Sulina branch is the single access way between Tulcea and Sulina. It has the aspect of an arranged channel having the banks super elevated by well consolidated dikes protected by flagstones. Its characteristics are: 63 km long, at least 7 m deep, rectangular shape and 7 km of prolongation into the sea arched and curved to south. It is also a big artery which supplies the depressions from the center of the delta with the water necessary for these ecosystems life maintenance. This branch is the easiest to follow in order to reach the network of streams, lakes or swamps from the depressions situated on the left and right side of it. It is also the easiest way to reach the zones of floating reed islets or reed thickets situated on the fluvial or fluvial-marine levees.

On the seacoast sands the vegetation presents a characteristic graduation, passing from the sand of beaches to the high dunes and middle dunes. Grassy species can be found: sand purple thistle, sand alfalfa, sand wormwood, sand woundwort, sand knot grass, sand bird’s foot trefoil. Grassy species characteristic for saline soil of the seashore are present too. Underbrush and small willow tree are some of the wooden species which belong to the zone.

Fauna is rich. Wild boar can be found in Sulina vicinity. South of Sulina branch, swans are nesting. Cormorants’ colonies are usual presences in the territory between Sulina branch and Sfântu Gheorghe branch.

Big contrasts define the climate. They are reflected either by the phenomenon’s frequency or by the phenomenon’s intensity. The predominant element is the wind. Sulina has only 31 days of calm. Breezes are present on the seashore in summertime. Air temperature and precipitations have moderated year average values: 11°C and 400 mm. Usually, winter comes later and it is relatively warm. Spring comes 2-3 weeks later than inside the country.