Monday, 5 September 2016

More on Sewage and something on Bream

As a recap, there was a large spill of sewage onto Green Lane Recreation Ground and the Hogsmill river 8.2.16, when 2,500 bags of waste were removed (posted 21.2.16). Since then it has continued to be bad news for the Hogsmill river, with sewage entering the river every month (see: sewage spill into the Hogsmill River 19.4.16; spates and sewage 23.6.16).

Much of this has been via the 'channel of cess' on the north-east bank near California Road as well as other surcharging manholes. But a large release of sewage occured last Thursday, in the early hours of the morning from the final settlement tanks. Something of a puzzle is that an amount of rag was also noted, which should not be associated with the final stage of sewage treatment. 

As usual this has largly gone  uncommented upon. This silence is not commensurate with the large amount of sewage that has entered the water course.  On the tiday Thames there are regular announcements for rowers when there is a spill see http://www.rivertac.org/thames-sewage-events/ http://sdn.rivertac.org/ Thames Water re: Hogsmill say......
How it will impact you/environment?
  • Based on our initial results from water testing we have been advised that any discharge has quickly dispersed and no further remedial action, such as aeration, is considered necessary.
  • There may be increased traffic on the local roads as we tanker out the liquid waste over the next 4 days.
rag hanging from trees
weed and rag hanging from trees
The inadvertent release caused a rise in the river level, which can be see here from the amount of weed and rag hanging from trees. 

This appears to be at least a metre above the current water levels (40cm at Villiers Road).

In order to validate the observation in the level of the rise, depth and flow date has been requested from the Environment Agency. This is provided from the gauging stations and can be seen in real time. https://flood-warning-information.service.gov.uk/station/7266

 

During sewage discharge events it is important not to use the water to water vegetables if you have a riparian allotment or garden and take care fishing (especially if you smoke)!

Bream netting, dehooked
and gently released
There has been no obvious affect on the chub at the Clattern Bridge or the shoal of bream that hang around the confluence with the Thames as a few days later these amazing bream  were caught by some  well informed young chaps!




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