This is an HTML version of an attachment to the Freedom of Information request 'Information pertaining to the desision and construction of Pontoon / Boom on Thames in Oxford'.

 
 
 
 
 
Our ref:  Customer number 8076378 
 
1 December 2010 
 
Mr Mark Boardman 
No address – contact details:- 
07878 597004 or 07986189074 
xxxxxxxxxx@xxxxxxx.xxx 
 
 
 
 
 
 
Dear Mr Boardman 
 
ISIS LOCK 
 
My name is George Ballinger and I am Head of Engineering for British 
Waterways.  I have been asked to investigate your complaint which has now 
been raised to the second level. 
 
The first thing I would like to say is “thank you” for meeting me at ISIS Lock on 
the 18th November 2010.  It was very useful to be part of the demonstration 
given by Mike Stanley and yourself and you made your arguments firmly but 
politely. 
 
The background to your complaint is that British Waterways actions have, you 
believe, hindered your ability to turn, either in to the Thames or back to the 
Oxford Canal, after leaving ISIS Lock.  Many boats can turn within the Oxford 
Canal at a winding hole just before ISIS Lock.  This, however, only caters for 
craft of up to around about 50ft in length.  The nearest turning point for larger 
craft is 3½ miles away at Duke’s Cut. 
 
British Waterways have undertaken two specific actions which affect turning in 
the area.  The first is to install a pontoon alongside the embankment between 
the Oxford Canal and the Castle Mill Stream which prevents you pointing your 
bow into this embankment which had over many years suffered severe 
erosion.  The second is to install a weir boom across the southern section of 
the Castle Mill Stream and you state that this action hinders the turning 
movement and may, in fact, put craft in jeopardy.  The before and after 
layouts are shown below. 
 
 
 











 
 
 
 
 
 
 
Photograph 1 – Site 
 
prior to works 
 
 
 
 
 
 
 
 
 
 
Photograph 2 – Site 
showing moorings, 
weir boom and 
direction of flow 
 
 
The area is unique in the waterway network and the navigation authority is in 
fact the Environment Agency, not British Waterways.  The EA operate a weir 
about ½ mile downstream and this weir tends to operate continually 
throughout the winter and sometimes, after heavy rain.  There can be a 
considerable flow/draw generated in both the Castle Mill Stream and the cut 
to the Thames.  The nature and direction of the flow further accentuates the 
turning difficulties experienced by boaters in this area. 
 
There are several strands to your complaint and I will try and go through them 
in some sort of order. 
 
1  Repairs to the Existing Bank:  you highlight that the new bank 
protection has failed and I met with our contractor, Land & Water, on 
the morning of the 18th November at 0800 hours along with our Project 











Manager.  I informed them that the design and the construction of the 
bank were totally unacceptable and subsequently they have emailed 
British Waterways accepting full responsibility and liability for the 
situation, along with an assurance that they will put matters right in the 
very near future. 
 
Without your complaint and photographs it is possible that this problem 
would not have been brought to my attention and I would not have 
been able to take immediate corrective action as well as issuing a stern 
warning to our contractors. 
 
2  EA Agreement:  As you will have heard on site the EA were closely 
involved in the design and fully approved the scheme prior to its 
construction but they did not construct any of the Works.  Their 
statement to you that “The Environment Agency have not taken part in 
any of the works” and “it is solely British Waterways carrying out the 
works” are factually correct but, as the navigation authority their 
consultation and approval were all in place prior to the commencement 
of the Works. 
 
3  Requirement for the Pontoon:  The pontoon is designed for the EA 
requirement to withstand a 1 in 200 year flood event – hence the height 
of the piles.  It is also in place to give safe access and egress to any 
boater using the lock.  The existing bank slopes down from the towpath 
to the edge of the stream, the top sits about 1m above the normal 
water level.  It also allows for disabled access to and from the bank.  
By using a pontoon the cross sectional area of the channel is 
maintained so the speed of any flow is not increased. 
Photograph 3 – 
General view of 
Lock Landing 
 
 
Your position is that the pontoon should be completely removed and 
protection put along the existing line of the bank.  In addition you feel 
that the access to the bank, being at the furthermost point from the 










lock, will lead people to try and climb from the pontoon onto the sloping 
bank with the resultant possibility that they may slip into the water. 
 
Taking everything into account I am of the opinion that the pontoon 
structure is the appropriate solution for this location.  My reasons are 
that it is designed to withstand impact from craft, unlike the severely 
damaged original structural embankment.  Furthermore it meets all the 
requirements of the navigation authority and permits disabled access.  I 
do agree that the access point would be better located at the end 
nearest the lock and I will ask the Project Manager to incorporate a 
further, albeit steeper, ramp or step arrangement at that end of the 
Pontoon. 
 
4  Signage:  I am of the opinion that, although the EA and British 
Waterways work well together at this location, the signage requires 
radical improvement.  I think the signage problems start back at the 
Duke’s Cut where red and green boards could be shown as this is the 
last turning point for a craft greater than 50ft in length.  Clear signage 
indicating this is the last full size turning point is also essential. 
 
There also needs to be advisory signage to tell boaters what is the 
recommended way to turn as the inexperienced boater trying to turn 
into the Thames will naturally turn to starboard and end up cutting 
across the flows of both channels.  The directional arrow on the lock 
side currently exacerbates the problem. 
 
Photograph 4 – 
Signage at 
Lock Side 
 
Some of the people at our site meeting were keen to assist us in 
developing a proper signage strategy and I will pass this on to Jeff 
Whyatt so he can form a small team to take this forward. 
 
5  Turning of Craft:  The diagrams on your complaint letter are a good 
guide to the problems faced by craft trying to turn at this site.  I found 











these sketches most helpful in assisting my understanding of the 
issues.  It was also apparent to me during the narrow boat 
demonstration that “sliding” along the pontoon is a major issue.   
 
This sliding action forces the boat further along the pontoon before it 
“bites” enough to allow the flow to help turn the boat.  British 
Waterways will now investigate what alterations can be made to the 
pontoon to provide a “notch” or a “vee” to hold the bow during the 
turning operation.  It may be that a few of these are required to suit 
boats of different lengths. 
 
I would very much appreciate it if Mike Stanley and you could assist us 
with this somewhat unusual design so as we get the best fit possible 
for this unique location. 
 
I believe an inexperienced boater will tie up to the pontoon and, by 
passing a line around one of the piles, they will be able to turn their 
boat while retaining control.  This would be difficult for a single handed 
boater but such boaters tend to be more experienced and, while I 
accept there is a loss of about 6ft in turning width, I believe there is still 
sufficient room left to turn the largest craft.  However, there are areas 
of vegetation on the banks which I will again ask the Project 
Manager/Waterway to remove even although it is actually the 
responsibility of the EA to maintain the navigation. 
 
Photograph 5 - 
Bank side 
vegetation 
obstructing 
turning 
manoeuvre 
 
 
 
6  Weir Boom:  It was evident during the trials that it is possible to turn a 
70ft craft within the space allowed between the lock and the proposed 
weir boom location.  This was achieved while a small craft was moored 
to the pontoon.  However, the turn was only possible due to the 
considerable skill displayed by Mike Stanley and I would expect a 
“single-handed” novice or occasional boater to find it difficult to 
undertake such a manoeuvre.  It is absolutely essential that no craft is 


moored to the pontoon when another is trying to turn in this area and 
signage must be erected to emphasise this point.  It is also vital that 
this convenient location does not become a haven for illegal craft. 
 
   
There are positives and negatives associated with the weir boom.  The 
main positives are the restriction of access for illegal mooring and the 
ability of the boom to prevent craft being swept downstream towards 
the weir.  The negatives are that the central piles necessarily impinge 
on the navigation, particularly for a single-handed inexperienced 
boater. 
 
   
I conclude that BW did seek to ensure that there was adequate turning 
space upstream of the boom.  I have also examined the design of the 
boom (drawing enclosed) and that shows that any craft getting into 
difficulties will naturally be drawn to the side of the channel.  Again, it is 
vital that the boat which is currently illegally moored alongside the bank 
immediately upstream of the boom is removed. 
 
   
The photographs in your letter of the “Cleopatra” navigating between 
the piles will simply not be possible once the boom is completed. 
 
   
I appreciate that any obstruction in the Castle Mill stream can be 
viewed as a potential hazard to navigation.  Currently however, if a 
craft does end up being swept downstream it will become wedged 
across Hythe Bridge where the channel is at it narrowest and the water 
flows are at their greatest. 
 
Photograph 6 - 
Hythe Bridge 
 
 
   
At present there is also an illegal craft moored in the centre of the 
channel just downstream of the weir boom location – a considerable 
danger to navigation. 
 
 


 
 
 
 
Photograph 7 - 
Boat moored in the 
centre of Castle 
Mill Stream 
 
 
   
I therefore believe, taking everything into account, that the weir boom 
should represent an improvement to the safety of the area by 
preventing boats being carried downstream and channelling them in 
towards the banks. 
 
I appreciate that you may feel my response does not sufficiently address your 
complaint against British Waterways, and if you remain dissatisfied then you 
are of course eligible to take your complaint further to the Waterways 
Ombudsman, at any time within six months of the date of this letter.  Details of 
how to contact the Waterways Ombudsman are as follows: 
 
Hilary Bainbridge 
The Waterways Ombudsman 
PO Box 35 
York 
YO60 6WW 
Tel:  01347 879075 
E-mail:  xxxxxxxxx@xxxxxxxxxxxxxxxxxxx.xxx 
 
Yours sincerely 
 
 
 
GEORGE BALLINGER B.Sc., C.Eng., M.Sc., M.I.Struct.E 
Head of Engineering 
British Waterways