Rivers and Lakes Without Rain on Mars

One puzzle of the martian rivers is the presence of rivers and lakes and the apparent absence of erosion that would be caused by rain. This has lead many to suggest that the source of water was groundwater sapping or subsurface ice melt. Here we explore an alternative hydrological model for Mars based on the hydrology of the dry valleys of Antarctica. These valleys have a mean annual temperature of about --20°C and only about 50-100 degree-days above freezing in the summer. Precipitation occurs only as snow and the production of meltwater results from the occasional days above freezing. The liquid water accumulates in ice-covered lakes stabilized by the thick ice covers. The result is rivers and lakes without rain.