Hi Michael,
I have two par-3 courses to comment on: my home course and the Quarry in La Quinta.
We used to have one at my home course, well I guess I should say we still do but the members don't own it any more. Eight months ago the members negotiated to take control of the country club from the original developer. Negotiations about this transfer of ownership went on for months and one of the biggest issues was who would get stuck with the par-3. We didn't want it because the financial drain on our future business would have been crippling. We projected the maintenance budget to be at least $600,000 a year. Unfortunately it has it's own 16,000 sq ft clubhouse (not a misprint) that requires a minimum of 10 staffers to run. Add utils, property tax, etc, etc and we were looking at expenses of 1.7 million per year.
The course averages 2 rounds per day. Not two foursomes - two rounds. Nice business model huh?
Looking back we made the right call to stay away from that financial drain. When it first opened a few years ago I played the par-3 maybe 8 times. I only had fun on it once when we played it as a 10-some late one afternoon while we discussed taking over the "real course".
The problem that we saw was that if you had a choice of playing a few holes on the "real" course versus 18 on the par-3 that 99.9% of the members picked the "real" course. A 4 hole loop on the "real" course was a lot more fun. As a result of the above we thankfully no longer own the par-3.
I have many friends at the Quarry and I've played as a guest many times. The Quarry built a really nice par-3 course of I think 11 holes. Luckily they were smart enough to not build a separate clubhouse but they still face some of the same issues we did. Their maintenance budget has to be very high (you should see it!) and I'd guess they spend at least $600,000 per year on maint. They see very little use even though they have very relaxed rules on the par-3. Their lack of use is for the same reasons we saw - you'd just rather play a few holes on the big course.
Two courses is not much of a data sample and I'm sure there are cases where par-3's have worked successfully but I would guess that Augusta's par-3 gets very little use.
I would rather have a parallel 6-hole full sized additional course than a par-3. The 6-holer would get used. Oh, and no clubhouse please!
Best,
Peter