I used to play on the eddy lines on the canal near Patterson (F Road) hill, and 29 road. Theres a long cement slide (very flat) that kicks up a narrow wave that we could surf in longer boats, but doubt you can catch it in anything under 7 feet. The eddy line offers a 1/2 hour of fun. I quit going because I was busted by the canal authority too many times, and then I moved.
Junction desperately needs a whitewater park. The amount of volume year round in the Colorado would make for an amazing park, and the population would support its use.
Spent a lot of time driving the canals, never found anything else worth paddling.