Wraysbury level and drainage issues

This e-mail (dated 15 September 2016) is for Samina/Andrew/Emma in particular - and copied to Graham Sinclair (Wraysbury PC) and Ian Thompson (Datchet PC)

Having attended your Imber Court, Molesey session on Tuesday 13^th September……………I have since realised that having focussed on the channel(s) and water bodies I neglected to refer to the local water courses and drainage channels.

I will write a short report in due course but just wish for you to record my apprehension at this time.

You already know that the area is very flat and laced with a ‘web’ of drainage channels many of which lack maintenance.

My first concern is that the proposed channel cuts through the Datchet Common Brook, the Wraysbury Drain and the Horton Drain. I feel that I need assurance that the channel flows upstream and downstream of the intersections will be at least maintained and possibly even improved.

My second concern is the effect of the new channel on the overall ‘responsiveness’ of the water system in the area – in particular that water levels will rise much earlier and also at a faster rate. This is precisely what happened previously with the Jubilee River by-passing the natural attenuating features of the Thames.

At present the Wraysbury Lakes respond relatively slowly to changes in River Thames water levels. When overland flood flows start to fill the lakes although the rate of change increases - lake levels still lag well behind the rising Thames levels.

The reverse is also true – with falling Thames levels well ahead of and much faster than lake levels. Indeed I have evidence of Thames water entering lakes and of that water (i.e. water from the lakes) returning to the Thames some days later. There is then a stage when remaining water trapped in the lakes and unable to drain raises local groundwater levels for a long period after the floods have receded.

These are important points and I am happy to discuss them with you.

Please confirm receipt of this e-mail

Thanks

Ewan Larcombe