Back in 2015, for its first planning application to quarry Straitgate, Aggregate Industries suggested:
The proposed surface water management plan would use Sustainable Drainage Systems (SuDS), where all surface runoff originating within the workings will be captured in infiltration areas. These areas will have impermeable bunds at their downstream edges preventing any discharge to nearby watercourses. All runoff from the site will be captured in this way and allowed to infiltrate into the ground. A detailed drainage scheme would be developed and submitted for approval prior to the commencement of operations. 3.39
Devon County Council was having none of that, warning:
The surface water management is inextricably connected to Flood Risk Management/Airport safeguarding and the need to maintain and recharge watercourses. This issue is so important in terms of the likely significant impacts of the proposal the MPA would wish to ensure that a SWM scheme can be designed to meet all of the requirements identified in advance of the determination of this application.
That was when:
The pattern and distribution of infiltration will be similar to that experienced under greenfield conditions…. It is intended that for each phase contouring of the eastern part of the excavation bases will be carried out to ensure that infiltration is distributed across the site in the same way as under greenfield conditions and to prevent too much water infiltrating from storm-water accumulation emerging at any one spring or part of the spring-line. 3.34
With regard to surface water management at the site entrance and ancillary areas: ... There will be no runoff allowed from the site entrance and ancillary areas onto Birdcage Lane 3.37
But it’s not just that. Look what we find Aggregate Industries suggesting in its "final response":
...the access road will drain to a swale, constructed alongside the road to hold back the additional runoff from the new access…. it will have a flow control mechanism fitted, the detailed design of which can be controlled by condition, to prevent uncontrolled discharge in to the [Birdcage Lane] roadside ditch.
...can be controlled by a condition. After six years of trying to work out how to quarry the site without causing untold damage, six years to come up with detailed design, Aggregate Industries again wants to leave the detailed flood design for a condition.
Lest we forget, and as repeated in May this year, DCC Flood Risk Management warned Aggregate Industries six years ago that details were needed, that the surface water strategy:
...should identify location of the infiltration features and how these fit into the site and the proposed phasing of the site. This should include detailed design regarding their size, details whether infiltration is permitted at the proposed locations and where targeted at areas where infiltration is required to support the spring lines of the existing watercourses (as commented by the Environment Agency), together with details of exceedance pathways.
...details, not concepts, not wishful thinking, not left for conditions away from the public gaze.
A recent letter, from a lawyer representing a third party whose land is at risk, warned:
Absent of revised calculations, there is no knowing whether "a flow control mechanism", as mentioned in the Letter, would have any chance of working.Policy M24 of the Devon Minerals Plan says (emphasis added): "All proposals for mineral development on a site exceeding one hectare, or any site within Flood Zones 2, 3a, 3b or a site in a Critical Drainage Area within Flood Zone 1, will be accompanied by a FRA that must demonstrate that the proposal will be safe for its lifetime taking account of the vulnerability of its users, without increasing flood risk elsewhere and, where possible, will reduce flood risk overall."Given the FRA is now more than four years old and has not been informed by the revised base of extraction nor by the revised mitigation strategy, the Applicant has clearly not demonstrated that the proposal will be safe.
Too right it hasn’t.
It hasn’t even answered how flooding prevention is meant to work here:
