Waste(d) waters

Gently, as the river flows,
Crystal clear hydration like a dream of light.
But it has secret poison that is also clear as glass as it flows intwined
So I pull out my canteen,
On this hiking excursion.
and I filter the dreams.
As I gasp from my thirst again.
Gotta keep my head clear.
And my freshwater too.
So I lie down to rest on my journey.
Slowly falling asleep safe and sound for now.
Until I thirst again.