Earlier quoted context omitted.
Rising temperatures melting glacial/mountain ice more dramatically contributing to river water carry? I'm not saying that's specifically the case, just throwing out a possible hypothesis. Plenty of others exist (bad rainy season, tributary re-routing due to industry, removal of forested areas that would have previously soaked up water, etc). Could be a global warming thing, could be a seasonal thing, could be anythin…
As a general rule, higher temperatures lead to atrophied snowmelt rivers because there's not as much accumulation. That's one of the contributing factors for water problems in a lot of Western (U.S.) areas.
I'm not saying it's anything one way or the other since this is a hyper-empirical piece of data to be working off of. Based on context I'm assuming OP meant to imply that this is a sign of rising water levels, but I was just posting some alternate theories.