What are the differences between rowing programs for DI, DII, and DIII schools? I know only DI and DII can offer scholarships but other than that what’s the difference as far as intensity and daily routine go?

Each program at each division is as intense as they want to be. I think it’s assumed, and in most cases subsequently shown, that D1 programs operate at a higher level of intensity than other programs, mainly because the expectations (from the athletic department, alumni, overall history/legacy of the team, etc.) are so high.

Related: What differences are there between being a collegiate coxswain versus a coxswain for a high school level team? What would a typical practice session look like?

In terms of daily routine, that’s also going to differ between programs. The two D1 programs I’ve been a part of had/have two practices a day, at least four days a week, and then one long Saturday morning practice. Lifting was typically done twice a week but that changes based on the season. These are done as a team whereas at the D3 level lifts are done on your own, which gives you the flexibility to work around your schedule and fit it in when you can. The number of hours you can practice with a coach present differs between division 1/2 and division 3 with D3 getting less time than D1/2 (hence why they only practice together once a day).