Attributes for NHDplus Catchments (Version 1.1) for the Conterminous United States: Population Density, 2000

This data set represents the average population density, in number of people per square 
kilometer multiplied by 10 for the year 2000, compiled for every catchment of NHDPlus for 
the conterminous United States. The source data set is the 2000 Population Density by 
Block Group for the Conterminous United States (Hitt, 2003).
		
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: 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, population-density, rio-grande-colorado-and-great-basin, sagt, south-atlantic-gulf-and-tennessee, sparrow, usgs-d26914e4-b7ee-4c56-9c3a-988a2dadaf5c
Organization: Department of the Interior