Theo Thomas, from the Thames 21 clean water campaign group Love The Lea, has provided this blog post explaining the background to the pollution of several local water courses - and the action underway to rectify the problems.

Enfield has the most rivers of any London Borough and some of the most polluted. But it could become the Capital’s first River Friendly Council - and it must - the rivers are getting sicker.

Enfield Council is keen to take action which is great. The shocking sewage pollution of Pymmes Park Lake in November 2012 made it clear that it can take a stewardship role and be a voice for the rivers. The local newspaper reported that sewage got into the lake because a device to prevent polluted water from people’s homes ended up diverting sewage the wrong way.

The rain drains that take the water from the streets around Pymmes Park are contaminated by waste water from people’s homes. Rain water from 4,369 properties feeds Pymmes Park Lake. If this was just rain it would be a healthy source of water that would renew the lake. But just over 5% of homes are misconnected. This includes wastewater from 60 washing machines, 54 sinks, 25 dishwashers, 10 toilets and 9 showers.

These have all been detected by Thames Water and the Environment Agency and so far 162 have been sorted out by the people living in the property. 21 have been sent to Enfield Council’s Environmental Protection department for further action (it’s the home owner’s responsibility).

In 2004 it was decided that while these misconnections were being resolved it would be a good idea to divert the polluted water away from the Lake to the sewer. To do this a ‘dry weather flow diverter’ was installed. During wet weather the larger amount of water would still flow into Pymmes Park Lake.

Unfortunately in November the sewer became blocked. As it backed up it got closer to the diverter. Without the diverter the sewage would have come out of a manhole cover and have been quickly noticed. Sadly it reached the diverter and went into the Lake. The Environment Agency investigated the event and called out Thames Water who unblocked the sewer, pumped out the sewage and pumped in oxygen (levels of dissolved oxygen had fallen to zero). The diverter has now been adjusted so it can’t happen again.

Whilst Thames Water is close to solving the misconnections evidence from other places in London suggests misconnections start to come back because people don’t know that it’s possible to send your waste water to a river.

Without this awareness people can’t make a choice. This is one of the reasons behind the Love the Lea campaign. We also need Enfield Council to use its website, newsletters etc to tell people about their rivers and how they can help them. The advice on the Building Control section of the LB Enfield website should have more information about misconnections. These actions won’t cost much as it uses existing resources, but they are crucial in reaching people. The meeting the Council called in the wake of the Pymmes Park pollution will take these actions forward.

We’ve met with Enfield Council’s Building Control staff – they carry out inspections on homes that have extended the property or converted rooms. The brilliant thing is that Enfield Council’s Building Control Department always checks the drainage and makes sure it is put right if a washing machine is sending its water down the drainpipe and to a river.They’ve been doing this for years and so misconnections are about 5% of properties. In Haringey they are up to 10%.

People from Environmental Protection were in the meeting too. When they see homes with bad pipe work they knock on the door and inform the person living there. The majority of people get it put right as soon as they can. In the majority of cases it is a simple, cheap job.What this tells me is this – if a Borough addresses water pollution in this way the incidence of it drops. Other Boroughs have many more misconnections. Secondly that if people don’t know about it they can’t put it right, but when they are told about the misconnection they sort it out. And lastly that fixing it is most often cheap.

The perception seems to be that it is expensive and complicated. In many cases it is just switching a dishwasher or shower pipe to the next drain along.

Check the Misconnection website www.connectright.org.uk. While most rain water in Enfield Borough ends up going to a river, too much still enters the sewers. Not only can this cause local sewers to overflow (for example Slades Rise) but it causes Deephams Sewage Works to spill over into the Salmons Brook, Pymmes Brook and the Lea. Deephams takes the sewage from everyone in the Borough. It is due be upgraded so it can treat the sewage to a higher standard which is great. But when it rains it has to deal with up to six times the dry weather flow. This space should be for sewage, which would also extend the life of the upgrade. We need green drainage across the Deephams sewage catchment as well as the upgrade.

Montoring and updating will continue

What you can do

To support the campaign:

• Sign the Pledge to Love the Lea
• Download and share our handy Love the Lea campaign leaflet and help reduce river pollution
• Like the Love the Lea Facebook Page
• Follow on @TheoJThomas on Twitter
• Keep in touch at the Love the Lea Campaign Site

Kind regards,
Theo Thomas