The Delube river is the lifeblood of Acanthia. The outlands’ farms & greenhouses draw on it exclusively for irrigation, it provides fresh bounties of fish every day in Fisherman’s Paradise (a major exporter to Acanthia), and Caldera City indulges in virtually unlimited water use because of its steady flow.
The Delube starts in the mountain ranges to the north, flows to the northernmost point of the Acanthian volcano, and then splits into 2 overland flows and an underground flow. The overland flows encircle the volcano like a natural moat, meeting at the south-west corner of the mountainside and continuing to flow towards the ocean. The underground flow pools into a massive aquifer underneath the city which also connects back up to the south-west corner of the mountainside.
Guys, you may notice that I have made one significant change to the geography with respect to the flow of the river Delube after it hits Acanthia. I’ve decided the river flowing above ground rather than continuing underground is both more plausible and makes certain story elements fit together more nicely. It will not affect anything you’ve already done.