|waterway = dam|
|A wall built across a river or stream to block and regulate the flow of the river|
|Rendering in openstreetmap-carto|
|Used on these elements|
|Tools for this tag|
A wall built across a river or stream to impound the water. A dam normally does not have water flowing over the top of it.
How to Map
- Smaller dams can be drawn as a way and tagged with waterway=dam.
- Bigger dams can be drawn as an area and tagged with waterway=dam + name=*.
Validators and QA tools generally want that the waterway=river have shared node(s) with the waterway=dam if and where they cross it (flow through it). If the river runs in a tunnel well underneath the dam it should be mapped as waterway=river + tunnel=yes + layer=-1 without any shared nodes with the dam.
|small dam as a way|
|big dam as an area|
(High-)ways over a dam
|The following section is disputed. You can join the discussion.|
Validators and QA tools may complain about this combination because many have an overly generic rule saying that highways and waterways can not share a single way - this is one of the valid exceptions and tools should be fixed to accept it.
Example of ways over dam: