#' A list of statistic codes can be found here: \url{http://nwis.waterdata.usgs.gov/nwis/help/?read_file=stat&format=table}
#'
#' @param siteNumber string USGS site number. This is usually an 8 digit number
#' @param ParameterCd string USGS parameter code. This is usually an 5 digit number.
#' @param StartDate string starting date for data retrieval in the form YYYY-MM-DD.
#' @param EndDate string ending date for data retrieval in the form YYYY-MM-DD.
#' @param parameterCd string USGS parameter code. This is usually an 5 digit number.
#' @param startDate string starting date for data retrieval in the form YYYY-MM-DD.
#' @param endDate string ending date for data retrieval in the form YYYY-MM-DD.
#' @param interactive logical Option for interactive mode. If true, there is user interaction for error handling and data checks.
#' @param convert logical Option to include a conversion from cfs to cms (35.314667). The default is TRUE,
#' which is appropriate for using NWIS data in the EGRET package. Set this to FALSE to not include the conversion. If the parameter code is not 00060 (NWIS discharge),