Ombla

The Ombla is a short river in Croatia, northeast of Dubrovnik. Its course is approximately 30 metres (98 feet) long, and it empties into the Rijeka Dubrovačka embayment of the Adriatic Sea near Komolac in Dubrovnik-Neretva County. Rijeka Dubrovačka is actually a ria, a flooded river valley formed through changes in sea surface elevation on a geologic time scale. The river rises as a karst spring fed by groundwater replenished by Trebišnjica, which is an influent stream flowing in Popovo Polje, in the immediate hinterland of the Ombla. The elevation difference between the river's source and its mouth is just over 2 metres (6 feet 7 inches). The average discharge of the river is 24.1 cubic metres (850 cubic feet) per second. The drainage basin of the Ombla encompasses 600 square kilometres (230 square miles) and, besides the short surface course, includes only groundwater flow.