<URL:http://water.usgs.gov/nawqa-only/gis/gis_data.html>
<URL:http://water.usgs.gov/nawqa-only/rb/mrb.gif>
This data set consists of generalized boundaries of the NAWQA Surface-Water Regions (formerly called Major River Basins) proposed for regional synthesis in cycle II of NAWQA. For the most part, any Surface-water
This is one of the GIS base layers developed for DISPLAY of water-quality data. The data is not to be used for analysis.
The source of the data is the 1:2 million Hydrologic Unit Boundaries (November 2002) in the National Atlas.
NAWQA Surface-Water Regions are combinations of Water-Resources Regions (2-digit HUCs) and are referenced by a number from 1-8.
1----- New England and Mid-Atlantic: CONN, DELR, HDSN, LINJ, NECB, PODL 2----- South Atlantic-Gulf and Tennessee: ACFB, ALBE, GAFL, MOBL, SANT, SOFL, TENN 3----- Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy: EIWA, LERI, LIRB, part of MISE, part of OZRK, UIRB, UMIS, WHMI, WMIC 4----- Missouri: CNBR, KANS, part of OZRK, SPLT, YELL 5----- Lower Mississippi, Arkansas-White-Red, and Texas-Gulf: ACAD, CACI, MISE, part of OZRK, SCTX, TRIN 6----- Rio Grande, Colorado, and Great Basin: CAZB, GRSL, NVBR, RIOG, UCOL 7----- Pacific Northwest: CCYK, PUGT, USNK, WILL 8----- California: SACR, SANJ, SOCA 9----- None: Great Lakes (water; included in this coverage in case the area is needed for display) ------ None: COOK, OAHU (excluded from this coverage)
<URL:http://water.usgs.gov/nawqa-only/gis/gis_data.html>
Selected the cataloging units in the water-resources regions comprising each Major River Basin and made 8 individual MRB coverages each coded by MRB. Polygons coded as water (PLYTYPE NE 0) are excluded.
Revised REG 4 and REG 5 as requested by Dave Mueller. Generalized by 6000 m (to match the tolerance used when generalizing the NAWQA study unit boundary coverage NAWQAGENCYC2) and merged with the coastline of the standard NAWQA display coverage (NAWQAGENCYC2). Changed the field called MRB to REG to match revised terminology. Revised names to match Water Resources Region names.
REG Water Resources Regions 1 New England and Mid-Atlantic 2 South Atlantic-Gulf and Tennessee 3 Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy 4 Missouri 5 Lower Mississippi, Arkansas-White-Red, and Texas-Gulf 6 Rio Grande, Colorado River and Great Basin 7 Pacific Northwest 8 California 9 Great Lakes (water; included in this coverage in case the area is needed for display)
kjhitt@usgs.gov
kjhitt@usgs.gov