Odd shaped lock in China

[magpie patrick]

Heaven knows where this belongs, but it's not general boating. As the lock in question is now closed I though H&H would do! 

 

Photo below taken from the IWI website where the 2019 World Canal Conference is featured. The lock is on the old route of the Grand Canal in Yangzhou, a city on the north bank of the Yangtze. The lock drops to the level of the Yangtze from the canal level. What drew my attention was the odd shaped inlet on the right side of the lock 

 

 

Next is a pic of the same lock in 2007, taken from the Flickr account of John Meckley. It shows the lock in use and thus it is clear that the inlet is part of the chamber

 

 

And finally a view from Google Earth which clearly shows the inlet leading to what looks to be a non-navigable drainage channel. The weed growth suggests the lock is no longer in operation and there are parallel locks on the new canal route

 

 

Question - im pretty sure no one will know but if anyone wants to speculate.... why would a drainage channel join in a lock in this way? Why put the inlet in rather than just a pipe? Why not above or below the lock? The lock is fairly new (post war) so there would have been some flexibility over it's location

 

For those who are curious, these are the locks on the new route

 

[Mike Tee]

Chinese side-pond?

[magnetman]

Maybe the level below is or was subject to surges and this worked as an accumulator to prevent water going over the sides when the lock is empty with the guillotine gate open. 

A great big pressure relief valve. 

 

[Pluto]

Almost certainly something to do with drainage control, as almost all Chinese canals have several purposes, not just transport. I did visit the new locks at Shaobo, Yangzhou, accompanied by an interpreter, who didn't know that much about the canal's history. The photos are of the main lock, with the one closest to the embankment being the earliest in this phase of canal building here. Prior to the locks, some of the earliest wharves serving Yangzhou were located here. Several bits of canal were suggested as the earliest, and I had visited the proper one with academics working on the application for World Heritage states for the Grand Canal.

 

The latest newsletter of Inland Waterway International dropped through my letter box today, and it includes details of planned canals to link the Hong Kong area with the Yangtse.

[magpie patrick]

15 hours ago, Pluto said:

 

 

 Both great photos, but I like this one especially - just look at the way that cargo is retained!

[Pluto]

1 hour ago, magpie patrick said:

 Both great photos, but I like this one especially - just look at the way that cargo is retained!

It looked like coke, and some of the barges had tarpaulins laid over the cargo.