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Renewable Energy: Fish passes

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1 to 18 of 18

  1.  
    • CommentAuthortony
    • CommentTimeMar 27th 2014
     
    Fish passes are required whenever a hydro turbine is installed.

    My problem with this is how do fish and eels get up the river now?

    The biodiversity of fish and aquatic species on English rivers would seem to be good and in general identical above and below the vast majority of weirs and locks.

    The cost of fish passes is high and will run into many millions of pounds for in my view no perceivable gain.

    Makes me wanna leave Europe.
    • CommentAuthorJonti
    • CommentTimeMar 27th 2014
     
    Tony,

    I think you will find that a lock or weir is easier to negotiate for river wildlife than swimming through a turbine. However, I am amazed how the fish passes cost as much as they do as they are really quite simple to construct.

    Jonti
    • CommentAuthortony
    • CommentTimeMar 27th 2014
     
    £100,000 each I'm thinking of coming out or retirement and starting to install them!
  4.  
    What's the background here? ie I'm interested but know little.

    Ferdinand
    • CommentAuthortony
    • CommentTimeMar 28th 2014
     
    Hydro schemes on the thames, but it is EA applying EEC directive on biodiversity on the river Thames eels, salmon and lamprey, they can all get up the river now!

    £100,000 per weir, x number of hydro schemes = millions. I like biodiversity but what difference does a hydro scheme make? Is biodiversity lacking now on this type of river??
    •  
      CommentAuthorSteamyTea
    • CommentTimeMar 28th 2014 edited
     
    It all depends on how they are changing the weir.
    Most weirs on the Thames have two parts, the gates that are used to control flow and the actual weir. If they take the weir part away and fit turbines where the gates were, then they have taken away an area of slower moving water.

    I used to kayak on the Thames in the 1970, never seen a fish jumping up the weir, though it is a lot cleaner now than it used to be. 1976 it was a stinking ditch with dead fish, alga and foam over large tracks of it. Water was warmer though.

    Some eels can cross land, but trout and salmon can't. If there are a lot of Brown Trout in the river that is usually a sign that there is a problem. Brown Trout are evil predators and can devour just about anything. If anyone knows Bibury in the Cotswolds and noticed how clean the water is and how many trout there are there and wondered why, it is because they are escaped farmed Brown Trout. They scour the stream clean, no Daphnia left.
    • CommentAuthorJonti
    • CommentTimeMar 28th 2014
     
    What amazes me is the cost. I built a few fish passes out in Switzerland and the idea is very simple, construction easy and materials can be quite cheap. Its not rocket science so why does it cost so much. For £100K you could do one for the Hoover Dam :shocked:

    ST,

    I am sure that in there applications there were many contingencies and measures put in place to ensure that fish could not escape. Therefore, you must be wrong :wink: Seriously though why do they not insist on fish farms been in separate ponds ad lakes to prevent this sort of thing?

    Jonti
    •  
      CommentAuthorSteamyTea
    • CommentTimeMar 28th 2014
     
    Ask them, not me. Though it is hard to stop a Heron picking one up.
    • CommentAuthorBeau
    • CommentTimeMar 28th 2014
     
    Posted By: SteamyTeaIt all depends on how they are changing the weir.
    Most weirs on the Thames have two parts, the gates that are used to control flow and the actual weir. If they take the weir part away and fit turbines where the gates were, then they have taken away an area of slower moving water.

    I used to kayak on the Thames in the 1970, never seen a fish jumping up the weir, though it is a lot cleaner now than it used to be. 1976 it was a stinking ditch with dead fish, alga and foam over large tracks of it. Water was warmer though.

    Some eels can cross land, but trout and salmon can't. If there are a lot of Brown Trout in the river that is usually a sign that there is a problem. Brown Trout are evil predators and can devour just about anything. If anyone knows Bibury in the Cotswolds and noticed how clean the water is and how many trout there are there and wondered why, it is because they are escaped farmed Brown Trout. They scour the stream clean, no Daphnia left.


    Thought all trout farming was Rainbow trout. Brown being the native species that sometimes become migratory and are then known as sea trout.
    •  
      CommentAuthorSteamyTea
    • CommentTimeMar 28th 2014
     
    I think (was a long time since I was at the rout farm) that Browns are farmed too. I think the Rainbow is a premium product.
    • CommentAuthorBeau
    • CommentTimeMar 28th 2014
     
    Looks like they are farmed for the purpose of stocking lakes and rivers. The rainbows are farmed for the table.
    • CommentAuthorBeau
    • CommentTimeMar 28th 2014
     
    Tony said

    "My problem with this is how do fish and eels get up the river now?"

    in some cases with difficulty. I sat and watched a Salmon trying to jump up an old salmon leap. It would jump every 7 mins for hours and I suspect never made it. I recent hydro project has seen this replaced with a more navigable one. As an ex fisherman I am happy to see efforts made to improve Salmon migratory route from sea to redds improved. The fish passes I have seen are quite major constructions so don't think £100,000 sound shocking.
    • CommentAuthorJonti
    • CommentTimeMar 28th 2014
     
    Posted By: BeauTony said

    The fish passes I have seen are quite major constructions so don't think £100,000 sound shocking.


    Beau,

    that maybe so but they do not have to be 'major constructions' I suspect they cost so much because those spending the money are not spending money that is their own.

    Jonti
    • CommentAuthorBeau
    • CommentTimeMar 28th 2014
     
    Yes I have only seen a few and I am sure they vary in construction a lot. The rivers here are spate rivers so the passes have to be pretty tough.
  15.  
    If a fish pass costs that much maybe it would be less expensive to install Archimedean Screw hydro turbines, like what has been installed at a private estate where I grew up.

    http://ecoevolution.ie/blog/shanes-castle-green-generation/

    Not sure what the inital cost to the O'Neills where as they got a grant - but it seems to be a nice little earner.

    http://www.variablepitch.co.uk/finance/station/1215/
    • CommentAuthortony
    • CommentTimeMar 28th 2014
     
    I am taking about them!
  17.  
    Hi tony

    Aren't you talking about fish passes like this?

    http://yorkshiredalesriverstrust.blogspot.co.uk/2010/09/many-of-yorkshire-rivers-have-endured.html

    The link I gave isn't a fish pass, it's a type of turbine that doesn't need a fish pass as it rotates slowly, is open to the air and so lets the fish pass freely. But it's still a turbine, just not a closed with blades that chop fish up finely type.
    • CommentAuthortony
    • CommentTimeMar 28th 2014
     
    On the Thames all the turbines are Archimedes screws but all have to have fish passes now too.

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