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Delta

A depositional landform built where a river delivers sediment into a sea, lake or other relatively still body of water.

As flow slows, sediment is deposited and the river may divide into distributary channels. Delta shape and growth depend on sediment supply, waves, tides, currents, sea level and human alteration.

For navigation, deltas may contain shifting bars, shoals and channels with rapidly changing depths. Current surveys, buoyage and local knowledge are more reliable than assuming charted channels remain fixed.

Alternative Meanings:
  • Delta

    The standard spoken code word for the letter D in the international radiotelephony spelling alphabet.

    It is pronounced “DELL-tah” and is used to spell names, call signs and other information clearly over marine radio. The same standard word is used in the NATO phonetic alphabet.

    Delta is also associated with International Code of Signals flag D, which has a separate visual-signal meaning. That meaning should be covered by its own linked entry.