Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Base-Flow Index, 2002

This tabular data set represents the mean base-flow index expressed as a percent, compiled for every catchment of
MRB_E2RF1 catchments of Major River Basins (MRBs, Crawford and others, 2006). 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 MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's
(USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality
modeling (Nolan and others, 2002; Brakebill and others, 2011).

Data were compiled for every catchment of MRB_E2RF1 catchments for the conterminous United States
covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes,
Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi,
Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6),
the Pacific Northwest (MRB7) river basins, and California (MRB8).