Catford Flood Risk: The Ravensbourne and Pool Today

The risk is lower than in 1968, but it has not gone. On 15 September 1968 the Ravensbourne, Quaggy and Pool burst their banks and several hundred homes and businesses in Lewisham and Catford flooded. A flood alleviation scheme has been built since, and big storms are now held back upstream, but some low streets near the rivers are still in mapped flood zones. In Catford today the more common problem in a heavy storm is the drains: sewers fill up and push water back up through the lowest toilet, shower or gully in the house. Check your postcode with the Environment Agency, and think about a non-return valve if your drains have ever backed up.

Where do the rivers run in Catford?

Catford is where two rivers meet. The Ravensbourne rises at Caesar’s Well in Keston, runs north past Bromley town centre, through Beckenham Place Park, and on through Catford and Ladywell Fields to the Thames at Deptford Creek. The Pool River, which starts as the Beck in Spring Park and runs through Kelsey Park and Cator Park, flows north through Lower Sydenham and Bell Green and joins the Ravensbourne in Catford. A little further north the Quaggy joins near Lewisham station.

So a storm that falls over Keston, Beckenham and West Wickham all arrives in Catford.

What happened in 1968?

On 15 September 1968, after exceptional rain, all three rivers burst their banks and much of Lewisham flooded. The government’s summary of the Lewisham and Catford flood alleviation scheme describes it as the last major flood there, with several hundred homes and businesses affected. Upstream in Bromley, river flooding the same month hit Bromley, Elmers End, New Beckenham and St Paul’s Cray.

What has changed since?

A lot of work has been done to hold flood water back before it reaches Catford, including the flood storage on the Quaggy at Sutcliffe Park, and the Lewisham and Catford flood alleviation scheme on the Ravensbourne and its tributaries. Bromley Council, upstream, says the rivers in its borough are extensively culverted and that the Ravensbourne catchment has seen floods since 2001, including 40 houses flooded in Bromley in December 2013 when the Ravensbourne burst its banks.

The honest summary: the chance of a 1968 repeat is reduced, not removed, and surface water from intense storms is a separate risk.

Why do Catford drains back up?

Catford’s Victorian and Edwardian terraces, including the long streets of the Corbett estate between Hither Green and Rushey Green, were built on drains that run into older public sewers, some of which take rainwater as well as waste. In an intense storm, the sewer fills. When it is full, water has to go somewhere, and it comes back up the drains to the lowest open point it can find. In a terrace with a bathroom added over the kitchen extension and a downstairs toilet or shower, that lowest point is inside the house.

Signs it is the drains, not the river:

• Water comes up through a toilet, a shower tray, a floor gully or a manhole.
• It smells of sewage.
• It drains away within hours once the rain stops.
• The street has flooded but the river has not.

What is a non-return valve, and do I need one?

A non-return valve, sometimes called an anti-flood valve, is fitted in your drain and lets water flow out to the sewer but not back in. If sewage or storm water has ever come up through your drains, it is the single most useful thing you can fit. It needs to go in the right place on the drain, usually in or near the inspection chamber, and it needs occasional checking so it does not jam. A drainage camera survey first will show whether your drain is in good enough condition to take one.

How do I prepare?

1. Check your address on gov.uk’s “Check your long term flood risk” service, looking at river and surface water results separately.
2. Sign up for free flood warnings on gov.uk if you are near the Ravensbourne or the Pool.
3. Ask a plumber or drainage engineer whether a non-return valve would help if water has ever come up through your drains.
4. Keep your insurer’s claim line and your policy number saved in your phone.
5. Make sure everyone in the house knows where the stopcock and consumer unit are.
6. Keep valuable and irreplaceable things off the ground floor if you are in a mapped flood area.

What do I do if water gets in?

• Switch off the electrics at the consumer unit if you can reach it safely, without standing in water.
• Stop using water if it is coming up through the drains.
• Photograph everything before moving it, including the water depth against a wall.
• Call your insurer for a claim number and ask what they want done first.
• Keep damaged items until the insurer says they can go.

After the water goes down, have the drains, ground-floor pipework and any water heater checked. A flooded gas boiler needs a Gas Safe registered engineer before it is used again, and if you smell gas, call National Gas Emergency on 0800 111 999.

Upstream, our guide to Quaggy flooding near Eltham and Mottingham explains how Sutcliffe Park’s storage works. Our insurance help page covers what a plumber’s report needs for a claim.

Need a plumber now?

If water has come up through your drains or a flood has damaged your plumbing, Call 07868 281022. Tell us your postcode, where the water came in, and whether the electrics and water are off. We handle insurance claims work in Catford and blocked and backed-up drains across SE6, including Hither Green and Bellingham, and we agree the price with you before any work starts.