swimming or running in college?

In my experience, it should be possible (at least at some schools) to do both the running and the swimming. Obviously, you would need to have cooperative coaches, because cross season extends well after the beginning of swim training, but I think you might be able to find such coaches at the D3 shools you're looking at (and in terms of running times, at least, I'd say D3 is your best bet).

During your summer buildup for xc, I'd say there's certainly nothing wrong with doing a portion of your general aerobic work as swimming. As the summer progressed, the proportion of your training that was running would probably increase; but you'd still want to retain a modicum of swimming, if only to stay in touch with your stroke skills.

In the fall, you'd want to do the full team running workouts. But that's not to say that you couldn't do a brief morning swim session (given that most D3 schools don't do team double workouts), which could actually loosen you up for your afternoon running; or you could jump in the pool for a few minutes *after* your PM running, which could help your recovery for the next day. Depending on your team's training situation, your Sunday long run might end up all running, followed by some easy swim; or even half run/half swim, or all swim for all I know. In the last few weeks of cross, your swimming would probably be more limited, and almost entirely for recovery, not for conditioning.

Still, if you kept in touch with your strokes throughout xc it should be possible to move (late) into swimming, once cross is over, and get up to normal workouts pretty quickly, probably within a week or two. Then during the swim season you could keep a lot of your running conditioning if you put in one, maybe two hours of running per week--again, probably as morning sessions. Once or twice a week, you'd want the running to include some turnover work (strides or whatever). Again, the concept is to stay in touch with your *skill* of efficent fast movement.

Collegiate swimming extends to, what, mid-March if you make NCAAs? It should still be possible to do outdoor track, if you have a cooperative coach. You might not be able to handle the team's full running workouts, in terms of volume--or you might--but your aerobic conditioning should be at a high level, and your running skill should still be there. Try steeplechase--seriously, not just because of the water jump!--because your strength and flexibility from swimming might help you there.

I've had students at the D3 level who were both successful runners and swimmers, so I know it can work--again, depending on the coaches involved. I've heard the argument that you should concentrate on swimming in college, because "you'll be able to run for the rest of your life, but won't be able to swim once you get out of school"--but that hasn't been my experience. People who *want* to stay with swimming are generally able to find a post-collegiate club program that allows them to do so.

And yes, triathlon may be in your future. In fact, I had a cross-country guy who had a fairly substantial triathlon season during the early- and mid-summer months, then gradually moved his emphasis to running as the xc season approached. He ended up our MVP that year!