Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: Average Saturation Excess-Overland Flow, 2002

This data set represents the average value of saturation overland flow, in percent of total streamflow, 
compiled for every catchment of NHDPlus for the conterminous United States. The source data set is 
Saturation Overland Flow Estimated by TOPMODEL for the Conterminous United States (Wolock, 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, elevation, 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, saturation-excess-overland-flow, south-atlantic-gulf-and-tennessee, sparrow, usgs-1ebf0eec-b989-4df9-a4e7-8a147dd17066
Organization: Department of the Interior