I find John Heathcote's letter (NCE 16 May) somewhat disturbing when he states that sewage leaking into groundwater is an important source of groundwater recharge. A far better way of recharging the groundwater is by use of SUDS - sustainable urban drainage systems.
These systems involve the use of swales and permeable paving among other things, to allow rainwater to permeate into the ground rather than piping them directly into a watercourse.
Much more sensible and far more hygienic!
Michael Woods (AM), WSP Development, Croythorn House, 23 Ravelston Terrace, Edinburgh EH4 3TP