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<br />Errata Sheet for U.S. Geological Survey Water. Resources <br />Investigations Report 94-4002 <br /> <br />The foUowing errors or omissions were noted in U.S. Geological Survey Water-Resources Investigations Repon 94- <br />4002 after is was printed. This e1Tllla sheet corrects those errors or omissions. <br /> <br />Page 20 - #7 - The National Flood Frequency (NFF) program allows the weighting of the logarithms of the estimated <br />and observed peak discharges using the equivalent years of record of the regression estima!e and the number of <br />years or observed record as the weighting faclOrs, When equivalent years of record are available for the regression <br />equations. the user is prompted 10 enter the numbec of years of observed record and the observed peak discharges. <br />NFF was changed to allow the user to enter observed values of the SOO-year flood and 10 compute a weighted estimate <br />of the 500-year flood even if the 500-year regression equation is not available for a given State. The equivalent years <br />of record of the l00-year regression equation and the extrapolated 500-year flood are used in this calculation. <br /> <br />Page 124 - North Dakota - The regression constant for Q2 for Region C should be 4.08. not 7.08. <br /> <br />Page 127 - Ohio - The exponents for (l3-BDF) in the statewide urban equations are incorrecL For completeness. the <br />correct equations are given below: <br /> <br />UQ2 = 155 AO,68 (P_30)0.50 (13_BDF)-ll.50 <br />UQ5 = 200 AO.71 (p_30)0.63 (13.BDF)-ll.44 <br />UQIO = 228 AO.74 (p_30)O,68 (13.BDF)-ll,4l <br />UQ25 = 265 AO,76 (p-30l.72 (13_BDF)-ll.37 <br />UQ50 = 293 A 0.78 (p_30)0.74 (13.BDF)-ll.3S <br />UQlOO = 321 AO,79 (p.30)O,76 (13.BDF)-ll.33 <br /> <br />Figure 2 showing the average (mean) annual precipitation for Ohio was inadvertently omitted from the <br />documentation. The necessary figure is given on the back of this page (Sherwood. 1993). <br /> <br />Page 176 . Wyoming - The Plains and High I>esen Regions regression equations are shown cooectly below (note <br />that A is raised to a power of A): <br /> <br />Q2 = 41.3A O,60A ".0,05 Of Q2 = 6.66A 0.59 A ".0.03 PRO.60 Of <br />Q5 = 63.7Ao,60A",o.OS SBo,09 Of Q5 = 10.6 A0.56A".o.03 PRO,8t Of <br />QIO = 76.9Ao.S9A".o.OS 5Bo.14 Of QIO = 13.8 Ao.SSA"-ll.03PRO.900f <br />Q25 = 94.2A0.59A".o,OS 5Bo,19 Of Q25 = 19.4 Ao.S3 A".o.03 PRo.98 Of <br />Q50 = 112 A 0.58A".o,OS SBo.23 Of Q50 = 24.2 Ao.S2A"-ll,03 PR1.02Of <br />QlOO = 130 A0.58A".o.OS SBO.2S Of QlOO = 30.1 AO.5t A".o.03 PR1.OS Of <br />Q200 = 182 AO,S7A".o,OS 5Bo,26 Of Q200 = 36.0 Ao.Sl A".o.03 PR1.07 Of <br />Q500 = 245 AO.S7A".o.OS 580,27 Of Q500 = 47.1 AO.SOA".o,03 PR1.09 Of <br /> <br />Page 190 . The fonnat of the outpUt file for the flood. frequency curve ordinates was modified 10 appear as foUows: <br />------.--..-----....---.-----------National Flood Frequency Progmm-.-....---------------- <br />Flood Peak Discharge, in cubic feel per second <br />Date: 09/21/1994 10:30 <br />Basin: Hypothetical River near Example <br />Consult the log file for the input data. <br /> <br />Recurrence Interval. years <br /> <br />2 <br /> <br />5 <br /> <br />10 <br /> <br />25 <br /> <br />50 <br /> <br />100 <br /> <br />500 <br /> <br />Rural <br />National Urban <br />Statewide Urban <br /> <br />8120 <br />24000 <br />19000 <br /> <br />13200 <br />32000 <br />25100 <br /> <br />17400 <br />35000 <br />29200 <br /> <br />22100 <br />40000 <br />34500 <br /> <br />26700 <br />44000 <br />38500 <br /> <br />29800 <br />47500 <br />42100 <br /> <br />39900 <br />59800 <br />55000 <br />