“Jetsam” alliterates with June but is totally inadequate to describe the stinking debris in the Misbourne downstream of the Amersham Balancing Tanks where Thameswater have recorded over 3000 hours discharge of sewage this year – equivalent to continuous discharge from 26th January to 31st May. Residents near Bottom House Farm and all the way to Chalfont St Giles Mill Lane continue to live with the overbearing smell and the river is clogged with “paper”: the water is deep grey and cloudy. Discharges of less duration from Gerard’s Cross STW are relatively “out of sight” but have caused further pollution. And it has been disturbing to hear, for the first time ever, of relatively brief sewer overflows affecting the river ecosystem at Little Missenden. You may have also seen videos of horrendous discharges into the Chess at Chesham, the Ver at Markyate and elsewhere further afield. You will be pleased to learn that Thameswater’s survey work from 2014 etc has been found, possibly enabling an earlier start to substantial improvements than otherwise anticipated.
Bucks CC has convened a “Flood Working Group” to consider all aspects of local flooding, including the sewage issue – 1st meeting was to have been 11th June, but now postponed citing General Election “purdah” rules !!! Meanwhile, the 2nd Chiltern Chalkstreams Project “Mending the Misbourne” workshop again brought together a wide range of interested parties. Following an update on general matters, table groups tackled reaches of the river prioritising problems identified in meeting 1 and suggesting solutions. Not surprisingly, there is no shortage of desirable projects but funding in the next 5 year water industry asset management plan (AMP) period 2025 – 2030 will be hard won.
Although we still see exceptional groundwater inundation of the flood plain from Amersham through to the Chalfonts, groundwater levels have been falling. Looking at our data since 1992, the picture broadly continues to be very similar to 2001, maybe slightly less severe overall, but a bit worse at Quarrendon Mill and Chalfont St Peter – see graphs below. The two places where the curve has been more noticeably more severe than 2001 are Quarrendon Mill (up to 1.5 m in March/Aprtil) and Chalfont St Peter (just 0.25 m in February) but, oddly, not Chalfont St Giles, or upstream of Amersham. Why 2024 is not consistently above or below 2001 all along the valley is a puzzle and comparisons with 2014 as another year of interest show a different enigma.
Another puzzle is why the sewage issue has been so much worse this year than the modest, short duration and localised pollution experienced in 2001. Part of the answer could be the exceptionally high groundwater levels around Quarrendon Mill – i.e., just above the Balancing Tanks – causing greater infiltration to the sewer network. But, it is that reach where some work was done a few years back on the manholes! Perhaps that demonstrates infiltration through pipes and joints rather than the manholes? Other differences between the years include the “restoration project” just up stream of Q Mill; HS2 – is that part of the puzzle? – and various housing developments. As always, plenty of questions.
Thanks to this who have already volunteered to join us at Chiltern Open Air Museum’s Green Festival this Sunday 9th June https://www.coam.org.uk/events/green-festival – we look forward to seeing you if you pop by.
Similar requests for assistance and droppers-by at Chalfont St Peter Feast Day on 29th June and Chalfont St Giles Show on 7th September. MRA will also be represented at “Midsummer in the Meadow”, Boug’s Meadow, Great Misenden on 30th June.
Please let me know as soon as possible if you can join us for the work party with the Environment Agency, well above any sewage contamination, near Quarrendon Mill on Wednesday 12th June, 10.00 am.
Ditto, a standard work party at Chalfont St Peter, now effectively clear of sewage, on Saturday 15th June between tennis courts and village centre 10.00 and 2.00.
“Not a Meeting” last month was very enjoyable. All welcome to join us for drink and a natter about all of the above (and probably some completely unrelated matters!) at The Greyhound on Wednesday 12th June from 7.15pm. We may then plan for a future work party near Shardeloes but still avoiding Chalfont St Giles where work is required but still somewhat contaminated.
That’s al folk. Look forward to seeing you by or in some clean water soon.
Sewage debris in our chalk stream between Amersham Balancing Tanks and CStGiles village
