- Main article: Books (Online)
- Location: On a table near Abante in the hidden basement of Shornhelm's abandoned house, Rivenspire
- Author: Anonymous
- Quest: Children of Yokuda
- Collection: Plots and Schemes
Shornhelm's substructure includes many interconnected cisterns, a honeycomb of pocketed caches which is connected to every potable well within the city.
Many of them leak into each other as a consequence of age and shoddy craftsmanship, but only one distributes water on a grander scale! This cistern is referred to as the master source, as it allows flow from an underground river directly into every smaller cistern in the city.
- To open the distribution channels you must first open both sluice gates, then turn the winch to start the external water flow.
- To clear the cistern before distribution of any residual water, close both sluice gates and then turn the winch. This will flush all water from the system in a matter of days!