What happens after a stream's discharge increases? stream velocity, channel width, and depth all decrease. stream velocity and channel depth increase, but channel width remains the same. stream velocity, channel width, and depth all increase. stream velocity increases, but channel width and depth remain the same.

The correct answer is - Stream velocity, channel width, and depth all increase.

When a stream is faced with a sudden increase of water, than the stream is starting to increase in velocity. The velocity is becoming bigger in the lower part of the stream. As the velocity increases, it is followed by an increase in width of the stream because it starts to flood the surrounding area, and because of the much bigger amount of water it also experiences increase in depth.