Attributes for NHDPlus Catchments (Version 1.1) in the Conterminous United States: Bedrock Geology

This data set represents the area of bedrock geology types in square meters compiled for every 
catchment of NHDPlus for the conterminous United States. The source data set is the "Geology 
of the Conterminous United States at 1:2,500,000 Scale--A Digital Representation of the 1974 
P.B. King and H.M. Beikman Map" (Schuben and others, 1994).  
		
The NHDPlus Version 1.1 is an integrated suite of application-ready geospatial datasets that 
incorporates many of the best features of the National Hydrography Dataset (NHD) and the 
National Elevation Dataset (NED). The NHDPlus includes a stream network (based on the 
1:100,00-scale NHD), improved networking, naming, and value-added attributes (VAAs). 
NHDPlus also includes elevation-derived catchments (drainage areas) produced using a 
drainage enforcement technique first widely used in New England, and thus referred to as 
"the New England Method." This technique involves "burning in" the 1:100,000-scale NHD 
and when available building "walls" using the National Watershed Boundary Dataset (WBD). 
The resulting modified digital elevation model (HydroDEM) is used to produce hydrologic 
derivatives that agree with the NHD and WBD. Over the past two years, an interdisciplinary 
team from the U.S. Geological Survey (USGS), and the U.S. Environmental Protection 
Agency (USEPA), and contractors, found that this method produces the best quality NHD 
catchments using an automated process (USEPA, 2007). The NHDPlus dataset is organized 
by 18 Production Units that cover the conterminous United States.
		
The NHDPlus version 1.1 data are grouped by the U.S. Geologic Survey's  Major River Basins 
(MRBs, Crawford and others, 2006).  MRB1, covering the New England and Mid-Atlantic River 
basins, contains NHDPlus Production Units 1 and 2.  MRB2, covering the South Atlantic-Gulf 
and Tennessee River basins, contains NHDPlus Production Units 3 and 6.  MRB3, covering the 
Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy River basins, contains NHDPlus 
Production Units 4, 5, 7 and 9.  MRB4, covering the Missouri River basins, contains NHDPlus 
Production Units 10-lower and 10-upper.  MRB5, covering the Lower Mississippi, Arkansas-White-Red, 
and Texas-Gulf River basins, contains NHDPlus Production Units 8, 11 and 12.  MRB6, covering the 
Rio Grande, Colorado and Great Basin River basins, contains NHDPlus Production Units 13, 14, 15 
and 16.  MRB7, covering the Pacific Northwest River basins, contains NHDPlus Production Unit 17.  
MRB8, covering California River basins, contains NHDPlus Production Unit 18.

Tags: bedrock-geology, cali, california, catchment, cogb, conterminous-united-states, environment, geoscientificinformation, glmr, great-lakes-ohio-upper-mississippi-and-souris-red-rainy, inlandwaters, lmtg, lower-mississippi-arkansas-white-red-and-texas-gulf, major-river-basin, missouri, mori, mrb, mrb1, mrb2, mrb3, mrb4, mrb5, mrb6, mrb7, mrb8, nawqa, nema, new-england-and-mid-atlantic, nhdplus, pacific-northwest, panw, rio-grande-colorado-and-great-basin, sagt, south-atlantic-gulf-and-tennessee, sparrow, usgs-d9605097-3065-456e-b8c8-a6fca5f0d228
Organization: Department of the Interior