Maidment & Tarboton: The CUAHSI Hydrologic Information System enables water data to be delivered through the internet in a common language called WaterML, which describes time series of observations measured at a point locations for quantities such as streamflow, water quality, climate and groundwater conditions. Collections of water observations data from a variety of sources are stored in the CUAHSI Observations Data Model and published in WaterML as CUAHSI water data web services....