Usually for waterproof printing you need an oil based ink such as soy ink, this is what a lot of the magazines and newspapers use.|
That's not to say this is the only way to waterproof an inkjet print,
You can use a waterproofing agent such as Thompsons waterproof seal to cover the printed canvas which will protect it.
Probably the easiest way to achieve the print is to print the image onto a high quality transfer paper and then iron it onto the canvas, I once did this on a canvas bag and it worked well, I used this paper
Information on waterproofing: