Exploratour - Water on Mars
Mars Pathfinder
That is why measurements from the Mars Pathfinder mission became important. Mars Pathfinder touched down in what appeared to be the remnants of a catastrophic flood. Thus, scientists had the opportunity to study the remains of what is thought to be a surface created by flowing water.
A map of the region, shown here, shows what are called the Ares and Tiu outflow valleys. Channels are visible throughout the scene, and may indicate a great deal of drainage in the region. The two main channels seem to be examples of "straight" channels, rather than meandering river channels.
This may mean that during the flood, the water came gushing directly out of the ground. The image also shows many tear-dropped shaped tails around craters in the area.