Featured post

10,000,000 Miles in a Nissan Leaf?

Monday, 13 May 2013

 Why Don't you just Share the Water??

This is the question that many of you may be asking and of course it is very relevant.

This is what happened.

A few months after we bought the Mill - we offered to do a 50:50 joint scheme on the recommended north end of the weir with Weaver's Mill but they rejected our proposal on the basis that they were intending to make a "DIY Kaplan" turbine (1)

In March 2010 the EA told us they were minded to refuse our license as they didn't know what to do!. We offered to reduce our water usage from 10 m3/sec to 6.8 m3/sec flow  - but we wanted "first call" (2) on the water as we were ready to go- Weaver's Mill were not.- Nothing happened- no response from the EA!

The EA fought the first Judicial Review partly on the basis that there was not enough water for two schemes. We even had a meeting about it with all parties- the outcome of which was that there was still not enough water.

Through FOI we were given two emails from Weaver's Mill stating that due to' financial constraints and access issues' they could not mend the weir if it failed or indeed, it must be assumed - perform significant maintenance involving heavy civil engineering activity - on this basis the regular clearance of a 12mm mandatory debris screen would seem problematic...

One has to wonder how the EA could rationally consider a "split scheme"  when one party volunteers an inability to both finance weir repairs and physically maintain their scheme. We have asked if this is still the case - but the EA state this is "not in their remit" - as the owners of half the weir - it's something that obviously concerns us...

Since the High Court Consent Order the EA have tried to force a split scheme (which actually conflicts with the EA's obligations in the consent order...)   - the EA were even happy to go against their own published GPG (3) as in change the flow arithmetic arbitrarily to 1.3 times Qmean (3) ,- without Advertising (5) ,- knowing that due to control issues - the turbines would be unstable and "fight against each other" - and that they could not impose control of "Hands off Flow"- even when they knew that the consent order stated one scheme.

Imposing a split scheme would have possibly ended the immediate "administrative problem" for the EA but would have left the rest of us and the likely the environment in a complete mess.

So why don't you have one scheme and share?

  •  Animosity created by the EA's assorted manoeuvrings certainly hasn't helped!
  •  Technological Differences -We had been told by the EA that Archimedes Screws are they way to go - Weaver's Mill insist on their own  "DIY Kaplan" turbine (1)  ( we are not confident this will work as efficiently as a German  / Austrian manufactured one!)
  • We have been fighting the first point for so long and so hard that time for negotiation and sharing has been lost - we remain financially disadvantaged due to the EA's activities regarding licencing at Avoncliff.

However we have maintained that the EA had the opportunity for one large scheme which controlled the water and then one smaller scheme- but they felt this wasn't fair-! So another opportunity lost!

DIY Kaplan (1) There have been blithe and airy assertions that since Kaplan turbines are such a mature technology that somebody can simply knock one up in a shed. Whilst there are no doubt talented engineers around - the likelihood of getting a prototype to work optimally first time is vanishingly remote. A Kaplan turbine is a precision engineered item of heavy machinery involving a considerable number of components - each of which has to be optimised for a mixture of hydrodynamic performance for the wetted bits, mechanical functionality, reliability and serviceability. If it was so easy - no doubt the various established manufacturers would be selling them for a lot less than the £300K++ they actually charge - it has to be assumed to recoup in part their considerable development costs on a design. Some enthusiasm, a stack of steel, an angle grinder and a welder...?

To our knowledge the suction piling technique proposed to secure the turbine has not been used in a Kaplan turbine installation anywhere (happy to be corrected on that). Weaver's Mill also at one stage proposed to raise the weir at Avoncliff (!?) to increase the head (water drop) which is near the limits of efficient Kaplan operation... with obviously some consequences upstream.

This is an imaginary turbine - it hasn't been built, as far as we know it hasn't been modelled, it hasn't been subjected to engineering review, it most certainly hasn't been tested. Any claimed performance figures claimed for this machine must be treated with extreme caution One has to assume that patent holders on Kaplan technology will not ignore a new player either....

First call (2) "First call" on the water would mean that a second scheme - if there was one - could take water when the 6.8 m3/sec flow was reached ("handover" point). It should be noted here that this is a considerable concession - as at this time we were given to understand by the EA that all the water over the weir was "reserved" for our application - three years ago! The actual North Mill formal application has never varied from the published 10 m3/sec flow.

GPG (3) - General Practice Guidelines. This is the matrix of environmental constraints, procedures and water flow arithmetic used to evaluate the suitability of a scheme. It is a document under continuous change.A copy can be viewed HERE (pdf) or here  with additional EA commentary here

Qmean(4) - This is the mean ("average") river flow.

Advertising(5)  - A change to a proposed scheme licensed under the Water Resources Act 1991 (as amended) and The Environment Act 1995 must be advertised in the local journal of record (i.e. the local newspapers) Both schemes at Avoncliff have been advertised unchanged twice - although the EA did not advertise that they were using entirely different and subjective arithmetic (130% of Qmean river flow) when they were attempting to impose a split scheme - some might say artificially inflating the perceived amount of water available in order to divvy it out between schemes... Which is a substantial change to the applications...

This reverse engineering example comes to mind when some people mention building their own Kaplan turbine.

A video of a Kaplan water turbine internals (with a Pelton wheel shown in parts too)

A CAD animation of a Kaplan turbine

One can certainly see why anglers and others see Kaplan turbines as fish mincers and are opposing them across the UK..... as the EA have discovered.


  1. This is precision stuff that is tweaked over 15 20 years what a joke, away with the fairy's ....

  2. The video is of a Francis turbine. Kaplans are propellers.


Get it off yer chest - please keep it civil