Really nice video and good information. There is no substitute for knowing where the water (you may be drinking) comes from and what is happening upstream from your position.
Where we moose hunt in Alaska there is a beautiful and fast river running past our camp. Closer to our camp is a tributary stream which runs directly down from higher hills behind camp. We get our water from the tributary, but always filter or boil it. I'm sure we could drink the trib water safely, but...
I was moving along a bluff above the water one afternoon and watching a band of caribou. Being water-lovers, caribou will often simply stand in a river or stream, sometimes walking right up the center. These animals did exactly that, and I think a half-dozen of them dumped a load of caribou poop directly into the water as I glassed. Great reminder about how beautiful water can hide ugly organisms. Remarkably enough, there is also a large colony of beavers about 5 miles upstream where other tributaries are small and slow enough to dam. If I don't KNOW...I filter.