Adrian Stott wrote... >Martin Clark <[EMAIL PROTECTED]> wrote: >>Adrian Stott wrote... >> >"Ralph Rawlinson" <[EMAIL PROTECTED]> wrote: >>>> Locks 1 and 2, originally next to the junction with the River Irwell, >>>>have been replaced >>>>by a single deep lock situated to the west of the railway further away >>>>from the river. >>> >>>(sort of XP from URW) >>> >>Since you have copied and pasted your reply to me in URW, I shall copy >>and paste my reply to you, for the benefit of any readers here who don't >>receive URW... > >Ditto (sort of). > >One answer is side ponds on the deep locks. [snip figures] >So if the double-depth lock is equipped with two side ponds, no >backpumping is required, as its use will consume the same amount of >water as the standard-depth lock (with no side ponds) above it.. > Ditto, ditto. (Why are we having the same discussion in two places?)
In the specific case we are talking about, Middlewood Deep Lock, back pumping will definitely be required for the forseeable future, as there is no canal in place feeding water into the pounds above. It wouldn't matter how many side ponds were constructed, once the water has gone down, there would be no way to refill the upper levels. -- Martin Clark Internet Boaters' Database http://www.lock13.co.uk/boats Pennine Waterways Website http://www.penninewaterways.co.uk
