I think it is great that they have found a way to use the water for more than one purpose (i.e. power and irrigation). But I don't think it is feasible in most canals. Canals are usually designed to transport water a long way with a minimum amount of drop in elevation. If you ever look closely at a topo map with a bunch of canals on it you'll see that they usually follow the contour lines. Because the power generated is a function of head (i.e. elevation drop) and volume of water moving across that distance, you wouldn't be able to generate much power in most canals.
Still, I think this is a cool project, especially because it is in a canal, and likely won't affect fish populations, or other environmental aspects that you get when you try and do this in a river.