Information Board: Springs on the Heath
This pond was created in 2010 around a natural spring emanating from a line encircling Hampstead Heath. Spring lines are governed by geology and occur where a clay-rich layer is overlain by a sandier layer. At the top of Hampstead Heath are the Bagshot Sands, laid down close to the coast about 50 million years ago. Rainwater percolates through the sands until it meets with the more clayey Claygate Beds beneath. Notable springs from this junction would once have been seen at ‘The Old Bath House’ at Kenwood House and the wells that supplied the Health Spa on Well Walk in Hampstead. The water is very iron-rich and was supposed to be a cure for all manner of ailments. This upper spring line provides the headwaters of both the Hampstead and Highgate branches of the River Fleet which runs through the ponds below and eventually enters the Thames at Blackfriars.
The lower spring line is where the Claygate Beds, meet the impermeable typical London Clay (about 52 million years old). The water from this junction is a pure soft spring water that was formerly supplied to the people of Hampstead from Shepherd’s Well in Fitzjohn’s Avenue. Here were the headwaters of the now ‘lost’ River Tyburn, on the same spring line that feeds this small pond.
Click here to download a pdf of this board.