What distinguishes a losing stream from a gaining stream?

A losing stream is characterized by the process of seeping into the water table, which occurs when the water in the stream flows downward through the streambed into the groundwater below. This means that the stream is effectively contributing its flow to the underlying aquifer, reducing its surface water flow as it loses water to the ground.

The other choices do not correctly describe the unique characteristics of a losing stream. For instance, while some streams may receive surface water, a losing stream is specifically defined by its interaction with the groundwater rather than surface inflow. Additionally, the position of the stream relative to the water table is crucial; a losing stream typically does not sit below it. Lastly, becoming perennial is not a defining characteristic, as a losing stream can be ephemeral or seasonal, depending on various factors.