London scoping - ukcip

Final Report
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Table 5.3 Potential water resource/quality impacts and responses identified by stakeholders
5.4.3 Case study
London’s water supply will be affected by climate change impacts outside of the
Thames Region;
Higher winter temperatures will reduce leakage due to burst pipes as a result of
freezing;
Wetter winters will lead to expansion of clay and more leaks/bursts in the mains
network;
Drier soils and subsidence of clay soils will increase leakage in summer;
Greater competition for finite resources between domestic and environmental needs;
Greater variability in water supply could be reflected in seasonally variable water
tariffs;
Development of any new reservoir(s) will compete with other land use demands;
Public health and hygiene issues associated with reduced water supply/increased
cost;
Greater use of grey water and rainwater harvesting;
More local abstractors, treatment and usage of rising groundwater;
Greater use of artificial groundwater recharge;
Reluctance of metered water users to respond to water-saving appeals;
Increased awareness of environmental ‘costs’ of water consumption;
Development and deployment of more innovative water resources options;
Increasing awareness amongst the population to use water wisely.
Soil moisture and water balance changes in the Rivers Kennet and Loddon
For this study, a preliminary assessment was made of potential water resource impacts for two
tributaries of the Rivers Thames. Soil moisture deficits (SMDs) were modelled for the Rivers
Kennet and Loddon under the Medium-High Emissions and Medium-Low Emissions scenarios
(Appendix C). Figure 5.2 shows the anomalies in the annual maximum SMD, and the length of
the recharge season with respect to the 1961-1990 average for the River Kennet. Table 5.4
reports mean changes in the water balance and recharge for the 2020s, 2050s and 2080s.
Figure 5.3 and Table 5.5 provides equivalent results for the River Loddon. In both catchments,
there is a general decline in annual precipitation of between 1 and 9% by the 2080s,
accompanied by a reduction in AET of 6 to 10%, despite higher air temperatures. This apparent