The ancient highland channels in this image empty into the Eridania Basin (not visible), a large topographically low enclosure with smooth-appearing terrains that may have once contained a large paleolake or ancient sea.
Water in these channels flowed to the east into Ariadnes Basin, a smaller basin located within the confines of Eridiana. Light-toned knobs are exposed in the northern channel, while the other channels are partially filled with smooth appearing lobe-shaped surface flows that are extensively fractured when viewed at high-resolution. [More at link]