The MWWT – the maximum winter water table – would be the base of any quarry at Straitgate. The MWWT is a prediction with huge uncertainties. In large areas it will not reflect reality.
The Environment Agency has proposed a number of updated conditions which "must be secured on any planning permission". Here are two:
1. No working shall be undertaken below the ‘Maximum Winter Water Table (MWWT) grid’.
2. The MWWT grid and the extent of the extraction phases shall be reviewed immediately before operation of the quarry begins, using all the collected data from all site piezometers plus the 1990 groundwater level readings given in SJ Parkhouse, 1990, ‘Report on the reserves of pebble beds at Straitgate Farm near Rockbeare’. If any of the maximum recorded groundwater levels exceed the height of the MWWT grid then the MWWT grid shall be updated using that data. Maximum groundwater levels in the site piezometers shall then be reviewed annually and if any exceed the height of levels on the MWWT grid then the MWWT grid shall be updated using that data. This analysis shall be provided in the annual monitoring reports to be submitted to Devon County Council.
So, the MWWT will be updated before any quarrying starts. Fine. But let’s think about what might happen in practice after that – because plainly the EA hasn’t. The EA says:
Maximum groundwater levels in the site piezometers shall then be reviewed annually and if any exceed the height of levels on the MWWT grid then the MWWT grid shall be updated using that data.
The fact that the EA is even talking about groundwater levels exceeding the height of the MWWT grid is acceptance that the model may not represent maximum levels, and therefore acceptance that quarrying could go below the maximum water table. But that’s an aside.
What’s worse is that the EA’s conditions – as currently worded – actually permit Aggregate Industries to dig below the MWWT. How so?
Say we have a wet spring. With climate change, anything is possible. Say, in an April, groundwater levels exceed Aggregate Industries’ MWWT model. It’s happened before.
Under the EA’s conditions, those levels would only be "reviewed annually" and the MWWT grid "updated using that data" – maybe at the same time, maybe not. Say this annual review were due in March of the following year, which Aggregate Industries might get around to doing, after reminders, if pushed, by November. Think that unlikely? Aggregate Industries has a history of not complying with Section 106 water conditions, submitting annual water reports years late, if at all.
For 18 months, maybe more, maybe less, the MWWT grid – down to which Aggregate Industries would be quarrying – would therefore be wrong.
However, following that breach in April, as long as water levels subside over the summer and autumn months, as they invariably do, and as long as Aggregate Industries can comply with the EA’s condition 5 – "the base level to which the quarry is worked is no closer to the contemporaneous measured groundwater level than 1m" – the company would be permitted to quarry down to this exceeded MWWT grid – i.e. below the maximum water table – until such time as the annual review has been completed.
This would give Aggregate Industries enough time to have quarried down to this wrong level – doing goodness knows what harm, that may only become apparent years later – to have replaced the overburden, and to have said terribly sorry, awful oversight, won’t ever happen again. And that’s if anybody even found out.
The EA and DCC rely on others to report breaches of planning conditions these days. DCC says:
... we encourage you to report suspected breaches of planning control, relating to permitted sites and unauthorised development or activity, as soon as possible.
How are others expected to report breaches of water conditions – such as groundwater levels exceeding the MWWT grid – particularly given that AI put a stop to public scrutiny of groundwater data for the Straitgate application after the public informed the EA and DCC of the last occasion that the MWWT was breached, by up to 1.6m, and in four locations?
