Stream bed is a term used to describe the bottom of a body of water, such as a river or stream. It is composed of sediment and rocks that have been deposited by the water. The stream bed is usually the deepest part of the waterway and is often the most important part of the ecosystem. WADI is a term used to describe a dry riverbed in desert regions. It is usually formed by seasonal rains and can contain water during certain times of the year. A CHANNEL is a man-made or natural passage for water, such as a river or stream. It is typically deeper than the surrounding area and is used to control the flow of water.