On Sat, 11 Dec 2004 09:09:26 -0500, Jeff Morris
wrote:

... here's a picture of the lock in the Shinnecock Canal:

http://www.sv-loki.com/shinnecock.jpg

.....

Looks like the right channel is the lock with upper and lower lock
gates. The two channels on the left look like tide gates to me.

On an inland canal like the Grand Union for example,
the tide gates are replaced by a weir/barrier to hold a constant
upstream height. Here's a flight of locks I walked up, last week,
near Kenilworth which illustrates these features:

=phRIQMCBh9i7Nllq

Brian W