National Streamflow Statistics Program: Known Issues

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The National Streamflow Statistics (NSS) Program compiles regression equations for estimating streamflow statistics for every state, Puerto Rico, and a number of metropolitan areas in the U.S. This page documents known issues with the NSS software program.

 

Return to the main National Streamflow Statistics Program site.

 

General program issues - last updated Jan. 10, 2017

No known general issues at this time.

Colorado

If input variables include "Percent_above_7500_ft", enter actual percentage (not percentage plus 1 as indicated in the associated report number SIR 2009_5136). The one will be added by NSS during its computations. Also note that prediction errors for Annual Monthly and Mean Streamflows have been corrected for Mountain, Northwest, Rio Grande, and Southwest hydrologic regions as well as Duration flows for Southwest hydrologic region.

Georgia

For Peak_Southeast_US equations in Georgia, North Carolina, or South Carolina, the sum of all percentages entered into NSS by the user must be equal to 100% in order for the equation output to be valid. If all output values report zero, the rounded sum of input values did not equal 100%. Since NSS rounds to 3 significant figures, it is best to enter only 3 significant figures and make sure that all rounded parameters add to 100%. See report number SIR 2009-5043 (GA), SIR 2009-5158 (NC), or SIR 2009-5156 (SC) for further details. Links to these reports can be found on the NSS publications page.

Note: NSS results from databases starting with the 2014-03-26 version and ending before the 2014-10-07 version may have produced incorrect results if the above input rule was violated. Results from inputs that added to 100% were unaffected by this error.

Montana

Errors were found in the Montana flood frequency equations from the NW_Region_BasinC_2015_5019F region installed in the 2016-04-20 and newer databases. This region has been removed until replacement equations can be developed.

North Carolina

For Peak_Southeast_US equations in Georgia, North Carolina, or South Carolina, the sum of all percentages entered into NSS by the user must be equal to 100% in order for the equation output to be valid. If all output values report zero, the rounded sum of input values did not equal 100%. Since NSS rounds to 3 significant figures, it is best to enter only 3 significant figures and make sure that all rounded parameters add to 100%. See report number SIR 2009-5043 (GA), SIR 2009-5158 (NC), or SIR 2009-5156 (SC) for further details. Links to these reports can be found on the NSS publications page.

Note: NSS results from databases starting with the 2014-03-26 version and ending before the 2014-10-07 version may have produced incorrect results if the above input rule was violated. Results from inputs that added to 100% were unaffected by this error.

South Carolina

For Peak_Southeast_US equations in Georgia, North Carolina, or South Carolina, the sum of all percentages entered into NSS by the user must be equal to 100% in order for the equation output to be valid. If all output values report zero, the rounded sum of input values did not equal 100%. Since NSS rounds to 3 significant figures, it is best to enter only 3 significant figures and make sure that all rounded parameters add to 100%. See report number SIR 2009-5043 (GA), SIR 2009-5158 (NC), or SIR 2009-5156 (SC) for further details. Links to these reports can be found on the NSS publications page.

Note: NSS results from databases starting with the 2014-03-26 version and ending before the 2014-10-07 version may have produced incorrect results if the above input rule was violated. Results from inputs that added to 100% were unaffected by this error.

Texas

Users needing to estimate peak streamflows for Texas should consult report number SIR 2009-5087 before using NSS to solve the regional regression equations. This report provides information needed by the user to determine input values and application limits. Failure to do so may result in improper estimates. This report replaces previous peak-flow equations from WRIR 96-4307.

Return to the main National Streamflow Statistics Program site.