Incorporate a huge concrete wall into the canal design--if sight of the other side is an issue, put solar powered cameras on the top of the wall.
Well, if we are going to pour concrete,I actually like the wall that Israel has. What is is--30, 35 feet? Too high to easily climb over, cant see through it, and unlike current designs that let you fall off and get a spinal cord injury that results in a hospitalization in the U.S. you wont even get to the top.
Or.