The DataDescriptor element defines one type of data at a location for a site and contains the computation instructions for this data and contains the actual data (unit values, daily values, Peaks, and statistics). The Data descriptor sequence number. The Data descriptor sequence number. The Data descriptor parameter code. Flag indicating if this DD is the official DD for this parameter at this locationon The label used to identify the data descriptor. The default daily values table format to use. The code identifying type of access to the data of this data descriptor. NWIS data services flag indicating if this DD is to be deleted