Fish screens on abstraction intakes at Datchet, Laleham, Shepperton etc.

One of the most important and promising things I learned at the AGM, for me anyway, but which I forgot about almost immediately in the excitement of Duncan's talk, was Stu's mention of fish screens being fitted on the water company abstraction intakes.

We know from one of the fish surveys a few years back that some of the highest levels of biodiversity occur just upstream of the intakes, and the lowest just downstream.  They are literally sucking the life out of the river.  As Stu said, the new screens are quite fine, and arranged over a large surface area, specifically to prevent fish from being sucked through or held against them.  This is brilliant news and over the medium to long term could make an enormous difference to the fish stocks in our river.

I just now did a bit of research and found a few documents:

- Testing of different types of screen, done 2006-2008. Shows several different types of screen and how they performed.  Lower Thames Water Intakes Investigation  AS MUCH AS 30% OF FISH FRY STOCKS COULD BE BEING LOST TO UNSCREENED ABSTRACTION!

- Environment Agency screening best-practice guide (2005)
http://therrc.co.uk/MOT/References/EA_Screening_Intake_Outfalls.pdf
(Mike Depledge, any relation of yours Neil?!)

- Lower Thames Operating Agreement - Sept 2013 - sets out the maximum abstraction quantities allowed at the various intakes and flows that must be maintained over Teddington weir - I'm pretty sure Dave is a bit of an expert on this one having sat through many meetings about it.
http://www.thameswater.co.uk/wrmp/lower-thames-operating-agreement-stage-2-final-report.PDF
this should be available but Thames Water's website is broken at the moment, Google has a cached version though

He's not a relation as far as I know.

Yep - biggest killer of fish on the Thames - way ahead of pollution, cormorants and human fish eaters.

The EA Thames team were also looking at underwater strobes near the intakes to scare the fish away.

I think it was an idea for when funding wasn't available to fit new screens.

Not sure what happened to that idea...does anyone know?

Wow, bit to heavy going for me but I think you will find your answers here Steve, Proper bed time reading to digest the whole lot


https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/297342/geho0411btqd-e-e.pdf

Kevin Russell wrote:

Wow, bit to heavy going for me but I think you will find your answers here Steve, Proper bed time reading to digest the whole lot


https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/297342/geho0411btqd-e-e.pdf

That's an absolutely brilliant link, loads of info in there. There seems to be test data missing for strobes though, so obviously more work to be done.

With continuous lights I see they're worried that will attract fish. I guess they have to fully test that on strobes.