Annual rainfall in our area is about 60cm a year which the the ditch can handle easily. However, if the Thames gets into the ditch , the culvert under Norlands Lane can't handle the volume . Floodwater should have still been able to get both under and over Norlands Lane . There used to be a 900 metre wide flood plain stretching from the Norlands Lane Bridge to Ten Acre Lane that should have assisted drainage. Someone in the EA or SCC must have sanctioned this work to be done.

There appear to be no planning documents held by any of the agencies covering changes to the land drainage of the southern end of the Viridor site. We must therefore assume that no planning application was ever submitted for this work. It's very unlikely that all three agencies ( SCC , RBC and the EA ) destroyed their records at the same time.

In February 2014 we had excessive rainfall. The Thames broke its banks again and overflowed more than normal due to the Jubilee River causing it to flow into the Meadlake Ditch.

Instead of draining south into Thorpe Park and the River Bourne it was seen to flow backwards ( North ) flooding homes up to three kilometres upstream in Egham. This was due to blockages in the culverts under Norlands Lane, a service road inside Thorpe Park and a culvert topped by earth banking 50 metres north of Norlands Lane that diverted the ditch in 1998 . The earth banking above and around the culvert that diverted the ditch is what caused the backflow upstream in 2003, 2007 and 2014.

As previously mentioned , floodwater also failed to drain across the Viridor Landfill Site.

Satellite images show that , despite the level of the Thames falling , floodwater water levels north of Norlands Lane didn't because it couldn't drain away quickly enough. The land 250m south of the Norlands Lane Bridge on both sides of the ditch is dry because raised landfill created banks on both sides of the ditch that were up to 3 metres higher than their original levels making them higher than the floodwater level upstream.

Normally, the depth of water in the ditch is only about 30 cm ( 12 inches ) and between July and September, the bed of the ditch is normally dry . However, in February 2014 the depth of floodwater in the ditch 50 metres north of Norlands Lane was 3 metres.

The Meadlake Ditch drainage problem in the culverts downstream was caused by silt and debris under the Norlands Lane Bridge and the Thorpe Park service road culvert . The silt came from the dewatering plant in the Coldharbour Lane Landfill Site that operated between 1998 and 2012 . There is still a land drainage problem on the Viridor site on the western side of the ditch.

Both culverts were cleared in October 2014 and an extract of the report produced by the divers who dealt with the problem is shown at the bottom of this page.

The full divers report with comments is under this link.

Doug Hill who was working for the EA at the time very kindly arranged for this work to be done . When all of this was going on both RBC and SCC had no idea that this work in progress due to poor communication and lack of interest.

After realising the Meadlake Ditch is classed as a main river, which the EA responsible for, SCC and RBC dropped all interest in looking into whatever could be done to prevent a repeat of the problem.

2. A blocked culvert inside Thorpe Park containing five tonnes of silt and debris.

SILT REMOVED FROM THORPE PARK CULVERT

FLOOD MODEL

DIVERSION CULVERT AND EARTH BANK ( AFTER )

AFTER ( June 2015 ) - CULVERTS REMOVED LEAVING AN OPEN DITCH

6. Lack of maintenance

Saving money that should have been spent on maintenance caused millions of pounds worth of damage to infrastructure and properties upstream.

We hope that the Environment Agency and Surrey County Council learn from this and adopt a higher profile than they currently have by performing regular inspections and using enforcement notices where necessary.

Link to a letter from Surrey County Council to our local MP dated April 2015 admitting they never realised there was a culvert under Norlands Lane and that they were responsible for maintaining it .

6.1 Poor supervision of contractors

The EA and SCC both have a poor track record in getting contractors to complete works properly first time every time . This can only be due to poor supervision and management and they probably pay double or treble when calling contractors back.

7. A concrete beam that restricts the capacity of the culvert under Norlands Lane Bridge was inspected by us in 2017 .

We were informed that the "beam" ( the flat pit at the top of the culvert ) under the the road was either a high pressure gas main or electricity cable . It's actually a joint where the upstream concrete culvert reduces to a smaller steel one.

We know this because we went into the culvert ourselves to have a closer look . The "beam " catches flytipped debris and traps it under the bridge and we estimate that it reduces the capacity of the culvert by about 25%.

All utility companies know what plant they have running over or under a bridge because they have to maintain it.

8. Viridor Landfill Site Landfill Levels

We contacted the CEO of Viridor and visited the problem area with his site manager . He recognised the problem and said he would speak to his technical people and get the land drainage problem sorted . The lowest point in the site is through the main gates entry gates in Norlands Lane.

The site manager wrote to us confirming this but we haven't noticed anything being taken to remove the problem . The site is fenced off and is not open to the public.

Viridor Site Meeting ( September 2017 ) - Email to the CEO of Viridor in August 2017 athat resulted in a site meeting a few weeks later .

Viridor agreement to clear the problem - Email conversations with Viridor Site Manager who agreed to put a flood drainage path in .

9. Twynersh Lakes

Twynersh Lakes 2009 - 2018 - LINK showing alterations made to Lakes 7 and 4 between 2013 and 2014.

Major changes were made to the lakes between 2013 and 2014 . We are concerned because they not acrried out as agreed with local planners. Work was being carried out on this site before , during and after the floods of February 2014. Further recent unauthorised changes have resulted in the flooding of both the Twynersh and Chertsey fishing lakes and also the field opposite the Twynersh Restaurant.

Twynersh Lakes during alterations - September 2014

This is a satellite view of the site after the work . The service road has been routed across Lake 7 which is the main flow route from the Thorpe Park Lakes into the River Bourne. it;s 80 metres west if where it was supposed to be. There are no culverts under the two bridges that are blocked with landfill . An EA representative visited the site a number of time but failed to realise this .

Twynersh Lakes based on a report from Runnymede Borough Council - July 2015

Runnymede Borough Council kindly visited the site and informed us that the planned work had been completed on Lake 4 and that the service road had been built in the wrong place ( 80 metres east of the agreed location ) . They also informed us that there had been changes in the flow channels between the lakes.

We produced this map shown below based on the information they gave us. It needs to be verified with a site visit as it may not be completely accurate .

The moat which is north of the lakes had been blocked.

The feed into the River Bourne from Lake 7 is no longer there

The main Chertsey Lake now flows into Lake 6

The bridging work across Lake 7 has been removed

The Environment Agency have informed us that they had visited the lakes in 2013 and 2014 which was before during and after the work . They failed to notice the unplanned changes which included two bridges being built over Lake 7 that were in the wrong place.

We've asked them to visit the site again and confirm that the new channels and unplanned work have been done properly . They will also check that the channels are big enough and whether there are culverts under the two bridges across Lake 7 . They have also been asked to provide site reports and photos to prove that they had actually visited the Twynersh Lakes in 2013 and 2014.

CONCLUSIONS

The Meadlake Ditch is the main drainage channel for Egham Hythe . It has caused flooding on three occasions which were all due to man-made problems . The Environment Agency and SCC have failed to tackle these problems and recently we were alarmed to hear that that they were actually condoning them.

The lack of action is shameful but this seems to be a national problem because similar incidents have been mentioned elsewhere. The common thread is the Environment Agency and poor communication between agencies.

The EA and SCC and RBC need to be very clear about what they are actually responsible for so they can be held accountable. If they are not capable or prepared to use their enforcement powers they should be disbanded and replaced by a more dynamic organisation that is fit for purpose.

We are aware of all of the key locations along the watercourse that need monitoring . In the event of future flooding we will provide evidence to enable Egham Hythe Residents to seek compensation retrospectively. It's a shame that we may have to wait for another tragedy in order to prove our point .

If you have any concerns please contact both your Runnymede Borough and Surrey County Councillors to find out what they are doing about the problem. At the moment you will probably find that they are doing nothing.

A Facebook page will be set up soon to allow two-way dialog between the Flood Group and local residents .

John Simmonds

The Meadlake Action Group

meadlake.action@gmail.com

c/o The Compasses Pub Egham