Answer:
salinity.
Explanation:
The stream size and speed are term related with river streams, and discharge si the volume of water that is being discahrged per minute or second, that affects the speed and size of the stream, as well as gradient and load, the only one that does not affect the stream size and speed, would be salinity, because that wouldn´t affect the amount of liter of waters being discharged or moved, gradient is the elevation or slope, the more the slope the higher the velocity, and the load is the matter carried out by the stream organic matter, and that will slow down the stream size and increase the size. So the answer would be salinity.
