Abstract: A submersible water clarifier for use in a flowing stream is disclosed which has at least one longitudinally elongated conduit which has an open end which opens in a downstream direction in use and a settling chamber extending inwardly from the open end. The settling chamber has a floor toward which sediment settles in use and the improvement of the present invention is in the provision of a sediment removal passage opening through the floor through which sediment may be removed from the chamber.

Abstract: In a water treatment plant which extracts water from a large open main body of water, the improvement of; a settling enclosure submerged in said main body of water and having a settling chamber therein which is isolated from the main body of water by an enclosure wall, a substantially quiescent body of water located within said settling chamber, input passage means communicating between said settling chamber and said main body of water for admitting water to said settling chamber, output passage means communicating between said settling chamber and said water treatment plant for conveying water from said quiescent body of water to said water treatment plant, said quiescent body of water having a volume which is substantially greater than the instantaneous requirements of said water treatment plant whereby water entering said settling chamber is held in a substantially quiescent state within said settling chamber for a period of time sufficient to ensure that the turbidity of water drawn from the quiescent bod