Although the River Thames and others in London are much cleaner than in the period before the building of the network of sewers by Sir James Bazalgette in the 1860’s, there are still problems of pollution due to the heavy demands placed on the capital’s waterways. It’s having the effect of forcing leisure users such as kayakers and small boating enthusiasts out of London’s rivers at times.
Unfortunately, pollutants and contaminants are getting into the rivers, and on some occasions can cause them to be quite unpleasant for kayakers and other users in close proximity to the actual water.
Why are pollutants getting into the rivers?
London’s sewers are struggling to deal with the amount of water during times of heavy demand. Due to the increase in the hard surfaces as the capital has expanded over the years, and a population four times the size the present sewers were designed to cater for, the overflow system cannot cope.
This has the effect of raw sewage entering rivers such as the Thames just as it did back in the days before the Victorian sewers were built. Because surface water has nowhere to go due to the increased hard surfaces, it enters the river untreated so materials such as oil, diesel and other matter washed off the roads finds its way into the water.
Around 39 million tonnes of sewage enters the Thames alone each year and generally stays in the river for several weeks before eventually emptying into the sea. This explains why the river is less habitable following heavy rainfall – periods of heavy demand cause the overflow system to kick in with the result that water and sewage enters the river.
Domestic appliances such as automatic washing machines and dishwashers sometimes discharge their waste water directly into rivers instead of at local sewage treatment works if they haven’t been plumbed in properly.
The confusion here sometimes stems from understanding the difference between surface and foul water sewers. Appliances should be connected to foul water sewers not surface water sewers; these are only for rainwater.
Thames Water targeted the area of Chingford some years back where it was thought around one in ten houses had appliances incorrectly connected.
Other inept plumbing can contribute to poor river quality such as incorrect plumbing of toilets, baths and sinks undertaken by inferior plumbers and DIY enthusiasts with insufficient knowledge.
Householders misusing the drains
Some people are careless in the way they use their drains – or a drain near their home. Pouring dirty water or worse down the drains contributes to the river pollution. In recent times there have been cases of huge deposits of fats and other substances requiring a major clearing away job under the streets of UK cities.
Apart from helping educate householders to use drains properly and ensure their appliances are connected correctly, there is a major upcoming engineering project that should help the capital’s water pollution.
Construction of the Thames Tideway Tunnel is due to commence in 2016. This 15 mile long ‘super sewer’ – stretching from Acton in west London to Stratford in the east of the capital – is designed to help combat the overflow problem. Thames Water claims that the amounts of sewage entering the Thames during periods of heavy demand will reduce by around 97%.
It won’t be completed until around 2023, but the hope is that it will make for a much cleaner River Thames.
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Fraser Ruthven is the Marketing Associate for London Drainage Facilities, one of London’s leading drainage companies. London Drainage provides a wide range of drainage diagnostic and repair services in and around London.