Flood warning: after six years, Riddlesdown works set to start

Yesterday’s heavy rain – with a month’s rainfall in 24 hours – exposed again flooding issues around the borough

More than a month’s average rainfall was deposited on Croydon and parts of southern England yesterday, exposing once more the areas of the borough more prone to flooding, and in many cases also illustrating the failures of council contractors’ to carrying out routine unblocking of flood drains.

While much work on major roads falls under the responsibility of Transport for London, on routes which are the borough council’s responsibility, that comes under the control of Steve Iles, who was awarded an MBE for all the hard work of his staff and department during the extensive Croydon floods seven years ago.

Some parts of the borough are worse affected by heavy rainfall than others, and since the Kenley floods of 2014, when the Bourne overflowed on the A22 causing flooding all the way to Purley Cross for almost two weeks, there have been regular promises of flood alleviation work. Some have happened. Most have not.

There’s been plans for six years to carry out work to reduce flooding around the area of Lower Barn Road, Mitchley Avenue and Ridlesdown railway station.

According to ward councillors, work is now scheduled to begin on Mitchley Avenue on July 24, and will take until September 16. The engineering works will endeavour to prevent or reduce the flow of water down Lower Barn Road.

There have been promises  of flood alleviation works at Riddlesdown for at least six years

“Unfortunately, there will be some cross-over with the school term but most of the work falls within the quietest travel period,” according to ward councillor Helen Redfern.

“I met with the council director for public realm, together with a representative of Riddlesdown Residents’ Association at the start of the month,” Redfern said.

“We have yet to see the final plans but enough people have asked me whether it’s going to happen, for it to seem right to share the news that we already have. Hopefully, this time the project will go ahead after several false starts!”


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11 Responses to Flood warning: after six years, Riddlesdown works set to start

  1. seandeclare2782 says:

    It is 7 years since the Bourne rose above ground in Woldingham, which lead to severe floods in Kenley & Purley. I was watching and waiting for the 7 year cycle to repeat itself earlier this year . It has not happened – yet. I live on the banks of the River Bourne which is sourced from the pond on the junction of Limpsfield Road and Hallilloo Valley Road.

    • The seven years we calculated is a long term average rather than a regular cycle. As with many weather related events you could get an event in successive years.

      • seandeclare2782 says:

        I have lived here since 1985 and there is no doubt the underground Bourne has risen at the rail viaduct in Woldingham every seven years without fail since then. In this century in 2000, 2007 and2014.

        Surrey County Highways have spent a fortune over the last three years, in Woldingham building three artificial lakes complete with dams to allow for it to flood to reduce the flow into the drainage system beneath Wapse Lodge roundabout .

        S.E.C. extract drinking water from the Bourne at Kenley , which is sold to us through our taps after treatment

        • You obviously don’t know what my role was at Croydon from 1987 to 2010. The “we” in my post is the clue and the records we had go back many years.

          • seandeclare2782 says:

            I am well aware of all the records and documents published by Croydon Council contractors in compliance with the flood prevention act .

            I have no idea what your role was or is but it is a fact that very little has been done to prevent flooding in Kenley or Purley. Surrey County Council spent a fortune clearing blocked surface water drains in March 2020. They were lucky the Bourne did not rise, as at one time it was only 1.2 metres below the surface at the Woldingham rail viaduct. ( Environment Agency figures )

  2. Micky D says:

    Well if Mr “I’m so important” Iles is involved in these works, I guarantee they don’t solve the flooding problems!!

    It’s the guys and girls who were actually out dealing with the floods on Godstone Road every day seven years ago that should have got the MBE, not the over promoted, underqualified former Council storeman Steve Iles!!

    • seandeclare2782 says:

      Well said. all traffic was diverted for about a month, and Boris came to have a look as Mayor of London

  3. Lewis White says:

    The Bourne was long-reputed to rise around every 7 years, and that matches my memory prior to the more recent past. Seandeclare has confirmed it has been rising at this interval in the last 14.

    The Bourne is ground water- rainfill falling on the land in the Caterham and Woldingham area seeps down to fill the pores and cracks in the chalk rock, saturating the porous rock, and raising the “water table” in the 1000 feet thickness of the chalk. When it fills up to meet the surface, it breaks out in a very beautiful manner in the valley bottom, just up from the railway viaduct about 3/4 mile East of the Wapses Lodge roundabout. Just a shame that this stream crystal clear water does not flow all year and that the Victorians built loads of houses right in the valley bottom, so the residents get flooded.

    If Climate change results in a lot more winter rain, we should expect the Bourne to rise more. If we get a huge amont more, it could even flow all year. . It would be good to see as much as possible of the bourne to flow in a natural way, above ground, in a “Bourne Linear Park”.

    Many roads in our hilly area now are torrents in heavy rain.

    Much flooding in our area seems to happen on roads where the road gullies are blocked. Any roads built on the chalk will be drained via road gullies to “soaakways” located underneath the middle of the road. As these are generally now 100 years old, how many of these are silted up ? Perhaps David Wickens could comment on both factors ?

    Another, increasing problems is the replacement of front lawns and flower beds with impervious surfaces like concrete, block paving and tramac, in order to build car parking spaces, plus the twin enviro-menace of plastic astroturf laid on concrete. Rainfall once soaked in to the soil, to provide water for trees and to refill the aquifer. Now, in a the concreted over world, the water flows off instantly into the street. The area of hard surface has massively added to the aleardy huge area of hard surfaced street, and the many house roofs which drain onto the front gardens

    Sadly, Government’s atempts to introduce controls to stop rainwater flowing off front gardens have so far been ineffectual. Any new block paved or tarmacked front garden is meant to have a line of channel drainage with slotted gratings, each terminating in a mini soakway on the private property. In reality, few soakways are really installed. The drainage chanels just fill up with water and then discharge over the highway, which is actually illegal under the longstanding ” Highways Act” as far as I recall.

    In my view, tedious as it woukld be be as a process, each “front garden paving project” big enough to house a vehicle should have to have “planning permission”. There would need to be a simplified “Mini Planning Permission” for this purpose. The soakway construction would need to be checked by a loal government or approved inspector prior to approval.

    Not a vote winner. A cynic might say ” It will only happen when the ground floors of politicians and their supporters start to drown regularly.”

    Sad, but perhaps true.

    • Mr. White has a very romantic view of the Woldingham Bourne rising under the rail viaduct in Woldingham. It is caused because the underground flow of water from the Halliloo Valley and the Marden Park Valley meet at the rail viaduct and rise above the surface because the foundation of the viaduct block the flow underground.

      It is also most certainly polluted by grazing animals , garden weed killers and oil run off the road surfaces.

      It must also be pointed out that Sutton & East Surrey Water extract water from the chalk substrate at Kenley to provide us with drinking water.

      During heavy rain surface water flows through a number of open gulleys and underground pipes from Caterham to Purley. The open man made gulleys on that route are often thought to be “The Bourne”

      Yet another work of fiction to perpetuate a long standing superstition.

    • Croydon Council also granted consent to build the large block of flats on the old Ann Summers site in Kenley which lies in the flood plain of the Bourne and adjacent to the gulley which carries surface flood water on the the other side of the railway line

    • Lewis is correct that in the south of the Borough highway drainage and no doubt private rainwater drainage systems drain to soakaways in the chalk substrate. Around 2008 I lobbied for an increase in my drainage sections funding for cleaning soakaways of accumulated silt. That programme was ongoing when I retired. The gullies and their cleansing is crucial to catching and stopping silt from entering the soakaways and reducing their capacity. This cleansing was not one of my responsibilities so I cannot comment on the frequency other than to say that flooding risk areas received more frequent cleaning. As to age of the soakaways, it varied as we had a programme of installing new ones in areas where flooding was a higher risk. However some would be as old as the road they served.

      The hydraulics of the Caterham Bourne are much the same as other “Bournes” and Lewis has described them very well. Finally and exactly as Lewis has said, one of my Directors once said “there are no votes in drains”.

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