Following the strong aquifer recharge over the winter, flow reached down the valley as far as Misbourne Farm in April (where the Gorilla sign is on the A413 half a mile N of Chalfont St Giles). And, while never progressing much further towards Chalfont St Giles village, there is surprisingly still a trickle into the leat. This graph shows how the groundwater levels at the farm are still at least average and the resumption of flow after it dried in July last year. Assuming we do get some more rain in 2018, it seems we are well set for return of flow next year.

To all those – generally not MRA readers – who ask if the lack of flow in the Chalfonts is because “They” are abstracting too much water, my reply is fairly robust. First) It isn’t really “They” who abstract water from the aquifer, “We” do – for our showers, our washing machines, our paddling pools and our gardens etc – our area has the highest per capita consumption in Europe. Second), as far as we have seen the data, it appears that abstraction continues at normal rates – significantly less than before the Alleviation of Low Flow Scheme licence reductions in 1998. And Third), Affinity Water have completed the work to enable an actual permanent reduction in abstraction from the Amersham source. This is a very welcome part of their Asset Management Plan for the period 2015 – 2020 and further reductions in abstractions from the Chilterns can be expected in the next AMP: 2020 – 2025.

What else could be done? Some of you may be aware that when the sewage works at High Wycombe was closed and sewage piped to Little Marlow for treatment, a compensation stream was introduced into the river Wye to maintain its flow as the final effluent from the works now runs directly into the Thames. Well, back in 1954, the Amersham sewage works treating the upstream catchment was closed and sewage has been piped to Maple Lodge and thence to the River Colne ever since, depriving the Misbourne of that final effluent flow. The environmental lobby in 1954 didn’t exist and I doubt the idea of a compensation scheme was ever mooted. But, in 2018, what about it? As abstraction for supply is reduced by other measures, why not use the saving as recharge for the river? Could we get behind this idea and push for it to be included within AMP6 provisions?

Another idea that has long been promoted by the Chiltern Society is, of course, lining of the mill leat between Misbourne Farm and Mill Lane – i.e where flow disappears at present. The likely benefit of this scheme was clearly demonstrated in studies by the late John Norris.

What I personally believe would not be a good idea – indeed a complete waste of money would be work to redirect the river into its “original course”. You may well ask what is the “original course” – that of 100 years ago?, a 1,000 years ago?, pre Ice-Age? – I don’t know. Taking it to mean a route that avoids particularly Quarrendon Mill, my arguments against include our heritage and the disruption to the established farm fields and drainage – involving inevitable legal and consultants’ fees and compensation. But, most significantly, at most times of the year the river relies upon the developed bed to flow over the complex strata as a “perched” stream. Diverting it over open farmland will surely mean it just disappears as soon as it starts; also that we will have a problem with the “wrong” vegetation in the watercourse. Sadly, substantial sums of money have already been spent by the authorities on surveys for this scheme. I hope we can make our case for projects with a clear benefit instead.

We had a very productive work party in May opening up the flow for the mile and a bit from above Quarrendon Mill to the back of Arklow Kennels. Since then we have deliberately held back as there is little pleasure in weeding a dry riverbed. However, it is probably time to see what is going on in the leat below Misbourne Farm and prepare through to Mill Lane and beyond ready for the rains that can’t be far away. Now the growing season is nearly over, this is an ideal opportunity to make a difference.

So I am proposing we set forth again with work parties on Wednesday August 15th at 10.00 and on Saturday 18th at 09.30 and 2.00 p.m. Please let me know if you can join us.

That’s all folks.

Best wishes

Bob

Bob Older
Tel: 01753 885131
Mob: 0781 651 4868
e-mail: bob.older@me.com
http://www.misbourneriveraction.org/