DCC’s Reg22 wanted to know why:
Some (but not all) of the information on headwaters impacts has been reproduced in the current submission (AFW December 2016), but the information on the loss of the unsaturated zone has been mainly excluded.
The information on both the headwaters and the unsaturated zone is important and should be included so that it can be considered in relation to the current planning application.
AI has now supplied Technical note: Straitgate Farm – summary hydrogeological assessment of dry working: further clarification, AFW, June 2015, "so that the salient points can be taken into consideration".
Why did AI not include this document before? One of the salient points is this:
In removing a proportion of the unsaturated zone including the soil layer there will be a reduction in the storage capacity/buffering and so recharge may move more quickly through the unsaturated zone. The extent to which this makes the groundwater hydrograph more "flashier" would be difficult to quantify with a high degree of certainty… Within the proposed development the establishment of a 1m freeboard over and above the highest known water level provides for this eventuality.
As we all know by now, AI’s unorthodox seasonal working scheme does NOT propose to leave "a 1m freeboard over and above the highest known water level". Obviously we can now assume, by inference, that a flashier groundwater hydrograph has NOT been provided for.
