retval dataframe with first column dateTime, and at least one qualifier and value columns
(subsequent qualifier/value columns could follow depending on requested parameter codes)
# NOT RUN {site1 <- whatWQPsites(siteid="USGS-01594440")
type <- "Stream"sites <- whatWQPsites(statecode="US:55",countycode="US:55:025",siteType=type)
# }