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Flood is one of the worst natural disasters that
causes significant damage to infrastructure,
services and agriculture plus the loss of valuablelives.
To minimize the future flood damage, themagnitude of floods that is likely to be exceeded
in a projects lifetime need to be estimated with
sufficient accuracy
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Regional flood estimation methods are used for
estimation of design floods in ungaugedcatchments, which is required in the design of
culverts, small to medium sized bridges,
causeways, farm dams, soil conservation works
and many other water resources management
tasks.
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provides vital information for the planning anddesigning of many hydraulic structures and for
risk assessment in flood plain use
Provide useful statistical relationships for the
transfer of flood frequency information from
one river basin to another within the same
homogeneous region
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to stabilize site-specific estimates based on
limited data
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is to estimate a flood magnitude (Q)
corresponding to any required return period (T)
of occurrence
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area is divided into disjoint regions and a
dimensionless flood frequency relationship isderived separately for each. Flood quantiles for
ungaged or poorly gaged drainage basins may
be estimated by assigning the basin to its
appropriate region
quantiles
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'Regions' may be contiguous geographical
areas of land or areas of a space defined
by the physical characteristics of gaged
basins
regions are located in the intense-rainfall
flood-prone areas with one of the highest
frequencies of tropical cyclone passage
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Station A, km2 n Qmean S CV Gs Qmax
Baua 103 19 280 167 0.5957 1.4340 777 Banurbor 112 24 61 15 0.2382 -0.9215 83
Abulog 1432 18 2815 1258 0.4469 0.5102 5120
Sinundungan 189 16 432 264 0.6096 0.6028 961
Matalag 655 15 382 314 0.8220 1.5155 1195
Pangul 312 21 824 1164 1.4122 1.6807 4014
Pinacanauan 655 23 1000 638 0.6385 1.1851 2776
Casile 195 24 131 65 0.4967 0.0693 241 Mallig 563 24 426 247 0.5799 0.5679 1000 Siffu 686 22 423 223 0.5257 0.8948 997 Magat 4150 24 2688 1596 0.5937 0.7232 6795
Magat 1784 18 674 425 0.6302 0.4307 1541
Matuno 558 22 436 244 0.5593 1.0598 638
Diadi 196 23 153 144 0.9402 2.4532 663
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Station A, km2 n Qmean S CV Gs Qmax
Baua 103 19 280 167 0.5957 1.4340 777 Banurbor 112 24 61 15 0.2382 -0.9215 83
Abulog 1432 18 2815 1258 0.4469 0.5102 5120
Sinundungan 189 16 432 264 0.6096 0.6028 961
Matalag 655 15 382 314 0.8220 1.5155 1195
Pangul 312 21 824 1164 1.4122 1.6807 4014
Pinacanauan 655 23 1000 638 0.6385 1.1851 2776
Casile 195 24 131 65 0.4967 0.0693 241 Mallig 563 24 426 247 0.5799 0.5679 1000 Siffu 686 22 423 223 0.5257 0.8948 997 Magat 4150 24 2688 1596 0.5937 0.7232 6795
Magat 1784 18 674 425 0.6302 0.4307 1541
Matuno 558 22 436 244 0.5593 1.0598 638
Diadi 196 23 153 144 0.9402 2.4532 663
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Method of Moments
The moments of annual flood data, {Qk ,
k=1,2, 3,n}, are estimated as follows:
Mean: Qmean = (1/n) Qk (1)
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