I guess that it's only a waste of money and time. Sure, you can create some artificial streams to improve the view or so but most probably they will never be used for spawning (even if they would, no results will be achieved).
I've never heard about any fishkeeper working this way. Everything is done in hatcheries with special fish tanks, proper temperatures etc.
An example. My country - Latvia. Brown trouts live here and our trout streams are suitable for their reproducing. Some decades ago rainbow trouts were introduced to our rivers and streams. Nobody know why but they don't do the same. Yeah, they live their lives succesfully but they do not spawn eggs. There are plenty of rivers with perfect "configuration" for brown trouts but these rainbow trouts somehow don't like something.
