In response to Oliver Statham’s article on the Wendover Arm of the canal, in fact the restoration would actually be very detrimental for Wendover’s wildlife. He says that people’s fears about the canal restoration adversely affecting the long term wildlife of the rest of the canal are unfounded, I strongly disagree.
As a professional, freshwater ecologist of 20 years standing, who has often assessed the consequences of development on rivers and wetlands and as an advisor to government and planning authorities, I can assure readers that if the restoration works join the two wet sections of the canal, then the long term ecological health of the Wendover section is at grave risk and the canal as we know it will no longer exist. His comments on “habitation (sic) and wildlife” are incorrect, as any basic environmental assessment would reveal. No independent environmental assessment of the impact of the works would support his view and none has been undertaken.
Rivers and canals are complex and rely on the way the water quality, water quantity, bed and banks interact with channel life. The result is that the “restored” canal’s wildlife is likely to be very poor. The section with boats will have little wildlife and is likely to be algae dominated due to increased sediment and nutrients in the water. The upper section, even if it doesn’t have boats on it, is likely to be infested by signal crayfish which are already resident in the local catchment. These carry crayfish plague meaning that we will never have the prospect of native crayfish returning. They also remove the submerged water plants (which provide oxygen and the main habitat structure in canals). Fish, fish eggs and invertebrates, which form the main biodiversity within the canal, are also targets for this invasive crayfish. There is no known way to remove signal crayfish once they are in your canal without using a biocide called rotenone which would poison the whole canal. Further, there are resident fish species in the catchment which are officially classed as high impact invasive species, which will keep making the water nutrient rich and continue the loss of plants and animals.
The canal will also be very vulnerable to mink; the main threat to water vole and all the water birds we find on the canal, including the little grebes. It was mink that wiped out our water vole population a few years ago and joining the two parts of the canal again will prevent a stable water vole population being established without constant management.
The large cross sectional area of the canal required for boat movements, coupled with the minimal gradient and a minimal summer flow of between 0.05 and 0.03 cubic metres per second, means that there will be no perceptible flow within the new channel, making it susceptible to algal blooms and oxygenation problems.
There are also many other significant issues which have not been assessed, including the works creating a possible failure of the Water Framework Directive, failure to protect Habitats Directive Annex II species e.g. Bullhead and failure to comply with the Natural Environment and Rural Communities Act 2006. Although it fails to take into account many important ecological issues and is over 10 years old, it’s interesting that even British Waterways’ own “Environmental Matters” document which was written to support the restoration predicts significant ecological problems.
I realise this won’t be a popular letter, considering the work people have put into the restoration of the Wendover Arm but feel there should be a clearer picture of what will happen, so that decisions can be made as to whether the inevitable long term environmental costs are acceptable when measured against the benefits.
In order for the people of Wendover, the Parish Council and sponsors to decide if they want to carry on supporting the restoration, I think we should at least have an honest environmental assessment and debate about what the restoration will actually mean to our wildlife. What we’re moving towards is a wildlife poor canal which we will not be able to put right.