tide lock

The story is set on a tide locked planet.

Mercury is primeval, tide locked and possesses only rudimentary lifeforms.

A control lock may also be known as a tide lock where it is used to control seawater entering into a body of fresh water.

Framilode lock at the entrance to the canal was a tide lock, with multiple gates to cope with all states of the tide.

In 1805, Sollom lock on the Rufford branch was abandoned, and a new tide lock was built further downstream at Tarleton.

Planets around such stars will have a hard time supporting life, because any world close enough to the star to stay warm will also be tide locked, one side baked and the other freezing.

Of course, since the Moon is tide locked, any colony on the far side of the Moon has this same benefit; a lunar facility, however, would suffer from "Moonquakes".

The river is still tidal at Richmond, so to allow traffic to continue to operate during low tide, a half tide lock was opened in 1894 and is used when the adjacent weir is in position.

Commercial traffic also grew steadily, helped by the construction of new basins at Chester and the provision of a tide lock into the Dee, which made access into the lower basin possible at all times, and helped to keep it free from silt.

Meanwhile, work on a new canal to bypass the lower sections of the river began in 1777, and the Rufford Branch, which dropped through seven conventional locks and a tide lock to join the river near its mouth at Sollom, was completed in October 1781.