Dear Ivan, I suggest you ...
Published by Chris Bosher
Dear Ivan,
I suggest you contact the Urban Drainage Group at CIWEM (Chartered Institution for Water and Environmental Management). http://www.ciwem.org/groups/urban-drainage-group/
and/or http://www.ciwem.org/policy/flooding/
There are many professionals working in the area of Urban Drainage and/or Flood Control who are part of UDG/CIWEM. They will also be able to point you to some very useful papers and/or reports/publications (eg the 'Journal of Flood Risk Management') that might help you. you can email them on udg@ciwem.org
Hope this helps - let me know if you have any difficulty in access/contacting them.
@CIWEM #CIWEM
Regards,
Chris Bosher