Ex worked in an NGO that fights the expansion of hydro in Portugal.
There are several reasons. It's destructive, has very high emissions, and doesn't actually generate that much power because we have long-ish drought seasons. Hydro was fueled or fueling corrupt construction deals while destroying natural reserves and wildlife. In some cases, night-time hydro was much more expensive than any other power source.
You mean low water levels? Isn’t it caused by agriculture water use? A dam allows to use more water (for agriculture) but one can choose not to use more.
Why or when wouldn't one consider hydropower a renewable energy source?