between actors from the academic and consultancy sectors. Any Questions?