Tag:sinkhole=ponor
 sinkhole = ponor
|
 |
| Description |
|---|
A sinkhole draining water, either temporarily or permanently, from a water body or a water stream 
|
| Group: natural |
| Used on these elements |
    |
| Requires |
| Useful combination |
Status: approved
|
| Tools for this tag |
|
A ponor is a sinkhole draining water, either temporarily or permanently, from a water body or a water stream. It can be associated with polje as the draining orifice, and with rivers and streams, leading to their complete, permanent, or partial, temporary disappearance. It lies in a natural=water polygon or, if swallowing the water of a waterway, on a node along the waterway=* way. The waterway, when entirely and permanently losing in the ponor, stops on its node; else, its course downstream the ponor is often intermittent and should be tagged intermittent=yes accordingly. Of course, the waterway can already be temporary before the sinkhole, so tag it according to its nature.
Ponors does not always have a well-defined orifice, and often are few square meters areas filled with permeable alluviums or simply punctured by dozens of holes, whose location will only be clear by the sucking noises they make while water drains through them, or by the orientation of aquatic plants, curved in their direction by the water flow. Such area being also a ponor, it should me mapped as one unoccupied orifice.
Ponors can lead to complex karst systems, constitute karst fensters or be the source of the waters of a karstic spring. In addition, you should not try to map the course of the disappeared water. For details on what to map, not to map, and how, see sinkhole=*.
Example
The 
Danube river water is drained by several ponors, among them the Danube Sinkhole; downstream, the Danube is intermittent. The sinkhole would be tagged as a node of the Danube way, this way:
natural=sinkhole sinkhole=ponor name=Danube Sinkhole name:de=Donauversinkung
The Danube way would be cut on the node, and you would add intermittent=yes on the section downstream.