Europe's scorching summer has sent water levels plunging, disrupting cruises on the Danube and Rhine - but the Seine, Douro and Nile are among the rivers still offering holiday options.

(Bloomberg) -- Water levels on the Rhine river are dwindling further, with no relief in sight, forcing companies that rely on the waterway to adjust rapidly to keep goods flowing.

Low water levels are increasingly bedevilling some European rivers. Here’s what you need to know about river cruising’s new norm.