The US Geological Survey has software applications available for use in the public interest and advancement of science. A full listing of software applications - streamflow, groundwater, water quality and chemistry, and statistics and graphs - are available to the public, subject to the USGS software User's Rights Notice.
GCLAS (Graphical Constituent Loading Analysis System) is a program designed primarily to compute daily and annual loadings of constituents transported in streamflow. GCLAS provides a visual environment for evaluating the relation between covariate time series and the constituent chemograph, and has an interactive graphical interface that permits easy entry of estimated values and provides tools to aid in making those estimates.
StreamStats is a Web application that provides access to an assortment of Geographic Information Systems (GIS) analytical tools that are useful for water-resources planning and management, and for engineering and design purposes. The map-based user interface can be used to delineate drainage areas for user-selected sites on streams, and then get basin characteristics and estimates of flow statistics for the selected sites anywhere this functionality is available.