Thames Water’s New Eel Screens

[FishingMagic]

Last Thursday, a number of people from various local fisheries groups were invited to view the new eel screens at Thames Water’s Kingston Advanced Water Treatment Works.
This is Thames Water’s (TW) latest investment across it’s network of water intakes, to fill local reservoirs, so that small juvenile fish, especially eels, no longer get sucked into the pumps.* The ones at Kingston are the largest to date and cost £3.5m to install. The total budget set by TW is £35m by 2021 and these at Kingston should protect up to 30% of juvenile fish from either being killed in the intakes or transferred to the reservoirs.




The old screens still in use, but almost redundant
The existing screens were no more than garden rakes with wide gaps of 50-60mm allowing many fish to pass through once the intake pumps were switched on. They were just designed to remove weeds and have been like that since they were first installed around the middle of the last century and are the same as at many other water company’s intakes.
These new screens are a large wide belt revolving vertically and the slots that allow water through are no more that 2mm wide thereby preventing any eels from being sucked in and most other fish fry too. As the screen rotates to the top of the system, a heavy jet of water cleans off the belt, clearing the slots read for their next immersion into the Thames.
The systems differ at each location with the idea of suiting the intake site, but always with a view to protecting the eel, now a red list endangered specie.

The array of screens.
The day started with a presentation on how the screens operate along with the costs etc. Then EA Fisheries Officer, Darryl Clifton-Day, gave a short presentation on the plight of the European eel and how stocks have plummeted since the 1950s – 1970s. There was a marked increase in 2014 that cannot be explained and it was a hopeful sign that the eel was making a recovery. However, the counts for the subsequent 2 years have again been very poor so the story is still very depressing.
Following a safety advice lecture for the site, everyone had to wear PPEs, fluoro coats or vests, hard hats, safety glasses, gloves, and protective boots, before we proceeded to the see the screens. They are on view to the public from a public bridleway that separates them from the main site and protected behind a high fence. We climbed onto the units, hence the PPEs.



The array from the other side
One question was, what about flooding, would the screens still be of any use or would water bypass them? The answer is, they are designed against all but a once in 200 year flood when water can bypass the screens.
Another point raised was about eel counts and how anglers might help. Martin Salter, representing the Angling Trust, has offered to speak to the ATr people to see if a phone app can be developed that anglers can download and record any eels that they catch along with sizes and location. With anglers cooperation this will be very useful in succeeding years.



Screens and you can just about see the tiny slots


The cleaned belt as it enters the water again
The main benefits of some of these get-togethers are we get to meet people again that we haven’t seen for some time. The social contact is nice, but I got to make contact with the guy who represents the Loddon Consultative who will soon be creating some habitat improvement projects and also caught up with Luke from Thames 21 Charity who are doing some work on a stream with us.
Our big thanks should go to our local EA Fisheries Officer, Stuart Keable, for organising the visit.



The system being explained to John Collins of TVAA

Top:* Keith Arthur and organiser Stuart Keable behind














Source Article...

 

[thecrow]

Good to see some action being taken but disappointing to see it will only stop up to 30% of small fish being sucked into pumps.

Just needs the EA to stop issuing licences to trap European Eels which are on the IUCN Red list as critically endangered and decreasing.

 

[no-one in particular]

I also thought 30% was not great, however, they must have looked at many engineering options and found this the best one for the money. I expect a higher figure could be achieved but probably would cost a lot more. Still, 30% is better than 0%.
Its odd with eels, I catch loads of them albeit in rivers that are close to the sea and the creeks are full of them. I put them back as I don't like them and would rather not catch them at all but I often wonder if they are that endangered, however; to be fair I expect on a national scale they must be or they wouldn't go to all this trouble.

 

[Jeff Woodhouse]

Good to see some action being taken but disappointing to see it will only stop up to 30% of small fish being sucked into pumps.

No. perhaps I worded that badly. It will stop almost ALL juvenile fish being sucked in, that would have represented 30% of juvenile fish in the river. The only creatures that would get through are larvae just hatched, once they become fry, they would be too big. Sorry for confusion.

Just needs the EA to stop issuing licences to trap European Eels which are on the IUCN Red list as critically endangered and decreasing.

Agree, but only 8 tonnes are caught in this country now, which is bad enough, the rest required to satisfy demand are imported from Netherlands and France. We need a European law to stop them!
8 Tonnes represents around 16,000 eels averaging just over 1lb, that's 16,000 eels that will never get the chance to make it back to the Sargasso Sea to breed. It is shameful, but apparently "Jobs depend on catching them..."

 

[Alan Tyler]

Do many "European" eels actually make it back to the Sargasso sea to spawn, or are they just waifs and strays on the Gulf Stream, the unlucky portion of a population spawned by eels with a much shorter return trip?
If the latter, any conservation efforts over here are misplaced by the width of the North Atlantic.

 

[Jeff Woodhouse]

Do many "European" eels actually make it back to the Sargasso sea to spawn

Alan, I'll do another article on the eels and include what is known about their migration. I've asked for some supporting documents to show with the piece, I've seen them in talks before, but I don't have the actual graphs etc. They'll be useful.

 

[barbelboi]

That would be very interesting Jeff as, as far as my limited knowledge goes, much of the migration is still a bit of an 'iffy' with things such as parasites, swim bladders, etc., thrown in.

 

[Alan Tyler]

Thanks, Jeff. The last bit I could find in a quick google was dated 2009, by which time eels had been tracked to the Azores area but no-one knew if they managed to hang a right and travel west to the Sargasso.

 

[Jeff Woodhouse]

I had a little correction made by an old friend from TAC, Ed Randall. I've been banging on that these screens had slots 2mm wide, enough to keep out all but the smallest larvae of any fish species, but that's not correct. Sorry!

In the manufacture of these screens, 2mm was the requirement, but the Hydrolux screens purchased had slots just 1.75mm wide, apparently. So even less chance of any fish getting through. I stand corrected, Ed. mg:

Other good news is, Darryl (an EA fish man) has sent along some charts etc about eel counts and some other stuff. So in the next few days I'll try and get something together on eels. I do hate catching them though... hno: