NSS Known Issues as of 2012/05/14

TABLE OF CONTENTS

A. General program issues
B. Alabama
C. Colorado
D. Georgia
E. Illinois
F. Maine
G. Massachusetts
H. Missouri
I. North Carolina
J. Rhode Island
K. South Carolina
L. Tennessee
M. Texas

A. General program issues

Versions of NSS prior to 5.1.2 allowed the user to select Peak-, Low-, or Probability-flows from a popup that appeared immediately when opening the NSS program. Newer versions now have these selections located within the Options screen, found in the File menu. users will need to set this and other options before using the NSS program in order to see the relevant flow types. This new Options screen also allows the user to select English or Metric units. It is hoped that these selections will be moved to the front screen of NSS in future versions to make them more obvious and accessible.

The current version of NSS has not been tested by the USGS to run on 64-bit operating systems, including Windows 7. Users have attempted to install and run NSS with some success despite errors along the way. NSS will be modified to run cleanly on Windows 7 during the next major update which is currently awaiting funding.

B. Alabama

Due to a bug in the current NSS program, Standard Errors will not be displayed with urban peak streamflow estimates. Please read the associated report, SIR 2010-5012, found on the NSS publications page, to see the corresponding standard errors of prediction.

C. 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_xxxx). The one will be added by NSS during its computations.

D. 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. 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 at: http://water.usgs.gov/osw/programs/nss/pubs.html

E. Illinois

NSS peak flow estimates from Region_7_AMS from Illinois report number SIR_2004_5103 have been modified in NSS database version 2012-05-09 to correct typos which created inaccurate prediction intervals for the PK2, PK10, PK25, PK50, and PK500 flood estimates. While the flood estimates themselves have not changed as a result of the modifications, the prediction intervals associated with those estimates may have changed considerably. Prediction Intervals for Illinois Region 7 esimates made with versions of the NSS database prior to the 2012-05-09 version should not be used.

F. Maine

All non-peak-flow equations in NSS for the state of Maine produced incorrect estimates in NSS versions prior to the 2010-11-15 release. It is recommended that any work done using the non-peak equations between 2006 and November 2010 should be checked against the published equations found at: http://water.usgs.gov/osw/programs/nss/pubs.html#me

G. Massachusetts

The Massachusetts-Rhode Island Water Science Center strongly recommends contacting a hydrologist from their office before using any peak flow estimates generated by NSS for Massachusetts or Rhode Island.

H. Missouri

Due to an error in the NSS program, prediction intervals and standard errors are not currently being displayed for Missouri urban peak-flow equations. Equation estimates have been verified by the Missouri Water Science Center, but the user will need to refer to report number SIR 2010-5073 for information on the errors associated with these estimates.

I. 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. 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 at: http://water.usgs.gov/osw/programs/nss/pubs.html.

J. Rhode Island

The Massachusetts-Rhode Island Water Science Center strongly recommends contacting a hydrologist from their office before using any peak flow estimates generated by NSS for Massachusetts or Rhode Island.

K. 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. 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 at: http://water.usgs.gov/osw/programs/nss/pubs.html

L. Tennessee

ROI equations for Tennessee (peak-flow and low-flow) are under construction and have been marked accordingly. Please do not use these equations until futher notice.

M. 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.