[Gaffer]

Just stumbled across this old thread. I grew up in Woodnook - Hudson Street in the 60's.
Priestly Clough was our playground too.
Picnics and paddling - the water wasn't that bad IIRC.
Just hearing the name 5 arches, brings it flooding back!
I brought my now wife up there back in the 70s to show her what a special place it was and ended up proposing to her on the bridge which is down at the lodge end if I remember correctly.
As a nipper, I remember the steam trains struggling up the hill to Baxenden - clouds of steam billowing up over the valley.

On another topic - we were still breaking in to the shelter under Riley Hill in the late 60s.
It was a labyrinth of passages... at the end of each it formed a 'Y', and then another, making a honeycomb pattern. There were escape holes and hatches buried in the hill, which several groups of kids unearthed. It was bulldozed in the 70s I think, but it was a great place for an adventure!