London's Underground Water

The chalk under London can no longer be looked upon as a source of gTeat additional supplies of water. Thisis already utilized by upward of 200 wells, and while at the connnencement of the century the water when tapped rose in many places to the surf ace it stands now at a level of about 40 f eet below Trinity high water mark. It is considered that the rate of depression now varíes from one to two feet per annum. The effect of the continuous pumping of water from the chalk has thus been to lower the }ilane of saturation, whereby the flow of distant springs and streams has been more or less seriously affected. Practically, the amount of water pumped from the chalk under London is so much taken from the streams that are f ed by the natural overflow from that formation. -