In message , at 13:35:14 on Tue, 6 Aug 2019,
NY remarked:
"Roland Perry" wrote in message
...
The spillways appear to drain into the River Goyt, while the water
that's drawn of for the canal is from a valve at the base of the
reservoir.

Ah, I wasn't sure if the River Goyt was connected to the canal, in the
same way that the River Cherwell and the Oxford Canal intermingle every
so often.

It's very likely that the canal has its own spillways and sluices into
the River Goyt, which would help spread the load. Given that they are
almost side by side all the way to Marple.

Last month I was on the waterways west of Nottingham and the Trent and
Mersey canal has a "level crossing" with the river Trent at Alrewas.

https://www.openstreetmap.org/#map=16/52.7336/-1.7441

A month earlier that crossing was closed because the Trent was flooded a
good 4ft above what's normal for the time of year. That's an awful lot
of sideways flowing water.

But I digress; the canal from there towards Burton on Trent has multiple
spillways and sluices to channel excess water back into the Trent.
--
Roland Perry