Cicadas' singing

I could finally hear the voice of cicadas' along the river side, green leaves big trees were standing beautifully.

At around 4:00 pm in the afternoon I stopped my car and walked hearing the songs by them.
I wonder why the water in the river was muddy brown………it hasn't been rainy for a while.
I don't know what makes water impure.
Every creature wants clean water and air which are great gift from the nature.
We shouldn't pollute wonderful gift. Give them back to purify themselves.

I hope you can hear the sound but this video doesn't have clear sound…sorry.