Low water levels in the Danube river have left ships to queue close to the town of Zimnicea in Romania.

The present heat wave torturing Europe means the level of the Danube has dropped and triggered traffic problems.

Thanks to the first two Sentinel satellites, a cluster of ships has been spotted near the riverbanks. This information is being used by the Romanian Lower Danube River Administration to monitor navigation at critical points such as those close to the town of Zimnicea.

"Some 120 ships are stuck on the Danube now, 100 of which are not equipped with an Automatic Identification System," said Ion Nedelcu, Director For Environment and Security Projects at the Romanian Space Agency.

"The main goal was to identify the ships that do not carry it and this is where the Sentinel images have proven to be extremely useful."