Tantras/Sewers

The sewers of Tantras were a sanitation system of fragmentary pipe and tunnel networks beneath the city of Tantras in the Vast in the mid-to-late 14 century DR.

Structure
Due to the city of Tantras being built in some areas upon solid rock and in others upon layers of ooze, much of this network was lined with stone blocks or large sections of round tile.

The city streets had many central gutters where runoff washed down into the harbor, in some cases passing through pipes that laid beneath the wagon-ways right along the docks.

Various small parts of the pipe networks emptied through grated outlets into the harbor from western parts of the city.

Functionality
Like many sewer systems in the Realms, this one operated on a tidal flushing system. Throughout its history, the sewers often suffered from flooding due to the Dragon Reach's tides washing the sewage back into the system whenever the wind blew eastward, though the gratings on its outlets prevented the tides from washing in large objects.

Over time, efforts were made to lessen the severity of this backwash, but they could not fully solve the issue. These included enlarging the size of pipes and hollowing out increasingly large water-chambers along the network of pipes. Attempts at establishing a huge, dungeon-like network across all of Tantras, similar to the sewers of Waterdeep, were always thwarted by flooding.

In the eastern reaches of subterranean Tantras, some of the larger chambers were outfitted with a form of primitive water-wheel—a string of buckets on chains powered by mule locomotion—which raised up to empty into silo-like water-towers. Occasionally these silos were drained in a gravity-powered flood through the easternmost sewers, carrying the dung out into the marshy fields immediately east of Tantras.

During the winter season, cold weather would cause the sewers to freeze and, even with the heat that dung generated, the system would become inefficient. On th other hand, the cold air also cut down on the smell and caused disease-carrying insects to be largely or wholly absent. Around this time of year, Tantras would resort to nightsoil carts (sometimes mounted on sledges) to carry their waste away to be spread over the farm fields surrounding the city.