Article from Status and Trends of the Nation's Biological Resources on the serious impacts to river systems due to damming and flow regulation, and rehabilitation, monitoring, and research on such rivers.
Homepage linking the historic journey of Lewis and Clark and the research of the USGS in the same region with links to mapping history, remarkable points on the Missouri River, educational activities, photo gallery, and publications.
Portal for Missouri River Infolinks, a clearinghouse to multiple links giving Missouri information, photo gallery, river weather forecast, projects and features, maps, meetings, history, and science research.
Main page for National Hydrography Dataset (NHD), a comprehensive set of digital spatial data about surface water features, with links to references, data, software tools, applications, tutorials, technical support, and data maintenance.
Homepage for description of the National Stream Quality Network (NASQAN), a long-term program monitoring the concentrations and flux of sediment and chemicals in the Nation's largest rivers (Mississippi, Columbia, Colorado, Rio Grande, and Yukon).
Explains how the NHD specifies point locations within streams by using a code to indicate the reach (including the hydrologic unit) and a measure, which indicates how far the point is from the downstream end of the reach.