John Watermolen, U.S. Geological Survey 19990401 Version 2.0 vector digital data Reston, VA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?huc2m This file contains hydrologic unit boundaries and codes for the conterminous United States along with Alaska, Hawaii, Puerto Rico and the U.S. Virgin Islands. It was revised for inclusion in the National Atlas of the United States of America, and updated to match the streams file created by the USGS National Mapping Division (NMD) for the National Atlas of the United States of America. For the most current data and information relating to hydrologic unit codes (HUCs) please see http://water.usgs.gov/GIS/huc.html. The Watershed Boundary Dataset (WBD) is the most current data available for watershed delineation. See http://www.nrcs.usda.gov/wps/portal/nrcs/main/national/water/watersheds/dataset Due to its small scale (1:2,000,000), this file is intended primarily for display and analysis of regional and national data rather than for analysis of specific data. The file has been updated for inclusion in the National Atlas of the United States of America and to match the base data created for the National Atlas. 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 ARC/INFO format, this metadata file may include some ARC/INFO-specific terminology. Hydrologic Unit Code (HUC) areas in this file do not necessarily match those published in Water-Supply Paper 2294 (Seaber et al). The file has finer resolution than the maps used to determine areas published in the Water-Supply Paper. The ARC/INFO version of this file contains two additional annotation layers. One layer is called anno.maplabel1, and contains the first six digits for each accounting unit. The labels for Accounting Regions 1 though 9 have a "0" in front of the number. The second layer is called anno.catnum, and contains the last two digits for each cataloging unit. All numbers were checked manually against a 1:2,000,000 plot of the data. Also in the ARC/INFO version, imbedded in the INFO file is the HUCS_2M.TRACE file, which points to the next downstream cataloging unit for each basin. If a basin flows into another cataloging unit, that unit's code is given for the HUC_TO item. Not all basins flow into other basins; in these cases, the following codes were used for HUC_TO: - HUC_TO Meaning - 0 Ocean - 1 Flows across a national border - 2 Closed drainage A second imbedded file is HUCS_2M.AML_INDEX, which is a listing containing an index of all user-defined items in the .PAT and .AAT files. Note. HUCS_2M.TRACE and HUCS_2M.AML_INDEX are accessed through INFO by selecting for the file. These files have not been updated for Version 2.0. INDEX_HUC.AML, which creates the index file, is also available through INFO. 19981001 Ground Condition Complete As Needed 170.87 -66.88 71.77 17.68 none Hydrologic Unit Boundaries Hydrologic Unit Codes Drainage Basins Cataloging Units Hydrologic Units Watersheds inlandWaters none United States Alaska Hawaii Puerto Rico Virgin Islands None. Acknowledgment of the National Atlas of the United States of America and (or) the U.S. Geological Survey would be appreciated in products derived from these data. For the most current data and information relating to hydrologic unit codes (HUCs) please see http://water.usgs.gov/GIS/huc.html. The Watershed Boundary Dataset (WBD) is the most current data available for watershed delineation. See http://www.nrcs.usda.gov/wps/portal/nrcs/main/national/water/watersheds/dataset None John Watermolen U.S. Geological Survey Cartographer mailing and physical address

505 Science Dr.

Madison WI 53711-1061 USA 1-888-275-8747 (608) 238-9334 jmwater@usgs.gov Others who have helped with this data set and the metadata include Steve Denowski, Greg Allord, Curtis Price, Ken Lanfear and David Lorenz, in addition to other colleagues within the U.S. Geological Survey. The file is stored in Windows NT 4.0 Intel, ARC/INFO version 7.1.1. U.S. Geological Survey 1987 map Reston, VA U.S. Geological Survey http://water.usgs.gov/GIS/huc.html The arc attributes were manually checked by assigning unique line weights and colors to the values, and then plotting the data. The plots were then compared to the source. The polygon attributes were checked by comparing a 1:2,000,000-scale plot to the source. The attribute accuracy is estimated at 99%. Polygon and chain-node topology are present. All polygons are labeled and were tested by using the ARC/INFO command labelerrors. All polygons were checked for closure and intersections by using the ARC/INFO intersecterr command. The file is clean. This file contains hydrologic unit boundaries and codes for all 50 States, Puerto Rico, and the U.S. Virgin Islands. Boundaries and codes are included for regions, subregions, accounting units, and cataloging units. The accuracy of the original data set was checked by comparing the digital files to several data sources. First, both the line work and the polygon labels were checked against the source compilation. No digitization errors were found during this phase. Next, the hydrologic unit boundaries were compared to the 1970 1:2,000,000-scale DLG stream file and the 1:500,000- scale Hydrologic Unit Maps. Plots containing both the streams and the hydrologic unit boundaries were made at a scale of 1:2,000,000. Hydrologic unit boundary intersections were checked, as well as problem areas such as points where streams crossed hydrologic unit boundaries on the plot but not on the hydrologic unit map. More than 400 errors were found. All errors that could be corrected were corrected. The remaining errors could not be corrected because the streams were in error rather than the hydrologic unit boundaries. Finally, the hydrologic unit boundaries were plotted at 1:2,000,000 scale and compared to the NMD 1998 1:2,000,000-scale hydrologic data set. Any discrepancies were addressed by reference to either the 1:500,000-scale or the 1:100,000-scale maps. The exceptions to this were the hydrologic unit boundaries for Alaska, Hawaii, Puerto Rico, and the U.S. Virgin Islands. The Alaska boundaries were checked on a 1:2,500,000-scale plot but not modified, because the boundaries cross glaciers, and it is difficult to distinguish flow from the glaciers. The Hawaii hydrologic unit boundaries were not reviewed because each island represents a cataloging unit. The Puerto Rico and U.S. Virgin Islands boundaries were not plotted but were reviewed on-screen using a 1:1,000,000 hydrologic data set created for the 1991 National Water Summary. The Horizontal positional accuracy of the data matches the positional accuracy of the original compilation. U.S. Geological Survey 1974-1987 map Reston, VA U.S. Geological Survey, Office of Water Data Coordination http://water.usgs.gov/GIS/huc.html 500,000 mylar separate 1974 1987 publication date HUCmaps Linework for the data set. Seaber, Paul R., Kapinos, F. Paul, and Knapp, George L., U.S. Geological Survey 1987 Water-Supply Paper 2294 Reston, VA U.S. Geological Survey http://water.usgs.gov/GIS/huc.html paper map 1987 publication date Seaber Cataloging unit names for all States except Alaska. U.S. Geological Survey 1987 map Reston, VA U.S. Geological Survey http://water.usgs.gov/GIS/huc.html 2,500,000 mylar separate 1987 publication date HUCAKmap The source contributed line work and names for hydrologic units in Alaska. U.S. Geological Survey 1972-1980 Reston, VA U.S. Geological Survey 2,000,000 digital file 1972 1980 publication date DLGHY Location of streams for accuracy testing. U.S. Geological Survey 1986 Version 1.0 map Reston, VA U.S. Geological Survey 2,000,000 digital file 1986 publication date HUCS10 Intermediate digital file. U.S. Geological Survey 1992 Version 1.1 map Reston, VA U.S. Geological Survey 2,000,000 digital file 1992 publication date HUCS11 Intermediate digital file. U.S. Geological Survey 1994 Version 1.1.1 map Reston, VA U.S. Geological Survey 2,000,000 digital file 1994 publication date HUCS111 Intermediate digital file. U.S. Geological Survey 1989 map Reston, VA U.S. Geological Survey 2,000,000 digital file 1989 publication date DLGCO Determination of boundaries for identification of offshore and onshore areas. U.S. Environmental Protection Agency 1975 map Washington, DC U.S. Environmental Protection Agency digital file 1975 publication date RF1 Information on flow between cataloging units. U.S. Geological Survey 1998 map Reston, VA U.S. Geological Survey 2,000,000 digital file 1972 1998 publication date NAStates Coastline information U.S. Geological Survey 1998 map Reston, VA U.S. Geological Survey 2,000,000 digital file 1985 1998 publication date NAHydro Coastline information The original hydrologic unit boundaries file (HUCS10) was created through the following steps: a) 1:2,000,000-scale stable-base map plots of drainage (streams) and the latitude/longitude grid were obtained from the USGS National Mapping Division (NMD). These plots were in the Lambert Conformal Conic projection, and used 1:500,000-scale State base map projection parameters. Fifteen sections were plotted using 1970 National Atlas 1:2,000,000-scale sectional boundaries. b) Individual State 1:500,000-scale hydrologic unit maps in the Lambert Conformal Conic projection were photoreduced to 1:2,000,000. c) Hydrologic unit boundaries were compiled and the edges were matched on scale-stable 1:2,000,000 plots. The boundaries were combined with the streams plots for digitizing. d) The hydrologic unit boundaries were digitized by Automated Datatron, Hyattesville, MD., which digitizes materials on contract for NMD. e) Digital data from Automated Datatron was converted to an ARC/INFO coverage, then checked and corrected. f) A detailed, annotated list was compiled, listing locations where hydrologic unit boundaries and streams were coincident, or where 1:2,000,000-scale DLG streams were in error. Wherever possible, conflicts and errors were resolved. HUCmaps DLGHY 1985-1992 HUCS10 HUCS11 was created by modifying and correcting the HUCS10 file in ARC/INFO, and combining it with a 1:2,000,000-scale U.S. counties file to identify onshore and offshore areas. Other county attributes were excluded. This process was done in ARC/INFO, and used a fuzzy tolerance of 2 meters. A small part of the original map, which laid on top of part of the Canadian Great Lakes, was deleted. The attributes were renamed and expanded. HUCS10 DLGCO 1992 HUCS11 The HUCs_2M.TRACE file was created from the River Reach 1 (rf1) coverage, which includes a pointer to the next downstream segment of each reach. The resulting file was added to INFO, along with an index created using HUC_INDEX.AML. HUCS11 RF1 1994 HUCS111 Using ARC/INFO, HUCS111 was compared with the most recent 1:2,000,000-scale streams file created by the USGS National Mapping Division (NMD) for inclusion in the National Atlas of the United States of America. Where a stream crossed a hydrologic unit boundary, the boundary was compared to the 1:500,000-scale State hydrologic unit map (Seaber). If a stream and hydrologic unit boundary intersection could not be resolved by this comparison, the USGS 1:100,000-scale topographic quadrangles were used. All corrected hydrologic unit boundaries were given a value of 5 for the Error_type attribute. The boundaries were changed by moving vertices to include the stream in the appropriate hydrologic unit. All editing was done on-screen. This step happened May 22, 1998 and November 10, 1998. The Region, Subregion, Accounting unit, and cataloging unit names from Seaber were added to the data set and spot-checked. Cataloging unit names for Alaska were added from the Alaska Hydrologic Unit Map (HUCAKmap). Values for BNDTYPE were determined from the bounding polygons using INDEX_HUC.AML. This same procedure also indexed the coverage on all user-defined items in the .PAT and .AAT files. A listing can be found in the file, HUCS_2M.AML_INDEX (imbedded in the INFO file). The attributes Error_type, Reg_name, Map_label, Catalog_Unit_Nam, and Catalog_unit_num were added to the file. Two annotation layers were also added to the coverage. One layer is called anno.maplabel1, which shows the first six digits for each accounting unit. The labels for accounting Regions 1 though 9 have the "0" in front of the number. The second annotation layer is anno.catnum, and this layer has the last 2 digit codes for each cataloging unit. All numbers were checked manually on a 1:2,000,000-scale plot of the data set. The cataloging unit names were spot-checked. The file was modified to agree with the official National Atlas coastline (NAStates) The ARC/INFO coverage was exported to create the shapefiles and SDTS files. HUCS111 Seaber HUCAKmap NAStates NAHydro 1998 Vector GT-polygon composed of chains 5348 0.0000716142749 0.0000716142749 Decimal Degrees North American Datum of 1983 GRS1980 6378206.4 294.98 Hydrologic Unit (described by US_HUCS_ALB.PAT or Hucs00p020.dbf) A subdivision of the Earth, used for the collection and organization of hydrologic data. Regions, subregions, accounting units, and cataloging units are all types of hydrologic units. U.S. Geological Survey Shape The representation of the entity in the data U.S. Geological Survey Polygon 2-dimensional element ESRI GIS software Area The size of the shape in coverage units U.S. Geological Survey 0.000 9.069 Perimeter The perimeter of the shape in coverage units U.S. Geological Survey 0.004 41.175 US_HUCS_ALB# or Hucs00m020 Internal feature number U.S. Geological Survey 2 5348 US_HUCS_ALB-ID or Hucs00m020 User-assigned feature number U.S. Geological Survey 1 5345 Plytype A code indicating the classification of offshore polygons U.S. Geological Survey 0 Land, including islands. U.S. Geological Survey 2 Open Water. U.S. Geological Survey Huc The Hydrologic Unit Code. The code is 8 digits and can be subdivided as follows: Digits Type 1-2 Water Resource Region 1-4 Subregion 1-6 Accounting Unit 1-8 Cataloging Unit This is the same as Cat. There are six polygons in the file with a Huc of 0; these polygons are not assigned to any hydrologic unit. U.S. Geological Survey 1010001 21020002 Reg_name The Water Resource Region name. U.S. Geological Survey Hydrologic Unit Maps: Seaber, P.R., Kapinos, F.P., and Knapp, G.L.: U.S. Geological Survey Water_supply Paper 2294; 1987 U.S. Geological Survey Alaska State Hydrologic Unit Map, U.S. Geological Survey map; 1987 U.S. Geological Survey Map_label A 6-digit character string of the hydrologic unit code. This was created to help map production and a zero was added in front of the single digit regions. U.S. Geological Survey 010100 210200 Subregion The Subregion name. U.S. Geological Survey Hydrologic Unit Maps: Seaber, P.R., Kapinos, F.P., and Knapp, G.L.: U.S. Geological Survey Water_supply Paper 2294; 1987 U.S. Geological Survey Alaska State Hydrologic Unit Map, U.S. Geological Survey map; 1987 U.S. Geological Survey Account_na The Accounting Unit name. U.S. Geological Survey Hydrologic Unit Maps: Seaber, P.R., Kapinos, F.P., and Knapp, G.L.: U.S. Geological Survey Water_supply Paper 2294; 1987 U.S. Geological Survey Alaska State Hydrologic Unit Map, U.S. Geological Survey map; 1987 U.S. Geological Survey Cat_nam The Cataloging Unit name. Except in Alaska, this includes the State(s) in which the unit is located. The State name is spelled out except where the cataloging unit name is very long and the cataloging unit is located in several States, in which case the State names are abbreviated with the 2-letter State FIPS code. Occasionally, State names are truncated rather than abbreviated. U.S. Geological Survey Hydrologic Unit Maps: Seaber, P.R., Kapinos, F.P., and Knapp, G.L.: U.S. Geological Survey Water_supply Paper 2294; 1987 U.S. Geological Survey Alaska State Hydrologic Unit Map, U.S. Geological Survey map; 1987 U.S. Geological Survey Huc2 The number of the Water Resource Region. This is also the first two digits of the Hydrologic Unit Code and is the same as Reg. A region is one of 21 major geographic areas within the U.S. or Caribbean area which contains either the drainage area of a major river or the combined drainage area of a series of rivers. U.S. Geological Survey 1 21 Huc4 The number of the Subregion. This is also the first four digits of the Hydrologic Unit Code and is the same as Sub. A subregion is a subdivision of a region and includes the area drained by a river system, a reach of a river and its tributaries in that reach, a closed basin, or a group of streams forming a coastal drainage area. There are 222 subregions. U.S. Geological Survey 101 2102 Huc6 The number of the Accounting Unit. This is also the first six digits of the Hydrologic Unit Code and is the same as Act. The accounting units nest within or are equivalent to the subregions. There are 352 accounting units. If the last two digits of this number are 00, the accounting unit and subregion are the same. U.S. Geological Survey 10100 210200 Reg The number of the Water Resource Region. This is also the first two digits of the Hydrologic Unit Code, and is the same as Huc2. A region is one of 21 major geographic areas within the U.S. or Caribbean area which contains either the drainage area of a major river or the combined drainage area of a series of rivers. U.S. Geological Survey 1 21 Sub The number of the Subregion. This is also the first four digits of the Hydrologic Unit Code and is the same as Huc4. A subregion is a subdivision of a region and includes the area drained by a river system, a reach of a river and its tributaries in that reach, a closed basin, or a group of streams forming a coastal drainage area. There are 222 subregions. U.S. Geological Survey 101 2102 Acc The number of the Accounting Unit. This is also the first six digits of the Hydrologic Unit Code and is the same as Huc6. The accounting units nest within or are equivalent to the subregions. There are 352 accounting units. If the last two digits of this number are 00, the accounting unit and subregion are the same. U.S. Geological Survey 10100 210200 Cat The number of the Cataloging Unit. This is the same as Huc. A cataloging unit is currently the smallest element in the hierarchy of hydrologic units, and represents part or all of a surface drainage basin, a combination of drainage basins, or a distinct hydrologic feature. There are 2150 cataloging units. If the last two digits of this number are 00, the cataloging unit and accounting unit are the same. Cataloging units may also be referred to as watersheds. There are 6 polygons in the file with a Cat of 0; these polygons are not assigned to any hydrologic unit. U.S. Geological Survey 1010001 21020002 Cat_num The number of the Cataloging Unit. This is a redefined Huc or Cat number changed into a character string. U.S. Geological Survey 1010001 21020002 Hydrologic Unit Boundary (described by US_HUCS_ALB.AAT or Hucs00l020.dbf) A boundary between hydrologic units. U.S. Geological Survey Shape The representation of the entity in the data U.S. Geological Survey Polyline 1-dimensional element that surrounds a 2-dimensional element. ESRI GIS software Fnode# or Fnode_ Internal number of the from-node U.S. Geological Survey 1 9039 Tnode# or Tnode_ Internal number of the to-node U.S. Geological Survey 1 9039 Lpoly# or Lpoly_ Internal number of the polygon to the left of the arc U.S. Geological Survey 1 5348 Rpoly# or Rpoly_ Internal number of the polygon to the right of the arc U.S. Geological Survey 1 5347 Length The length of the arc in coverage units. U.S. Geological Survey 0.000 6.143 US_HUCS_ALB# or Hucs00m020 Internal feature number U.S. Geological Survey 1 11576 US_HUCS_ALB-ID or Hucs00m020 User-assigned feature number U.S. Geological Survey 1 11576 Bndtype The code number describing the location or type of the hydrologic unit boundary. Boundaries occur between hydrologic units and between onshore and offshore parts of the same hydrologic unit. U.S. Geological Survey 0 Coastline or International Boundary separating offshore and onshore parts of the same hydrologic unit. U.S. Geological Survey 2 Land and occasionally water boundary between two Water Resource Regions. U.S. Geological Survey 4 Land and occasionally water boundary between two Subregions. U.S. Geological Survey 6 Land and occasionally water boundary between two Accounting Units. U.S. Geological Survey 8 Land and occasionally water boundary between two Cataloging Units. U.S. Geological Survey Error_type A code indicating the type of conflict between the streams file and the hydrologic unit boundary. U.S. Geological Survey 0 No conflict exists. U.S. Geological Survey 4 There was an error in the streams file. The hydrologic unit boundary was not changed. U.S. Geological Survey 5 There was a conflict between the NMD streams data and the 1:500,000-scale Hydrologic Unit Boundaries map. The hydrologic unit boundary was changed to agree with the streams. U.S. Geological Survey 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 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 4858 kb http://water.usgs.gov/GIS/dsdl/huc2m.e00.zip Export Full coverage zipped 48 http://water.usgs.gov/GIS/dsdl/huc2m.e00.gz Export Region 01 New England zipped 155 http://water.usgs.gov/GIS/dsdl/huc01_2m.e00.gz Export Region 02 Mid-Atlantic zipped 349 http://water.usgs.gov/GIS/dsdl/huc02_2m.e00.gz Export Region 03 South Atlantic-Gulf zipped 702 http://water.usgs.gov/GIS/dsdl/huc03_2m.e00.gz Export Region 04 Great Lakes zipped 369 http://water.usgs.gov/GIS/dsdl/huc04_2m.e00.gz Export Region 05 Ohio zipped 257 http://water.usgs.gov/GIS/dsdl/huc05_2m.e00.gz Export Region 06 Tennessee zipped 90 http://water.usgs.gov/GIS/dsdl/huc06_2m.e00.gz Export Region 07 Upper Mississippi zipped 310 http://water.usgs.gov/GIS/dsdl/huc07_2m.e00.gz Export Region 08 Lower Mississippi zipped 307 http://water.usgs.gov/GIS/dsdl/huc08_2m.e00.gz Export Region 09 Souris-Red-Rainy zipped 101 http://water.usgs.gov/GIS/dsdl/huc09_2m.e00.gz Export Region 10 Missouri zipped 656 http://water.usgs.gov/GIS/dsdl/huc10_2m.e00.gz Export Region 11 Arkansas-White-Red zipped 377 http://water.usgs.gov/GIS/dsdl/huc11_2m.e00.gz Export Region 12 Texas-Gulf zipped 389 http://water.usgs.gov/GIS/dsdl/huc12_2m.e00.gz Export Region 13 Rio Grande zipped 171 http://water.usgs.gov/GIS/dsdl/huc13_2m.e00.gz Export Region 14 Upper Colorado zipped 144 http://water.usgs.gov/GIS/dsdl/huc14_2m.e00.gz Export Region 15 Lower Colorado zipped 138 http://water.usgs.gov/GIS/dsdl/huc15_2m.e00.gz Export Region 16 Great Basin zipped 167 http://water.usgs.gov/GIS/dsdl/huc16_2m.e00.gz Export Region 17 Pacific Northwest zipped 414 http://water.usgs.gov/GIS/dsdl/huc17_2m.e00.gz Export Region 18 California zipped 241 http://water.usgs.gov/GIS/dsdl/huc18_2m.e00.gz SDTS Full coverage zipped 41 http://water.usgs.gov/GIS/dsdl/huc2m.sdts.tgz SDTS Region 01 New England zipped 148 http://water.usgs.gov/GIS/dsdl/huc01_2m.sdts.tgz SDTS Region 02 Mid-Atlantic zipped 306 http://water.usgs.gov/GIS/dsdl/huc02_2m.sdts.tgz SDTS Region 03 South Atlantic-Gulf zipped 584 http://water.usgs.gov/GIS/dsdl/huc03_2m.sdts.tgz SDTS Region 04 Great Lakes zipped 316 http://water.usgs.gov/GIS/dsdl/huc04_2m.sdts.tgz SDTS Region 05 Ohio zipped 230 http://water.usgs.gov/GIS/dsdl/huc05_2m.sdts.tgz SDTS Region 06 Tennessee zipped 92 http://water.usgs.gov/GIS/dsdl/huc06_2m.sdts.tgz SDTS Region 07 Upper Mississippi zipped 264 http://water.usgs.gov/GIS/dsdl/huc07_2m.sdts.tgz SDTS Region 08 Lower Mississippi zipped 257 http://water.usgs.gov/GIS/dsdl/huc08_2m.sdts.tgz SDTS Region 09 Souris-Red-Rainy zipped 95 http://water.usgs.gov/GIS/dsdl/huc09_2m.sdts.tgz SDTS Region 10 Missouri zipped 541 http://water.usgs.gov/GIS/dsdl/huc10_2m.sdts.tgz SDTS Region 11 Arkansas-White-Red zipped 309 http://water.usgs.gov/GIS/dsdl/huc11_2m.sdts.tgz SDTS Region 12 Texas-Gulf zipped 310 http://water.usgs.gov/GIS/dsdl/huc12_2m.sdts.tgz SDTS Region 13 Rio Grande zipped 153 http://water.usgs.gov/GIS/dsdl/huc13_2m.sdts.tgz SDTS Region 14 Upper Colorado zipped 134 http://water.usgs.gov/GIS/dsdl/huc14_2m.sdts.tgz SDTS Region 15 Lower Colorado zipped 130 http://water.usgs.gov/GIS/dsdl/huc15_2m.sdts.tgz SDTS Region 16 Great Basin zipped 158 http://water.usgs.gov/GIS/dsdl/huc16_2m.sdts.tgz SDTS Region 17 Pacific Northwest zipped 370 http://water.usgs.gov/GIS/dsdl/huc17_2m.sdts.tgz SDTS Region 18 California zipped 218 http://water.usgs.gov/GIS/dsdl/huc18_2m.sdts.tgz 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://answers.usgs.gov/cgi-bin/gsanswers?pemail=h2oteam&subject=GIS+Dataset+huc2m_v112 FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998