Flood Estimation Handbook: Corrigenda and FAQs


All significant FEH corrigenda notified by CEH are listed in the tables below.


Chapter / Page



15/21The reference in the last paragraph of Section 5.6 should read (see 3 10 and 4 7.3.2), not (see 3 10 and 4 7.3.1)28/4/00
110/52Figure 10.1 - the vertical axes should read 'Flood peak (m3s-1)'24/9/02

Brackets have been omitted from the numerator term of Equation (2.6), which should read:

InR - f - d1In12 + d2 (In12 - InD)

22/6In the third sentence of Section 2.4, replace the word 'consistent' by 'internally consistent'21/6/00
23/9The first sentence of section 3.3 should read previous chapter, not previous section28/4/00
28/39The factor 0.005 in Equation (8.5) is wrong. The correct value is 0.0510/7/01
29/43Figure 9.2 is not correct. Figure 9.3 has been duplicated in place of the correct Figure 9.223/7/01
210/51Within Table 10.1, the 'Duration (hours)' value of 16 is wrong. The correct value is 8 (as shown correctly in Table 2.1 on page 8 of FEH Volume 2).10/7/01
215/87Section numbering shown as 15.6 should be 15.7  (ditto on Contents page vii)4/2/02
21/101The heading for the second block of data should be 'South-west England' not 'South-east England'10/10/01
311/69With Example 11.2, the vertical axis should read 'Flood peak (m3s-1)'24/9/02
312/88The 'In' function within equations 12.15 and 12.18 should be replaced by '-In'11/7/00
312/89In Example 12.4, the 'In' function in the expressions for calculating RV7 and RV8 should be prefixed by a minus sign. The numerical values resulting should be of opposite sign to that shown, ie RV7 = +0.112, RV8= -0.06011/7/00
313/101The 10th (bottom) line of Table 13.1 should be assigned as 0.0198RESHOST and not RESHOST. The contents of the line have also been 'reversed' and should read: 1.81 1.12 1.01 0.93 0.4819/3/02
313/106Caption to Figure 13.2 should include: (3463 'ungauged' catchments) rather than 'gauged'1/2/02
313/117The beginning of the fourth line should read '13.6 - 13.8' not '13.6 - 3.8'4/8/04
314/136Figure 14.3 - the vertical axes should read 'Flood peak (m3s-1)'24/9/02
315/146In the paragraph below Equation 15.12, the third sentence should read 'If k < 0 the distribution is known as a type II GEV distribution'. The fourth sentence should begin 'If k > 0, the distribution is known as a type III GEV distribution'.26/3/04
315/150Within Equation 15.44 a minus sign is missing so that the parameter k is defined as k = -t3[...]. Within Equation 15.45 the last term within curly brackets in the denominator is incorrectly shown as 1-exp (-k2/2). It should read 1-exp (k2/2).8/10/04
316/154Within Section 16.1.3, under the sub-heading: Choosing an appropriate size of pooling-group, the words 'longest return period', should be replaced by 'return period for which the flood frequency estimate is principally required'.8/10/04
316/156Within Section 16.2.2, line 7 of the last paragraph should read: 'which ranges from 0.17 to 1'24/9/02
316/163Within Equation 16.8, the superscripts on t2 and t3 should be P, not R24/9/02
316/180The reference in the second sentence (Bayliss and Jones, 1994) should read (Bayliss, 1994). It has been omitted from the references listed on page 282 and should have been included there as: Bayliss, A C, 1994. On the variability of flood occurrence. Report to MAFF, Institute of Hydrology, Wallingford, UK.28/6/00
322/264Within Figure 22.2, the two diagrams labelled (a) and (b) have been transposed. Fig 22.2(a) is in fact the Annual maximum data, while Fig 22.2(b) illustrates the POT records.10/5/00
322/269Within the first sentence of Section 22.5.3, 'extending holdings' should read 'extending pre-FEH  holdings'26/6/00
318/198Equation 18.13 should read: In UAF = g In (1+URBEXT) + In PRUAF3/10/05

In Figure 2.5, the annotation should read:
'Up = 2.2 AREA'
(ie the same as Eqn 2.6)

42/23The top line of the equation at the top of the page should read:
'= ∑pi (i -δT/2)'

The exponents used in the intermediate step of example 2.3a are incorrect as listed. The line should read:

Tp(0) = 4.270 (101.40)-0.35 (0.54)-0.80 (8.50)0.54 (1.026)-5.77

The answer, 3.80 hours, is correct as shown

43/55Line 5 should read 'D/Tp ratios between 1.4 and 3.4', not '...between 1.4 and 5.0'.18/7/00
43/55The y-axis scale on the graph in Figure 3.10 is a factor of 10 times too large; it should run from 0.25 to 0.60 (rather than 2.5 to 6.0).22/7/02
44/69The title of the top part of Table 4.2 should read 'Winter PMP as % of all-year value' NOT '...all-year 1-hour value'.4/2/02
46/101Near the start of Section 6.2, URBEXT should be assigned the value 0.038 and not 0.077.7/6/00

Step 3: The API5 calculation equation, and computed answer, are incorrect. The equation should read:

API5 = √0.5 [Pd-1 + (0.5)Pd-2 + (0.5)2 Pd-3 +
(0.5)3 Pd-4 + (0.5)4 Pd-5]

API5 = √0.5 [5.4 + (0.5) 33.3 + (0.5)2 5.0 +
(0.5)3 1.6 + (0.5)4 26.7] = 17.80 mm (not 10.80 mm)

The incorrect value of 10.8mm has been used in the remainder of the example, so the suggestion is to consider the example as simply illustrating the technique for a value of API5=10.8mm.

46/111The first sentence of Step 9 should refer to BF from Step 8, not from Step 7.28/4/00
49/136In Example 9.1, the DPSBAR values for the total catchment and East subcatchment are quoted as 101.40 m/km and 76.29 m/km but the equivalent values abstracted from the FEH CD-Rom are 145.90 m/km and 138.60 m /km respectively. It is unclear where this discrepancy originated. The incorrect values of 101.40 m/km and 76.29 m/km have been used in the remainder of the example, so the suggestion is to consider the example as simply illustrating the technique assuming these values.22/7/02
4Appx A/163

Equation A.2 is incorrect. It should be:

API5 = √0.5 [Pd-1 + (0.5) Pd-2 + (0.5)2 Pd-3 +
(0.5)3 Pd-4 + (0.5)4 Pd-5]

4Appx A/164

Example A.1c. API5 equations should read:

API5 = √0.5 [Pd-1 + (0.5) Pd-2 + (0.5)2 Pd-3 +
(0.5)3 Pd-4 + (0.5)4 Pd-5]

API5 = √0.5 [3.0 + (0.5)0.0 + (0.5)2 0.0 +
(0.5)3 2.8 + (0.5)4 0.0] = 2.4 mm

4Appx A/191'g mean' for station 33045 should be 17.4 and not 7.4 as shown22/10/01
4Appx C/247

Under RSMD - the equation to estimate ARF is incorrectly given as ARF = exp (- 0.020 AREA)0.25. The bracket should be outside the 0.25 power, ie 'ARF = exp (- 0.020 AREA 0.25)'.

4Appx D/275Equation D.3 should read 'A (dh/dt) = i + Ap-q'
not 'A (ds/dh) = I + Ap-q'
4Appx D/276Equation D.8. Delete the term (dS/dh) and replace it by (dh/dt).18/7/00
48/124In Example 8.1, SPR from HOST is incorrectly shown in two places as 36.5%. The correct value is 52.6%. The incorrect value of 36.5% has been used throughout the example, so the suggestion is to consider the example as simply illustrating the technique for a value of SPR = 36.5%.7/2/01
56/53Equation 6.8 - the term within the parentheses is in radians.30/6/05

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Corrections to the Defra/EA R&D Technical Report FD1913/TR "Revitalisation of the FSR/FEH rainfall-runoff method" are listed below. The report is available on the Defra website: enter "FD1913" in the box entitled 'Project search by', then select the Technical Report "Revitalisation of the FSR/FEH rainfall runoff method".





Equation 5.5. Missing "-" in front of ∅ for winter. See Eq. (G.3) for the correct form.

8/89Wrong Tp equation: it should be
Tp = 1.563 PROPWET-1.09 DPLBAR0.6 (1+URBEXT)-3.34 DPSBAR-0.28

Table G.1. Values of a for 2h, 6h and 1d should be negative.
See Table 5.2 for correct values.


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FAQs and Support Information

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