Specific Problem Areas & Proposed Improvements - 2
24: Stour Canterbury to Fordwich
ConclusionIn the urban area there was no major overtopping or bursting of its banks by the Stour. There were some localised problems where flooding directly and indirectly came from the river. These were at Thanington, St Peters Canterbury, Broad Oak Road/St Stephens Canterbury, Sturry and Fordwich. In total 20 houses were flooded. At Fordwich there is a related land drainage problem, which also caused some flooding. Backing up of surface water drains that outfall into the river at a number of these locations may well have made the situation worse.
RecommendationThe Environment Agency should ascertain the various possible reasons for flooding and carry out improvement works. Non-return valves should be fitted to outfall pipes. The banks of the river should be surveyed to find any low spots where attention would reduce the possibility of flooding. Dredging of the river should be carried out where necessary to improve the flow. Canterbury City Council should examine the land drainage problems at Fordwich.
Action The Environment Agency has agreed to remove the shoals in the river at St Stephens and the work will be carried out in October. The situation with the riverbanks there will also be checked at that time. The City Council will survey the banks in the St Peters area to see if any raising can be carried out- survey planned for September. Southern Water has agreed to fit flap valves to outfalls - work to be carried out shortly. At Fordwich the Environment Agency will carry out works in October/November to ensure that the river walls and banks are continuous and at the correct level. The damaged expansion joints will also be renewed. The City Council, with the landowner, is looking into the land drainage problems there and the situation will be advised to residents shortly. An action group, Floodlinks, has been set up by affected residents and parish councils at Fordwich/Sturry and the City Council is liasing with that group in order to try to solve some of the issues.
March 2002 Review The removal of shoals in the river and the raising of the banks at Willow Close/St Stephens were not carried out by the Environment Agency due to higher priority work elsewhere and the need for a detailed survey to ascertain the downstream implications. The work is in the EA programme for Year 2002/2003. Non-return valves have not been fitted at this location and Southern Water is being requested to action this quickly. At St Peters the fitting of non-return valves to highway drains is in the 2002/2003 KCC programme for this type of work along with other locations. The survey by the City Council of the riverbanks in this location has not yet been carried out and is now programmed for early Year 2002/2003. Any minor improvements works deemed necessary from the survey will also be carried out in that financial year. At Fordwich the Environment Agency has completed maintenance works to river walls and banks to restore them back to their original level. Contact continues between the City Council and the Floodlinks Action Group. A formal application has been submitted to DEFRA for grant aid for a detailed study into the whole problem of land drainage at Fordwich.
25: North Canterbury
ConclusionThere has been a land drainage problem in existence for a long time at north Canterbury from Harbledown right through to Broad Oak. This is allied to the catchment of the Sarre Penn watercourse. Many land drains and watercourses are not functioning properly and water flows unchecked from the hillsides above into residential areas. In the past there have been minor landslides and failures of retaining walls. Although there was considerable flooding of a large area a number of times over the last year the number of houses reported flooded internally was 5. Except for at the Cherry Gardens locality where the condition or capacity of the Southern Water foul and surface water sewers have added to the problem, there are no other agencies involved.
RecommendationThe City Council should carry out an in depth study to ascertain the problems and options for improvement. All incidents reported should be followed up to try to instigate short-term measures that may help. Landowners should be contacted and made aware of the problems and their responsibilities where relevant.
Action The City Council will shortly be applying to central government for funding of a detailed study here. Some problems have been investigated but because of priorities there are many still to be checked up on.
March 2002 Review A formal application has been submitted to DEFRA for grant aid for a detailed study into the whole problem of land drainage in this area. Until this is done and conclusions drawn any improvements can only be short term and very localised. As for elsewhere there is still a backlog of investigations into individual site problems but some minor improvements have been made at a few sites.
26: Great Stour
ConclusionConsidering the large developed floodplain of the Great Stour and its massive catchment, there was not widespread flooding from it. Houses as Shalmsford Street and Chartham were very close to being flooded in November 2000 and February 2001. Some houses were flooded at Canterbury and Fordwich directly or indirectly (see elsewhere in this report) from the Stour. However, the main problems were at its confluence with the Little Stour where large tracts of land at Grove were under water for many weeks around February 2001. It is concluded that the holding reservoirs at Aldington and Ashford worked well and the Environment Agency are praised in this respect.
RecommendationImprovements and raising of the banks of the Stour need to be made in the vicinity of Grove to prevent overflow and flooding of the low lying land. Significant dredging of the riverbed is urgently needed at Plucks Gutter and further downstream and more frequent maintenance should be planned in future. The pumping capacity at Stourmouth, where the Little Stour is pumped into the main river, should be investigated with a view to increasing flow rate. The whole catchment including the Little Stour and Nailbourne should be studied and the resulting long-term improvements put into Environment Agency=s capital programme for action as soon as possible.
Action The Environment Agency has confirmed a programme for dredging 3 km of the Stour downstream of Plucks Gutter commencing in October. Due to insufficient funds the next stage of dredging will not start until autumn 2002. The environmental problems in repairing the banks at Grove Ferry have been solved and the work will be carried out in October. Other major improvements to the Stour including possible increased pumping at Stourmouth will be examined as part of the in depth catchment strategy study which is about to commence. The Agency has been requested to urgently repair and bring into use the two (out of six) damaged gates at Stonar Cut and to look into reinstating the original width of the river in the Grove area.
March 2002 Review The Environment Agency now has in place, and funds available, a programme for capital dredging of the Stour from Sandwich back to Fordwich with an annual rate of about 3 km per year. The first length from Sandwich towards Plucks Gutter was completed in 2001. Repair/raising of the banks and some reinstatement of river width at Grove Ferry did not go ahead because of the need for a full environmental impact study. This work is now programmed for summer 2002. The three gates at Stonar most in need of repair have been repaired/renewed. The other three will be actioned in 2002. The question of the possibility of additional pumps at Stourmouth (to pump up the Little Stour) will be examined as part of the Stour Catchment Flood Management Plan, which is tentatively programmed to start in mid 2002. Some additional telemetry is being installed to improve flood forecasting - ready by autumn 2002.
27: Herne Bay & District
Conclusion In the centre of Herne Bay and the surrounding communities of Herne, Broomfield and Beltinge there were quite a large number of flooding incidents from a variety of sources. It is estimated that at least 15 houses were flooded internally, at about ten different places, over the April 2000, October 2000 and February 2001 storms in this area. The probable causes were foul sewers backing up, minor streams being blocked, problems with highway and public surface water sewers, possible land drainage changes due to the new A299 and water flowing off fields.
RecommendationCity Council engineers should investigate all these problem areas and ensure that the responsible agency is aware and is looking into possible solutions. Where no other agency is involved the City Council should consider what action it can take to assist.
Action Some of the issues have been followed up and other agencies are also investigating but most of the problems have yet been looked into in detail. Sewage flooding at Herne has happened again recently and Southern Water is being pressed to solve this problem.
March 2002 Review A number of the flooding and land drainage problems have been resolved but there remains several still to be dealt with - some of these have no solution without very expensive works. The sewage flooding problem at Herne appears to have been solved by Southern Water by the installation of non return valves. The surface water flooding at Reculver Road and Beltinge has not been solved although Southern Water is currently looking into ways to alleviate the situation - but major capital improvements are not deemed to be a priority. See also Action 15.
28: Little Stour & Lower Nailbourne
ConclusionSerious flooding occurred in the parishes of Bridge, Patrixbourne & Bekesbourne, Littlebourne, Ickham and Wickhambreux due to the Little Stour and Lower Nailbourne main river bursting its banks. A total of 60 houses were flooded. Some of these properties were affected continually from November 2000 to April 2001 with the flooding peaking in February 2001. Not all houses were flooded directly from the river as a number of these were flooded as a result of run off from fields and roads where the outfalls to the river also backed up. In February 2001, particularly at Bridge, some houses were flooded due to foul sewers backing up. Restrictions in the river that reduced its flow at highway culverts, water mills, numerous obstructions constructed both privately and as a result of nature all contributed to the problem. The outfall with the Great Stour (see Action 26) was also a major factor.
RecommendationThe whole of the Nailbourne and Little Stour should be investigated as one entity as the problems and potential solutions affect the full length. This includes Elham and Lyminge, which, although outside the City Council's area, are equally affected. A survey of the river should be undertaken to determine all restrictions and to be the basis of action to remove them where practicable. Care must be taken to ensure that any works do not make the situation worse downstream. The Environment Agency should increase the scope of annual maintenance to the river to ensure that it is in its optimum condition. The work of weedcutting and removal, dredging and bank remedials must be carried out before this winter. Other sources of flooding in the area should be investigated and actioned where possible. Means of keeping the source aquifer at a lower level before winter should be assessed. A detailed study of the entire catchment should be carried out to determine long-term solutions.
Action The parishes affected along the entire length of the river have set up the Little Stour and Nailbourne River Management Group to co-ordinate action and are working with the Environment Agency and City Council. This has proved to be a very beneficial partnership, which has been instrumental in getting many projects under way. The City Council has completed a survey of the Nailbourne and issued a report detailing maintenance work required. The Environment Agency has surveyed the Little Stour and has begun to action some of the issues. The Environment Agency will carry out some limited dredging of shoals and bank repairs (including at Scoutlands) in September. Some weedcutting and reed pulling has been completed and a further programme of work for the full length of the river will commence in October. The Environment Agency is looking into possible flow improvement works at the water mills. The City Council has completed the high flow by-pass channel at Patrixbourne. The proposed by-pass channel from Littlebourne through to Seaton has been drawn up and set out on site. Subject to satisfactory agreements with landowners and some other legal requirements, Environment Agency considers the channel could be completed (excluding road crossings) by December.The Environment Agency has been asked to check on the feasibility of pumping at the source of the Nailbourne during the summer - no response on this has yet been received. The City Council and Kent Highways have carried out minor local drainage improvements at Bridge and Littlebourne. Kent Highways will carry out drainage improvement works at Ickham in September to provide an outfall for the pond.
March 2002 Review The Little Stour and Nailbourne River Management Group continues to meet regularly and close liaison is being maintained with the City Council. At various locations along the length of the river the Environment Agency has carried out dredging, mainly at the location of shoals. However, it is still considered that a more comprehensive dredge of the entire river should be carried out. Considerable weedcutting and reed pulling has been undertaken. The major improvement to the river, comprising a new high flow diversion channel from Littlebourne to Seaton, is virtually complete. This should noticeably reduce flooding to the villages along this length. Local drainage improvements at Bridge, Littlebourne and Ickham by Kent Highways have been carried out. The joint project for improvements at Patrixbourne has been completed. This comprised a high flow diversion channel, clearance of material under bridges, dredging and some widening of the river and lowering of the ford. There has been no response from the Environment Agency on the suggestion to look into pumping of the aquifer during summer. It is understood that this may be one of the considerations when the Stour Catchment Flood Management Plan is carried out by the EA.
29: Upper Nailbourne
ConclusionThe Upper Nailbourne from its source to Bridge is not a designated main river and does not come under the auspices of the Environment Agency. The villages of Barham, Kingston and Bishopsbourne suffered from flooding just as badly as down river and a total of 40 houses were flooded from the river overtopping its banks and other related causes. Flooding due to run off from fields and from natural springs was particularly bad in this area. The main problems are identical to those for the main river (see Action 28) with respect to restrictions and lack of maintenance reducing the flow.
RecommendationThe main recommendations are as for the rest of the river (see Action 28) and must be carried out in conjunction with them. The City Council should co-ordinate action and organise an inspection and detailed survey of the Nailbourne to assess restrictions and possible improvements in conjunction with the parish councils, riparian owners and Kent Highways and Bridges. Possible local drainage improvements should be investigated by the City Council to try to reduce flooding from other sources. After the surveys the riparian owners should be requested to undertake urgent maintenance to the river in the form of removal of vegetation, trimming of tree branches, removal of debris, repair of fallen in banks and dismantling of any unapproved structures restricting the flow.
Action The main actions follow those of Action 28 for the lower part of the river. Both the inspection and detailed survey/analysis of the river has been completed by City Council engineers and the report issued. The new culvert at Black Robin Kingston, currently being installed by Kent County Council, will have some four times the capacity of the original structure. The actual maintenance by the riparian owners is now well under way and considerable improvements have been made along a number of lengths of the river through the villages. All bridges and culverts have been cleaned out by Kent County Council. KCC Bridges have surveyed and reported on all the structures and, together with the City Council, will shortly issue a report on the short and long term works proposed. It is likely that improvements to the culvert at Frog Lane Bishopsbourne will be the first priority and that the culvert at Valley Road Barham will also be proposed for improvement in the future. Other improvement works by the City Council, either under way or soon to commence, are channel deepening and improvements downstream of Bishopsbourne, flood wall at Barham plus a number of local drainage improvements in conjunction with Kent Highways.
March 2002 Review Considerable improvements have been made to the river by the riparian owners in clearing it out and improving the channel. There are now only two lengths where some further works are required and these are not serious problems. All bridges and culverts, both KCC and private, have been cleared out. A joint CCC and KCC investigation into the capacity of all the bridges has been completed and a priority list has been drawn up - its action will depend upon KCC financing and benefit cost analysis. KCC has made funds available for the first item on the list, the Frog Lane culvert at Bishopsbourne. The works have been designed and a start could have been made but there are land problems with the downstream owner. The Black Robin culvert and the adjacent river improvements have been completed. The City Council has carried out a number of small and medium sizes improvements to the river at Barham, Kingston and Bishopsbourne. For some of these the Parish Council and KCC Highways has contributed to the cost.
30 : Nailbourne Sewerage
Conclusion Inundation of the foul sewerage system by flood water causing failure of pumping stations and pumping raw sewage into the river has been a major concern to residents as it continued over such a long period at nearly all the villages along the Nailbourne and Little Stour. Particularly in February 2001 there were a number of houses that had previously escaped problems that were flooded from the sewers. Residents advised that even prior to last year there had been indications of infiltration of ground water into the pipelines and that they considered the system was becoming worn and running at over capacity.
RecommendationSouthern Water needs to fully investigate the situation and carry out works to improve the infrastructure. A cctv survey of the whole system should be carried out and leaking pipelines replaced or relined. A review of the system's capacity is needed to ascertain any upgrading works to both pumping stations and sewerage.
Action Southern Water has carried out some localised inspections and repairs to damaged pipework and is considering carrying out cctv surveys in all villages to check for cracks and significant displacement of pipes.Since the flooding ceased there have been further reports of failures of the system and a list of known problems is being compiled by the River Management Group for Southern Water's action. There are no proposals at this time by Southern Water for major improvements to the system as the company considers the system has the capacity for normal operation.
March 2002 Review Southern Water states that they have completed all their investigations into known and reported leaking and damaged pipe locations. Where any problems have been found, repairs have been carried out. Southern Water has reiterated that it considers the Nailbourne and Little Stour sewerage system is in adequate condition and no major improvements are proposed. The company states it will continue to react as quickly as possible to any pumping station problems and that it has an action plan, based on the lessons learnt from last year, to quickly bring into operation additional pumps and equipment should there be future flooding of the Nailbourne.
