Low water levels on Danube causing cancellations and changes.

Low water levels on the Danube is still causing disruptions to river cruise itineraries.
Cruise lines are having to cancel sailings , change itineraries or have even been busing passengers between ports in order to complete sailings…..if i was doing a river cruise I certainly wouldn’t want to taken by bus , i’d rather cancel and sail at at later date .
This water shortage comes after a spring of heavy rain and melting snow so why is there now a shortage?
A lack of summer rain has caused water levels to drop which means ships cant sail .
Fluctuating water levels are common in Europe, and the Danube has been hit particularly hard in recent years. In June 2013, historic floods inundated riverside towns like Passau in Germany and caused disruptions to dozens of river cruise itineraries.