I'm going to generously assume that you're asking a sincere question and not trying some tired political baiting, even though you mentioned climate change out o

I'm going to generously assume that you're asking a sincere question and not trying some tired political baiting, even though you mentioned climate change out of nowhere. Yes, rivers are extremely dynamic -- they run dry, flood, and change course over time. Often, those changes are dramatic and oscillatory so the same path may repeatedly run dry or wet over periods of years, decades, centuries, millennia, and longer. This is why we can often predict where droughts and floods are likely to recur, without precise timing of when. None of that has anything to do with climate change. I hope this answered your question!