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Thames Water Utilities Limited
EIR Requests
Clearwater Court
Vastern Road
Reading
Berkshire
RG1 8DB

Email: [1][email address] 

1 December 2022

Our Ref: EIR-22-23-330

Environmental Information Regulation (EIR) Request
Dear Mr Soper

 

Thank you for your e-mail dated 3 November 2022.  Please see our response
below to your request as set out in your e-mail.

 

Your Request/Our Response

 

Do you know how much water was lost by the burst water pipes both at the
Littlemore Roundabout in August and the Heyford Hill Roundabout in
October? Please give the estimated volumes in meters cubed and as a
percentage of the total capacity of Farmoor Reservoir.

 

Littlemoor Roundabout (Botley)

 

With regards to the volume of water lost in August due to the Littlemore
Roundabout 9in leak:

 

As this was more a large leak across an ~ 2-week period rather than a
discrete burst, we have had to take estimates of the flow rate of the leak
(10l/s – 15l/s) across the duration of the leak (~14 days) to come up with
a value of between 12.1Ml – 18.1Ml.

 

The reason we took so long to repair the leak after it was first reported
in early August is evident in the table below showing we were navigating
into a very high demand period the second week of August with demands
forecast to be +700Mld and temperatures +30C. This meant finding a window
to shut the 24in the 9in leak was fed from for sufficient time for the
repair and not cause supply interruptions downstream needed to wait until
demands reduced on the 15^th due to a break in temperatures and some
rainfall.

 

 

There was 12229Ml in Farmoor Reservoir at the start of the Littlemore
Roundabout 9in leak on 1^st August 2022 meaning the loss of 18.1Ml would
be a loss of ~0.15% storage.

 

Heyford Hill

 

To calculate the approximate volume of water lost to the 24” burst, we
calculated the difference of the outputs of Cleeve, Farmoor and Swinford
on the day of the burst to their average outputs leading up to the 4^th
October. We assumed that SWOX demand on the 4^th would have been very
similar to the days prior if not for the burst and the other SWOX sites
other than the major sites where broadly on plan meaning the difference
between Supply and Demand on the 4^th October would be a combination of
the 24” burst volume lost and the reduction from plan in output volume
from the major works to manage the burst.

The tables below show the volume lost to the burst is in the region of
14.4Ml.

 

WTW Average Output Prior to 24" Output on Day of Burst  
Burst 04/10/22 04/10/22
Cleeve 98.3 74.8 Mld
Farmoor 65.2 69.9 Mld
Swinford 55.1 58.2 Mld
Total 218.6 202.9 Mld
Difference   -15.7 Mld

 

  Burst Day    04/10/22  
SWOX Supply Demand Difference (Mld) -30.0 Mld
Loss of Output at Major Works (Mld) -15.7 Mld
Burst Volume (Mld) -14.4 Ml

 

For the Heyford Hill burst on the 4^th October 2022 there was 8940Ml in
Farmoor Reservoir meaning the loss of 14Ml would be a loss of ~0.16%
storage.

 

Please also give an estimate as to how much water has been saved by your
hosepipe ban since it came into effect.

 

The estimated water savings were:

 

• London                438 Ml
• Thames Valley    322 Ml
• Company             760 Ml

Disclaimer

The information provided with this letter is taken from the information we
hold on our records as at the date indicated. We cannot guarantee the
accuracy of this information and it should not be relied on for any
purpose.

 

Retention

Please note that we will also retain a record of your request to allow us
to evidence our compliance with the law relating to EIR.

 

Charging

Although in accordance with our published charging regime, we are able to
charge fees/costs for dealing with requests under EIR, on this occasion,
we have chosen not to do so. We reserve the right to charge in accordance
with the fees published on our website for any requests, now or in the
future.

 

For more information about our interim charges scheme please click
[2]here  (please note that you will need to use an up to date web browser
and that the web pages will not support access by an older browser, such
as Internet Explorer).

 

Should you have any questions, please don’t hesitate to contact me.

 

Internal Review

If you are dissatisfied with the handling of your request, you have the
right to ask for an internal review.  Internal review requests should be
submitted within three months of the date of receipt of this response and
should be addressed to the Environmental Information Requests Manager and
emailed to [3][email address]

 

If you are dissatisfied with the outcome of the internal review, you can
apply, without charge, to the Information Commissioner, who will consider
whether Thames Water has complied with its obligations under the EIR, and
can require Thames Water to remedy any problems. You can find out more
about how to do this, and about the EIR in general, on the Information
Commissioner’s website at: [4]www.ico.org.uk. 

 

Yours sincerely

 

Paul

 

Paul Bridgens

Data Protection Advisor

Data Protection Investigations

 

 

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