Maps for HDS

[780sjc]

I know Navionics has a ton of maps out there for lakes and some stuff on the coast, but im looking for maps on most major river systems in western Canada. The Hot maps by navionics again has a good number of lakes in ab but nothing river wise if I'm not mistaken. Lowrances freedom maps aswell, has a good number of topographical info on quite a few bodies of water in western Canada but im looking at getting more bathymetrical info in waters such as the NSR or Fraser for example.
I guess my questions is, for the guys running the HDS or I suppose even humminbird units is there any river specific maps I can get on an SD card or even something that's downloadable??