Reconstructs URLs to retrieve data from here: https://waterdata.usgs.gov/nwis/wu
Arguments
- years
integer Years for data retrieval. Must be years ending in 0 or 5, or "ALL", which retrieves all available years.
- stateCd
could be character (full name, abbreviation, id), or numeric (id)
- countyCd
could be numeric (County IDs from countyCdLookup) or character ("ALL")
- categories
character Two-letter cateogory abbreviation(s)