Some of the recent posts over on this thread got me thinking that a fun community project would be developing a new Mars habitat city communally. Arenamontanus suggested one possible area for a new major habitat could be Dao Vallis near the Hellas crater. As he put it...
I would suggest a location along the northern side of Hellas (warmer in the winters than the centre or south part). Maybe along the edge of or in Dao Vallis, since that is an area with water deposits and might become a fairly nice river once the hydrological cycle starts properly.This way it would have a good location as a base for terraforming work dealing with freeing and controlling the buried ice resources in the area. The habitat could make use of the canyon geography to create a warmer microclimate by roofing over some arroyos and side-canyons.
I did a bit of research on Dao Vallis and it does seem like a strong suggestion for a new boomtown hab. Here's some background:
Dao Vallis is a valley on Mars that appears to have been carved by water. It runs southwestward into Hellas Planitia. It and its tributary, Niger Vallis, extend for about 1200 km. It is named after the Thai word for star.
Dao Vallis begins near a large volcano, called Hadriaca Patera, so it is thought to have received water when hot magma melted huge amounts of ice in the frozen ground.
The landing site proposed for the exploration of the Dao Vallis is the western branch of the outflow channel of Dao Vallis. This branch of the channel is between the Hadriaca Pantera volcano and the seemingly smooth Hesperian plains.
The actual texture of these plains can not yet be determined, because the only images currently available of this area are from the Viking orbiters, and are limited by the resolution of the cameras aboard the vehicles. The channel as a whole has a 5 km drop in elevation from its origin on the southern slope of the Hedriaca Pantera volcano to its end at the edge of the great impact basin of Hellas Planitia. The formation of the channel, which occurred after the formation of the Hadriaca Patera volcano, is probably due to spring sapping and hydrothermal activity from the nearby volcano.
This site presents explorers with the opportunity of simultaneously investigating an outflow channel, a mixture of volcanic and plain materials throughout the channel, and the disruptions at the edge of the Hellas basin. At the same time, it posses a technological challenge to explorers derived from its high degree of complexity.
The complexity of Dao Vallis is both geological and climatic. Orbital analyzes of the atmosphere over the region shows that water frost, water vapor clouds, and dust storms are common on the channel floor as well as in the surrounding regions.
The complexity of this site has caused the great interest for the carrying out of extensive exobilogical experiments. The hydrothermal activity of the area, which is associated with mineralization, increases the possibility of finding biological traces or fossils, because of the known biological productivity of thermal springs and fossil burial. These assumptions about thermal springs are based on experience on Earth and may or may apply to the case of Mars.
Here's some helpful images of the proposed Dao Vallis site:
Image of the Dao Vallis area. The Hellas Planitia crater lowlands would be in the lower left of that image.
Sunward has a little bit of information about the area:
Hellas is another big project. It’s an impact basin, left over from a helluv big asteroid impact that happened so long ago it boggles the mind thinking about it. The glacier at the center—what’s left of it—is a major source of water for the settlements around it. Hellas is dotted with a dozen or so towns and a lot of smaller settlements, and it’s the heartland for the part of the Movement that
concerns itself most with terraforming politics.
Outfts like the Dalton Gang in Argyre, the Family Sung in the Valles midlands, and the Ryukyu Uumakus on the Hellas periphery have gotten into everything from train jobs and highway robbery to kidnapping and small-time extortion. Their relations with the locals vary. The Daltons’re thugs who terrorize everyone around them, while the Uumakus are sort of folk heroes to the Okinawans in Hellas.
"It's a poor sort of memory that only works backwards." --The White Queen, Through The Looking-Glass