1. Drainage Challenges The need for LoDEG
Owen Davies
Sustainability Engineer
Environmental Services & Highways
21st November 2011

2. Introduction

3. What is London at risk from?
Coastal
Fluvial
Pluvial
Groundwater
Reservoir
Sewer
Human EA LA TW
TW (generally)

4. Pluvial Flooding Hampshire 2000 Boscastle 2004 Leeds 2007 Cumbria 2009
Bournemouth 2011
“There has been an instance of serious Surface water flooding every month in the UK since June 2007”

5. Groundwater Flooding Water table rising
No industry
Natural Spring lines/resurgence points
Peckham spring
Geology
Clay

6. Worked Example

7. Lambeth Pluvial Risk (1:100+CC)

8. Historical Rivers

9. Historical Flooding

10. Sewer Network

11. So what is the Problem?
1:15 design standard too low for a modern city?
Combined sewer
Has it encouraged a “Three Monkey” approach?

12. Anything else? Loss of front gardens? Did we ever need grass verges?
Traffic calming?
Enforcement?
Efficiencies?
Design?

13. Nothing else then?
“I am informed that the flooding has been the same for the past eight to ten years in times of sudden and heavy rainfall. If you have any suggestions to offer as to dealing with the trouble I shall presume to hear from you in due course“
Mr Fitzmaurice, LCC to Borough Engineer 29th August 1911

14. What we Know (Lambeth) Not a case of if but when
49,813 properties at risk (3-10cm) = 37% of the entire housing in Lambeth.
Insurance cost at 2007 prices of £1.2bn
Does not include asset or EP costs (Roads £83m)
The areas at risk from Surface/ground Water flooding
The areas Lambeth controls/influences

15. What we Know (Lambeth) Cont…
19% or 22,976 increase in housing stock
9.8m/l a day increase in potable water use
159m/l a day increase in sewage
(not including surface water)
Population growth to exceed 300k

16. Who can we blame? Thames Water? TfL? Housing? Education?
Environment Agency?
Defra?
Victorians?
Planners?
History?

17. Challenges Understanding pluvial flooding Understanding Groundwater
Understanding resources
Understanding infrastructure & Assets
Understanding responsibilities
Understanding funding
Understanding ownership

18. What do we understand?
Pfra’s
SWMP’s
Hazard mapping
CDA’s
Assets

19. Solutions SUD’s Green Infrastructure (GI) Blue Corridors Design
Maintenance
Enforcement
LoDEG

20. LoDEG 19 Boroughs responded + TfL & London Councils 60% response rate
Q1 100% in favour of LoDEG
Q2 90% in favour of meeting quarterly
Q5 100% in favour of training

21. Areas of concern Resource/Funding = 25% Asset = 15% SUD’s = 15%
SAB = 8%
Communications = 8%
Flood Risk Plans = 7%
Water companies = 2%

22. What will - is happening
First Full Meeting 30th November 2011
2 Seats on TAG Coastal & Fluvial Committee
Representation on ATDA
Representation on LoTAMB
Seeking acceptance to LoTAG 8th December 2011

23. Conclusion We are all in this together
We cant control when it will happen
We can control it’s affects and influence

24. Owen Davies
Sustainability Engineer
Environmental Services & Highways