Dorney’s Waterways – Roundmoor Ditch 

 

The Anglo-Saxons named our village ‘Dornei’, meaning Island of Bumblebees. The 
completion of the Jubilee River made this a fact and we are now, truly, on an island. 

 

The two rivers – the Thames, which forms our western and southern parish border, and the 
Jubilee – are well-known to all of us, but there are two other waterways that are also 
important to Dorney and are not so obvious, namely, Roundmoor Ditch and Cress Brook. 
This article will focus on Roundmoor Ditch, with Cress Brook following in a later edition. 

 

Roundmoor Ditch, despite the name, is in fact a chalk-fed stream that rises in Taplow and 
flows southeast to Dorney Common. There, it is joined by the Cress Brook and continues 
as the Boveney Ditch, until it joins with the River Thames. 

 

Roundmoor Ditch forms much of the northern and eastern boundary of Dorney Parish. 

 

 

 

Roundmoor Ditch is about 4.5km long and its volume is increased significantly just north of 
the Jubilee River by outfalls from the Slough Sewage Works. It then passes in a culvert 
underneath the Jubilee River near Manor Farm Weir coming out between Dorney Common 
and Eton Wick. 

 

In the winter of 2014, the Thames Basin suffered significant flooding. This included 
extremely high groundwater levels in many areas, including Slough. Surface water 
infiltrated the sewer systems and overwhelmed the sewage treatment works. 

Under these extreme conditions, the Thames Water sewage treatment works in Slough 
were permitted to discharge storm flows into the Roundmoor Ditch. This continued for an 
unprecedented period of about three months. 

 

Significant concerns raised by residents in Eton Wick, community groups and landowners 
highlighted that the public highly values the river, its ecology and its use as an open space 
for people to enjoy. 

 


Thames21, in partnership with Thames 
Water, embarked on a two-year project in 
2017 to restore the series of waterways at 
Roundmoor to a significantly better state 
than before the 2014 pollution incident and 
to address community concerns. 

Thames21, using its strong reputation and 
experience with communities to improve and 
protect waterways, worked with local groups 
to improve and protect the 750 metres or 
more of the Roundmoor Ditch as it flows 
between Dorney Common and Eton Wick. 

Those groups include the Eton Wick Waterways Group, Thames Valley Angling 
Association, Dorney Court Estate, Eton College, Environment Agency, the Royal Borough 
of Windsor and Maidenhead, and Berkshire, Buckinghamshire, & Oxfordshire Wildlife 
Trust. This project was successfully completed with the help of many volunteers from the 
community. 

 

However, the remaining 3.75km from Taplow to the Jubilee River were not included in this 
project and have lain unattended and unkempt for many years. There was a time, in the 
Thames Conservancy days (pre Environment Agency) when a couple of workers arrived 
every year to clear this stretch of river – but no longer. 

 

So Roundmoor Ditch is now blocked by uncut and uncleared vegetation, fallen trees, 
illegally dumped aggregate and at least one blocked culvert. 

 

The water that still comes down from Taplow has 
to find somewhere else to go – and hence the 
flooding this summer of Lake End Common (next 
to the Pineapple) which is endangering properties 
in Ashford Lane. It is also coming up the garden of 
adjoining properties in Lake End. 

 

 

Residents in Lake End have called in the 
Environment Agency and they have carried out 
surveys – but no action appears to have been 
taken by them to date. 

 

The legal responsibility for looking after such waterways as the Roundmoor Ditch (which is 
classified as a main river) lies with the riparian owners (those, generally, who own the 
adjoining river banks). Interestingly, the Environment Agency, for a considerable stretch of 
Roundmoor Ditch is one of the riparian owners. Another is Thames Water. 

 

Fortunately, a precedent for solving problems related to the Roundmoor Ditch has been 
set, through the Thames21 project for the 750m from the Jubilee River to the confluence 
with Cress Brook. 

 

It looks like the time has now come for everyone to address the rest of the 4.5km of this 
important main river to the Thames. 

 

Bill Dax 


 

A close up of a sign
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