Tom,
I agree it seems high, but as per above, some supers estimate even higher, perhaps out of self interest. I had pegged it at about $15,000 per year, but rainfall varies and the shoveling could be five days one year and 50 the next.
I recently had a similar experience on a 20 year old course of mine. Start with the $1.25-$1.5M irrigation system, reduce and upgrade bunkers that had no sand, at maybe $360K, level some tees, add some forward tees, fix a few rickety bridges and broken cart paths. The total came out over $2M just to stay in business, which is a hard pill to swallow, especially since it was built by a company that promised no city funds would ever be needed, etc., and the council knows the voters remember that well.
Still, the city owned a course (and leased it) for 20 years, and put no money in it, and now needs to spend that $2M, mostly because it didn't (and couldn't because it wasn't meeting pro forma expectations) enforce their minimum annual investment clause, and now they have it back. By industry standards, they would have been investing 3-4% of course construction cost every year for capital improvements, and at today's new course construction cost of maybe $7M, that would be $200,000 annually, or $4M total. In essence they are playing catch up, like most courses with deferred maintenance.
I feel badly for them, but no one cares about feelings, right? Eventually, all courses need to invest something, and the question is whether that $100K extra (which should cost them only $8-10 K per year depending on their bond rating) pay off in maintenance savings (which would be at least $8K in maintenance savings by nearly anyone who estimates these things) and, given how golfers feel about nice sand in the bunkers, at $40 per round, will they get just 200 more rounds due to better maintenance?
If they take the long view, they may very well want to invest in bunker liners, but then, its there call. It is usually short term thinking that leads to deferred maintenance anyway, and management companies have certainly left more than a few cities in similar binds.