The Oxford Flood Alliance has responded to the recent Newsletter from the Hinksey and Osney Environment Group (on our website). We enclose their response on a number of topics which Dr Tim King answers (in italics).
OFAS on Green Belt
If the scheme is approved we believe it will help to safeguard the Green Belt in this area as it will need to remain as a functioning flood alleviation scheme for at least the next 100 years. This will help to preserve the openness and permanence of the Green Belt. The natural design for the scheme includes the creation of over 20 hectares of new habitat. The scheme aims to bring a long term green legacy to the area.
Dr Tim King: The current Green Belt is a historically important legacy which contributes to Oxford’s green leafy heritage. As a result of the destruction of the trees, the vehicle intrusions and the mechanical digging in a muddy situation, the whole area will turn into an open industrial wasteland for at least the next 25 years. The total area of habitat is fixed. Grassland will remain as grassland, except when a new linear flood channel and ponds reduce its area. The ‘long term legacy’ will be the replacement of a green leafy wildlife corridor, which enhances Oxford’s setting, with a much more open habitat, which only slowly recovers from the shock, and to which many species may never return.
OFAS on Maintenance
The scheme will have a long term maintenance plan for the lifetime of the scheme, 100 years. This includes managing the vegetation in the area by grazing. The ‘second stage’ wider part of the channel has been designed to be grazed by cattle to create floodplain grazing marsh. Temporary fencing and removable barriers will allow the second stage channel area to be grazed. We will also create many wetland features within the second stage channel to maximise available habitat for wetland and aquatic species. The backwaters, scrapes and ponds will have a variety of depths, dimensions and gradients, to encourage diversity of wetland wildlife.
Dr Tim King: In the EA planning documents there is still no hint of the details of the long-term maintenance plan requested by Mary Thompson (OCC) in her letter of August 2017. There are plenty of references to 5 years and 10 years, but nothing worthwhile for 100 years. In his letter to me of October 2018, Richard Harding (EA) refers to a budget of £250,000 a year for ten years. This is despite the recommendations in Oliver Letwin’s 25-year DEFRA plan, which recommends at least 25 years. The grazing scheme suggested is vague and hypothetical. It depends on successful compulsory purchase, binding agreements with landowners and local wildlife organisations, cattle becoming available in the right places at the right time of year and their efficient and costly management and transport. The success of this scheme depends critically on its subsequent maintenance regime. The set of vague promises which the EA is currently making could easily be broken after the scheme is completed. Even the OFA, one of the scheme’s partners, has expressed its qualms.
OFAS on Existing streams
The new flood alleviation scheme does not divert water away from Seacourt, Bulstake and Hinksey Streams. The scheme lowers the existing natural floodplain so that in the event of high flows it can carry more water. In the Hinksey Meadow area, the existing Seacourt Stream will act as the first stage channel.
Dr Tim King: Only the upper part of the Hinksey Meadow area will be served by the existing Seacourt Stream. Below that, the current Seacourt Stream, and the lower reaches of the Hinksey Stream and the Hogacre ditch, will have markedly reduced water flow, especially in summer. They must do, if the new channel takes their water. The scheme only makes a minor contribution to lowering the natural floodplain. This may be unnecessary anyway, because once the culverts and streams around the Old Abingdon Road and southwards are improved the water will drain far more rapidly from the existing floodplain alongside the Hinkseys.
OFAS on Tree planting
To mitigate for the estimated 2,000 trees that will need to be felled during construction, we will be planting 4,325 trees. Approximately 15,000 smaller tree species, such as hawthorn, hazel and elder, will also be planted, along with many more native shrubs such as dogwood, goat willow, dog rose and wild privet.
Dr Tim King: Many of the ‘single’ willows are multi-stemmed below breast height, so that the visual and wildlife effect of their removal will be as great as removing several trees. The planted trees start small and even-aged. Between 20-75% may survive for at least five years.
Tim King
16 January