Canal investigation works to commence in East Wichel
During 2010 work started on a new 1km section of the Wilts and Berks Canal constructed alongside the new housing development in East Wichel. The works were completed in the summer of June 2011 and the canal water level was maintained at the expected level for a period of time, being topped up in winter and dropping a bit lower in summer in line with normal seasonal fluctuations . The photos below show the canal in November 2012 with the water at the correct level.
Over the next few years the water levels have gradually reduced and Swindon Borough Council and the Wilts and Berks Canal Trust have been working together to explore the reasons behind this. A number of mitigation measures have already been trialled including pumping from the lakes and adjustments to the adjacent road drainage to divert additional water into the canal. Unfortunately none of the measures have provided a long term solution and during last year’s warm and exceptionally dry summer levels dropped particularly low.
We appreciate that this has been frustrating for the residents of East Wichel and the Council and Canal Trust have agreed that something more now needs to be done.
The first step to fixing the problem is to try and understand exactly why the water is low. Is the canal leaking and if so where? Is there not enough water being fed into the canal to compensate for evaporation and normal infiltration into the surrounding ground?
In order to try and answer these questions a programme of investigation has been agreed. A number of clay bunds will be installed within the canal (see image below) and filled to the correct level. These sections will then be monitored for up to 3 months to examine water losses due to either leakage or evaporation. It is expected that there may be some drop in the levels at the start of the process as the conditions stabilise and the water levels may need to be topped up after this initial period. The area to the east of the bunds (towards Yelland Walk) will act as a second test section with one of the objectives for this section to determine how much water enters the canal from the surrounding development through the drainage outfalls.
Alongside these test sections, a number of trial pits will be dug in and around the canal to explore the make-up of the surrounding ground.
Depending on the initial results, further similar tests may then be carried out along the length of the canal alongside other investigation. Once all the results are analysed a proposal for remediation works will be developed.
What happens next?
The works are due to commence on 20th May and will be carried out by Alun Griffiths (Contractors) Ltd who will be based in a small compound to within the East Wichel lakes car park. There will be some disruption to the towpath and the pedestrian accesses from the site whilst the clay bunds are being installed but we hope to maintain access along the towpath at all times.