§ Mr. Brothertonasked the Secretary of State for the Environment what advanced machinery and techniques are to be used in the cleaning of the lake in St. James's Park.
§ Mr. MarksThe contractors use special flexible dams made of structural steel frames covered with plastic sheeting. The lake is divided into sections so that water from the area being dealt with can be pumped into the other sections and retained there. When the contractors judge that the silt is of the right consistency, it is pumped by suction into sealed tankers, thus avoiding spillage which would be offensive in this heavily used part of the Royal parks. The concrete base of the lake is then cleaned and the water is returned.
§ Mr. Brothertonasked the Secretary of State for the Environment what would 341W be the cost to public funds of cleaning all the lakes in the London parks for which he is responsible if such an operation were conducted at the same rate as that for cleaning the lake in St. James's Park.
§ Mr. MarksNo estimate of this cost is available. It would not be meaningful to apply the rate for the cleaning of the St. James's Park lake to other lakes because conditions vary and different methods are called for. There are many lakes in the Royal parks, the majority of which have never had to be cleaned, nor is there any expectation that they will have to be cleaned in the foreseeable future.