Draw a boundary on the water. Read it.

A lake, a reservoir, a river reach, an estuary, a bay, a stretch of open sea. Search it by name or coordinates and AQUA drops a square kilometre on it; or turn the map and draw the exact edge.

Every body of water is read from global sources — Sentinel-2 for how it looks from orbit, four decades of Landsat for whether it stays, WorldCover for its shore, the public map for what stands on it, the same climate record TERRA reads for the land. The score is a Water Score; the verdict runs Wellspring · Current · Eddy · Slack.

Every reading you run is public and joins the water wall.