SERC Data Table of Contents

meta key # modl013
dataset or series of data Reach File Version 3 (RF3) stream map and stream topology, Chesapeake Bay watershed
keywords GIS, hydrology, rivers, modeling, water quality
originator U.S. Environmental Protection Agency
file format ARC/INFO line coverage
platform Windows NT
study site locale Chesapeake Bay Watershed, USA
beg. date (yyyymmdd) acquired 19970523
ongoing? no
end date (yyyymmdd)  
meas. freq.  
site size 86838 arcs
# of stations  
west long. -80.633
east long. -74.58
north lat. 43.055
south lat. 36.602
parameters 93 reach attributes, including: basin name, cataloging unit, segment, marker index, reach length, reach type, reach name, latitude, longitude
current sharing status publically available at
current advertising status advertised by originator
abstract The U.S. Environmental Protection Agency's (EPA) Reach Files are a series of hydrographic databases of the surface waters of the continental United States and Hawaii. The structure and content of the Reach File databases were created expressly to establish hydrologic ordering, to perform hydrologic navigation for modeling applications, and to provide a unique identifier for each surface water feature, i.e., reach codes. A key characteristic of the Reach Files are their attributes which define the connected stream network. These attributes provide connectivity regardless of the presence or absence of topologic continuity in the digital linework. Flow direction is inherent in the connectivity attributes. This attribute-level connectivity enables the Reach Files to provide hydrologic ordering of stream locations using reach codes (what is upstream and downstream of a given point in the stream network) as well as network navigation proceeding in either the upstream or downstream direction. RF3 production is described as a two-step process involving the compilation of spatial and attribute data from a variety of different sources and the validation of the resulting file to ensure the integrity of the reach codes and hydrologic connectivity. The compilation of the data from RF1 and RF2, the USGS Geographic Names Information System (GNIS) database, and the 1988 USGS 1:100,000 scale Digital Line Graph (DLG) hydrography produced the interim database known as RF3-Alpha. []
additional documentation / reference article STORET User Assistance U.S. Environmental Protection Agency 401 M Street SW (4503F) Washington, DC 20460 800-424-9067 

Last Updated on 12/28/00
By Michelle Berger