Statistical features of drainage basins in mars channel networks. Can one guess from the landscape the past presence of water?

Erosion by flowing water is one of the major forces shaping the surface of Earth. Studies in thelast decade have shown, in particular, that the drainage region of rivers, where water is collected, exhibitsscale invariant features characterized by exponents that are the same for rivers around the world. Here weshow that from the data obtained by the MOLA altimeter of the Mars Global Surveyor one can performthe same analysis for mountain sides on Mars. We then show that in some regions fluid erosion might haveplayed a role in the present martian landscape.