Sandbank; Песчаная банка, отмель; Liivavallid; Hiekkapenkka

(or tidal current ridge) (1) In geology type of sedimentary barform. Sandbanks are elongate sediment deposits common in macrotidal environments, ranging from 100s of meters to many kilometers in length, 10s to 100s of meters in width, and rising from the seabed to the intertidal zone. Sandbank crests are commonly exposed at low tide. They are aligned with their long axis subparallel to the main current. (2) Sandbanks are elevated, elongated, rounded or irregular topographic features, permanently submerged and predominantly surrounded by deeper water. They consist mainly of sandy sediments, but larger grain sizes, including boulders and cobbles, or smaller grain sizes including mud may also be present on a sandbank. Banks where sandy sediments occur in a layer over hard substrata are classed as sandbanks if the associated biota are dependent on the sand rather than on the underlying hard substrata. "Slightly covered by sea water all the time" means that above a sandbank the water depth is seldom more than 20 m below chart datum. Sandbanks can, however, extend beneath 20 m below chart datum. It can, therefore, be appropriate to include in designations such areas where they are part of the feature and host its biological assemblages. (EU’s Habitats Directive underwater habitats, http://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/Int_Manual_EU28.pdf)