The major source of a stream's flow.
The upstream portion of a watershed.
Referring to the source of a stream or river
The upstream section of the river before the main tributaries join it. This section is typically much smaller in width and flow than the main section of the river
The area just above the beginning of a stream
The source and upper part of a stream; water upstream of a dam or powerhouse.
(1) the source and upper reaches of a stream; also the upper reaches of a reservoir. (2) the water upstream from a structure or point on a stream. (3) the small streams that come together to form a river. Also may be thought of as any and all parts of a river basin except the mainstream river and main tributaries.
The water level above the powerhouse.
The waters immediately upstream of a dam. For power dams, also referred to as the water in the impoundment which supplies the turbines (see also forebay).