Thames 21 and Kingfisher

Paul and Caitlin with Kingfisher

Thames 21 are an organisation that aims to: connect local communities with their rivers; demonstrate what is happening to them; and design bespoke solutions for them. I have blogged  some of their amazing projects elsewhere see Rainscapes in Enfield
    Ewell storm tank outfall

We are lucky that one of their research projects - using robot boats to  measure water quality- includes  the Hogsmill,  and a boat known as KINGFISHER. The hulls are  made by a company called Platypus' and the first step is to install and calibrate  its monitoring systems. We met last Friday to introduce the superboat to the range of different chemical and other influences presented at different stretches including the various outfalls along the Hogsmill.This included the Ewell Storm Tank outfall   where water quality can be affected by sewage overflow.

sediment from the Bonesgate
The floating labs offer benefits for rivers and local communities and want to stop localised pollution. Ordinary citizens will be able to use the boats to collect research evidence themselves and find out just how healthy their local river is.The sensors and boats will be linked to user-friendly online decision support software providing a chemical analysis, which can be downloaded on a spreadsheet by any of us.

Our rivers are still far more polluted than they should be. Heavy metals leak into them through stormwater from roads, and waste water and sewage from misconnected plumbing and pipes. The Bonesgate flowing into the Hogsmill at Tolworth brings with it  sediment, pesticides and even more nutrients.
The Hogsmill (Epsom and Ewell) Storm Tanks are both located in the upper reaches of the Hogsmill river. The tanks function as temporary storage for untreated sewage as it travels through the network of pipes towards the Hogsmill Sewage Treatment Works (STW). During heavy rainfall, rainwater as well as sewage fills up the system: to prevent it backing up into homes, there are temporary storage systems like these storm tanks, and sometimes overflow pipes into rivers, which help to relieve the pressure. Usually the storm tanks contain the sewage until the rain has passed and the sewage can drain back into the network to be treated at the Hogsmill STW. Occasionally,  the storm tanks fill up completely and will discharge any excess sewage to the Hogsmill river itself see storm tanks overflowing here

In addition, an incident took place on Saturday 27th January 2018, in which sewage sludge from the Hogsmill Sewage Treatment Works was released into the Hogsmill river. Sewage sludge is one of the final products from the sewage treatment process and so it does not contain any rag.

The crew will be out again this Friday and anyone is welcome to join them


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