A Lens Into The Past: Using Hec-Ras To Visualize Probable Paleoflood Conditions In Osuga Valles, Mars
Presenter: Dalia Portillo1
Co-Author(s): -
Advisor(s): Dr. Virginia Gulick (LPL)
1Department of Hydrology and Atmospheric Sciences, University of Arizona
Osuga Valles (OV) is one of many catastrophic outflow channels found on the surface of Mars. It is located just southeast of Valles Marineris, the largest canyon system on Mars. Unlike rivers we see on Earth, OV provides evidence for paleoflood events that appear to emerge from a collapsed region called ‘chaotic terrains’ and terminates into depressions or cavi. The current morphology depicts that the fluid subsequently eroded the channel downstream before flowing back into the ground into another region of collapse (not into any delta or lake). There are several Palseostage Indicators throughout the system that provide insight into the magnitude of the most recent flood events. OV contains enormous channel bedforms, such as streamlined islands and grooves, and forms both singular and anastomosing channel segments, and a cataract downstream as it empties into its terminal collapse region. We can infer floods occurred periodically - if not seasonally - from the cross-cutting channels in the anastomosing region. Additionally, there are two sources in the chaotic terrains where the lower southern region appears to be the most recent collapse and source of flow. Because of this unique geomorphology, we are interested in the history of flooding in this system and the properties of the subsurface which produced these high magnitude flows. In this study, we utilize HEC-RAS to generate a 2D model of the catastrophic outbursts that could have flown through this channel. The magnitude of discharge and volumes of each flood event can provide implications for the characterization of the Martian subsurface and possible future catastrophic outbursts on Earth.