Helvander Cataracts

The Helvander Cataracts are a series of falls and rapids on the central part of the River Helvander, where it passes over the fall line separating the upper part of its valley from the lower part. The cataracts are not navigable by boat and pose a barrier to river-borne trade; goods being moved along the river, from the lower to the upper part or vice-versa, must be portaged around them. This is accomplished via the aptly named Portage Road, which connects the great river-port city of Torrune below the falls to the much smaller (but, practically speaking, equally important) subsidiary town of Sillport above them. The cataracts themselves, the Portage Road, and Sillport all lie within the territory of the Archon of Torrune and are part of his domain.
At the cataracts, the single channel of the upper Helvander splits into many smaller channels which twist and diverge as they rush down over the fall line. These channels form a complex, braided system of whitewater rapids roaring between many small, rocky islands and outcroppings, here with calm pools between fierce torrents, there with racing cascades that plunge down into whirling eddies. In times of dry weather when the river is low, the cataracts subside to a maze of little runnels winding their way between great masses of dry boulders. In rainy weather, or in springtime when the river runs high with the meltwater of the mighty Adhemars, the cataracts thunder deafeningly and the rocky outcrops are almost hidden in masses of churning white foam. These twisting channels reunite at the bottom the cataracts where they plunge over a final, single long ledge of stone and then widen back out into the lower Helvander, suddenly slow and placid again.