Which of the following best defines discharge in relation to stream channels?

Discharge refers specifically to the volume of water that flows through a stream channel over a given period of time, typically measured in cubic feet per second (cfs) or cubic meters per second (cms). This measurement is crucial in hydrology and water resource management, as it helps to assess the stream's capacity, health, and the environmental conditions of the aquatic ecosystem.

Understanding discharge is essential for several reasons. It influences the stream's erosion and sediment transport processes, which can affect habitat and water quality. Additionally, discharge plays a vital role in floodplain management and predicting flood risks, as higher discharges can lead to flooding events.

Other options, such as temperature of the water, type of sediment being transported, and width of the stream channel, are important characteristics of a stream but do not define discharge. Temperature affects water density and biological activity, sediment types provide insights into geology and ecological processes, and channel width can influence flow velocity, yet none of these aspects directly capture the concept of discharge. Therefore, the definition of discharge is accurately described by the volume of water flowing through the channel.