Comments on City Council plans for Osney Mead

Oxford City Council has issued a draft Supplementary Planning Document for the development of the western end of the city centre, an area which includes Osney Mead. The council is inviting comment. The relevant documents can be found here: https://www.oxford.gov.uk/news/article/2217/council_invites_views_on_latest_stage_of_major_transformation_of_oxford_west_end_and_osney_mead.

Osney Mead floods and will continue to do so even after the Oxford Flood Alleviation Scheme is built. How flood risk will be managed as plans come forward will need very close scrutiny. OFA believes the SPD should be strengthened in a number of areas to set an appropriate framework for managing potential future flood risk, including from sewers. We also believe the approach to biodiversity needs strengthening in line with the approaches adopted by the Oxford Flood Alleviation Scheme. OFA has submitted the following comments to the City Council:

a) Flooding and flood risk – the documents acknowledge that Osney Mead floods and will continue to do so after the completion of the Oxford Flood Alleviation Scheme, and that any development there needs to create capacity to contain and manage flood water. This can only be done, the documents say, if the whole Osney Mead site is developed in a joined-up way. The documents also recommend the creation of the appropriate infrastructure before any other development. We strongly support this view. Management of flood risk needs to be taken very seriously in any plans which come forward, not just for Osney Mead itself but also for adjoining areas. There is a risk that piecemeal re-development of the site could increase flooding locally and it would be challenging to monitor and manage.

While we welcome the general statements made about flood risk we do not see how some of the descriptions and images of proposed redevelopment on Osney Mead are consistent with flooding of the area. We therefore have serious questions about how well flood risk has been understood by the authors of these documents. In particular, the documents talk about ‘activating’ the riverbank south of Osney Lock and down to Grandpont. The proposals envisage a new, wider cycle and pedestrian route along here, river-facing buildings (apartments, offices) and new spaces for people to sit. The illustrations of what this might look like show a heavily urbanised and landscaped river frontage with paths and building all at the same level. But the towpath floods most years and is often impassable. This is flood zone 3b, part of the natural flood plain, and the types of development permitted in such an area by the National Planning Policy Framework are very restricted.

How can the envisaged ‘activated’ frontage as illustrated in these documents possibly be realised in these circumstances? Will the bank be raised to create the kind of structures shown in the SPD? If so what happens to flood water which currently overtops the Thames banks and inundates adjacent areas? Canalising the Thames at this point would create significant flood risk for existing communities both up and downstream of the area. Or will the riverside path remain at existing levels and be allowed to flood? This is very unclear in the documents. We would like to see explicit statements in the SPD and design guidelines about the challenge of ‘activating’ the riverbank given that it is in flood zone 3b. Illustrations in the documents should also present a more realistic view of what the redevelopment might look like.

The design guidelines talk about new bridges connecting the towpath by the Punter to Barret St on the other side of the Thames, and one at the eastern end of South St crossing the Osney Stream to connect to Osney Mead. In both of these locations temporary flood barriers are currently deployed when river levels are high. These barriers are critical to preventing houses on Osney Island from flooding. At the end of South St there is a large wall where the proposed new bridge would come across. This wall helps to contain flood water in Osney Stream. The demountable flood defences for the island  are stored in the EA’s Osney depot. If this depot is to close and move we need to understand how flood defences will be deployed during a flood emergency. A large pump located on EA land behind the houses on the eastern end of South St is also a critical part of the local flood defence system. This pump evacuates flood water from the island and pumps it into the weir pool. Even after the completion of OFAS houses on Osney will continue to be vulnerable to flooding and temporary defences will still be required. We would like to see the SPD/design guidelines explicitly state that any developments must not compromise flood defences for Osney Island.

A holistic approach to redeveloping Osney Mead potentially creates an opportunity to help reduce flood risk to Osney Island as well as addressing the challenges of the Osney Mead site itself. We would like to see the SPD flag up this opportunity as something to be explored. We have a rare opportunity to reduce risk for vulnerable Osney residents and this should not be missed.

Redevelopment of the Castle Mill area could potentially affect streams and weirs in that section of the city. Any plans coming forward should ensure there is no reduction in the capacity of these streams to help move flood water through the city. Could the performance of these water courses be improved to help alleviate flood risk in the city? Has this been considered?

b) Sewers – the current sewer system on Osney Mead does not cope with floods and is quickly infiltrated by flood water. Sewage is pumped from Osney Mead up Bridge St on Osney Island to join the main sewer on Botley Rd. In a flood the pressure in the system means sewage bubbles out of the sewer covers and has to be pumped into the river. Some people on Osney Island cannot use their toilets during a flood. We raised this issue in a previous consultation but there is no mention of sewer infrastructure in the Supplementary Planning Document or the Design Guidelines issued for consultation.

We need assurances that adequate sewer infrastructure will be put in place and this must be a prerequisite for any redevelopment of Osney Mead. The increased density of proposed redevelopment will greatly increase pressure on the sewer system. Failure to address this infrastructure requirement could be disastrous for some Osney residents and would mean regular discharges of sewage into the local wate ways to the detriment of the wildlife. When we have tried to raise these issues with Thames Water in the past they simply say ‘it’s caused by fluvial flooding which is nothing to do with us’. We know what an appalling track record the water companies have on river pollution. A holistic approach to the redevelopment of Osney Mead must include addressing the sewerage problems, including using flood mitigation measures to reduce risk of sewers being infiltrated.

c) Biodiversity – throughout the development of the Oxford Flood Alleviation Scheme we have been strong supporters of the ‘environmental vision’ of the scheme and the idea of making the new stream as natural as possible. This helps reduce long-term maintenance of the assets being created and is far more sustainable than a more engineered approach. We believe a similar approach should be adopted for Osney Mead. The design document talks about ‘sensitivity to habitat’ and of retaining ‘existing trees where possible, especially those of good ecological and amenity value.’ A glance at Google Earth shows the two main areas of tree cover on Osney Mead are along the bank of Osney Stream opposite the houses in Bridge Street extension, and along the towpath south of Osney Lock down to the railway bridge. The SPD seems to envisage the elimination of all of these trees. This is a major contradiction in the documents. Removing them would take out most of the existing habitat. There is a considerable difference between the carefully thought through strategies in OFAS for how biodiversity will be enhanced through the project, and the vague reliance on street trees and green roofs in the SPD design document. Green roofs need regular maintenance including irrigation and addition of fertiliser. There are some positive words in the design guideline but protecting and enhancing existing biodiversity in the area, including incorporating wild, unmanaged space into the design, hasn’t been adequately thought through. Continuing to allow the river frontage to operate as natural floodplain as it does currently, with the trees and other wild vegetation retained, would be less environmentally destructive and cheaper to maintain. We would like to see approaches here better aligned with OFAS’s approach to enhancing biodiversity. The SPD should include explicit references to OFAS and its environmental vision, and alignment with this should be a requirement of any developments coming forward. The OFAS project covers an area which borders Osney Mead and includes important targets for new wild flower meadows in the area. Opening access into the greenbelt from Osney Mead must not compromise the biodiversity targets OFAS is committed to delivering.

Oxford flood scheme – next steps

The revised planning application for the Oxford Flood Alleviation Scheme will be submitted soon for planning permission. OFA has worked closely with the Environment Agency over many years on the development of OFAS. The scheme will, in our view, greatly improve the level of protection to communities and businesses at risk from flooding, and will make the city far more resilient to climate change. We believe OFAS is the best option for Oxford, and that it strikes the appropriate balance between the many competing factors which have to be accommodated within the scheme design. Apart from providing high levels of flood protection it also includes ambitious targets for increased biodiversity. We’ve been through a long consultation process on the scheme and taken on board many suggestions from local people. That broad consultation phase is now at an end and we’re moving into the planning process through which those who continue to have reservations about aspects of the scheme will be able to argue their case. OFA’s view is that we need to come to a decision at this point so the project team can get on and build the scheme. Major revisions to the design now would result in significant delays and might even jeopardise the scheme altogether. Risk of severe flooding is increasing all the time and further postponement is not in the interest of the large flood affected community in the city. OFA will be doing all it can to help ensure the scheme secures planning permission.

Flood compensation for new Oxpens development

The proposed redevelopment of the Oxpens area involves the lowering of some land to compensate for the raising of other areas to lift them out of the flood plain. The initial round of consultation in the summer attracted a fair amount of comment on the need to preserve floodplain capacity as this helps reduce risk of property flooding.

A new set of consultation documents has just been issued and OFA is pleased to note that flood compensation has been calculated on what is known as a ‘level for level’ basis. In other words any land which is raised will be compensated for by lowering land within the same height band elsewhere on the site. We understand the Environment Agency insisted on this.

One of our major concerns with the Seacourt Park & Ride extension was that compensation was not calculated on this basis resulting in a loss of floodplain capacity. The Environment Agency allowed this at the time despite our protests. We’re please that for this new development the appropriate industry recommended approach has been adopted. The compensation includes an additional allowance for climate change and should help with reducing flood risk in the city if the development goes ahead.

Seacourt car park safety concerns

One important area of concern for us during the planning process for the Seacourt park & ride extension was the safety of users of the car park. The speed with which the site flooded on Christmas Eve underlines the risk here. In the planning application the Council argued that: ‘Historically, river levels have risen fairly slowly in this location even during extreme events, giving sufficient warning for mitigation measures to be put in place.’ But the recent flood did not conform to this pattern.

Are the Council’s safety measures at the car park robust enough? We doubt it. Had the park and ride extension been operating there would probably have been several cars bobbing about down there. Flood barriers were only erected by the City Council at Bulstake Close after the flooding had already happened.

At the peak of the flooding river levels were so high water from the Seacourt stream west of the existing car park started to encroach onto the parking area (see photo below). There were several cars parked there. Had river levels been higher these cars would have been stranded. Flood management plans for the park and ride need to be reviewed.

Seacourt car park extension flooding

The recent flooding of the extension to Seacourt Park & Ride is further evidence that the City Council seriously underestimated the vulnerability of the site to flooding. The area flooded rapidly during the night of Christmas Eve, and as of today is still partly inundated though water is now being pumped out.

View of the extension down the main access ramp on Christmas Day

The Flood Risk Assessment (FRA) submitted with the Planning Application stated: ‘An analysis of historic flooding incidents relevant to the site suggests that the site will currently flood roughly once in every 1.7 years and will remain out of operation for around 10 days during an average flood event.’ That’s just under 6 days a year average.

Over the course of last winter (2019/20) the site was inundated four times and for prolonged periods. This latest incident represents a further 12 days of flooding. In our opposition to the planning application we argued that the Council had grossly underestimated the likely extent of flooding at the site. Events seem to be proving us right.

Frozen

The Seacourt car park extension site has been pumped out for a few days following Storm Brendan which has brought huge amounts of water from our extensive catchment in the Cotswolds. But today the site is again filled with water, which has frozen overnight.

Seacourt P&R extension – further updates

Work began again briefly as mentioned in the last post. Water was pumped from the site into a ditch newly dug nearby and leading to Seacourt Stream.

River levels have now risen further. Pumping has stopped and the site is again abandoned.

Were it a car park it would be unusable of course.

This post will be updated periodically (see photos).

Work resumed on 7 January 2020. This latest flood was another 18 days, taking total flooding of the site this winter to 6 weeks 5 days. The prediction in the planning application was for 2 weeks a year. It remains to be seen how it averages out over a number of years.

Work resumed at Seacourt P&R today

Work resumed at Seacourt P&R extension today, 4 weeks and a day after it had to stop because the site had flooded. Here is the sequence from 11 November to today.

Update on Seacourt P&R extension

Following up on our post of the 15th about the Seacourt P&R extension:

First, a budget figure of £5,156,122 was approved by Council in February 2019. That’s the last official figure we know of.

Second, the area remains flooded as this picture from this morning shows.

Edit – still flooded 25/11/19.