On 05/08/2019 12:53, charles wrote:
How do you remove surplus water from the canal without opening the locks -
which are specifically designed to stop that happening. The relevant canal
appears to run through Whalley Bridge and is presumably fed by a pipe under
gravity.

You open the sluice gates top and bottom of each lock. The ones that let
you fill and empty the locks with the gates shut.

That takes several minutes per lock full - but every little helps.

Andy