Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: Base-Flow Index

This tabular data set represents the mean base-flow index expressed as a percent, 
compiled for every catchment in NHDPlus for the conterminous United States. Base 
flow is the component of streamflow that can be attributed to ground-water discharge 
into streams. The source data set is Base-Flow Index 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: base-flow-index, 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-cbe96d52-d957-4158-b0fc-74890f7f5e37
Organization: Department of the Interior