Small outline map

Wandle Valley relief model

This model shows in graphical detail the drop in height from the sources of the Wandle to its mouth in the Thames.

Sources of the Wandle

From Frederick Braithwaite’s survey of 1853

THIS account is compiled from a careful survey, made early in the spring of the year 1853, of the River Waudle from its rise at Carshalton, 111 feet 2 inches, and at Croydon, 123 feet 10 inches above Trinity high-water mark, to its outfall in the Thames, at Wandsworth. In the course of the survey, special notes were taken of the several springs, tributaries, and of the sewage from drains, which contributed to swell the amount of the water. Levels of the successive falls of the river, from its spring heads, through the mills, were carefully taken ; and a complete set of gaugeings of the water from the numerous springs and tributaries, flowing into the river.

The branch of the River Wandle rising at Carshalton, is supplied from three .principal springs, the highest of which, issuing from the chalk, in Carshalton Park, is called the ‘Grotto Spring Pond,’ and is 105 feet log inches above Trinity highwater mark. The next in elevation is the ‘ Hogs’ Pit Pond,’ which is situated in the same park, and is 111 feet 2 iuches above T.H.W.M. The third spring rises in the grounds of the Ordnance School, and is 109 feet 3& inches above T.H.W.M. The two latter springs unite at the Carshalton town ponds, and thence descend through the mills, except a portion of the Hogs' Pit Pond, which, with the whole of tlle water from the Grotto Spring, and from other underground sources, forms a separate mill stream. The head of water at the lake in the grounds attached to the Ordnance School, varies 4 inches, or 5 inches, according to the rainfall ; aud when the lake is emptied, it is refilled from the springs, in thirty hours. Besides the principal head from the west side, there are numerous springs in the bottom. A drain from the kitchen of the school discharges into the lake; to insure the pnrity of the water, a special pipe is, therefore, laid into the head, for some distance, leading thence to the cistern on the tower.