U.S. Environmental Protection Agency USEPA Reach File Version 1.0 (RF1) for the Conterminous United States (CONUS) Table of Contents 1.0 Identification Information 1.1 Citation 1.2 Description 1.2.1 Abstract 1.2.2 Purpose 1.2.3 Supplemental Information 1.3 Time Period of Content 1.4 Status 1.5 Spatial Domain 1.6 Keywords 1.7 Access Constraints 1.8 Use Constraints 1.9 Point of Contact 1.10 Browse Graphic 1.11 Data Set Credit 1.12 Security Information 1.13 Native Data Set Environment 2.0 Data Quality Information 2.2 Logical Consistency Report 2.3 Completeness Report 2.4 Positional Accuracy 2.5 Lineage 3.0 Spatial Data Organization Information 3.2 Direct Spatial Reference Method 3.3 Point and Vector Object Information 4.0 Spatial Reference Information 4.1 Horizontal Coordinate System Definition 5.0 Entity and Attribute Information 5.1 Detailed Description 5.2 Overview Description 6.0 Distribution Information 6.1 Distributor Organization 6.2 Resource Description 6.3 Distribution Liability 6.4 Standard Order Process 6.7 Available Time Period 7.0 Metadata Reference Information 7.1 Metadata Date 7.4 Metadata Contact 7.5 Metadata_Standard_Name 7.6 Metadata_Standard_Version 7.7 Metadata_Time_Convention 8.0 Citation Information 8.1 Originator 8.2 Publication Date 8.4 Title 8.5 Edition 8.6 Geospatial Data Presentation Form 8.8 Publication Information 8.10 Online Linkage 9.0 Time Period Information 9.1 Single Date/Time 10.0 Contact Information 10.1 Contact Person Primary 10.2 Contact Organization Primary 10.4 Contact Address 10.5 Contact Voice Telephone 10.8 Contact Electronic Mail Address The following text conforms with the hierarchy of data elements in the FGDC Content Standards for Digital Geospatial Metadata. This ARC/Info coverage supersedes all earlier copies, translations or coverages of the RF1 database which may have been made by the U.S. Geological Survey (USGS) or the U.S. Environmental Protection Agency (EPA). 1.0 Identification_Information: Originator: United States Environmental Protection Agency Publication_Date: 1996 Title: USEPA Reach File Version 1.0 (RF1) for the Conterminous United States (CONUS) 1.1 Citation: See Section 8.0 - Citation Information 1.2 Description: Reach File Version 1.0 (RF1) was developed by EPA in 1982 and this is an accurate translation of that database into an ARC/INFO coverage. The RF1 source file has been maintained without modification on the EPA-IBM mainframe computer since 1982. Abstract: Reach File Version 1.0 (RF1) is a vector database of approximately 700,000 miles of streams and open waters in the conterminous United States. It is used extensively by EPA and States,and has been used by the U.S. Fish and Wildlife Service and the National Weather Service for many years. This configuration of RF1 for the geographic information systems community, extends the use of RF1 to ARC/INFO users in the U.S.Geological Survey, the U.S. Environmental Protection Agency and others. RF1 was prepared by the U.S. Environmental Protection Agency (EPA) in 1982 from stable base color separates of National Oceanographic and Aeronautical Administration (NOAA) aeronautical charts having a scale of 1:500,000. These charts provided the best nationwide hydrographic coverage available on a single scale at that time. They included all hydrography shown on USGS maps having a scale of 1:250,000 with extensive additions, corrections and improvements in detail made by NOAA from aerial photography and satellite imagery. All hydrographic features on those charts were optically scanned from the color separates using a scanner resolution finer than feature line width. The surface water features selected for inclusion in the RF1 database were converted from the scanned raster form to vector form with coordinates expressed as latitude and longitude. Surface water names in RF1 were derived from the source maps and supplemented by names from miscellaneous state maps and maps of the USGS. Many other RF1 attributes are described herein. In the 1980's, RF1 was used by EPA for performing water quality modeling on whole river basins for all of the hydrologic regions in the conterminous United States. In this role, it was used to provide national assessments and overviews of water quality and to provide the foundation for a nationwide stratified sampling frame for performing statistical summaries of modeled and measured water quality on all the surface waters of the 48 States. In the 1980's, environmental data integration was strengthened significantly by EPA using the Reach File. Whereas, STORET had, for many years, integrated the water quality monitoring data of EPA, States, the USGS, and other Federal agencies by agency codes, standard water quality parameter codes, date, time, depth, site coordinates, state, basin, and user-definable polygons, the Reach File provided STORET with the capability to search upstream and downstream to relate the environmental data of many agencies to each other along stream paths. This brought about the ability to integrate ambient water quality at sites sampled by the several hundred official monitoring agencies using STORET in a new and powerful manner. Thus, for example, any and all water quality measurements made by the USGS and stored in WATSTORE were easily accessed via STORET prior to the introduction of the Reach File, but with the Reach File, it became possible to integrate the data from USGS WATSTORE records with the much larger holdings of environmental data from EPA, States and other Federal agencies on a station-by-station basis along stream paths. Stream ordered data integration of this type was important in the development of effluent guidelines pursuant to the Clean Water Act during the 1980's, and is but one example of the new dimension in data integration made possible by the standard reach numbering scheme and the hydrologic networking provided in RF1. Linking multiple databases to RF1 and hence to each other, was accomplished by a process called reach indexing. The process takes advantage of the facts that each reach has been assigned a unique identifier and the stream path for each reach is described in terms of latitude/longitude coordinates. Using simple algebraic processing, each lat/lon point for every point of interest in a database is indexed to the closest point in the nearest RF1 reach. The unique reach number for that reach and its relative position, prorated against the full computed reach length, is placed in the database being reach indexed. From then on, access to all points that have been reach indexed in that indexed database, may be achieved in hydrological order by navigating upstream or downstream through RF1, picking up reach numbers in hydrological order from RF1 and retrieving the points of interest, if present, from the indexed database by reach numbers as the reaches are encountered in the navigation of RF1. Purpose: This ARC/INFO coverage is intended for general water resources applications within the GIS user community. It was created to replace two earlier USGS translations of RF1. This coverage supercedes all previous ARC/INFO coverages. Supplemental_Information: Limitations_of_Data: The coordinates and the attribute data of this coverage are machine conversions by EPA of the data in the EPA RF1 files exactly as it exists in the original RF1, archived in 1982. No coordinate data were altered beyond mere conversion to an Albers Equal Area projection. The RF1 streamflow data were obtained without alteration directly from EPA Storet files as data developed for RF1 in June, 1982. The RF1 streamflow data consist of mean annual flow and 7Q10 low flow estimates made at the downstream ends of more than 60,000 transport reaches coupled to an estimate of the time-of- travel velocity for the full length of those same reaches under each of those two flow regimes. EPA needed to estimate flows for more than 60,000 reaches because it needed flow data on all RF1 reaches and the USGS had consistent streamflow data on fewer than 2000 of them. Even on these few reaches where consistent data were available, the data were needed at the downstream ends of the reaches rather than where the USGS gages were typically located. Thus, in fact, all of the RF1 flow data are estimates at locations other than USGS gage sites. An additional limitation in the gage network was that vast areas of the country were without USGS data for drainage areas under 500 square miles, except for gages with data gaps, data skew, and anomalous conditions. Approximately 2,000 gages in this category were included in the data set used, such that 4112 gages with flow data were actually used in producing the estimates for all RF1 reaches. Another group of gages was used in the flow estimation process. Drainage area, an attribute essential to the flow estimation process used, is usually available from all USGS flow gages. All of the 4112 gages that included useful flow records, and approximately 4000 additional gages that did not have useful flow data for the project, were used to assign drainage area to reaches in RF1. The drainage area attribute available for gages was thereby used on approximately 8000 gages. By snapping gages to reaches, the project was able to acquire drainage area for approximately one reach in every eight reaches in RF1. Thus some gages were used for streamflow data and their drainage area measurement, and the remaining were used for only their drainage area measurement. Streamflow data from the USGS Daily Values File for the 4112 gages were used to develop estimates of mean annual flow and 7Q10 flow at the gage sites. Because of data skew and anomalous conditions at many of these gages, interactive graphics techniques were applied to the solution of the mean annual and 7Q10 flow estimates at the gage sites. The interactive graphics provided visual displays of all of the daily values at the 4112 gages to visually detect skew and data anomalies within an automated framework in which the team of hydrologists in the project were able to apply graphical procedures generally used manually by hydrologists all over the world to solve for the mean annual and 7Q10 flows. It was determined in 1982 that these estimates were essentially equal to those produced for the same gages by USGS fully automated methods, except where the data were skewed or anomalous. Hydrological procedures described in "ESTIMATION OF STREAMFLOWS FOR THE REACH FILE," June, 1982 were used in an EPA contract with W.E. Gates and Associates, Inc. to transfer the mean annual flows and 7Q10 low flows at gaged sites to the downstream ends of all reaches including ungaged reaches. The average velocities over the length of each transport reach in the Reach File were developed for those two flows using streamflow, measured time-of-travel data where available, and watershed characteristics under the same contract with W.E. Gates and Associates. EPA has advised users (1983 EPA memo to Regions, States and other RF1 users), that the overall flow estimation methodology used in producing the RF1 flow estimates was not designed to produce accurate results on start reaches or small ungaged tributaries, nor in estuaries or ungaged coastal streams. Thus the accuracy of the flow estimates in these types of streams is not expected to be adequate for many applications. The principal use of these estimates, it pointed out, was intended to be on reaches where the estimates had been made between upstream and downstream gages. Reviewers commented at that time, that the flow estimates in this latter category were essentially the same as their own which had been made by methods of their choice. EPA added that use of these flow values may benefit from an initial evaluation on a basin-wide or watershed basis, distinguishing between accuracies of the flow estimates among the various reach types, such as start reaches, and reaches in which the flow is regulated by man's activity. Factors such as irregular density of reaches in a particular area of a state or data problems within the period of record for a particular gage, may introduce local variations in the accuracy of these flow estimates. The USGS Water Resources Division cautions users that since the RF1 flow estimates are provided at the downstream ends of gaged and ungaged reaches and not at the actual gage sites, these RF1 flow estimates may differ from USGS records at the gage sites. Furthermore, the USGS Water Resources Division cautions users that these 1982 RF1 flow data are from EPA files and may not accurately represent current records of the USGS. Procedures: All procedures applied in generating this ARC/INFO configuration of RF1 consisted of database handling procedures applied by EPA to produce intermediate files appropriate for ARC/INFO import requirements, and common ARC/INFO procedures described in the ARC/INFO users manuals. The RF1 Trace File was used to generate a line coverage as an Albers Equal Area projection. The RF1 Structure File was used to provide topological attributes, hydrological modeling attributes, surface water names, and other data for this coverage, and the RF1 Reach Characteristics File was used to provide the coverage with streamflows and corresponding stream velocities. RF1 as used by EPA, retains its reach-to-reach topology in the Structure File for direct open access in mathematical modeling and upstream and downstream database traversals. All but 131 of the more than 60,000 reaches include this topological information, complete for all forms of stream path traversals and flow routing. At present, the RF1 Trace File is used by EPA for graphical display purposes and for reach indexing purposes, and it is not needed in any topological role, because all necessary topological information is contained in the RF1 Structure File. However, of interest to ARC/INFO users is the fact that a total of 3,607 reaches are not provided with reach traces in the Trace File. This is of concern because ARC/INFO builds its own topology from stream traces and is constrained to the topology it builds. Therefore, ARC/INFO users may experience difficulty where traces are not available. It uses data sources such as the RF1 Trace File as input to its topology building process, and will fail at any location within a network where there is a missing reach trace. The RF1.STRUCTx files therefore may be useful to ARC/INFO users where difficulties associated with this situation may be encountered. The following summary of differences is provided to help the ARC/INFO users assess the significance of this situation relative to his or her application: Summary of Differences: Total vector-object count in the AAT file: 64,955 arc features, some reaches represented by 2 records due to the 500 point limit per record in ARC/INFO Reaches without attributes: 129 CUSEG's in the RF1.AAT file have no match in the RF1.STRUCTx files, i.e., topologic attributes are missing on 129 reaches in RF1 Structure File. Attributes without traces: 3607 RF1.STRUCTx CUSEG's have no match in the RF1.AAT file. Since ARC/INFO builds its own topology from the RF1 trace file, it will produce topologic anomolies on 3607 reaches except where the missing trace records are isolated reaches. To be of further assistance in this matter, a file which details the presence and absence of Trace File data and Structure File data on a reach-by-reach basis has been incorporated in this coverage under the Entity_Type_Label RF1.CUSEGLIST. Reviews_Applied (February 1996): Related_Data_Sets: RF1 was built as a database consisting of two groups of record types. The first group contained three record types which provided reach-by-reach information related by Catalog unit and reach segment number (CUSEG); the second contained two record types which provided information on areal objects namely, open waters and watersheds, which were also related by CUSEG. This ARC/INFO coverage was assembled from the three record types of the first group through a reconfiguration process beginning with the use of the following three intermediate files retrieved from EPA STORET system: RF1struct.all RF1flow.all RF1trace.all The rf1trace file consists of all records of the RF1 Trace Record Type; the rf1struct consists of all records of the RF1 Hydrologic Structure Record Type; and the RF1flow file consists of a subset of the RF1 Reach Characteristics Record Type. The rf1trace was used to produce the necessary AAT file and the other two files were used as sources of attribute data. References_Cited: Reach File Manual, draft of June 30, 1986, EPA, C. Robert Horn. 1.3 Time_Period_of_Content: See Section 9.0 - Time Period Information Currentness_Reference: publication date 1.4 Status: Progress: complete Maintenance_and_Update_Frequency: As needed 1.5 Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -123.7196 East_Bounding_Coordinate: -56.9772 North_Bounding_Coordinate: 46.5590 South_Bounding_Coordinate: 21.9543 1.6 Keywords: Theme: Theme_Keyword_Thesaurus: None Theme_Keywords: RF1, Stream, Map, Reach File, Reach File Version 1.0, Hydrography, Hydrology, Flow, Velocity, Stream Names 1.7 Access_Constraints: None 1.8 Use_Constraints: None 1.9 Point_of_Contact: See Section 10.0 - Contact Information 1.10 Browse Graphic Browse Graphic File Name: rf1.gif Browse Graphic File Description: National RF1 for conterminous United States. Browse Graphic File Type: GIF - Graphic Interchange Format 1.11 Data Set Credit: 1.12 Security_Information: Security_Classification: Unclassified 1.13 (Native Data Set Environment) Source_Data_Set_Environment: The source data set environment for RF1 is STORET; the data set environment for this coverage is ARC/INFO. 2.0 Data_Quality_Information: 2.2 Logical_Consistency_Report: Chain-node topology present. 2.3 Completeness_Report: See Supplemental_Information 2.4 Positional_Accuracy: Locations in the rf1.trace.all file were given as degrees with 4 decimal digits. Thus, locations are specified to an accuracy of 0.0001 degrees, or about 11m, with the effect that all lines in RF1 retain the full positional accuracy of the RF1 source maps (scale 1:500,000). Double precision was used in ARC/INFO. 2.5 Lineage: See Supplemental_Information for overview. Process_Step 1: Process_Description: EPA provided the USGS with an official complete copy of RF1 in the 1980's with full documentation. That copy was converted by the USGS WRD to an ARC/INFO coverage which is herewith replaced. Process_Date: late 1980's Process_Step 2: Process_Description: EPA provided the USGS with another copy of the same RF1 database in 1994. That copy was converted by USGS WRD to an ARC/INFO coverage to replace the previous USGS conversion, and it is herewith replaced due to anomolies. Process_Step: 3 Process_Description: EPA translated RF1 from its native form to ARC/INFO form to produce this coverage. It provides all data elements in the RF1 Structure File; flow and velocity data elements from the RF1 Reach Characteristics File, and vector traces of streams and shorelines from the RF1 Trace File. Process_Date: May 1996 3.0 Spatial_Data_Organization_Information: 3.2 Direct_Spatial_Reference_Method: Vector 3.3 Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Point Point_and_Vector_Object_Count: 0 SDTS_Point_and_Vector_Object_Type: String Point_and_Vector_Object_Count: 64955 SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains Point_and_Vector_Object_Count: 0 4.0 Spatial_Reference_Information: 4.1 Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: Albers Conical Equal Area Alber_Conical_Equal_Area: Standard_Parallel: 29.5 Standard_Parallel: 45.5 Longitude_of_Central_Meridian: -96 Latitude_of_Projection_Origin: 23 False_Easting: 0.00000 False_Northing: 0.00000 5.0 Entity_and_Attribute_Information: 5.1 Detailed_Description: Entity_Type: Entity_Type_label: RF1.AAT Entity_Type_Definition: Arc Attribute Table (An ArcInfo artifact) Number_of_Attributes_in_Entity: 13 Attribute: Attribute_Label: - Attribute_Definition: Arc Attribute Table (An ArcInfo artifact) Attribute_Definition_Source: EPA Attribute_Domain_Values: - Attribute: Attribute_Label: FNODE# Attribute_Definition: Internal number of from-node (An ArcInfo artifact) Attribute_Definition_Source: Computed Attribute_Domain_Values: Sequential unique positive integer Attribute: Attribute_Label: TNODE#