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FLOWROUTING

TECHNIQUES

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Flow Routing Techniques1.Channel Routinga. Muskingum Method

b. Reservoir Routing

2.Hydraulic Routing

a. St. Venant Equations

b. umerical Solutions

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Flow Routing! p oce!u e to determine

the ti"e #n! "#gnitu!e o" #o$

at a %oint on a w#te cou se$

&

!%%lications'(lood #o$ analysis

(lood Control )esign(lood (orecasting*ater Conveyance

Systems+eak (lo$ Estimation

," the #o$ is a #ood-

the %rocedure is kno$nas #ood routing.

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1. Channel Routing

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a. M/S0, /M ME H3)

CH%NNEL ROUTING4

S5 storage ,5 in%ut 35 out%ut0 6time constant "or storage coe7cient85 $eighing "actor 9:;8;:.4<

* e d g e s t o r a g e

+ r i s m s t o r a g e

i n # o $

o u t # o $

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a. M/S0, /M ME H3)&e i'#tion o( )us*ingu" Equ#tion:

at t = t 2 - S 2 = 0 >8 , 2 ? 91 5 88 , 1 ? 91 5 8

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a. M/S0, /M ME H3)

CH%NNEL ROUTINGD

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a. M/S0, /M ME H3)+ oce!u e:,$ -nowing - #n! ./ select #n #pp op i#te'#lue o( 0t$

1$C#lcul#te outing coe2cients 3#se! on 0t/-/ .$

4$C#lcul#te the out5ow h6! og #ph usingthe )us*ingu" outing equ#tion with t7,#n! t 8no$ o( ti"e steps$

CH%NNEL ROUTING

C3 C1 C2

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E9#"ple:

a. M/S0, /M ME H3)

CH%NNEL ROUTINGF

iven 9kno$ns

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b. RESERV3,R R3/ ,

CH%NNEL ROUTING1:

!lso kno$n as storage routing +rocedure "or calculating the out#o$hydrogra%h "rom a reservoir $ith ahori ontal $ater sur"ace (lo$ o" #ood $aves "rom rivers streamskee%s on changing the head o" $ater inthe reservoir h = h9t<

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b. RESERV3,R R3/ ,

CH%NNEL ROUTING11

,n%ut data needed "or storage routinginclude the in#o$ hydrogra%h andreservoir characteristics9storage and outlet "acilities<

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2. Hydraulic Routinga. St. Venant Equation

I5 discharge in channel!5 area o" #o$ in the channel

12

0 xQ

t

A

EquatiContinuity

=∂∂+∂

∂

0 xQ

t

A

EquatiContinuity

=∂∂+∂

∂

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2. Hydraulic Routinga. St. Venant Equation

I5 discharge in channel!5 area o" #o$ in the channelS : 6 bed slo%eS " 6 Jction slo%e o" channel

1&

( ) 0S-Sg-xy

gA

QxA

1

tQ

A1

:EquationMomentum

f o

2

=∂∂+

∂∂+

∂∂

Kinematic wave

Diffusion waveDynamic wave

( ) 0S-Sg-xy

gA

QxA

1

tQ

A1

:EquationMomentum

f o

2

=∂∂+

∂∂+

∂∂

Kinematic wave

Diffusion waveDynamic wave

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2. Hydraulic Routinga. St. Venant Equation

0inematic *aves he kinematic $ave method assumes that

the motion o" the hydrogra%h along thechannel is controlled mostly by gravity and

"riction "orces. here"ore- uni"orm #o$ isassumed to take %lace.

1

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2. Hydraulic Routinga. St. Venant Equation

)iKusion $avea. )iKusion $ave routing is accom%lished bycombining and solving equations. ManningLsequation is used to estimate the "riction slo%eS " . here"ore- the channel must be describedas a series o" cross sections that adequatelydescribe the hydraulic character o" the entire#o$ %ath- including slo%e- geometry- androughness

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2. Hydraulic Routing

1A

!ssum%tions "or St. Venant

Equations• (lo$ is one5dimensional• Hydrostatic %ressure %revails and

vertical accelerations are negligible• Streamline curvature is small.• ottom slo%e o" the channel is small.• ManningLs equation is used to

describe resistance eKects• he #uid is incom%ressible

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Sources'!%%lied Hydrology by Cho$+ro". , Eldho- )e%t. o" CivilEngineering- ,, ombayHydrogra%h Routing- )e%artment o"

eoscience- /niversity o" evada GasVegas

1D