London scoping - ukcip

Final Report
159
provides transport for 3 million journeys each year - either for leisure or commuting purposes.
The Strategy is looking to promote both aspects of river use.
Flooding and Rainfall Intensity Impacts
Both passenger and freight movements on the Thames (tidal and non-tidal) and the city’s canals
may, however, be jeopardised either by low flows that might, for example, accompany low
summer rainfall, or by high flows resulting from higher intensity rainfall events. Both climate
change-related events are suggested as threatening the navigability of the river. The 1976
drought provides a possible analogue for the first event possibility. In this case, the Thames was
threatened with total closure for any forms of traffic. It had significant impacts on the supplies
of raw materials for manufacturing and food products. Whilst the air freight system is now
likely to better cope with any equivalent event for food products, water transport remains
essential for bulk freight shipments. There may therefore be a significant disruption in
international trade links in raw materials for manufacturing and food products, and the domestic
industries that use these materials.
Operation of the Thames barrier blocks off shipping. More frequent operation of the barrier in
recent years has not compromised the viability of upstream docks, however. This is because
there is always at least one point in the day (i.e. low tide) when the barrier is open (even when
the barrier is operational) so some shipping can get through (although at low tide the larger
ships may not pass). However, much more frequent closure of the Thames Barrier, and the
construction of new barriers to combat future flood levels, may cut some areas off for docking
in the future. Inundation of docks may be a problem if both riverine flooding and sea level rise
contribute to rising river levels both up and downstream of the barrier.
With a more explicit strategy of using the estuary upstream or downstream of the Barrier for
water storage as an adaptation to climate change, e.g. during high tides or during periods of high
rainfall, then flooding of docks might increase. The draft London Plan includes the suggestion
that more freight could be handled using the River Thames and observes that there are 29
protected wharves between Wandsworth/Hammersmith and Greenwich/Newham. It also notes
the potential for freight operations on the Lee Navigation and the Grand Union canals (GLA
2002a). Clearly, the vulnerability of such water-based freight to a change in rainfall patterns
and more frequent use of the Thames Barrier requires investigation as part of the development
of the freight strategy.
Indirect Effects
River service disruption may act as a disincentive to potential tourist visits to the city from
overseas, though it is thought likely to change the length of stay in London rather than resulting
in a switch to an alternative destination.
Most of the 3 million a year boat journeys are for leisure purposes but with extensive
development in the Thames Gateway, it is likely that there would be enhanced demand for
travel along the river as a pleasant alternative to busy terrestrial routes. Some of London’s
canals could even potentially be used for this purpose, as happens in, e.g., Amsterdam. There is
existing empirical evidence that the London Thames does act to cool the air in areas adjacent to
the river (Graves et al, 2001).