According to the CUAHSI website (linked above):
Founded in 2001, the Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI) is a 501(c)3 research organization representing more than 130 U.S. universities and international water science-related organizations. CUAHSI receives support from the National Science Foundation (NSF) to develop infrastructure and services for the advancement of water science in the United States.
The NRDC currently has infrastructure to support being a CUAHSI data host. The CUAHSI WaterOneFlow web services are currently being hosted on the NRDC on a per-project basis. This means that each project gets its own database and web service, which are tailored to the individual needs of the project while still being consumable by HIS, as long as the dataset owner wishes their dataset to be hosted through us and registered with HIS.