A river that flows all year round, even during the dry season, because it is fed by groundwater baseflow, is best described as:

A perennial river flows year-round because it is sustained by groundwater baseflow even during dry periods. An ephemeral river flows only during and shortly after rainfall with no baseflow; an intermittent river flows for only part of the year as groundwater levels fall below the channel bed; an influent stream is one that loses water downward to the water table rather than gaining it, the opposite relationship to a perennial river's baseflow gain.