River Chess Association

The River Chess Association attended a presentation with HS2, Affinity Water and the Environment Agency on "The Environmental Impact on Water Resources" of the HS2 development on the 23^rd February 2017 at the offices of Affinity Water in Hatfield.

What we heard is of real concern. By their own admission, HS2 do not understand the chalk aquifer through which they are planning to drill and dig. Chalk aquifers are difficult to map and do not form a homogeneous reservoir: there are a number of strata through which groundwater percolates and water also migrates through a complex series of fractures and fissures. The aquifer is recharged by rainfall that drains through the ground until it connects with the chalk. Having passed through the chalk, there are two ways it can reappear: via natural springs, which eventually form our chalk streams, or through boreholes drilled into the chalk to supply drinking water. This precious resource thus meets two requirements and it is essential that both are protected.

So what are our concerns? The HS2 plan is to drive large bore tunnels through the aquifer over many kilometers. Without understanding the aquifer there is a danger that the tunnels will interfere with migration paths in the chalk, causing damage to the supply of water to our chalk streams. There is evidence that the aquifer in the chalk that supplies the Misbourne and Chess are connected, so there is a danger to both rivers. Another concern is that tunneling may introduce chemical and biological pollution into the aquifer, permanently damaging both drinking water supply and the source water for the Misbourne and the Chess.

Before any more work is done on this project, we suggest that HS2 commission studies to fully understand the aquifer, the pollution risk from drilling activity and, more importantly, to map the migration paths of water through the chalk that flow out into the Misbourne and the Chess. We have raised this issue for years, through all the consultation stages, and our fear is that a lack of understanding of the aquifer could result in major problems. Affinity Water recognise the risk and have negotiated a Government-backed indemnity to compensate them for the loss of this drinking water resource should this occur, and a similar indemnity needs to be in place for the possible loss of water to chalk streams. At the presentation, the EA representative stated that the loss of chalk streams would not be allowed and HS2 must recognise this.

We have to accept that HS2 is going ahead, so let's make sure it does not ruin our precious chalk streams in the process.

There is a worst-case scenario for the Chilterns: we suffer the disruption of 10 years of development work, we lose two chalk streams and we find our water bills sky rocket.

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