The Geology of Stoke Newington

The geology of Stoke Newington is a series of layers, one on top of the other. Gravel terraces and Brickearth rest on the London Clay. Far below is Chalk. Stoke Newington Church Street grew up on the edge of the gravel area. To the north of the street is London Clay: to the south is gravel with a thin layer of Brickearth still left in some places. This Brickearth has been largely worked off to make the red Queen Anne bricks seen in for example, Sisters' House in Church Street.

The Hackney Brook drained the south-eastern slopes of Holloway and the north-eastern slopes of Pentonville. It flowed along the flat land of Gillespie Rd and Highbury Vale, collecting more drainage water from Finsbury Park. It cut a valley south of the ridge on which the Seven Sisters Rd and Stamford Hill run. At Abney Park Cemetery the river turned south-east along Northwold Rd, past Hackney Downs through Victoria Park to Old Ford where it lost itself in a mass of drainage ditches before reaching the River Thames.

Water drains far better from gravel than from clay, so people preferred to live on gravel. The houses were healthier, with fewer cold mists and dripping walls; wood did not stay wet and so rot; the roads were passable in all weathers, whereas clay became a mire in winter and formed hard ruts in summer, upsetting carts or turning ankles. So long as there was gravel left to build on, nobody built on clay with its bad foundations and wet cellars. As it was, a high proportion of builders went bankrupt every year. Choosing clay foundations would have made this even more likely.

The Effect of our Hidden Streams

The John Rocque 1741-45 maps show that the Hackney Brook rose in Upper Holloway but it was fed by streams of surface water, and by springs which rose at the gravel/clay joints all the way along. Water soaked through the gravel, met the clay and seeped out. No river is shown to the east of Hampstead Heath before Upper Holloway. Presumably, all the rain in this area soaked through to the clay and fed the River Fleet or the Hackney Brook.

Today, in wet weather, parts of the Clissold Park football fields become very wet where the Highbury rain seeps out. When the tall, modern flats at the bottom of Queen's Drive were built, they ran into a spring and had trouble. The six-inch Geological Map shows a row of ponds along what is now Grazebrook Rd.

Standford’s map of 1862 shows,'The Hackney Brook now obliterated', curving from the Clissold Park fish ponds, around the northern edge of Abney Park Cemetery. The river here must have been swelled by the springs from Stamford Hill and South Hackney.

The total flow was large: in 1860, the flow was "400 cubic feet a minute in the driest weather".

Stoke Newington Church Street arose as a pathway, on the gravel, between the High St and Green Lanes. Houses there could find water by digging shallow wells. One, in the yard at the north end of Clissold House, had water only six feet (two metres) down in November. Deeper wells could reach the cleaner water of the chalk, far below.

The 1895 O.S. shows the Hackney Brook incorporated into the Hackney Sewer. This would have carried off most of the flow, but the springs and tributaries which fed it after Clissold Park, still continue to flow. These still fill the Fish Ponds in the Park and, no doubt, provide ornamental water and wet cellars all the way to Old Ford.

Hackney Brook