Base-flow index grid for the conterminous United States

May 7, 2014
Uploaded by Emily Granstaff
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Dataset was scientifically peer reviewed
Description:
This 1-kilometer raster (grid) dataset for the conterminous United States was created by interpolating base-flow index (BFI) values estimated at U.S. Geological Survey (USGS) streamgages. Base flow is the component of streamflow that can be attributed to ground-water discharge into streams.
Data Provided By:
David M. Wolock
Content date:
1884, 2001
Citation:
Wolock, David M. 2003. Base-flow index grid for the conterminous United States.  U.S. Geological Survey Open-File Report 03-263.  U.S. Geological Survey. Reston, Virginia.
http://water.usgs.gov/lookup/getspatial?bfi48grd

Spatial Resolution:
1000.0 (meter)
Contact Organization:
U.S. Geological Survey
Contact Person(s):
Use Constraints:
The BFI grid was interpolated from BFI point values estimated for USGS streamgages (Wolock, 2003a). These point values were computed using an automated hydrograph separation computer program called the BFI program (Wahl and Wahl, 1988; 1995). Regarding this computer program, the BFI Web page (http://www.usbr.gov/pmts/hydraulics_lab/twahl/bfi/index.html) states:

"The BFI program was developed to make the base-flow separation process less tedious and more objective. The program implements a deterministic procedure proposed in 1980 by the British Institute of Hydrology. The method combines a local minimums approach with a recession slope test. The program estimates the annual base-flow volume of unregulated rivers and streams and computes an annual base-flow index (BFI, the ratio of base flow to total flow volume for a given year) for multiple years of data at one or more gage sites. Although the method may not yield the true base flow as might be determined by a more sophisticated analysis, the index has been found to be consistent and indicative of base flow, and thus may be useful for analysis of long term base-flow trends. Users should be very cautious about using methods such as this for short-term storm events or for locations where streamflow is affected by upstream regulation, such as reservoir releases. In general, the method interprets most regulated releases as base flow. If the program is used for regulated streams, the effects of regulation must be carefully accounted for through manual adjustment of the program output."

The base-flow index grid can be used to estimate natural recharge to ground water. (See Supplemental_Information.) The base-flow index approach to estimating ground-water recharge is likely to underestimate "true" recharge in areas where irrigation is used extensively and also in areas where ground-water evapotranspiration is significant. More details about the approach and its limitations can be found in Wolock (2003b).

Use Constraints References:

Wahl, K.L., and Wahl, T.L., 1988, Effects of regional ground-water declines on streamflows in the Oklahoma Panhandle, in Proceedings of Symposium on Water-Use Data for Water Resources Management: Tucson, Arizona, American Water Resources Association, p. 239-249, information available on the World Wide Web, accessed March 25, 2003, at URL http://www.usbr.gov/pmts/hydraulics_lab/twahl/bfi/bfi_beaver_river.pdf

Wahl, K.L., and Wahl, T.L., 1995, Determining the flow of Comal Springs at New Braunfels, Texas, in Proceedings of Texas Water '95, August 16-17, 1995, San Antonio, Texas: American Society of Civil Engineers, p. 77-86, information available on the World Wide Web, accessed March 25, 2003, at URL http://www.usbr.gov/pmts/hydraulics_lab/twahl/bfi/texaswater95/comalsprings.html

Wolock, D.M., 2003a, Flow characteristics at U.S. Geological Survey streamgages in the conterminous United States: U.S. Geological Survey Open-File Report 03-146, digital dataset, available on the World Wide Web, accessed June 30, 2003, at URL http://water.usgs.gov/lookup/getspatial?qsitesdd

Wolock, D.M., 2003b, Estimated mean annual natural ground-water recharge estimates in the conterminous United States: U.S. Geological Survey Open-File Report 03-311, digital dataset, available on the World Wide Web, accessed August 20, 2003, at URL http://water.usgs.gov/lookup/getspatial?rech48grd













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Tags:
groundwater, inlandwaters, baseflow, base-flow index
Downloaded by 31 Members
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About the Uploader

Emily Granstaff
SARP Cartographer with SARP/USFWS

I work with the Southeast Aquatic Resources Partnership to support the development of regional aquatic habitat assessments and restoration projects in the Southeastern US.