I’m guessing you must live in the South West judging from your canyoneering posts, we should get together one of these days for some desert adventure.
Me? I worked with Tom Meyer on the Mars Underground, then I was a founding member of Mars Society. Engineer, dirtbiker, cannoneer -er and hope to god I can retire one of these days!

SE Jones

Well, my question was going to be if there was any dating on these water events.

In some cases you can see they flow around impact craters, so that would help if we had some people on the surface to do geology. Also, depending on when various flooding events took place, the atmosphere might not have allowed for liquid water to stick around for very long.

Either way, this Martian drainage indicates the presence of underground hydrology.

Yes. The megaflood(s) appear to have upwelled from beneath the surface of Mars.

If you are asking me to write this, I may. However, if you want a quick idea of the present state of knowledge, simply use the search box on Behind the Black and type in “Mars water”. You will have hours of reading of the many many posts I have made on this subject over the years, and will soon get a pretty good idea of where our knowledge stands.

To sum it up quickly: We know liquid water once flowed on Mars. We do not know exactly when, or how long, or how deep. Nor do we really understand all the factors that caused that water to go away. Moreover, we do not know yet exactly how much of that water remains there, below the surface.