Stability of the northern bank and the M25
The application has repeatedly alleged that the possibility of a failure in the Gault Clay on the northern slope could present a risk to the M25, which at its nearest point is 60 metres from the carriageway. Until very recently Highways England, the agency in charge of the motorway, has maintained that it had no concerns that the existing geology of the northern slope of the quarry poses a threat to the integrity of the M25. Previous correspondence about this can be seen by clicking here. However, KWG understands that Highways England has not objected to the Covers infill application and is now acknowledging that in the longer term there may be a risk from the “do nothing” scenario.
Highways England has however also made it clear that they want there to be monitoring of the stability of the slopes in case the proposed work has an effect on this.
The northern lake
The application claims that in twenty years’ time the water that has accumulated in a northern dip is not draining away and that in twenty years’ time t might overtop and flood the Croydon Road. The applicant supposes that there are silts and clay fines on the base of the dip, preventing the water from draining into the sandy stratum that lies beneath This is despite the concession made by Mr Warde and the December 2018 “Drop-in” meeting about the application that the water level of this northern lake goes up and down.