For the water-supply point, clay-lined dug-out ponds will work nicely as rainwater traps, if suitable hollows don't already exist. Channels from those can carry water downslope to wherever it's needed. However, the island's of a size and form that there could easily be wells dug, or even a natural spring or two (or a combination of all three) without needing to worry about more artificial means of water supply.

Interested to see how far back you'd faded the windrose lines in the latest map iteration.

Just a thought, but for Pern, maybe the windrose centres should be on a few of the more significant weyrs, not on the sea (probably without the fancy symbol though, if so)?

Glad you'd got it sorted now!

Have you thought about leaving the hatching off entirely? You really only need it if there's nothing else to show what's solid and what's not, I suspect.

There are various options for showing contouring beyond what's been discussed here, though some probably will work better, or with less effort, than others for this scale and type of map. The Fantasy Towns Annual issue might be the more suitable alternative to consider, which uses a version of shaded terrain using the transparent solid bitmap fills and bevel effects to generate a form of shaded terrain. I made extensive use of this style in mapping the Faerie City of Embra for the Community Atlas a couple of years ago, of which the "Hilly Places" maps are perhaps the more helpful to see some examples of what it can do (you can access the Atlas versions via the links in the last post at the end of the page, and also of course find the FCW files in the Atlas that way).

Shessar's Battlemat Tutorials (PDFs) provide another alternative, using cliffs drawn with symbols, and map shading, similarly to what you've been doing elsewhere using Sue's connecting cliff symbols, and not dissimilar to Sue's use of sheets in her famous Merelan City map.

Although it's more often used for larger-area overland maps, the various shaded relief options (again using bevel effects) may be worth exploring further, such as via the Shaded Relief Annual, or Hadrian VI's PDF tutorial.

Overall, nothing beats thinking things over and experimenting to see what works best for you, however!