1992/1 p4–6

Bourne Hall Lake, Ewell: II

As members will be only too aware, the main lake in the grounds of Bourne Hall has dried up, as have so many on the North Downs spring line during the past few years. This is mainly due to successive dry years lowering the London Basin water table which now seems to be more than twenty feet below that required to induce the springs to flow, and to fill the lake. Bourne Hall lake will not refill until the recovery of this water table takes place as it lacks a sealed bed. Any attempt to construct such a sealing, whether of puddled clay, concrete or plastic liner, would seem to be doomed to failure, as it would preclude natural filling when the springs do flow again.

Taking the opportunity afforded by the drying of the lake, in the summer of 1991 Bourne Hall Museum and the Archaeological Section of the Society, with the permission of Epsom and Ewell Borough Council, were able to conduct investigations in its bed. The route of Stane Street runs some 100m east of the lake and its associated springs, and preliminary examinations in 1990 revealed 38 Roman coins dating from the first to third centuries in the northern sector of the lake, which was presumed, therefore, to be the site of the natural pond at that period. The range of dates appears to negate the possibility of these coins forming a hoard and tends to indicate religious or casual deposition. Artefacts of medieval and later date were also recovered from the general lake bed, which contained a dump of seventeenth/ eighteenth century waste material.

A trench opened across the earliest pond showed that mechanical dredging of the lake in recent times had unfortunately removed all but about 10cm of the bed above the natural Thanet Sand. However, the natural springs rising in the pond bed have created pockets some 70cm deep through the sand to the underlying chalk, which had filled with sandy gravel. Within these pockets animal bones and Roman pottery, together with Iron Age or Saxon coarseware, were found, although water action had rendered stratification meaningless and abraded many of the sherds.

In a survey of 1577 referring to development of the site by Nicholas Saunder, the Hogsmill river was reported as being ‘lately inclosed with a stone wall & within the same a little banqueting house erected & ponds and fishe therein’. Saunder lived in a mansion on the present Bourne Hall site and in 1589 rights of fishing in the Hogsmill enclosed for this property were granted to his heir. Subsequent development of the lake, including the construction of two islands, is dated by documentary evidence to the nineteenth century. However, it seems unlikely that during a span of nearly three centuries, which encompasses a period of major garden rebuilding in the eighteenth century, no alterations were made to the lake. More work on documentary evidence as well as detailed consideration of the archaeological remains may shed further light on this apparent anomaly.

The pond has, therefore, been a formal lake, i.e. bounded by a wall, since at least 1577 and the present retaining wall appears to date from the nineteenth century. The dredging had carefully avoided the remains of walls still apparent in the lake bed and two or three retaining walls still exist of which one (wall A on the attached plan) of apparently late seventeenth century brick has unusual triangular buttresses which key into the lake bank which it supports. Another is constructed of Reigate stone, some pieces of which have been carved and may have come from Merton Abbey at the Dissolution. This wall is very fragmentary and runs parallel to the north/south section of wall A south of the north island, but as it appears to face away from the lake its purpose is as yet unclear. It is tempting to identify this Reigate stone wall as the remains of the ‘little banqueting house’, but at this early stage such identification is unsubstantiated speculation.

The inclosure wall referred to in the 1577 survey may be wall A, albeit of brick, which still exists up to three courses high and 23cm thick running north and south of the northern island to a point where it makes an acute bend to continue eastwards to run some three or four metres north of the southerly island. On the northern face of this wall on the east/west section strong wooden piles have been driven into the lake bed at intervals of about three metres, and one such pile has been found in a similar position to the south of wall B. Some two metres south of the east/west section of wall A it is paralleled by another, sturdier, brick wall (wall B), 48cm wide and possibly of similar date, which runs from the present eastern retaining wall to a point two metres short of the western, where two conduits may have been terminated by the construction of the nineteenth century wall. Both these earlier walls appear to continue under the eastern wall and brick patterns in the latter indicate that walls A and B may be only a few courses high.

In the water, at a point excavated against the nineteenth century wall, there may have been a narrow garden bed, supported by wooden planks, to provide suitable conditions for waterside plants. Parts of boats and a boat-hook found nearby indicate the use of the lake for boating, and it may be that members have recollections of this activity. The excavators were struck by the quantity of spherical flint nodules up to 5cm in diameter found on the site; these are all quite natural but the large numbers lead to the conclusion that slings may have been used for wildfowling during the lifetime of the pond/lake. Similar use may be attributed to the few musket balls found.

The full report is now in preparation but it is felt that if possible some further excavation should be undertaken next year; firstly in the northern sector of the lake and secondly to investigate the outlets of the two conduits towards the southwest.

Jeremy Harte and Hugh Waterhouse