Geograph - photograph every grid square

TL3503 : Cheshunt Reservoir South

As a comment to this, a reservoir this size was not for storage on a seasonal timescale (wet winter into dry summer, or, recently, vice versa). They were for holding water on a weekly (or shorter) timescale before the water was processed at a water treatment works locally. The London Ring Main, a much under-appreciated engineering feat, has allowed water treatment to be concentrated in fewer, larger treatment works. The small treatment works and reservoirs are therefore redundant.

The London Wetland Centre, TL2276, is another example of a redundant reservoir/waterworks - there housing on the waterworks helped to fund the new nature reserve.

For a comparison of scale, see TQ3796 and TQ0769 for seasonal water storage reservoirs around London