Llyn Fawr Tunnel.

[Engineer]

Some new and old pics of a water supply tunnel feeding the Rhondda Valley, constructed about 1913 by enlargeing a natural lake and tunneling through the Rhigos mountain ridge.
The tunnel has subsided and there is a pump that keeps the central section dry, (sometimes).
Length about 1.25 miles.

South entrance.

North entrance.

Reservoir discharge.

Steps down from north entrance.

Looking down steps.

Pump.

Pump starter.

Overflow tunnel.

Sorry about the pic size, will try harder next post.

 

[ashless]

Alright!
Nice pics mate, I love the Welsh dams and reservoirs. Visited Craig-goch reservoir and Caban-coch last year, very photo-able but I don't think my other half would of appreciated me wandering off for an explore!

 

[BigLoada]

Impressive bit of engineering that. Looks like a few old film photographs amongst that lot too.

 

[Urban Mole]

I was gonna say the same BL, looks like some scanned photos there.
Didnt you actually get in there yourself?
Doesnt look like theres much stopping you....get in there....

 

[Engineer]

Llyn Fawr Tunnel

I was gonna say the same BL, looks like some scanned photos there.
Didnt you actually get in there yourself?
Doesnt look like theres much stopping you....get in there....

Been there, done it, 1985ish, first trip water 4 feet deep for about 500 yards, no pics, the scans are from pics on the second entry.
The digital pics are from a recce in November 2007, all new pics when I get some time.

 

[Foxylady]

Very interesting construction. Love the photo of the reservoir discharge and look forward to seeing more about the site. Good report.

 

[Urban Mole]

Ah ok, having the key is cheating

Is this you, "back in the day" ?

 

[Engineer]

Llyn Fawr.

Nope, not me, an ugly mate.
No key required at the time.

 

[King Al]

Nice pics, looks like a beautiful end of the country. Would love to have a stroll in there!

 

[Engineer]

Llyn Fawr.

Thanks for the comments, a few more pics of the general area.

Dam overlow.

Small waterfall.

General scenery..

More scenery.

Nameplate on weir.

 

[sinnerman]

Is this the Tunnel that runs from the Old Mardy Colliery site to the lakes above Tower.

 

[Engineer]

Is this the Tunnel that runs from the Old Mardy Colliery site to the lakes above Tower.

Yep, thats the one.

 

[Engineer]

Update, found a slide from the 70's, shows one of the inlets to the pipe in the tunnel, two more still below water level.