Research from 2010 suggests that Mars had lakes along parts of the equator, which is where Echus Chasma lies.

Although earlier research had showed that Mars had a warm and wet early history that has long since dried up, these lakes existed in the Hesperian Epoch, a much later period.

Volcanoes would have released gases that thickened the atmosphere for a temporary period, trapping more sunlight and making it warm enough for liquid water to exist.

In this study, channels were discovered that connected lake basins near Ares Vallis.

[1] It is the source region of the Kasei Valles outflow channel, which extends northward from it.