I am glad you said any other method, and not all methods.  Ecologists, soil scientists, hydrologists, botanists, geologists and wildlife biologists might all contribute information on what was wetland reference condition, and what is it now.  Was it drained, farmed, connected to streams with ditch, intentially burned or not burned (fire suppressed).  Have invasive plants or other organisms taken over habitat or are present.  Is it polluted accidentially or intentionally.  Was it an isolated wetland, but now connected to water, originally no fish, now fish; this is a habitat alteration.  Is the wetland fed by rain, stream, runoff from vicinity, shallow groundwater, deep groundwater?  If I remember or find any references on wetland, I will send.

Hi Aravinda,

Please follow this link for the answer to your query.

https://water.usgs.gov/nwsum/WSP2425/functions.html

Good luck