The Environment Agency is most concerned about the condition of Vale Brook Culvert which runs beneath Chesham town centre. If urgent repair work is not undertaken soon Chesham is at risk of a major flooding event. The culvert runs from Townsend Road to where it joins the River Chess at Duck Alley (off Red Lion Street). The route of the culvert takes it under Sainsbury’s car park and the High Street, it affects 50 riparian owners (property on the edge of or over a water course). Riparian owners have a responsibility to keep structures like the culvert in good repair and it is the responsibility of the Environment Agency (EA) to ensure they are made aware of any problems and issue requests that work is carried out. The rights, responsibilities and obligations of riparian owners can be found in a booklet Living on the Edge published by the EA. Chiltern Voice reported Does the Riparian Owner Look After His Patch?
The culvert was originally designed to take the water of the Vale Brook, a spring fed chalk stream tributary of the River Chess. The springs now rarely rise due to abstraction from the Alma Road bore hole, operated by Veolia. The culvert is now mainly used as a drain for high levels of ground water and surface run off, which have an adverse effect on the water quality of the River Chess. In exceptional circumstances the springs do rise, most notably in 2000/1 when we had a very wet winter (a one in 150 years event) and the chalk aquifer was full. The culvert was unable to cope with the volumes and flow rates, which led to flooding in Chesham.
The condition of the culvert has been recently surveyed by the EA using remote controlled cameras. The state of repair of the culvert can be described as mixed. The section beneath Sainsbury’s is good, whereas the area beneath the Market Square is in a poor state and in need of immediate work. The problem facing the EA is coordinating the many riparian owners. Another issues is access. The culvert is too small to allow work from inside and needs access from above. This will be a complicated and disruptive process as the culvert runs underneath buildings.
Culvert problems include dislodged bricks, constricted capacity, illegal drain connections and in some places almost total collapse. The repair work could be carried out piecemeal by individual riparian owners, but it would be best handled on a coordinated basis. If this work is not carried out and we have consecutive wet winters, which tend to occur every seven to 10 years, it will lead to major flooding in Chesham town centre.
A process of agreeing who needs to pay for the work has started and an attempt has been made to contact all the riparian owners. This will be followed by a means testing process, which will determine who can pay. Only when this has been completed can work start.
The River Chess Association (RCA) would like to see the Vale Brook flowing as a spring fed chalk stream again. For this to occur, Veolia would have to stop or curtail their pumping activity at Alma Road. If this was to happen the capacity of the repaired culvert would be capable of carrying the water which would add much needed high quality water flow to the River Chess. RCA would also want to see the illegal drain connections in the culvert removed to improve the quality of water reaching the Chess. Re-routing the culvert may be the best outcome and possibly have it as an open watercourse. It could become a positive feature of Chesham as it once was. All options should ensure that the culvert is capable of absorbing high levels of ground water especially in the town centre, which has lead to flooding problems in the past.
Paul Jennings, Chairman of RCA, said, “The work needed on the Vale Brook Culvert gives us an ideal opportunity to address a number of issues if it is approached on a coordinated basis. The flood risk can be minimised, we can improve the quality and flow of water reaching the River Chess by reducing abstraction and redirecting illegal drains. The scenery of Chesham town centre can also be enhanced by reintroducing an open watercourse.”
For more information on the work of the River Chess Association visit www.riverchessassociation.org, www.facebook.com/pages/River-Chess-Association/112041455480210 or email firstname.lastname@example.org .