Andrew Davidson <thesw...@gmail.com> writes: > On 15/2/23 02:00, Greg Troxel wrote: >> For wetlands, the definitions in the US: >> >> https://www.fws.gov/media/classification-wetlands-and-deepwater-habitats-united-states >> > > Which is: > > In general terms, wetlands are lands where saturation with water is > the dominant factor determining the nature of substrate development > and the types of plant and animal communities living in the substrate > and on its surface. The single feature that most wetlands share is a > substrate that is at least periodically saturated with or covered by > water. The water creates severe physiological problems for all plants > and animals except > those that are specially adapted for such conditions. > > > The same definition is used in AU: > > https://wetlandinfo.des.qld.gov.au/resources/static/pdf/ecology/soils/qw-soil-indicators.pdf > >> More or less, a wetland is characterized by being wet for at least a >> portion of the growing season in a normal year. And, just because you >> don't see standing water doesn't mean the soil is not wet. > > I assume you are referring to this:
Yes, and I was aware of plant test above and skipped it for simplicity. Also because it seems that if the plant species are predominately those adapted for wet, then surely there must often be water. > If neither plants nor soil is present, then the wetland identification > must be made strictly on the basis of hydrology. In this case, the > substrate should be “saturated with water or covered by shallow water > at some time during the growing season of each year.” Cowardin et > al. (1979) fully realized how vague this hydrologic definition was > but, given the lack of detailed hydrologic data from the diversity of > wetland types, geologic regions, and climatic regions of the U.S., > there was no > way they could have been more specific. > > This is a rule of thumb that is used if the plant and soil > characteristics are not present (or if the information is not > available). It is a rule based on wetland data from the US. The > Australian ecosystem is far more fragile and inundation less often > than annually is enough to make it the dominant factor. So, if you want to say that wetland scientists in AU consider specific areas that do not have soil or plants but which are flooded every few years to be natural=wetland, that sounds fine to tag it as such. It won't be swamp, because that's a wetland with trees. Or if there are trees and AU wetland scientists call it swamp because of the every-few-years flood being dominant, I'm ok with natural=swamp. I do not think we should invent a new tag "dry_swamp", as that's drawing a distinction that seems not found in the professional literature. If there is some idea from the literature to adapt, that's ok too, but the hierarchy of OSM should follow the hierarchy of the literature (swamp first, subtype is less than annual, to make something up). _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
