NASA: water flowed recently on Mars

"The gullies may be sites of near-surface water on present-day Mars and should be considered as prime astrobiological target sites for future exploration," said Jennifer Heldmann, the lead researcher from NASA's Ames Research Center. "The gully sites may also be of prime importance for human exploration of Mars because they may represent locations of relatively near surface liquid water, which can be accessed by crews drilling on the red planet."