Each XML Web Service needs a unique namespace in order for client applications to distinguish it from other services on the Web.

WaterML namespace

This is an XML namespace defined in WaterML documentation. 
The documentation can be accessed at http://water.sdsc.edu/WaterOneFlow.
WaterOneFlow is a collection of web services developed by the CUAHSI HIS project.

For more details on XML namespaces, see the W3C recommendation on Namespaces in XML.

For more details on WSDL, see the WSDL Specification.

For more details on URIs, see RFC 2396.