Mapping wetlands in US

I was trying to figure this out since works of the US Government are public domain, is there a way to have the wetlands mapper by the US Fish and Wildlife Service as a base layer for being able to map out wetlands in OSM? I did see that the wetlands mapper program has OSM as an overlay on their site, but wonder if there is a way to do their overlay on OSM like what is done with USGS Topo Maps.

Another question related to this is since the wetland mapper program has different codes denoting type of wetland which one designation relates to how often it is flooded. Is there a general guideline as to determine what is a wetland or not? Mainly if its at least seasonally flooded since there are designations for duration of flooding from temporary, seasonal, or longer so was wondering if there is a general rule to determining what is and isn’t a wetland for OSM purposes.

I suspect most wetlands have been added from NHD imports (or (MASSGIS) which are a bit light in detailed attributes, and probably quite out-of-date. I’m not at all familiar with the additional data you mention: I think it would be worthwhile documenting it on the wiki.

There’s a lot of scope for improving wetland data, but really it needs someone relatively local for sense checking if using a federal source. I know I found the MASSGIS stuff a bit overwhelming for an area I know; and the NHD for Wrightsville Beach (NC) was certainly out-of-date (although that coastline gets remodelled every few years when a hurricane comes to land). There’s a tendency for mappers to be very wary of altering official data even when it’s clearly wrong, so its best done quickly after import.