HYDROML is an XML format developed for the transport and archival of hydologic data HYDROML was originally developed by the National Water Information System (NWIS) office of the United States Geological Survey for the purposes of importing, exporting, and archiving hydrologic data from and to the NWIS data base. AquariusHYDROML is a modification of the original work to allow it to be used with the Aquarius software. AquariusHYDROML is a variation of HYDROML and not and extension. The types of hydrologic data include site information, computation instructions, corrections, ratings, shifts, time-series data including unit values and daily value statistics, peak flows, and site visit measurements. There are many differrent uses possible for HYDROML and not all data elements are used in every case. In fact many data elements will not be used depending upon the data content desired or the usage of the XML file.There are many different usage examples that are possible but the combinations are too numerous to list here. Please refer to the web site for example XML files. Information describing the source of the data within this document and/or the device or software that has created this XML Document. The device that produced this XML document. The name of the software that produced this XML document. The version of the software that produced this XML document. The agency supplying this XML document. The name of the data base containing this data in this XML document. The NWIS internal database number of the data base containing this data in this XML document. Comments about the source of this XML document. The electronic-mail address of the person to receive notification of processing of this XML file.