Jacqueline V. Nolan, John W. Brakebill, Richard B. Alexander, and Gregory E. Schwarz 20020222 Version 2.0, November 10, 2003 map USGS Open-File Report U.S. Geological Survey Open-File Report 02-40 Reston, Virginia U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?erf1_2 The digital segmented network based on watershed boundaries, ERF1_2, includes enhancements to the U.S. Environmental Protection Agency's River Reach File 1 (RF1) (USEPA, 1996; DeWald and others, 1985) to support national and regional-scale surface water-quality modeling. Alexander and others (1999) developed ERF1, which assessed the hydrologic integrity of the digital reach traces and calculated the mean water time-of-travel in river reaches and reservoirs. ERF1_2 serves as the foundation for SPARROW (Spatially Referenced Regressions (of nutrient transport) on Watershed) modeling. Within the context of a Geographic Information System, SPARROW estimates the proportion of watersheds in the conterminous U.S. with outflow concentrations of several nutrients, including total nitrogen and total phosphorus, (Smith, R.A., Schwarz, G.E., and Alexander, R.B., 1997). This version of the network expands on ERF1 (Version 1.2; Alexander, et al., 1999) and includes the incremental and total drainage area derived from 1-kilometer (km) elevation data for North America. Previous estimates of the water time-of-travel were recomputed for reaches with water-quality monitoring sites that included two reaches. The mean flow and velocity estimates for these split reaches are based on previous estimation methods (Alexander et al., 1999) and are unchanged in ERF1_2. Drainage area calculations provide data used to estimate the contribution of a given nutrient to the outflow. Data estimates depend on the accuracy of node connectivity. Reaches split at water-quality or pesticide-monitoring sites indicate the source point for estimating the contribution and transport of nutrients and their loads throughout the watersheds. The ERF1_2 coverage extends the earlier drainage area founded on the 1-kilometer data for North America (Verdin, 1996; Verdin and Jenson, 1996). A 1-kilometer raster grid of ERF1_2 projected to Lambert Azimuthal Equal Area, NAD 27 Datum (Snyder, 1987), was merged with the HYDRO1K flow direction data set (Verdin and Jenson, 1996) to generate a DEM-based watershed grid, ERF1_2WS_LG. The watershed boundaries are maintained in a raster (grid cell) format as well as a vector (polygon) format for subsequent model analysis. Both the coverage, ERF1_2, and the grid, ERF1_2WS_LG, are available at: URL:http://water.usgs.gov/lookup/getspatial?erf1_2. This report describes the process of enhancements to the stream reach network, ERF1, which is an enhanced version of EPA's RF1. The U.S. Environmental Protection Agency's reach file (RF1) is a database of interconnected stream segments or reaches that comprise the surface water drainage system for the United States. A variety of attributes have been assigned to each reach in support of spatial analysis and mapping applications (see USEPA, 1996; http://www.epa.gov/waters/doc/rf1_meta.html). ERF1_2 was designed to be a digital database of river reaches capable of supporting regional and national water-quality and river-flow modeling by the water-resources community. ERF1, on which ERF1_2 is based, is used at the U.S. Geological Survey to support national-level water-quality modeling with the SPARROW approach (see Alexander and others, 2000; Smith and others, 1997). In the current and earlier analyses, the reach network is used to determine flow pathways between sources of point and nonpoint pollutants (e.g., fertilizer use, municipal wastewater discharges) and downstream water-quality monitoring locations in support of predictive water-quality models of stream nutrient transport. Acknowledgements: The authors would like to thank Richard Smith, a co-developer of the SPARROW approach, Kristine Verdin, an Stephen Char, all of the U.S. Geological Survey, for providing technical assistance. The reviewers of this report, Dave Stewart, and Mike Wieczorek, are also acknowledged for their significant contributions. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in ArcInfo format, this metadata file may include some ArcInfo-specific terminology. 19990107 Flow data calculated for 1987 Complete As Needed -127.85945237 -65.37738907 48.19440372 23.24348587 none stream river network SPARROW reach RF1 water quality reservoir inlandWaters none conterminous United States none The version of RF1 used to compile ERF1_2 was an early edition of a USGS RF1 translation and was updated by USEPA (USEPA, 1996). The capabilities of the enhanced version of RF1 (ERF1_2) and the current USEPA version have not been evaluated. The user is referred to the USEPA version [URL: http://www.epa.gov/owow/monitoring/georef/history.html] for discussions of streamflow accuracy and general background on the origin of RF1. Jacqueline V. Nolan U.S. Geological Survey mailing

12201 Sunrise Valley Dr., MS 413

Reston VA 20192 USA 1-888-275-8747 703 648-6693 jnolan@usgs.gov David L. Lorenz of the U.S. Geological Survey assembled initial versions of the documentation for this data set. Windows_NT, 5.0, Intel, ArcInfo version 8.3 U.S. Environmental Protection Agency 19960101 model Washington, D.C. U.S. Environmental Protection Agency http://www.epa.gov/waters/doc/rf1_meta.html Richard B. Alexander, John W. Brakebill, Robert E. Brew, and Richard A. Smith 19990228 map - digital data U.S. Geological Survey Open File Report 99-457 Reston, Virginia U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?erf1 The direct drainage area of each reach (RCHAREA) was computed by Smith and others (1997) using a Theissen method. It considers soley the distance to the nearest reach and does not consider any topographic features. It provides reasonably good estimates for higher-order streams, but is less accurate for lower orders. See process steps 1, 4, and 8, to assess the accuracy of MEANV and RCHTOT. This data set is believed to provide complete and accurate connectivity among the streams represented. These arcs representing streams are intended to be presented in an FNODE to TNODE orientation. The arcs are pointing in the downstream direction. The set of streams represented reflects the choices in the U.S. Environmental Protection Agency's RF1 (DeWald and others, 1985). Reservoir and lake boundaries were removed from the original RF1 data set. They are represented by a single trace to satisfy the connectivity requirements of the dataset. Centerlines were manually delineated within the RF1 shoreline boundaries (Alexander and others, 1999). The centerline reaches approximate the thalweg of each reservoir or lake. Shorelines of major estuaries and some coastal areas were added to the data set to serve as a stopping location for trace routines. Existing reaches extending within estuaries were deleted. Richard B. Alexander, John W. Brakebill, Robert E. Brew, and Richard A. Smith 19990228 map--digital data U.S. Geological Survey Open-File Report 99-457 Reston, Virginia U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?erf1 500000 Arc/Info coverages 19990228 Digital data set accessed October 1999 (none) linework, connectivity, areas Alexander, R.B., Slack, J.R., Ludtke, A.S., Fitzgerald, K.K., and Schertz, T.L. 1996 digital data U.S. Geological Survey Digital Data Series DDS 37 Reston, Virginia U.S. Geological Survey CD-ROM none Alexander and others, 1996 points and attributes Alexander, R.B., Smith, R.A., and Schwarz, G.E. 2000 model Nature Volume 403, pp. 758-761 London, England Nature 500000 Arc/Info coverages and ASCII files 2000 none Alexander and others, 2000 linework, connectivity, areas DeWald, T., Horn, R., Greenspun, R., Taylor, P., Manning, L., and Montalbano, A. 19850101 model Washington, D.C. U.S. Environmental Protection Agency 500000 Arc/Info coverage 19950101 none DeWald and others, 1985 linework and attributes Environmental Systems Research Institute, Inc. 1992 Redlands, California Environmental Systems Research Institute, Inc. paper none none none National Oceanic and Atmospheric Administration 19971201 model Washington, D.C. National Oceanic and Atmospheric Administration Arc/Info coverage 19971201 none NOAA, 1997 linework and attributes Omernik, J.M. 19870101 model Annals of the Association of the American Geographers Volume 77, pp. 118-125 unknown Association of American Geographers map 19870101 none Omernik, 1987 ecoregions Ruddy, B.C., and Hitt, K.J. 19900101 model U.S. Geological Survey Open File Report 90-163 Reston, Virginia U.S. Geological Survey Arc/Info coverage 19900101 digital data set accessed April, 1998 Ruddy and Hitt, 1990 points and attributes for reservoirs Seaber, P.R., Kapinos, F.P., and Knapp, G.L. 19870101 model Water Supply Paper 2294 Reston, Virginia U.S. Geological Survey http://water.usgs.gov/GIS/huc.html 5000000 Arc/Info coverages 19870101 none none Smith, R.A., Schwarz, G.E., and Alexander, R.B. 19971201 model Water Resources Research Volume 33, Number 12, pp. 2781-2798 Washington, D.C. American Geophysical Union http://water.usgs.gov/nawqa/sparrow/wrr97/results.html 500000 Arc/Info coverage and ASCII files 19971201 Smith and others, 1997 linework, connectivity, areas Snyder, J.P. 1987 model U.S. Geological Survey Professional Paper 1395 Reston, Virginia U.S. Geological Survey paper 19870101 none Snyder, 1987 map projections U.S. Environmental Protection Agency 19960101 model Washington, D.C. U.S. Environmental Protection Agency http://www.epa.gov/waters/doc/rf1_meta.html 500000 Arc/Info Export 19960101 none USEPA, 1996 linework and attributes U.S. Geological Survey 19970101 model The National Atlas of the United States of America parkwaysm Reston, Virginia U.S. Geological Survey http://nationalatlas.gov/ 2000000 Arc/Info coverage 19920101 digital data set accessed July, 1998 USGS, 1997a Wild and Scenic Rivers U.S. Geological Survey 19970101 model The National Atlas of the United States of America fedlandsm Reston, Virginia U.S. Geological Survey http://nationalatlas.gov/ 2000000 Arc/Info coverage 19920101 digital data set accessed July, 1998 USGS, 1997a Federal land polygons Verdin, K.L. 1996 model Sioux Falls, South Dakota U.S. Geological Survey http://edcdaac.usgs.gov/gtopo30/hydro/namerica.html online 20010101 digital data set accessed June 2000 Verdin, 1996 flow direction and elevations Verdin, K.L., and Jenson, S.K. 1996 model Sioux Falls, South Dakota Proceedings, Third International Conference/Workshop on Integrating GIS and Environmental Modeling, Santa Fe, New Mexico, January 21-26, 1996 http://edcdaac.usgs.gov/gtopo30/papers/santafe3.html online 19960101 Verdin and Jenson, 1996 flow direction and elevations (1) Estimation of reach time-of-travel: The reach time-of-travel (RCHTOT) in units of days was computed as the quotient of reach length and reach velocity for 59,364 reaches with positive values of velocity such that RCHTOT = C1 * LENGTH / MEANV (1) where C1 is a conversion factor of 0.00003797 ft-day/meter-second, LENGTH is the length in meters of the Arc reach segment, and MEANV is the mean velocity in feet per second. Reaches with missing time-of- travel are assigned a value of zero. 19981207 (2) Addition of coastal shorelines and estuary boundaries: Major estuaries and coastal shorelines were added from the National Oceanic and Atmospheric Administration USEPA Reach File Version 1.0 (RF1) (NOAA, 1997) for the conterminous United States (CONUS) as enhanced for NOAA's Strategic Environmental Assessments Division. Shorelines and estuary boundaries were snapped to existing reaches and assigned ERF1 and E2RF1 values of gt 80000. For identification purposes, the shorelines and estuary boundaries maintained the USEPA items for identification purpose. In addition, TERMFLAG = 3 was assigned to these shoreline segments. 19990404 (3) TERMFLAG check: A check was made for all coastal shoreline reaches where E2RF1 gt 80000, and TERMFLAG = 3; TERMFLAG for disconnected reaches and reaches flowing outside continental US (TERMFLAG = 2); and TERMFLAG for reaches ending at the shoreline to terminate modeling applications (TERMFLAG = 1). [E2RF1 81893, TERMFLAG = 3; correction date: 20000601] [Additional TERMFLAG changes were made to terminal and transport reaches. Correction date: 20020522]. 19990519 (4) Missing data: Reaches with missing or zero MEANQ or MEANV values (2739) were assigned a value of -9999.99. RESTOT and RCHTOT that resulted in a negative values were also assigned a value of -9999.99. 19990719 (5) Split reaches: ERF1_2 was edited to split reaches containing WQN and NAWQA sites. An automated graphical Arc AML was used for visual verification and splitting of the remaining reaches. A total of 768 reaches were split. Of the split reaches, the upstream ones were assigned a new identification number (E2RF1) and a STAID. One reach, E2RF1 29302, was assigned STAID 05020500, which was within the original 500m limit set by the AML, but remains unsplit. The radius limit was extended to 2000m to include data sampling sites that fit the criteria needed for modeling. Arc topology was updated following these changes. Manual verification of ERF1_2 arcs was completed by visual inspection for attributes E2RF1 and STAID agreement. 20000426 (6) E2RF1 check: Reaches containing multiple values for arcs were selected based on frequency of occurrence. A total of 40 reaches were selected. Arcs in ERF1_2 were edited to remove several dangle and duplicate arcs; flow direction was flipped for several arcs; several reaches were consolidated by removing pseudo nodes; STAID 01389500 was assigned to reach 61353, E2RF1 65607; TERMFLAG values were reassigned for a number of arcs, and TYPE = R was changed for one arc; several vertices were adjusted to enhance topology, and one arc was deleted to correct topology. The following new E2RF1 values were assigned to river reaches: 65608 to Waccamaw R; 65609 to *C; 65610 to Intracoastal Waterway; 65611 to Julington Cr; 65612 to Munuscong R; 65613 to Detroit R; 65614 to Rio Grande; 65615 to Sandy R; 65616 to Washougal R; 65617 to Kentack Slough. New E2RF1 values were assigned to the following shoreline reaches which were also renamed: 81893 to Delaware R; 81894 to Pacific Ocean; two segments 81895 and 81896 to L. Borgne; and 81897 to Pungo R. Arc topology was updated following these changes. [Correction date: 20010013] [E2RF1 44108, Green R, was assigned a new E2RF1 value, 65781; E2RF1 34672, PNAME "YELLOWSTONE", was changed to "MISSOURI R"; E2RF1 29130, PNAME "HEART R", was changed to "MISSOURI R"; the spelling of PNAME "KANKAKEE R" was corrected for reaches E2RF1: 20401, 20402, 20405, 40406, 20407, 20408, 20409, 20411, 20412, 20420, 20421, 20436. Correction date: 20020522]. 20000426 (7) TNODE, FNODE flipped: Reach flow direction for ERF1_2 was flipped. These arcs are currently in a FNODE to TNODE orientation. The arcs are pointing in a downstream direction. Arc topology was updated following this change. [E2RF1 10128, *B, and E2RF1 6219, Stono R, arcs were flipped to update topology. Correction date: 20020522]. 20000426 (8) Recalculate RCHTOT: An AML was used to recalculate the reach time of travel for flow for upstream and downstream portions of reaches in ERF1_2 that were split. The split reaches were identified by selecting the frequency of occurrence for ERF1. The stream reach time of travel [RCHTOT] values were recalculated. [Correction date: 20011102] [The MEANV value for E2RF1 29130 was recomputed to 2.61, and RCHTOT = 0.19611. Correction date: 20020522]. 20000426 (9) Assign FRAC: Item FRAC was assigned to ERF1_2 using an Arc AML program. The AML selects the fractional diversion of the load for reaches that share to-nodes. This fraction was applied to upstream sources and instream measurements of loads. Some special-case calculations were added to the AML based on specific knowledge of the location: ERF1 10527 Santee River, FRAC = 0.99835; ERF1 10534 Cooper River, FRAC = 0.00165; ERF1 22100 Mississippi River outflow channel, FRAC = 0.21170; ERF1 22197 Mississippi River, FRAC = 0.78830. 20000426 (10) Assign NAWQA pesticide site attributes and create site attribute file (ERF1_2.SITES): An AML program was used to create a point coverage, PEST_SIT. The PEST_SIT coverage was defined as Albers Equal-Area Conic projection. Sixty-three sites were added to ERF1_2; eight reaches were split and STAID values were assigned to the upstream reaches. A manual check was conducted to verify the association between the site and reach. In addition, several STAIDs were altered to maintain consistency with earlier versions of ERF1_2. These STAIDs were modified in both the point coverage SAMP_SIT, and the river reach coverage ERF1_2. The STAID values that were changed are as follows: 385234087071800, changed to 385234087071801; 391732085414400, changed to 391732085414401; and 393306086585200 changed to 393306086585201. Arc topology was updated following these changes. The time of travel for both reaches (RCHTOT) and reservoirs (RESTOT) was recalculated to account for the newly split reaches. FRAC attributes were also assigned to the newly split upstream reaches. ERF1_2.SITES associates a split reach with a monitoring site type. Monitoring types were associated with 723 reaches. 20000519 (11) Update NOAA Estuarine Drainage Area values: ERF1_2 reaches missing EDACDA attribute values were populated with NOAA Estuarine Drainage Area data by creating a shapefile of ERF1_2 containing missing EDACDA values and selecting the closest approximated polygon value to the missing reach. 20031120 (12) Generate watersheds for ERF1_2 reaches: The creation of a watershed grid for ERF1_2 reaches involved several preparation steps. Critical for future SPARROW modeling applications was the exact alignment of the coordinates for the reach network line grid and the boundary mask grid with the flow direction grid, NA_FD_G2 (modified version of USGS HYDRO1K flow direction data set, clipped to the conterminous U.S.) (Brakebill, J.W., 1999). The line coverage, ERF1_2_A, was projected from Albers Equal-Area, NAD 83 datum to Lambert Azimuthal Equal-Area, NAD 27 datum (ERF1_2_L), and was used to create a line grid, ERF1_2_LG, with the attribute "VALUE" set to the unique reach identification number, E2RF1. The window and snap options were set to the extents of the HYDRO1K flow direction grid, NA_FD_G2, with the cell size set to 1000 (Verdin, K., USGS, EROS Data Center, pers. comm., 7/2000). The boundary mask was registered to the coordinates of the flow direction grid by resampling the polygon grid of the mask with the cell size, window, and snap options set to the extents of NA_FD_G2. Using the flow direction data set (NA_FD_G2), and the mask of the U.S. (MASK_LG), a 1-kilometer cell-size raster grid of reach watersheds (ERF1_2WS_LG) was created (Environmental Systems Research Institute, 1992). The cell size, window, and snap options were set to the extents of NA_FD_G2, and the watershed boundary attribute "VALUE" was correlated with the unique reach identification number, E2RF1, that is associated with the coverage, ERF1_2. ERF1_2WS_LG has a Lambert Azimuthal Equal Area projection, NAD 27 datum. Several "no value" areas or "holes" were formed during the creation of the watershed grid where low elevations occur, as along coastal areas, and in the western U.S., where most of the closed basins are found. To edit these areas, a vector polygon coverage of the watershed grid, ERF1_2WS_LG, was created and an AML was invoked that assigned a unique identification number to the ERF1_2WS-LG basins draining to the interior cells that were unlinked to ERF1_2 reaches. A value greater than 95000 was assigned to these basins. Those cells adjacent to coastal watersheds were assigned a value greater than 80000 by selecting the basin value that contained the longest shared boundary. A new grid was created containing the edited watershed cells and was manually checked for errors. The final processing step was to assign a value of -9999 to the NODATA areas of the watershed grid: outgrid = con(isnull(existing ws grid),-9999,existing ws grid) A total of 93 closed basins were assigned cell values where E2RF1 gt 95000. 20030610 Vector String 62683 Albers Conical Equal Area 29.5 45.5 -96 23 0.00000 0.00000 coordinate pair 459.9360656738 459.9360656738 Meters North American Datum of 1983 GRS1980 6378206.4 294.98 Brief description of the attributes of the ERF1_2 geospatial data set and associated INFO files. Fields defined in original RF1 may not have the correct information because of enhancement processing. See USEPA (1996) for documentation on RF1. See Ruddy and Hitt (1990) for documentation of reservoir codes. See NOAA (1997) for documentation on NOAA codes. ERF1_2_A.AAT (Albers Equal Area, NAD 83): COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 FNODE# 4 5 B - 5 TNODE# 4 5 B - 9 LPOLY# 4 5 B - 13 RPOLY# 4 5 B - 17 LENGTH 4 12 F 3 21 ERF1_2_A# 4 5 B - 25 ERF1_2_A-ID 4 5 B - 29 HUC 8 8 C - 37 SEG 3 3 I - 40 RFLAG 1 1 C - 41 OWFLAG 1 1 C - 42 TFLAG 1 1 C - 43 SFLAG 1 1 C - 44 TYPE 1 1 C - 45 SEGL 4 5 F 1 49 LEV 2 2 I - 51 PNAME 30 30 C - 81 OWNAME 30 30 C - 111 OWNMCD 11 11 C - 122 RESCODE 4 5 B - 126 RESVOIR1 4 5 B - 130 RESVOIR2 4 5 B - 134 RESVOIR3 4 5 B - 138 RESVOIR4 4 5 B - 142 ERF1 4 5 B - 146 E2RF1 4 5 B - VALUE 150 STAID 15 15 C - 165 STAID_2 15 15 C - 180 PNAME-RES 30 30 C - 210 PNMCD-RES 11 11 I - 221 MEANQ 4 10 F 2 225 MEANV 4 10 F 2 229 FRAC 4 12 F 5 233 STRAHLER 4 5 B - 237 STATE1 2 2 I - 239 STATE2 2 2 I - 241 STATE3 2 2 I - 243 RCHTOT 4 12 F 5 247 RESTOT 4 12 F 5 251 TERMFLAG 4 5 B - 255 CONTFLAG 4 5 B - 259 LRATIO 4 12 F 5 263 EDACDA 5 5 C - 268 EDANAME 50 50 C - 318 HEADFLAG 1 1 I - 319 DEMIAREA 4 9 F 0 COUNT 323 DEMTAREA 4 9 F 1 327 HYDSEQ 4 5 B - ** REDEFINED ITEMS ** 29 RR 11 11 C - 29 HUC2 2 2 I - 29 HUC4 4 4 I - 29 HUC6 6 6 I - 150 STAID1 8 8 C - 158 STAID2 7 7 C - 150 SITEID 8 8 C - 29 CHAR 1 1 C - 39 CHAR2 1 1 C - Item Name Description CONTFLAG Continental flag (see below). DEMIAREA Incremental drainage area for a given reach, in square kilometers. DEMTAREA Total drainage areas upstream summed for a given reach, in square kilometers. EDACDA NOAA code identifying estuarine/coastal drainage areas for major estuaries in the United States. EDANAME NOAA name identifying estuarine/coastal drainage areas for major estuaries in the United States. ERF1_2# Arc internal number of the arc. ERF1 Unique key identifying the reach Version 1 files. E2RF1 Unique reach identification number for Version 2.0 that reflects revisions in process steps 6, 7, 10, and 11. ERF1_2_ID User assigned identification number. FNODE# Internal number of the from node. FRAC Fractional diversion of load for reaches that share to-nodes. HEADFLAG Headwater reach flag. HUC 8-digit Hydrologic cataloging unit of the reach. HUC2 2-digit Hydrologic region of the reach. HUC4 4-digit Hydrologic subregion of the reach. HUC6 6-digit Hydrologic accounting unit of the reach. HYDSEQ Sequence number for use in sorting the file in downstream order to perform network operations (e.g., summation of reach drainage area). LENGTH Reach length in meters. LEV The stream level used for hierarchical relationships, defined in RF1. LPOLY# Internal number of the left polygon, always zero. LRATIO Indicates fraction of reach lying within continental boundaries, see CONTFLAG. MEANQ Mean streamflow for reach, in cubic feet per second; a value of -9999.99 indicates nodata. MEANV Velocity corresponding to mean streamflow for reach, in feet per second. OWFLAG Open-water flag defined in RF1. OWNAME Open-water name defined in RF1. OWNMCD Open-water name code, defined in RF1. PNAME Name of the reach defined in RF1. PNAME-RES Reservoir name, defined in RF1. NMCD-RES Reservoir name code, defined in RF1. Link from arc attribute table (ERF1.AAT) to the reservoir attribute table (ERF1.RESINT). RCHTOT Reach water time of travel (days). A value of -9999.99 indicates no data. RESCODE Reservoir reach type code (see below). RESTOT Reservoir time of travel associated with the reach, in days (see below). A value of -9999.99 indicates no data. RESVOIR1 Reservoir identification number 1 (see below). RESVOIR2 Reservoir identification number 2 (see below). RESVOIR3 Reservoir identification number 3 (see below). RESVOIR4 Reservoir identification number 4 (see below). RFLAG Transport reach flag defined in RF1. RPOLY# Internal number of the right polygon, always zero. RR "River Reach" identifier. Key to RF1. SEG The 3-digit segment number. SEGL The reach length defined in RF1. SFLAG Start flag defined in RF1. SITEID Modified name for STAID STAID USGS station identification number where water-quality data was collected, assigned to the split reach. STAID1 8-character sampling site identification number (see STAID). STAID_2 A second monitoring site associated with a split reach and used for gaging channel flow beyond the station. STATE1 State FIPS (Federal Information Processing Standard) code 1. STATE2 State FIPS code 2. STATE3 State FIPS code 3. STRAHLER Strahler stream order of the reach. TERMFLAG Terminal reach flag used for model applications. TFLAG Terminal flag defined in RF1. TNODE# Internal number of the to node. TYPE The reach type defined in RF1. ERF1_2_A.NAT (Albers Equal Area, NAD 83): COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 ARC# 4 5 B - 5 ERF1_2_A# 4 5 B - 9 ERF1_2_A-ID 4 5 B - ARC# Internal number in the node attribute table. ERF1# Internal number of the arc. ERF1_ID Unique identifier. Primary key. ERF1_2_A.RESATTS (Albers Equal Area, NAD 83): COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 FIPS 5 5 I 0 6 STATE 2 2 C - 8 NUM 3 3 I - 11 DAMNAME 37 37 C - 48 RESNAME 26 26 C - 74 OWNERNAME 20 20 C - 94 OWNERCODE 1 1 C - 95 SIZECODE 1 1 C - 96 MAXCAP 9 9 N 0 105 NORMCAP 9 9 N 0 114 SURFCAP 9 9 N 0 123 POPNAME 37 37 C - 160 HUC 8 8 I - 168 RIVER 29 29 C - 197 YEAR 4 4 I - 201 PURP 10 10 C - 211 HEIGHT 5 5 N 0 216 HYDCAP 8 8 N 0 224 LOCKS 1 1 I - 225 SOURCE 1 1 C - 226 SURFAREA 9 9 N 0 235 SURFACODE 1 1 C - 236 STORAT 4 4 N 2 240 STORATCODE 1 1 C - 241 DRAINAREA 9 9 N 2 250 STLINE 1 1 I - 251 ALTST 2 2 C - 253 ALTID 5 5 I - 258 REV 4 4 F 1 262 LONDD 4 12 F 6 266 LATDD 4 12 F 6 270 RESERVOIR## 4 5 B - ** REDEFINED ITEMS ** 1 FIPSST 2 2 I - 3 FIPSCNTY 3 3 I - 6 STATENUM 5 5 C - 160 HUC2 2 2 I - 160 HUC4 4 4 I - 160 HUC6 6 6 I - ALTID Alternate state ID number, defined in reservoir. ALTST Adjacent state FIPS code, defined in reservoir. DAMNAME Name of dam, defined in reservoir. DRAINAREA Drainage area above dam, in square miles. Defined in reservoir. FIPS The 5-digit FIPS code for the state and county. FIPSCNTY The 3-digit FIPS code for the county. FIPSST The 2-digit FIPS code for the state. HEIGHT Height of dam, in feet. Defined in reservoir. HUC 8-digit Hydrologic cataloging unit of the reach. HUC2 2-digit Hydrologic region of the reach. HUC4 4-digit Hydrologic subregion of the reach. HUC6 6-digit Hydrologic accounting unit of the reach. HYDCAP Installed power capacity of dam, in megawatts. Defined in reservoir. LATDD Latitude of dam in decimal degrees. Defined in reservoir. LOCKS The number of navigation locks, defined in reservoir. LONDD Longitude of dam in decimal degrees. Defined in reservoir. MAXCAP Maximum capacity of reservoir, in acre feet. Defined in reservoir. NORMCAP Normal capacity, in acre-feet, of the reservoir of which the reach is part. Defined in reservoir. NUM Arbitrary sequence number of dam. Defined in reservoir. OWNERCODE Owner of dam code. Defined in reservoir. OWNERNAME Name of owner of dam. Defined in reservoir. POPNAME Popular name of dam. Defined in reservoir. PURP Major purpose of dam. Defined in reservoir. RESERVOIR## Link between the arc attribute table and reservoir tables. RESNAME Name of reservoir. Defined in reservoir. REV Revision number for reservoir data. Defined in reservoir. RIVER Name of river on which dam is built. Defined in reservoir. SIZECODE Reservoir size code. Defined in reservoir. SOURCE Source of changes to reservoir files. Defined in reservoir. STATE State FIPS code. Defined in reservoir. STATENUM State and sequence number for reservoir. Defined in reservoir. STLINE Flag to indicate dam is on state line. Defined in reservoir. STORAT Storage ratio. Defined in reservoir. STORATCODE Storage ratio code. Defined in reservoir. SURFACODE Surface area code. Defined in reservoir. SURFAREA Surface area of reservoir, in acres. Defined in reservoir. SURFCAP Capacity used to calculate surface area. Defined in reservoir. YEAR The year the dam was completed. Defined in reservoir. ERF1_2_A.RESEXT (Albers Equal Area, NAD 83): COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 ERF1 4 5 B - 5 RESERVOIR## 4 5 B - 9 RESCODE 4 5 B - 13 PNAME-RES 30 30 C - 43 PNMCD-RES 11 11 C - 54 MEANQ 4 10 F 2 58 RESTOT 4 12 F 5 ERF1# Unique key identifying the reach. MEANQ Mean streamflow for reach, in cubic feet per second. PNAME-RES Reservoir name, defined in RF1. PNMCD-RES Reservoir name code, defined in RF1. Link from arc RESCODE Reservoir reach type code (see below). RESERVOIR## Link between the arc attribute table and reservoir tables. RESTOT Reservoir time of travel associated with the reach, in days (see below). ERF1_2_A.RESINT (Albers Equal Area, NAD 83): COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 RESERVOIR## 4 5 B - 5 RESCODE 4 5 B - 9 PNAME-RES 30 30 C - 39 PNMCD-RES 11 11 I - 50 RESTOT 4 12 F 5 54 MEANQ-OUT 4 10 F 2 MEANQ-OUT Mean streamflow for reach below reservoir, in cubic feet per second. PNAME-RES Reservoir name, defined in RF1. PNMCD-RES Reservoir name code, defined in RF1. Link from arc. RESCODE Reservoir reach type code (see below). RESERVOIR## Link between the arc attribute table and reservoir tables. RESTOT Reservoir time of travel associated with the reach, in days (see below). ERF1_2_A.SITES (Albers Equal Area, NAD 83): COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 STAID 15 15 C - 16 STAID_2 15 15 C - 31 NAME 60 60 C - 91 TYPE 3 3 C - STAID USGS station identification number where water-quality data was collected, assigned to the split reach. STAID_2 A second monitoring site associated with a split reach and used for gaging channel flow beyond the station. NAME Sampling site name based on point coverage containing USGS water-quality data collection stations. TYPE Water-quality monitoring station type. WQN == Water-Quality Network - Including the National Stream Quality Accounting Network (NASQAN) and the Hydrologic Benchmark Network (BENCHMARK) BEN == BENCHMARK NSW == NASQAN and National Water Quality Assessment Program (NAWQA) NAW == NAWQA NS1 == NASQAN I NS2 == NASQAN II ********************************************************************* Additional explanation and domains of items in ERF1 and reservoir tables. Some attributes are from original RF1 data, and may have changed due to enhanced processing. CONTFLAG Code to approximately separate freshwater from tidal-influenced reaches. 0 == Freshwater reach, LRATIO gt= .50. 1 == Tidal reach, LRATIO .50. OWFLAG -- RF1 attribute Open-Water Flag 0 == Non-Open Water 1 == Open Water RESCODE [Note that hydraulic data displayed in the file RESV%%%%.TXT (where %%%% is a unique supplier intake and reach identification number), including water time of travel, are not available for all impoundments]. 1,2 == The reach is interior to RF1 shoreline features. 3 == The reach is the outlet reach for a reservoir with RF1 shoreline features. 4 == No shoreline features are present in the RF1 coverage. 5 == No shoreline features are present in the RF1 coverage; the reservoir is an "offstream "facility that may divert river flow (no reservoir characteristics are reported for these cases). RESTOT Where RESTOT is a positive value, the reservoir residence time (computed as a quotient of the normal capacity of the reservoir and the streamflow at the outlet of the reservoir) is used to define the water time of travel in the reach. Where multiple reaches are associated with a single reservoir, the reach share of the reservoir residence time is proportional to the reach length relative to the total reach length of the reservoir. RESVOIR1, RESVOIR2, RESVOIR3, RESVOIR4 Identification number for impoundments with hydraulic data. The ID number corresponds to RESERVOIR## in the ERF1.RESATTS file. [Note that multiple reservoirs may be associated with a reach.] RFLAG -- RF1 attribute 0 == Non-transport reach 1 == Transport reach, RF1 attribute SFLAG -- RF1 attribute 0 == Non-start reach, RF1 attribute 1 == Start reach, RF1 attribute TFLAG -- RF1 attribute 0 == Non-terminal reach, RF1 attribute 1 == Terminal reach, RF1 attribute TERMFLAG -- Modeling applications 0 == Transport reach 1 == Terminal reach 2 == Non-connected, or exits to a closed basin 3 == Shoreline reach TYPE -- RF1 attribute Reach Type - The term "reach type" not to be confused with any of the Reach File record types, refers to a one-character code assigned to each RF1 reach to categorize transport reaches and shoreline reaches as follows: A. Artificial Lake Reach (a transport reach). An artificial reach within a lake or reservoir inserted in the file to provide connection between input and output reaches of the open water. B. Bi-directional Reach (a transport reach). A reach for which the direction of flow is ambiguous. C. Coastal or Continental Shoreline Segment (a shoreline reach). A reach that represents a segment of a shoreline of a gulf, sea, or ocean. D. Dam Reach (a transport reach). A reach that is a dam through which and/or around which water flows. This type of reach has the same primary and open-water names as the next reach upstream. E. Entry Reach (a transport reach). A reach which receives flow from Canada or Mexico. F. Falls Reach (a transport reach). A reach that is either a waterfall, drop spillway, or a reach of rapids. G. Great Lakes Shoreline Segment (a shoreline reach). A reach that represents a segment of a shoreline of the Great Lakes. I. Island Shoreline Segment (a shoreline reach). A reach that represents a segment of a shoreline of an island. L. Lake Shoreline Segment (a shoreline reach). A segment that follows the shoreline of a lake other than one of the Great Lakes. M. Artificial Open Water Reach (a transport reach). An artificial reach within any open water, other than a lake or reservoir, to provide connection between input and output reaches of the open water. N. Non-Connected Reach (a transport reach). A reach not having codes to link it to other reaches. R. Regular Reach (a transport reach). A reach that has upstream and downstream reaches connected to it and that is not classified as another type of reach. S. Start Reach (a transport reach). A headwater reach that has no reaches above it and either one or two transport reaches connected to its downstream end. T. Terminal Reach (a transport reach). A reach downstream of which there is no other reach (for example, a reach that terminates into an ocean, a land-locked lake, or the ground). This type of reach has either one or two reaches connected to its upstream end. V. Open-Water Terminal Reach (a transport reach). A reach that is both a terminal reach and an artificial open-water reach. W. Wide-River Shoreline Segment (a shoreline reach). A reach that represents a segment of the left or right bank of a stream. X. Terminal Start Reach (a transport reach). A reach that is both a terminal reach and a start reach. Y. International Boundary Reach (a transport reach). A reach extending along a portion of an international boundary. Occurrences of this type of reach are not actual surface-water features. Instead, they are a type of artificial reach. They have been inserted in the file for database navigation between reaches along streams that flow out and then back into the U.S. They are not intended for usual studies of streamflow or the fate of pollutants. Z. Terminal Entry Reach (a transport reach). A reach that is both a terminal reach and an entry reach. ERF1_2WS_LG.VAT (Lambert Azmuthal Equal-Area, NAD 27): COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 VALUE 4 10 B - E2RF1 5 COUNT 4 10 B - VALUE Grid cell attribute value based on E2RF1. COUNT Grid cell count per attribute value. ERF1_2WS_LG.STA (Lambert Azmuthal Equal-Area, NAD 27): COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 MIN 8 15 F 3 9 MAX 8 15 F 3 17 MEAN 8 15 F 3 25 STDV 8 15 F 3 MIN Minimum cell value for the watershed grid. MAX Maximum cell value for the watershed grid. MEAN Mean cell value for the watershed grid. STDV Standard deviation for the watershed grid cells. none U.S. Geological Survey Ask USGS - Water Webserver Team mailing

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Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) http://answers.usgs.gov/cgi-bin/gsanswers?pemail=h2oteam&subject=GIS+Dataset+erf1_2 Although this data set has been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data and related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Export Full coverage zipped 1 http://water.usgs.gov/GIS/dsdl/erf1_2.e00.gz Export Full coverage zipped 1 http://water.usgs.gov/GIS/dsdl/erf1_2ws_lg.e00.gz None. This dataset is provided by USGS as a public service. 20041108 U.S. Geological Survey Ask USGS -- Water Webserver Team mailing

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Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) http://water.usgs.gov/user_feedback_form.html FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998