Water Clarification Project

[batrabill]

https://www.theguardian.com/uk-news/2019/may/11/bio-manipulation-to-restore-clear-waters-of-norfolk-broads?CMP=share_btn_fb

[MauriceMynah]

I hear alarm bells here. I usually do when I read gobbledygook.

"Now a new “bio-manipulation” project aims to restore clear waters to Ranworth Broad and Barton Broad," … Didn't Barton Broad have an awful lot of money spent on it doing just that?

"paving the way for the return of osprey, common terns and rare aquatic plants currently thwarted by the murky depths." ….And just how will the RSPB treat boating activities if Ospreys are seen on Barton?

"Predators such as pike can no longer hide among the plants, leading to unnaturally high populations of roach and bream. Roach feed on the zooplankton which would ordinarily eat algae" … Ahhh so Roach are a good thing. :-)

"Predators including pike and osprey will reduce the impact of the grazers – zooplankton-feeding fish – by moving them around more." … ahhh so Pike and Osprey are a bad thing?  :-(

"Forty years ago, conservationists closed off one of the Broads’ freshwater lakes, Cockshoot Broad, from the main river system to restore its water. Cockshoot’s water is still clear,"  Hmmm, So it's boats that are to blame.

 

Well, you all know I just love a conspiracy theory, and I smell a whopper here. 

They want to reduce the roach and bream population. They want to increase the Pike population. They want an Osprey population and Little Tern population. 

Well those alarm bells just keep on ringing.

 

[Poppy]

"Areas of both freshwater lakes equivalent to the size of 24 football pitches".  My alarm bells started to tinkle as well. The entire area of Baron Broad is a statutory navigation, NOT just the marked 'channel' and it is widely used, not only by 'saileys'.

[grendel]

Why does this strike me as having a great potential to go horribly wrong? - even if it does achieve its goal, it seems a little too close to playing god for my liking, surely the correct thing to do would be remove the root cause (they mention fertilisers draining into the waters, rather than playing around with the eco balance?

a lot of other factors have changed since they closed cockshoot broad and cleaned that, dredging practices, etc

was cockshoot ever open to boaters? and is it still open to boaters? hmm that could be a bad precedent to follow.

[Malanka]

Because Grendel my friend they have absolutely no idea what will actually result. 

A few questions first of all.

1.why is there a presupposition that clear waters are preferable? 

2. Who decided 1 on the basis of what? 

3. As clear and or murky waters have completely different micro ecologies why is it a good idea to suppress one in favor of another unless in an attempt to provide a habit for species not YET resident in the area is the goal? 

4. What is the goal of all these projects to introduce apex predators into what are artificial however reasonably stable ecosystems. Sea Eagles to the Isle of Wight, Ospreys and so on? Maybe someone doesn’t like how successful the otters have been or maybe they didn’t figure out how successful they would be. 

For an Apex predator anything that’s within its weight capability is a target, lambs, small dogs, otters, geese, ducks, wildfowl in general.

It wasn’t long ago we were talking about where have all the wildfowl gone and now more raptors ? 

If as the article claims the initial causes of the algal population levels have now been removed or as they say controlled then why is this necessary at all. Leave it alone it will clear in its own time as anyone with a large pond can tell them, unless there is another reason? Who knows..

Oh well who am I to question? Better to just keep my head down in “open forum” and let my betters decide eh? 

M

[MauriceMynah]

Martin, you will be delighted to read that I am in full agreement with you. Just thought I'd mention that.  :-)  

[Malanka]

Always delighted John. It’s what friends are, those that can’t stay calm whilst disagreeing should not hit send... LOL 

[Vaughan]

5 hours ago, grendel said:

was cockshoot ever open to boaters? and is it still open to boaters? hmm that could be a bad precedent to follow.

The dyke certainly was, in the 50s as the lease was owned by Blakes, so it caused controversy when it was closed off. I believe boats went on the broad as well, but not to moor.

The Cockshoot experiment was one of the first attempts at mud pumping, where all the silt is removed by a suction dredger. This, allied with improved water quality, allowed the sun to get through to the bottom, and the weeds to grow. I am sure this had nothing to do with the poor old roach, as there was no longer any silt for them to stir up - even if they do actually stir it up, to any great extent.

The same effect will also be seen when dykes are cleared out in the fields, to maintain drainage. Lovely clear water, and lots of pond life!

You don't need to be a university expert, to know that.

 

[webntweb]

Just been looking through some old Hamiltons. They rarely had a date on them so it is difficult to work out what year each edition is.

My edition 14 does have a date of 1961 and the map shows Cockshoot Broad closed and chained. My edition 7 doesn't have a date but is possibly older than 1954 as I don't think they published annually; this again shows Cockshoot Broad closed.

As Vaughan says Blakes had the lease on the dyke moorings then and for some time after.

 

[Malanka]

lol Vaughan what’s a university expert? 

In my experience they have a tendency to be a little academically inclined. One of the reasons I left that world behind. 

 

M

[marshman]

Incidentally it is, Ranworth Broad they are talking about and not Malthouse i guess.

[JennyMorgan]

10 minutes ago, marshman said:

Incidentally it is, Ranworth Broad they are talking about and not Malthouse i guess.

And Barton.

[marshman]

I know a bit about Barton - I am also a little sceptical of whether it will work or not.

Well I know it will work, as the existing fish barriers worked well  originally, but the trouble is momentum was not maintained and gradually they became a little like the rest of the Broad - having taken the fish out which they need to do that regularly as fish find their way back in, and it needs doing again. And again and that did not happen.

I know some people will always be sceptical, but almost all ecologists, would agree that clear water is best for almost everything, - anything is better than the turgid stew that exists outside the barriers. 

The BA regularly carry out plant surveys throughout the Broads and rivers and you would be really surprised how few have much at all - perhaps some would like it like that, but even not being an ecologist, even I can see the benefits of having a healthy underwater environment. Clear water really does improve the underwater weed growth and it is that that maintains the balance.

Incidentally ospreys do not need to be introduced - they come through Broadland on their annual migrations and one was resident for most of last year on Ranworth /Cockshoot. As to Sea Eagles? I don't think that will happen here and realistically, see little real pressure to do it. 

[Malanka]

I’m afraid I don’t know all ecologists or even almost all and so I wouldn’t know what to agree with or disagree with. But perhaps you might wish to discuss with the hundreds of ecologists you have canvassed on the topic the relative turbidity’s of the North Atlantic Ocean and the Pacific Basin then relate that in terms of productivity. N.B. You will be surprised, I know I was when I found out this fact 38 years ago.

Never a good idea to make an appeal from Authority especially one based on a fictional extended quotation, which if you care to research further will soon discover are both logical fallacies. 

When you presume to say “a healthy underwater environment” ask for which species, the fluffy cuddly ones or the ones that turn the water into a “turgid stew” whatever that is supposed to mean?

If what you meant to say was that you would prefer to see the water as clear as it was many many decades ago then just say that, please don’t decorate your desires, as justified and fully supported by me they may be, with fictitious or presumed agreement from “ almost all ecologists”. It lessens your argument as the use of “scientists say” does which is usually then followed by something that in fact not many scientists would or even have said. 

Clearer which in terms of this debate is perhaps the wrong word, is a better environment for some fish and some plants, however bogs are great too and have a diverse and thriving system in their dark and murky depths. It’s just not recognized as pretty or popular with the BA who have set their criteria as plant diversity and density levels. Clear waters with oodles of plant growth will present a whole raft of new issues the BA currently do not have to deal with with the exception of a few higher reaches. What you are discussing is a reduction in the dispersed algal population. Not great for the algae but fish are more marketable i’ll admit.

Give Barton chance and the nitrate / phosphate reduction and control measures will work on their own. The water didn’t become a turgid stew overnight, black water tanks and fertilizer control measures will work. Eventually.

You are correct in that high impact  immediate actions will not work on their own as the water system soon returns to its climax state after the pressure in one direction is removed via the natural equilibrium of natural systems. To give them a boost “ if that is what we want” is long term and very very expensive. Personally I would prefer to see more dredging with the money available and leave the water system to recover slowly and sustainably ( cheaply) to a new equilibrium climax state all by itself. 

[Poppy]

It would appear that all is not as the newpaper story tells us.  The existing barriers are now well 'past their best' and are to be replaced in the present locations , well as far as Barton Broad is concerned.

This should have no impact at all on the navigation, thankfully.

[Regulo]

Shouldn't worry. The rate the reeds are encroaching into Barton, it won't be there in 30 years time! (Wanted to put an emoji here, but it won't work for me).