From the introduction:
Arakhem exists along the banks and flood plains of a great river, the Aru, which flows eastward to the coast and the ocean beyond. Away from the fertile plains surrounding the Aru the land is rocky and arid and home to little except the usual dangers of inhospitable wastelands and bleak rocky mountains to the south (which are much quarried for the dark stone prized by the city builders of Arakhem).
Most of the inhabitable areas of Arakhem are taken up with small settlements of farming communities making the absolute most of the fertile plains. There are temple complexes and watchtowers created and maintained by whichever of the three cities of Arakhem is nearest to them and it is to those cities that the produce and output of the settlements flow.
The three cities are (from west to east) Aru-Tekel, Aru-Kala and Aru-Kamis (the latter being the subject of this document).