The search for extra water for the Basingstoke Canal continues.
A report from John How, the leader of the Water Strategy Group.
Despite this year’s success at keeping the Canal open throughout the summer (which has only occurred once since it was reopened over 20 years ago), the Water Strategy Group (WSG) continues with investigations to find or store more water in the event of future dry summers.
We believe the fact the canal could be kept open this year is due to a number of factors, such as:
- Investment by the owners in new lock gates and sluices
- Unusually heavy rainfall over the last couple of years
- Increased abstraction from the Wey Navigation through back-pumping
- Managed navigation – introduced by the new Canal management team in 2013 to limit the numbers of days per week that the principal lock flights are open
- Dedication of the small team of BCA Rangers
The more water which can be found, and stored, the less will be the need to caulk up lock gates, therefore allowing reduction of the restrictions on the principal lock flights and resulting in a less planned approach to boating the Canal.
However, if finding or storing extra water were an easy task then solutions would have been found many years ago, but despite a number of investigations from the 1970’s to the turn of the century, no solutions were found. During the period 2000 to 2011, no significant further progress was made.
The WSG was established November 2011, with a remit to:
- Develop a Water Strategy for Basingstoke Canal, to avoid water shortages
- Enhance availability for navigation and co-ordinate all water related investigations
- In partnership with Surrey County Council, doubling of the Environment Agency’s (EA) licence to back-pump water from the Wey Navigation at Woodham. The limit was increased from 1.7 megalitres (Ml) per day to 3.4Ml/day (the extra amount being equivalent to about 7 lockfulls). This water is pumped from the pumphouse at Lock 1 (right) into the Woking pound above lock 6. (A second pump transports water from below Lock 7 to above lock 11 at St John’s). We believe this extra water is sufficient to keep the eastern portion of the Canal in water throughout the year, even in dry summers. However Surrey County Council will have to apply to the EA to renew this abstraction licence, which expires in December 2015. We all understand the pressures the EA are under to manage the available water resources due to severe water stress and water shortages in the South of England. Our investigations will help the County Council make a successful application to retain this pumping limit beyond 2015.
- Support from Southampton University in producing:
- a very detailed study of the canal hydraulics
- an exacting water flow model of the Canal, that can be easily refined with detailed measurements and help to predict potential water shortages
- confirmation that the WSG estimate of a 3.5 to 5.5Ml/day shortfall during dry weather conditions is appropriate
- Detailed report from British Geological Surveys (BGS) on the potential of abstraction from boreholes at various locations along the Canal from Greywell to Deepcut.
The following are a few examples of the many topics currently under investigation:
- Revival of boreholes or new boreholes in the Frimley area where historically there was abstraction for domestic water supplies
- Use of existing water storage facilities, and other depressions alongside the Canal that could hold water to be used in dry summers
- Remote water level measurement and pump control (telemetry) to aid water management
- Canal depth survey to identify areas for dredging and potential water storage in Hampshire pound
- The Rangers are experimenting with lock gate sealing methods to avoid caulking
- An approach to South East Water with respect to their domestic water abstraction at Greywell (however, the expected closure of this pumping station by 2020 may result in more water for the Canal).
- Leaks around locks due to possible lock voids
- Seeking assistance from the numerous property developers alongside the canal
It is hoped that this brief summary shows that no stone is being left unturned. We cannot guarantee to solve the problems of water shortages in dry weather, but we are happy to investigate any suggestion and the work is being carefully documented to avoid repeat investigations in the future. Progress on any of these topics is usually slow due to the many interested bodies – for example, we need to be in contact with (or seek approval from) the Environment Agency; Natural England; Land Owners; Local Councils; Ministry of Defence; Network Rail etc.
If anyone would wish to volunteer to help the WSG, we will welcome any assistance you can give.