An interesting plus to the project is that 100% of irrigation is by gravity, not a single pump involved.
I managed a course in the Canary islands with a gravity fed irrigation system and absolutely loved it. You can't beat gravity for dependability.
Unfortunately, the same course also had bentgrass on volcanic sand-based greens, as you describe there. Have you had any issues with the sand? Are you using any amendments?
Steve, we have had no issues with the sand other than it blowing away during seeding and initial grow-in. What issues did you encounter? Will be interesting to know.
As a side note, Canary Islands have an average temperature 11 degrees Celsius higher than San Martin de los Andes, that has cool nights even in summer. I can see the difficulty of maintaining healthy bent over dark sand.
Mainly the Canary Island (Tenerife) sand was too coarse. There was no natural sand on the island (and precious little good topsoil for that matter). Good sand was prohibitively expensive to import, so all the golf courses were using a crushed volcanic rock known locally as
picón. The problem was nobody was crushing it finely enough, so what we could get drained wonderfully but had like zero holding capacity. Organic amendments were likewise expensive to get hold of, so they were often omitted as well. The picón would have worked great for bermudagrass greens like Tifdwarf (I proved it by establishing a small nursery to demonstrate) but back then the Spanish stubbornly refused to consider anything but bentgrass for green surfaces, even in a sub-tropical climate like Tenerife, where the bermuda never even went completely dormant.
Probably your volcanic material is better than what we had.