Definitely. The best the initial travellers could hope to do is set up infrastructure for the survival of future travellers.
We have the technology to terra-form Mars, but it will take at least 200-300 years to make any real progress.
http://io9.com/5868115/how-we-will-terraform-mars
I have a dumb question: Is there enough frozen water on Mars that if it were liquid would be enough to fill the Valles Marineris?
If not, then all we could hope for is to have the water (which always seeks the lowest level, to accumulate there?