The seminar, entitled, "An Introduction to the National Hydrography Dataset," will include a description of the dataset, details on how to use and access it, and some examples of how NRIS has utilized the dataset to store and disseminate stream information. The presentation will conclude with an audience question and answer session.

The National Hydrography Dataset (NHD) is a nationally consistent and comprehensive set of digital spatial data that contains information about surface water features such as lakes, streams, rivers, and wells. The U.S. Geological Survey (USGS) and the Environmental Protection Agency (EPA) developed it jointly over the past several years.

The NHD provides 'intelligent' Geographic Information System (GIS) network functions, like navigating upstream and downstream or selecting all river 'reaches' upstream from a single point. NRIS Director Jim Hill said, "These functions are quite powerful. For example, users can enter a single point on a stream and find the 'mainstem' downstream path, which would be very useful in tracking the path of a hazardous spill in a particular stream. Other stream related data, such as water quality problems, fish species present, and water right diversions can easily be 'attached' to NHD streams."

Hill added that the system has information on over 11,600 named streams in Montana, over 200,000 linear miles of the state's streams, and over 17,000 of her lakes and ponds.

Natural resource and water information professionals, as well as the public, are invited to attend. This seminar is free of charge. For more information, call (406) 444-5356. Interested individuals are also encouraged to visit the NRIS website at: nris.state.mt.us.

The Montana Natural Resource Information System (NRIS) was established in 1985 by the Legislature. NRIS, a division of the State Library, acts as a clearinghouse for natural resource information.