Our committee member Mark Gladwin has studied the five year plan proposed by the Environment Agency for York’s flood control following the Boxing Day 2015 floods that made such a mark on the city. Here’s a useful summary …
The report of the independent committee of inquiry into the floods was published on 22nd January 2017, and can be accessed at: https://www.york.gov.uk/downloads/file/12456/york_flood_inquiry_main_report
The inquiry committee report is principally concerned with the actions and omissions of the various responsible agencies after the flooding happened, during those frightening hours on 26th December 2015, and the days, weeks and sometimes months of misery that followed for many people in the 627 properties affected. Thankfully, nobody died or was injured; but lots of people had their lives turned upside down.
The report does not consider in any detail, however, the actions and plans for alleviation of future flooding in York that are now being brought forward by the Environment Agency. It is these plans and actions that are the subject of this article. They fall into three main categories:
- Upgrading the Foss Barrier;
- A five-year plan to upgrade and extend other defences in York against flooding from the Ouse, the Foss and the becks;
- A long term plan to tackle the causes of flooding in York on a whole-catchment scale.
All these plans were the subject in November 2016 of an Environment Agency exhibition, among whose many visitors were several members of the River Foss Society. To coincide with the exhibition, the Agency published a booklet entitled How we’re reducing the risk of flooding for York: Our 5-year plan. This booklet can be downloaded free from the Agency’s website at: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/568910/EA_York_Flood_Action_Plan__FINAL.pdf
Comments on the plan are invited at firstname.lastname@example.org – we hope that many members of the River Foss Society will avail themselves of this opportunity.
Upgrading the Foss Barrier
The failure of the Foss Barrier was the new factor in December 2015 that made the floods so devastating compared to those of 2000 or 2012. Record rainfall on an already saturated catchment resulted in an unprecedented volume of water flowing down the Foss, well in excess of the pumping capacity at the Barrier – a capacity that had been designed in 1987 to take account of expected volumes of rainfall in the foreseeable future. This record flow meant that a known design and construction fault beneath the pump house building, leading to water leakage through cracks in the service tunnel housing electric power cables – a fault which in normal conditions was sufficiently mitigated by the use of subsidiary pumps – became a critical failure. The electrical systems were overwhelmed, the power to the pumps had to be turned off and the Barrier had to be raised, leaving the Foss at the same level as the Ouse. If the power had not been turned off, there would have been catastrophic damage to the pumps. As it was, once an alternative power supply was set up thanks to generators helicoptered in by the Army, the pumps went back into action and water levels behind the Barrier fell very quickly.
It is perhaps worth noting that if the electrics had not been submerged and the pumps could have gone on working without interruption, there would still have been flooding along the Foss, because the water was coming down faster than it could be pumped; but the flooding would have been less severe.
Given the failings revealed on 26 December 2015, it is no surprise that the Environment Agency’s £17m upgrade of the pumping system at the Foss Barrier, at the time of writing already well under way, is based around three key objectives:
- Increasing the pumping capacity from the original 30 cubic metres per second (cumecs) to an eventual 50 cumecs. 40 cumecs of capacity has already been attained; the final extra 10 cumecs require an upgrade of the electrical power supply and rebuilding of the pumphouse. This work is scheduled for completion by the end of 2017. The 50 cumecs capacity takes into consideration estimated effects of future climate change.
- Rebuilding the pumphouse to raise all sensitive electrical equipment well above any conceivable flood level.
- Securing backup sources of electricity to create a failsafe power supply system.
Additionally, as part of the broader five-year flood defence plan described below, the Agency aims to raise the height of the Barrier gate and the associated flood walls on St.George’s Field, to take account of possible higher flood levels in the Ouse.
Since the Boxing Day floods, the Foss Barrier has been operated successfully five times.
The five year plan
In addition to the £17m allocated to improving the Foss Barrier, the Environment Agency is consulting on a £45m five-year flood protection plan for other areas of York, to take into account the likely future impact of climate change. This plan is set out in some detail in the booklet already referred to. The plan focuses on the City of York Council area, and is divided into ten areas or “communities”, viz. Bishopthorpe; Clementhorpe; Clifton and Rawcliffe; Foss; Fulford; Holgate; Naburn and Acaster Malbis; Osbaldwick and Tang Hall; Poppleton; and York city centre.
For reasons of space, this article will focus solely on the proposals for the River Foss catchment. Those seeking information about plans for other parts of the city are directed to the Environment Agency booklet. It should be noted that all the proposals set out in the Five Year Plan are consultative and are not yet firm action plans. Comment and criticism by local people on the draft plan will be vital in ensuring that any works undertaken are effective in alleviating flooding and acceptable to the communities concerned.
The five-year plan for the River Foss
The plan for the Foss has four main elements:
- Slowing down the flow north of the Outer Ring Road.
- Speeding up the flow between the Ring Road and the Barrier.
- New flood walls and embankments in selected places.
- Raising the height of the Barrier against higher flood levels in the Ouse.
Not included in the booklet, but referred to in other publicity at the exhibition, is the possibility that replacing existing fixed weirs, as at New Earswick and Yearsley locks, with tilting weirs similar to the one now seen at Castle Mills, could assist with managing water levels.
Slowing the flow
The plan envisages a new flood water storage area just south west of the junction between Haxby Road and the Outer Ring Road (approximate Grid Ref SE 608 564), linked to an enlarged culvert for the Westfield Beck under the Ring Road and increased pumping capacity. No details are given in the plan about the size or construction of this facility. The objective would be to slow the rate at which water from the Westfield Beck enters the Foss, by storing it and releasing it slowly into the river.
Speeding the flow
Inside the Outer Ring Road, options to create holding ponds for flood water become more difficult. The Agency’s proposals for this urban stretch of the river include dredging (or as they prefer to call it, “de-silting”) at six locations, with the aim of increasing capacity in the river bed and thus speeding the flow of water down towards the increased pumping capacity at the Barrier. The map shown in the Five Year Plan booklet is not accurate enough to enable these six dredging locations to be precisely identified, but they appear to be approximately as follows: Church Lane, Huntington; Willow Bank, New Earswick; Meadowfields Drive, Huntington; Rear of University of York St John sports grounds off Haxby Road; Fossway; and Gladstone Street.
Dredging clearly has the potential to be harmful to riverside wildlife. Advice received by the River Foss Society, however, suggests that so long as material is removed from the river bed rather than the banks, the harm caused by dredging itself is not too serious. Dumping of spoil on the river banks would be another matter. Conversations with members of Environment Agency staff at the November 2016 exhibition suggested that any dredged spoil would have to be transported off site, since if dumped on the river banks, the liquidity of the spoil would mean that much material would simply flow back into the river. The Society, however, will want to monitor any dredging operations closely, to ensure that wildlife damage is kept to a minimum.
Flood walls and embankments
Proposals in the Five Year Plan feature a long embankment along the Westfield Beck, behind the Eastfield estate in Haxby. The Plan also indicates short stretches of embankment at Willow Bank, New Earswick; at Meadowfields Drive, Huntington; and on South Beck in Bell Farm. Short flood walls are proposed at Church Lane, Huntington; at Mill Hill, Huntington; on Haxby Road near New Earswick Lock; on Huntington Road below Yearsley Grove; and on Geldof Road, Huntington. A long flood wall is proposed for the whole length of the west bank of the river from Monk Bridge to Yearsley Bridge. All these plans will require careful scrutiny by local residents and others. The River Foss Society will be particularly concerned to preserve the unity and accessibility of the Foss Walk.
Raising the height of the Barrier and the flood walls at St.George’s Field
No details of these proposals are given in the Five Year Plan booklet. They will be additional to the £17m Foss Barrier upgrade works already underway. Previous Ouse flooding has come close to overtopping the Barrier on a number of occasions, so the need for these improvements is clear in the face of climate change.
A long term flood prevention strategy?
The final page of the Five Year Plan booklet states: “The options in this document focus on improvements we can make in the next five years, but we also need a long-term plan to better prepare York for the risk of future flooding and to mitigate the effects of climate change. To achieve this, we need to look at the catchment as a whole and understand the risks of flooding beyond the city of York. We have therefore started to develop a plan of action, working with a wide range of partners across the city and the surrounding area, to prepare York for the future”.
Understandably perhaps, no specific details of elements of this long term strategy appear in the booklet. The overall aims of the strategy, however, are likely to include:
- Changing the local authority planning system to reduce the likelihood and impact of flooding in new and existing developments;
- Improving flood forecasting technology to provide more timely and targeted flood warnings;
- Upstream storage and natural flood management techniques that can slow run-off and regulate the flow of water downstream.
Where York is concerned, “upstream” measures to reduce downstream flood impacts must take account of the vast Pennine catchments of the Swale, Ure and Nidd, as well as the much smaller Foss catchment. Some specific themes that the Agency plans to investigate with partners are:
- Creating or expanding washlands and reservoirs on farmland and moors;
- Tree planting to absorb rainfall and slow run-off;
- Working with landowners to manage farmland run-off;
- Changes to land drainage systems to slow the rate at which rainfall enters watercourses;
- Working with builders and planners to adopt construction methods that lessen the damage caused to buildings by flooding.
Conversations with members of Environment Agency staff at the November 2016 exhibition suggest that for the Foss, “leaky dams” are being studied with interest, as is de-canalisation of the river and the reinstatement of old meanders. From an historical perspective, de-canalisation of the Foss would be a deeply ironic move. Should we be blaming York’s recent tribulations on the Foss Navigation Company and their Act of Parliament in 1793, which led to the construction of the Foss Navigation? We await with interest the reactions of farmers and the Foss Internal Drainage Board to any proposal to re-create meanders on the Foss.