Biswon River Delta
The Biswon River Delta is an area around Sun's Beacon, and is the most densely populated region of the Lowland Plains. While only the area around the High Cape is officially a part of the city, the greater Sun's Beacon Metropolitan Area extends across the whole of the delta.
The bulk of the permanently settled areas are on a series of raised tels called locally 'highlands'. These are spaces that are far enough above the river to avoid the cyclical floods, and are the site of most of the delta's permanent structures. The lower regions are used mostly for agriculture, though varying river levels can cause issues. Silt deposits from the annual and other frequent floods have produced some of the finest soil on the continent, to the point that it's among the city's exports.
During the Mage Wars, the highlands were fortified and served as bastions, using the river as a defense, and relying on the Mage Tower on the High Cape for protection. During annual floods, they were cut off completely, and required a system of boats and ferries to move between in other months. Most trade was carried out in winter, when dragons could be driven across the frozen waters.
In earlier eras, the highlands functioned as separate towns, but starting around the Golden Age the region began to be viewed much more as a homogeneous society. By the Second Age, the Highlands started to be linked by permanent bridges, making trade and travel between them possible year-round.