ABSTRACT
Water supplies to present-day cities generally come from groundwater, river water and water collected in reservoirs in the regions that surround them. 1 London (and the Thames Valley region), for example, with a high population but relatively low rainfall (740mm/y in the south-east region on average 2 ), is representative of expanding urban areas that need to manage precious water resources carefully. It is surprising to find that Surrey, in the south-east of England – a country derided for its rainy climate – is drier than Syria. 3
