London scoping - ukcip

Final Report
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because a seawall fronted by 80 metres of saltmarsh need only be 3 m high (at a cost of
£400/m), compared with a seawall without fronting/saltmarsh which may need to be 12 m high
(costing £5000/m) (EA, 1996). However, successful recreation of intertidal habitats and added
defence value requires a wider appreciation of coast cell functioning and sediment exchanges
within the entire Thames Estuary system, plus wider North Sea. In other words, soft
engineering solutions to rising sea levels involve a perspective that transcends the traditional
limits of local administrative boundaries.
5.5.5 Stakeholder Concerns
In addition to the issues raised above, stakeholder engagement highlighted further potential
flood risks related to climate change (Table 5.7).
Table 5.7 Potential flood impacts and responses identified by stakeholders
Associated Impacts
Threat to Thames Gateway developments east of the Thames Barrier
Greater public and corporate awareness of flood risk
Loss of freshwater/riparian habitats (see below)
Saline intrusion further up estuary and into adjacent freshwater marshland
Greater demands placed upon emergency services
Impact on existing floodplain landfill sites and loss of potential landfill sites
Improved design and flood protection for new developments
Mortgage and insurance difficulties leading to blighting of some communities
Flooding of the London Underground (already being pumped)
Greater threat to riverside developments and inundation of major assets such as sewage treatment
works
Access and aesthetics impaired by raised flood defences
More foul water flooding
Severe disruption to utilities and transport systems
Intangible costs to the environment, recreation, and stress to flood victims
5.5.6 Adaptation Options
First order adaptation costs for future coastal flooding and storm risks have recently been
produced by ERM(DETR, 2000b). The range of adaptation measures considered in this study
included: accelerated investment in existing flood defence programmes; improved floodrisk
identification, forecasting and awareness; and avoidance of at risk areas by new developments
(or ensure adequate protection is in place). Other options include: low cost, ‘no regret’
measures such as improved flood warning systems; long-term planning for managed
realignment (the discrete readjustment of existing defences to new proposed lines of defence
located further inland); promotion of flood-proofing, building materials and design; the