Researchers have found a number of examples of deltas that formed in Martian lakes.
 Deltas are major signs that Mars once had a lot of water because deltas usually require deep water over a long period of time to form.
 In addition, the water level needs to be stable to keep sediment from washing away.
 Deltas have been found over a wide geographical range.
 Below, is a pictures of a one in the Ismenius Lacus quadrangle.
Researchers have found a number of examples of deltas that formed in Martian lakes.  Deltas are major signs that Mars once had a lot of water because deltas usually require deep water over a long period of time to form.  In addition, the water level needs to be stable to keep sediment from washing away.  Deltas have been found over a wide geographical range.  Below, is a pictures of a one in the Ismenius Lacus quadrangle.
Ismenius Lacus quadrangle