This is a story about my most impressive experience in the Central Park of Banff.

I wonder if you mean something like "the experience that made the deepest impression on me"? "Impressive" can sometimes sound more like "this is something that I think people will be impressed by" - like you're bragging about it. Like maybe you think people will have a higher opinion of you after you've told them you had this experience :)

Here it sort of works either way, but if I say "let me tell you about the most impressive thing I did on my holiday", it doesn't mean something that I thoroughly enjoyed and will remember forever. It means something that I want to brag about, that I want to tell you about it because I believe you will think doing it makes me cool. The most impressive thing I did on my holiday would probably not be sitting in peaceful contemplation before a waterfall for an hour; it would be going bungee jumping.

When I had asome free time during my business trip to Canada, I triwanted to go to the Lake Louise in the Rocky Mountains.

"time" is generally uncountable in this sense, I think. "tried" implies that you probably did not succeed, and I think you just mean that you wanted to go. And the proper noun Lake X doesn't get a "the".

There was not a nonstop bus from Calgary to Lake Louise, so I decided to transfer in Banff.

More natural.

While I was waiting afor the next bus to Lake Louise, I took a stroll around the town.

"wait" requires a preposition when used with an object; you could say "I was *awaiting* the next bus", but people usually don't. And there's only one next bus to Lake Louise - the one that will arrive next - so "the".

At the Central Park, I could see beautiful scenery where the color of the Bow rRiver was emerald, and the forest wereas exotic.

Forest singular, was.

BesideAlso, some people went canoeing down the river.

Not sure exactly what you mean by "beside", it doesn't fit. Maybe this?

It was very peaceful and impressive.

Here "impressive" is fine because it's clear *you* were impressed by it.

To impressfix the scene in my memory, I stayed more than an hour and felt the atmosphere.

Here, on the other hand, it's weird :) I can see why you'd try to say it like this but it sounds strange, as if your memory is a person and you're trying to make your memory think you're cool.

We would perhaps say something like this, if we didn't want to simply say "remember".