The Danube reaches its final destination, the Black Sea, after an adventurous journey of 2850 km from the Black Forest. 70 km upstream of the estuary, it divides into two branches: the Chilean branch continues along a 117 km border, and the Tulcea branch after 17.5 km to the Sulina branch (63.7km) and the St. George branch ( 70 km). The downstream two-river regulation significantly shortened their original length, resulting in 58% of the arriving water reaching the sea on the Chilia branch. 82% of the 4152 km2 delta is located in Romania and 18% in Ukraine.
Its climate is predominantly continental, influenced by the mitigating effect of the sea. The average annual temperature is 11 ° C, the average annual precipitation is 400-500 mm. The average altitude of the sea is only 52 cm and the area is 20.5%. lies below. The morphology groups are divided in the following proportions: 3%, 10% lakes, 69% swamps, 8% Marshs, 7% goros, 7% plains and 3% plains.