Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: NLCD 2001 Tree Canopy

This data set represents the mean percentage of tree canopy from the Canopy Layer of the 
National Land Cover Dataset 2001,  (LaMotte and Wieczorek, 2010), compiled for every 
catchment of NHDPlus for the conterminous United States. The source data set represents 
tree canopy percentage for the conterminous United States for 2001. The Canopy Layer of 
the National Land Cover Data Set for 2001 was produced through a cooperative project 
conducted by the Multi-Resolution Land Characteristics (MRLC) Consortium. The MRLC 
Consortium is a partnership of Federal agencies (http://www.mrlc.gov), consisting of the 
U.S. Geological Survey (USGS), the National Oceanic and Atmospheric Administration 
(NOAA), the U.S. Environmental Protection Agency (USEPA), the U.S. Department of 
Agriculture (USDA), the U.S. Forest Service (USFS), the National Park Service (NPS), 
the U.S. Fish and Wildlife Service (USFWS), the Bureau of Land Management (BLM), 
and the USDA Natural Resources Conservation Service (NRCS).
		
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, rio-grande-colorado-and-great-basin, sagt, south-atlantic-gulf-and-tennessee, sparrow, tree-canopy, usgs-afec6afe-7fe0-4946-81aa-f6bb290f2bdb
Organization: Department of the Interior