London scoping - ukcip

8.5.2 Modelling
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The Thames Region Water Resources strategy used a range of scenarios that included potential
climate change, to inform the development of the strategy. However, more work needs to be
done to consider the impacts at the catchment level. The extent of probable impacts of climate
change on the Thames water resource strategy can only really be answered through an
integrated regional water resource modelling exercise, that incorporates more climate change
detail within the Environment Agency’s four socio-economic scenarios. Alternatively, research
could be targeted at critical elements in the strategy, such as modelling the reliable yield of a
new reservoir, or levels of leakage, under the full set of UKCIP02 scenarios.
The EA is developing Catchment Abstraction Management Strategies to assess the total amount
of water available in a catchment and develop a strategic plan for supply and demand. Another
process - the ‘Restoring Sustainable Abstraction’ programme is assessing other ways of
obtaining water for supplying needs in particular areas. Both of these processes should be
informed by the present study as well as seeking further ways of assessing the potential impacts
of climate change on water resources for London. Statistical downscaling techniques could
deliver the local, catchment scale scenarios needed to undertake these investigations.
The EA, working with a range of partners, is developing a strategy for flood risk management in
the Thames Estuary for the next 100 years. The project is co-ordinated by the Thames Estuary
Partnership. Its aim is to assess and understand the tidal defences in the context of the wider
Thames Estuary setting. This includes assessment of the residual useful life of the defences
together with an understanding of the ‘drivers’ including climate change, urban development,
social pressures and the environment. The project will take five years to complete and involve
research to build up a detailed understanding of the physical processes affecting the Thames
Estuary. Again, statistical downscaling techniques could be used to develop scenarios of tidal
surges that compliment existing work with physical models of the estuary. This project should
also examine the potential for the use of open and green spaces for temporary flood storage.
Research is also currently being carried out on the adaptation of urban drainage systems (see
water companies section above).More research needs to be carried out on the relative
significance of catchment land use and climate change.
8.5.3 Comparison with other Global Cities
The draft London Plan argues that it is most appropriate to compare London to other global
cities such as New York, Tokyo, Paris, Berlin and so on. The very preliminary comparison of
climate change impacts in Tokyo and New York carried out in this study, suggests that the
adverse effects would be slightly greater than in London, at least in the current socio-economic
conditions. Impacts upon other comparative European cities have not been evaluated. Our
guess is that they would be broadly similar, though possibly with a smaller negative effect. The
most robust conclusion to draw is that a preliminary comparison between competitor cities
indicates that London does not face any significantly greater adverse or beneficial impacts than
other cities. A more robust comparison between impacts on global cities is an important future
research task.
8.5.4 Dams
The condition of dams in London should continue to be assessed (the Reservoir Act 1975). This
should, and does, include consideration of the potential impacts of climate change on their
performance.