Mapping rainwater catchment surfaces

In Western Australia many small towns in low rainfall areas have large asphalt areas to catch and channel rainwater into reservoirs. These areas can cover acres. I’m trying to map them. I am using an area of type waterworks and labeling it “Surface Catchment Area” but this does not get rendered on the map. Does anyone have a suggestion for mapping such an area appropriately?

Tag:landuse=basin maybe suitable
An area of land artificially graded to hold water.

Other possibilities: landuse=reservoir_watershed or reservoir_catchment or water_catchment

Seems like those areas are similar to the ones in the discussion on the Australian mailing list: Although it is about forests there

Basin is fairly close and it is rendered, but in blue, same as water, which seems a bit wrong. Landuse=water_catchment turns it green which would indicate woods or some-such. Didn’t render. I also tried surface=asphalt but that doesn’t render either. If I could get a grey area with a name on it, it’d be a go-er.

The basic principle on OSM is that you map what is there and let the renderers worry about how to render it.

It sounds to me that you are more concerned about how it is rendered, which is called “tagging for the renderer”, and is incorrect.

Rather than trying to get a sensible rendering by tagging, try to convince the people who maintain the standard layer that you feature is important enough to justify its own rendering rules.