Restoration of Perennial Flow in the River Lathkill upstream of Bubble Springs

[graham]

Bit of an insight into why

Not really. According to the landowner, in that clip, the situation was very different in the 1920s to what it is now. That means that even if Magpie Sough had something to do with it, that is not the whole story and so concentrating on just that one aspect may not be sensible.

 

[droid]

It isn't sensible anyway.

The assumption that blocking Magpie Sough will lead to the resumption of pre-mining water paths is, IMHO highly unlikely. Not highly unlikely is a repeat of the spectacular events of the last blockage.

 

[unclej]

All of the above questions will be answered at the up-and-coming meeting.

The weirs were built in the 1850's by Symington. They restrict the passage of some fish to their chosen spawning grounds in the NNR.  They are taken out regularly, or rather their sluices are opened, to aid the distribution of sediment and the passage of fish.  Further downstream, most of the weirs have been removed.

I have attended the two WPRG roadshows held so far in Over Haddon and Monyash and heard the evidence presented by experts from studies carried out since the 1950's. The most recent report has been carried out by Professor Gunn and it is for him to present his evidence. You are invited to listen and ask questions at that meeting.

The point made by the landowner in the clip highlights concerns that the situation is getting worse.  The evidence suggests that it is. Come and hear it.

 

[unclej]

How would cavers interests be compromised by a control to flow in Magpie Sough?

 

[unclej]

Whilst not knowing or caring much about this either way knowing how construction costs tend to spiral I suspect ?7,000 a year to rehome a few fish will seem a very cheap deal compared to building a weir?

Come August, after the predicted 2014 rescues, the total cost of rescues carried out by the EA will top ?100 000. They manage to rescue about half the fish. The rest do not survive. A design has been carried out by an industry professional and quotes have been received from competent mining engineers. A control to flow in Magpie Sough would offer good value for money. 

 

[graham]

Question

If all this water currently draining out of Magpie Sough would be deemed 'spiffin' in Lathkill, what about the effect of removing it from the Wye? Just asking.

 

[unclej]

If you want to stop having to rescue fish every year (like in the video) then build some sort of weir that will stop them migrating upstream and then getting stranded when the river dries up each year. That will save everybody a lot of time and money! Concentrate on improving the current permanent flow stretches of the river and maybe making some spawning areas where the river is permanently flowing. (Around Bubble Springs maybe?)

Regards Mel. DCA Conservation Officer.

That is one option. An alternative would be a river full of biology including water voles, fish, kingfishers, otters, osprey, with aquatic insects supplying food for dippers, wagtails, little grebes,daubenton's bats, all the way from bubble springs to Head Cave. The management of the river has involved installing spawning and nursery habitat on the Lathkill for decades, but the place of choice for wild Lathkill brown trout is amongst the tufa oncoids within the traditional spawning beds above and below Batemans House in the NNR.

 

[droid]

When were otters and ospreys ever in the Lathkill?

 

[unclej]

Question

If all this water currently draining out of Magpie Sough would be deemed 'spiffin' in Lathkill, what about the effect of removing it from the Wye? Just asking.

A restoration of flow to 1880 levels may require some mitigation.  Studies have been carried out using the LIFE model of aquatic macroinvertebrates evaluation which have found no difference between population densities above and below the outfall at Black Rock Corner.  Professor Gunn offers some insight into likely distribution outcomes, post control.  Some water will continue to run to the Wye. I hope you are able to come along and find out for yourself.

 

[graham]

When were otters and ospreys ever in the Lathkill?

Possibly right up to the moment the forerunners of the current estate owners hunted 'em to extinction.

 

[Pete K]

Unclej, would you please tell us your involvement in this? Clearly you are well informed.

 

[graham]

I hope you are able to come along and find out for yourself.

I have already said that I am rather too far away for that to be feasible, hence my raising of queries on here. How caving interests fit into wider conservation interests and how non-specialists understand karst processes in these situations are what concern me in this case.

 

[unclej]

When were otters and ospreys ever in the Lathkill?

Osprey come as far upstream as Alport, which is a little village on the edge of the SSSI. Otters have been tracked to Conksbury Bridge and use the Lathkill all the time. A couple of years ago they spent the summer evenings swiping fish from the Raper Lodge ponds and the days kipping under His Grace's fishing hut.  :bow:

 

[unclej]

I hope you are able to come along and find out for yourself.

I have already said that I am rather too far away for that to be feasible, hence my raising of queries on here. How caving interests fit into wider conservation interests and how non-specialists understand karst processes in these situations are what concern me in this case.

Understood Graham. Thanks.

 

[droid]

So, as has been said, you are well informed.

Having already been to 2 'Roadshows' would you care to inform us of YOUR interests in all this, as requested above?

Call me a cynic, but I find your reticense rather intriguing....

 

[Bottlebank]

Droid, I'll call you a cynic if you ask nicely

I'm intrigued why so many of you are so concerned what UncleJ's involvement is? He seems to know what he's talking about.

It's not as though you post using your real or full names?

 

[droid]

It's the refusal to answer pretty direct questions, BB.

It's almost that he doesn't want people checking what's going to be said, before it's said. If the idea is a free exchange of information, this isn't helpful.

 

[Pete K]

Click my signature, it will tell you my full name and give you all my contact details, qualifications and even address.

I think it is simply common decency when arguing/debating a point to declare your involvement.

 

[Bottlebank]

I think it is simply common decency when arguing/debating a point to declare your involvement.

I'm inclined to agree with you, but don't think that's the way this thing works

 

[Tripod]

unclej, thank you for your assurance that my concerns will be alleviated by the presentations at the meeting. I would like to attend but meanwhile there are some more questions that need to be asked and points to raise.
There are some very high weirs between Bubble Springs and Conksbury bridge. Are you saying that opening the sluices in these allows Trout to migrate through this section? Is this done and has it been done every year, since the weirs were built? Are those deep pools drained completely to produce a natural river flow? Have any studies been carried out to assess how far Trout migrate along the Lathkill? Or even Derwent/Wye/Lathkill? My, educated, guess is that those weirs are a significant if not total barrier to fish migration. Could you state how dependent the Lathkill fishery has been, since the 1850s, on stocking and what proportion of  the fish stocks are produced by natural spawning? I am curious too about the "traditional spawning beds" above and below Bateman's House, where the river is entirely man-made. This is not a personal attack but a genuine interest in how high the Trout ascended the river and what conditions they found, bearing in mind that nothing below a point well above Carters Mill is natural.
If the river was to run on the surface from Lathkill Head Cave down to Bubble Springs - and I cannot believe that it ever did "perennially" in historical times, then significant cave systems would be permanently flooded. That 3D mapping would be very useful together with a review of known hydrology.
And back to basics:
To restore 1960s Magpie Sough water levels would mean that the sough would have to be blocked producing a 30'-40' head where it meets the Wye.
To restore 1880s levels the sough would have to be blocked completely at a point which would ensure that all water captured by it was trapped. The ideas of "control" and "access" do not fit in with these scenarios. All the consequences of blocking the sough can be estimated but some, I imagine, only guessed at.
As I have said and others above, the sough being open is one factor and obviously others play a part. In fact, the only consistent factor is the sough being open and the changes that are occurring must be due to other influences.