Managing water in an urban environment is a complex task with multiple facets. Priorities may change from one city to another and from one season to another across the following areas:
Public Water Supply
As shown in the graph below, there is enormous variation in per capita water use between different countries. To an extent, this controlled by the availability of water (as shown by average rainfall), but there is also a big divide between rich countries (shown in blue) and poor ones (shown in orange). This suggests that as we become richer, we use increasing amounts of water. Is this done in a sustainable way?
What more can we do to live within our means?
Whilst the graph above indicates the way in which citizens use their water supply, a key measure of water efficiency is the amount of leakage (sometimes referred to as ‘non-revenue water’) that occurs within the supply network. Even amongst European countries, there are large discrepancies in the proportion of water lost in transmission, as shown below.
Although the United Kingdom doesn’t fare badly in this comparison, there remains considerable room for improvement. In the case of London, there is the potential for serious water shortages occur in the coming decades, unless prompt action is taken, including in the reduction of leakages.
A London Perspective
London is approaching a critical period in its water supply history. For the first time in decades, demand is projected to exceed supply, with Thames Water predicting a 10 % deficit by 2025. In response, the office of the Mayor of London has made water supply security a key priority in its infrastructure plan from now until 2050. The proposed actions to address this shortfall focus on encouraging leakage reduction through improved detection and maintenance and encouraging more efficient use, through the use of innovative tariffs, raising public awareness and retrofitting water efficient devices.
You can read more about these measures and other infrastructure plans for London here.