Design of FC and Other Drainage Structures

8/18/2019 Design of FC and Other Drainage Structures

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Design of Flood Control

and Other DrainageStructures

ENGR. MONTR


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Objectives!" the end of the session# the $artici$ants %ill &e a&le

to

'. (earn the &asics of Flood Control Design)

*. +no% the design Criteria and Standards $ertainingto Flood Control and other Drainage Structure

Design ) and

,. -nderstand the $rinci$les of the design ofdrainage structures.


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Contents:I. Flood

'. Denition of /ood

*. Di0erent causes of /ood,. 1arious t"$es of /ood

II. Design of Flood Control Structures2Di3e4E5&an35ent4Re6et5ent7'. Design Data Re8uired*. Design Criteria and Standards

,. Design 9rocedures:. ;"drolog"

III. Design of Drainage Structures'. Design data re8uired*. Design Criteria and Standards,. Design 9rocedures


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I. Flood


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Flood is a te5$orar" co6ering of land &" %ater

outside its nor5al connes. This includes /oodfro5 ri6ers# 5ountain torrents and /oods fro5the sea in coastal area.

What is a food?


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Causes o Flood

E


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Stor5 Surge 2olanda

*?',7


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Causes o Flood

E


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Tsuna5i 2@a$an

*?''7


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Causes o Flood

E


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Flood Control Struct


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Causes o Flood

E


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Coastal Flood-r&an Flood9lu6ial Flood 29onding7Flu6ial Flood 2Rise of ri6er %ater surface7Flash FloodSe5i9er5anent Flood 2(and Su&sidence7

Types o Flood:


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After5ath

/o


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Design of Flood ControlStructures(Dike/Embankment/Revetment)


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Required Design Data

A. Field Sur6e" Infor5ation

'. To$ogra$hic Sur6e"

*. Crosssection Sur6e"

,. Soils Su&surface and Surface E


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C. Other Requirements

1. Topographic map of the proposed project area with

0.50 m contour interval at a scale of 1:10000 m.

!. "round profiles along the #an$s at hori%ontal and

vertical scales of 1:1000 m and 1:100 m respectivel&.

'. (ater surface profile indicating ma)imum e)perienced

flood level design water level and minimum water

level at hori%ontal and vertical scales of 1:1000 m.

1:100 m respectivel&.

*. +rofile of the river#ed along the centerline of the river channel at hori%ontal and vertical scales of 1:1000 and

1:100 m respectivel&.

5. Cross,sections facing downstream at 100 meters interval

for straight and uniform section !5 meters for river #ends

and !0 meters for sharp #ends indicating thereon the


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proposed structures ma)imum e)perienced flood level and

ordinar& water level as well as design water level and

character of #an$ and river #ed material.

-. oil investigation data and anal&sis.

/. &drologic and h&draulic design anal&sis supported #&

topographic map showing the watershed area and point

of interest.


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Design of Di3es4E5&an35ents

ridge constructed of earth stone or other material to

+revent water from passing #e&ond desira#le limits.

lso $nown as #an$.

. 2ocation and lignment

3. 4ree#oardC. lopes

. eight

6. Top (idth

4. 3erms


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Design of Re6et5ents

Revetments are flood control structures constructed alongriver #an$s su#jected to direct attac$ of the river flow

and along second di$e slopes for protection against

scouring and wave wash.


3. 4ree#oardC. lope

. eight


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1. Design of Dikes/Embankments/Levees

The term di$e7levee is an em#an$ment constructed parallel to the #an$s of a stream river la$e or other #od& of water for the purpose of

protecting the landside from inundation #& floodwater or to confine the

stream flow within its regular channel.

a8 T&pes of 2evee

1. 9r#an 2evees , 2evees that are constructed to provide protection of the densel& populated communities including their

industrial commercial and residential facilities against flooding.

!. gricultural 2evees , 2evees that provide protection from

flooding in lands used for agricultural purposes.

Design Criteria and Standards


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#. Classification of 2evees ccording to 9se.

1. ainline and Tri#utar& 2evees ; 2evees thatlie along a mainstream and its tri#utaries

respectivel&.

!. Ring 2evees ; 2evees that completel&

encircle or


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1. 6m#an$ment should #e located along high ridg

or natural #an$s where materials for constructio

of same are availa#le.

!. 6m#an$ment should not #e close to the river

#an$s otherwise it will #e in danger of #eing

undermined #& the caving of the river #an$.

'. The em#an$ment should #e well awa& from the

estimated meander #elt of the meandering river

*. The alignment should #e as straight as possi#le

as sharp curves are su#ject to direct attac$

from flow and should #e avoided.


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3. 4ree#oard

The free#oard allowance corresponding to th

esign flood discharge

6>"? >CR"6 @

A' 78

4R663OR f

Am8

2ess than !00 0.-0

!00 to less than 500 0.B0

500 to less than !000 1.00

!000 to less than 5000 1.!0

5000 to less than 10000 1.50

ore than 10000 !.00


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Top width of the em#an$ment ma& not #e of special importa

if ample free#oard and side slopes are alread& provided. owe

adequate widths of the top em#an$ment ma& #e required to serve

a road for facilitating the transport of materials during

construction stage and maintenance operations. 3elow are recommended top widths for the given design discharges.

esign ischarge Am'7s8

Top (idth Am8

2ess than 500

500 and over #ut less than !000

!000 and over #ut less than 5000

5000 and over #ut less than 10000

10000 and over

'.00

*.00

5.00

-.00

/.00

C. Top width

. lope


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p

1. The normal side slopes on #oth landside and riverside of

the em#an$ment are !:1 for low em#an$ment A*8 and ':1 fo

high em#an$ment AD*8.

!. side slope of *:1 is usuall& used for em#an$ment

consisting of sand and shall #e protected #& providing a covegood soil sodded at least 500 mm thic$.

'. 4or landside side slope the coarser or more permea#le th

material is the flatter would #e the side slope.

6. eight

The height of the em#an$ment is rec$oned from the design flooelevation plus an additional free#oard allowance depending on

design discharge as shown in Ta#le '.1.

l


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.lopes

RIVERSIDE LANDSIDEEMBANKMENT

1

2

FOR LOW EMBANKMENT

DFWLHf

1

2

4RIVERSIDE

Hf

FOR SAND EMBANKMENT

EMBANKMENT

1

DFWL

1

LANDSIDE4

3

FOR HIGH EMBANKMENT

Hf

3RIVERSIDE

DFWL

11

EMBANKMENTLAN

4. 3erm


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3erm are provided along the slopes of high em#an$ments as an er

control measure and also to improve the sta#ilit& of the side slopes:

1. Riverside

(hen the crest height from river #ed is more than -.00 metres

shall #e provided at ever& '.00 to 5.00 metres in height from crest elev

with a width of 1.00 metre or more.

!. 2andside

(hen the crest height from e)isting ground is more than *.00 m

#erms shall #e provided at ever& !.00 metres to '.00 metres in height

crest elevation with a width of '.00 metres or more.

'. asonr& di$e ma& have a minimum #erm width of 1 metre necessar& for sta#ilit& purposes.


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2. Design of Revetment


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. 2ocation and alignment

1. long meander #ends of the river.

!. t downstream and upstream of h&draulic and other related

structures where tur#ulent flow usuall& occurs.

'. >t should #e smooth to prevent formulation of vortices

dead water %ones.

*. long side slopes of irrigation canals to prevent loss of wat

due to percolations.

Scouring n!

D"gr!#ion $r#

R"%"#&"n#

Sn! Br

For&#ion

4igure '.5 2ocation of Revetment of River 3end


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3. 4ree#oard

"enerall& a minimum free #oard allowance of

0.-0 m a#ove the ma)imum e)perienced flood

level or design flood level as the case ma& #e is

provided for revetments confining flood flows.

C. lope

lope of revetment will depend on the $ind of

materials used and protection wor$s required for

the structures. Ta#le '.' shows the recommended

slopes of revetment with respect to the $ind of

materials to #e used in the construction of said

structure.


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. eight


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eights of revetment will depend on the ma)imum e)perien

flood level or design flood level. 4or other cases when com#i

with flood control wor$s such as levee7em#an$ment the height of

revetment is up to the designed height of the structures due to

possi#ilit& of the occurrence of floodwaters that ma& e)ceed

design flood level or the crest of the di$e. >f the height of revetmis more than 5.0 meters #erm must #e provided in order to separ

the revetments into segments as well as in consideration of site

geological condition and structural sta#ilit& of the revetment. 3er

shall #e at least 1.0 meter in width for maintenance purposes.

DFL

Fr""'or!

H

B"r&

('n)u"##"*

4igure '.- a 5 meters

4igure '.- # D5 meters

6.. epth of 4oundation


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p

a. 4or a narrow river Aless than 50 meters in width8 the

minimum depth of revetment foundation should #e 1.0 meter

#elow the deepest elevation of the original or design river#ed

where soil materials are su#ject to erosion7scouring.

#. 4or a wide river Amore than 50 meters in width8 and

su#jected to river #ed degradation more than 1.0,meter depth

of revetment foundation should #e considered. >n case of a

wide river where the velocit& is generall& mild and when the

mainstream course is fi)ed and flowing more than !0 meters

awa& from the #an$ the foundation ma& #e placed 1.0 meter

#elow the e)isting toe of the #an$. >f the mainstream coursehas a tendenc& to change the foundation depth should #e

determined.

c. >f the construction of the revetment foundation #elow the

original or designed river#ed is not possi#le due to high water

level the used of sheet piles or other t&pes of revetment

should #e considered.


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1+, M

- 2,+, MD""."/# ri%"r'"!

R"%"#&"n#

To"

1+, M

4igure './ epth of Revetment 4oundation


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4. egment 2ength

The length of one segment of revetment along the longitud

direction should not #e more than 50 meters in order to pre

damage on the adjoining section of the revetment onccollapses. 6dge of the segment shall #e provided with

protection and adequatel& filled with joint filler or seale

connect with the adjoining section.

". Thic$ness

The thic$ness of revetment is generall& #ased on the flowvelocit& sediment runoff topograph& geological conditions

scouring and degradation and soil and groundwater pressure

the #ac$ of revetment and other factors. inimum thic$ness

should #e '00 mm for all t&pes of revetment e)cept for

reinforced concrete t&pe.


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. (eepholes

Revetment should #e provided with weepholes ranging from

50 ; /5 mm in diameter +EC pipes spaced at !.00 meters on

center and staggered. +ervious materials consisting of gradedgravel or geo,te)tile is placed #etween the revetment and

original ground.

>. 6nd +rotection (or$s

Revetments should #e provided with end protection wor$s to

prevent scouring at the upstream and downstream ends. Thescouring causes the escape of #ac$fill materials resulting to the

gradual damage of the revetment. transition structure li$e

ga#ions7#oulders should #e provided on #oth ends of the

revetment.


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SECTION A - A

PLAN

' - 2, c& 0

- , c& 0

$ro%i/ion gin/# /couringof "i/#ing 'n !c"n#

#5" r"%"#&"n#+('ou6!"r7 g'ion #8."*

Ri%"r F6o9

Origin6 'n

, c&

AEn! .ro#"c#ion

4igure '.B 6nd +rotection (or$s

D i 9 d


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For Revetments

1. "ather all surve& and h&drologic information needed

for the design of revetments.

!. Compute the velocit& of flow #ased on the design

flood discharge and the river profile and the cross,

section using the anningFs formula.

'. etermine the t&pe of revetment to #e adopted #ased on the design flood level and the qualit&

and quantit& of availa#le construction materials

at the project area.

*. 4or dr& #oulders riprap the si%e of #oulders to #e

used can #e determined from the graph Ashow 4ig.*.!8

Design 9rocedures


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5. etermine #& #ac$water anal&sis the design fl

level along the #an$s to #e protected.

-. etermine the $ind and e)tent of foundation w

that would #e needed such as cut,off walls sh

piles #oulder aprons or other foot protection

#ased on the ma)imum pro#a#le depth of scou

determine from field conditions.


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For Dikes/Embankment/levees

1. 4rom the location or topographic map of the

project area esta#lish the alignment of the

em#an$ment As8 considering the present course and pro#a#le meander of the river.

!. 4or confining di$es the width of the floodwa&

distance #etween parallel di$es shall #e

determined

with due consideration to non,silting and7or non,scouring velocit& in the channel.

'. Then esta#lish the design flood level at a partic

section using the tage ischarge Relationship

Rating Curve if availa#le or #& the anningFs

4ormula.


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*. elect the most suita#le t&pe of di$e or em#an$m

to #e adopted #ased on the field conditions and

availa#le materials at the project site.

5. 6sta#lish an appropriate section for the di$e #ase

on the design criteria.

-. etermine the sta#ilit& of the em#an$ment slope

#& the wedish lip,Circle ethod and chec$ if

factor of safet& is within accepta#le limits.

/. Chec$ if protection wor$s are needed and so

determine the appropriate t&pe to #e provided.


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;"drolog"

Design Fre8uenc"


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g 8 "

!ridge B? "ears 2'??7 Esteros4Cree3s 'B "ears 2*B7

Ri6ers B? ears for areas of :?35* anda&o6e 2'??r7

*B rs for areas &elo%

:?+5* 2B?7

Runo0 Calculation Methods


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Rational Method areas less than *?35*

-nit ;"drogra$h Methodareas greater than *?35*

Gu5&els Methodrecord of annual discharges

S$ecic Discharge Method

MEF( = &ased on the result of eld sur6e"

;EC;MS Soft%are

E


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Delineated atershed Ma$deter5ine %atershed characteristicsResult of eld in6estigation=$resent %atershed condition 2co6er# to$ogra$h"# etc.9ara5eters

a. Area

&. (ength of %ater%a"

c. ;ighest and lo%est ele6ationsd. Runo0 Coecient# c 2fr. Ta&le *7

e. Ti5e of Concentration# tc 2for5ula &" +ir$ic37

f. Rainfall Intensit"# I 2fr. Ta&le , or Fig. *7

!. -NIT ;DROGRA9; MET;OD


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For areas greater than *? 35*

Delineated atershed Ma$

Rainfall Data = Ta&le :

-S Soil Conser6ation Di5ensionless -nit;"drogra$h = Ta&le B Coordinates

Sa5$le Delineated atershed Ma$


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Delineated atershed Ma$


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atershed 9ara5eters

Area# +5*

(ength of Strea5# +5;ighest Ele6ation Along the Channel4Strea5# 5

Ele6ation at 9oint of Interest# 5

(ength of Channel4Strea5 fro5 Center of Area# +5

(ag Ti5e Coecient 2to$ogra$h"7

-nit Discharge Coecient 2to$ogra$h"7: Rainfall Data

Ta&le :Rainfall De$th Duration Data

Read Rainfall De$ths at e6er" co5$uted ti5e

inter6al4incre5ent

SURFACE RU!"FF C"EFF#C#E$


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S U R F A C E R A % E

Concrete or As$halt 9a6e5ents ?.H? = '.??

!itu5inous Macada5 Dou&le !itu5inous Surface

Treat5ent 2 to Cla"7?.J? = ?.H?

Gra6el Surface 2Road Shoulder7 ?.,? = ?.K?

!uiltu$ Area 2Dense7 ?.,? = ?.K?

!uiltu$ Area 2(ight7 ?.*? = ?.B?

!are Surface 2Roc3"7 ?.J? = ?.H?

!are Surface 2Cla"e"7 ?.J? = ?.H?

Flattish Culti6ated Areas 2Not /ooded7 ?.,? = ?.B?

Grassed Area 2Stee$ or Rolling7 ?.B? = ?.J?

Forest Area 2 to Cla"7 ?.,? = ?.B?

Flooded 9addies ?.J? = ?.>?


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HYDRAULIC A!ALYI

DEI"! DA#A$

DICHAR"E% &'(

) ** m*/s

L+,E% ) (.((2'

R+U"H!E C+EF.% n ) (.(*

FI"URE$

3ed 6lev. G !5.'0 m

-.0 m

42

d

4.3.


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HYDRAULIC A!ALYI

DEI"! DA#A$DICHAR"E% &

2') ** m*/s

L+,E% ) (.((2'R+U"H!E C+EF.% n ) (.(*

FI"URE$

3ed 6lev. G !5.'0 m

-.0 m

42

d

4.3..4.2 G !B.10 m

& ) A-

- ) 1/n R 2/*


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- 1/n R

HERE$ R ) A/,

#RY$ 0 ) 2.2 m

A ) 2.23.(3 ) 1'.42 m2

, ) 2.223 5 .( ) 11.26m

R ) 1.42 ) 1.6 11.26

- ) 77177 1.632/* (.((2'31/2

(.(*

) 2.(8 m/s

& ) A- ) *2.48 m*/s 9** m*/s#:erefore$

DEI"! FL++D LE-EL% DFL ) 24.;2 m

C+UR A!ALYI

b< =len>: ?et:o0

DEI"! DA#A$


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DEI"! DA#A$

DICHAR"E% &'(

) ** m*/s -EL+CI#Y ) 2.(8 m/s

=ED ELE-. ) 2'.* m

-EL+CI#Y A# =A!@% -= ) 2/* v DEI"! FL++D LE-EL% DFL ) 24.;* m

) 2/* 2.(83 ) 1.*8 m/s

DE,#H +F A#ER% D ) 2.2 m

?EA! "RAI! IE% D'( ) (.'( mm•DEI"! FL++D DICHAR"E I!#E!I#Y% Br

Br ) -= D3

) 1.*8 2.23

) *.2 m*/s/m

•RE"I?E DE,#H% Yr

Yr ) Br2/Fbo31/*

For 0'(

) (.'( mm% Fbo ) (.6

Yr ) *.422/(.6(31/*

) *.1; m•?A C+UR DE,#H% ?D

?D ) *.1; 1.'(3) 6.4; m

•ELE-. +F C+UR% D

D

) 24.;2 6.4;

) 2*.1*

#:erefore$ ,rovi0e aron on t:e riverbe0

C+UR A!ALYIb< La>e


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DEI"! DA#A$

DICHAR"E% & ) ** m*/s

DEI"! FL++D LE-EL% DFL ) 24.;2RI-ER=ED ELE-. ) 2'.*

0m ) (.64 &/f31/*

) (.64 **/1.2'3 1/*

f ) 1.2' for straig:t rea>: >:annel ) 1.6( m

0s ) 0m f silt fa>tor

f ) 1.4'(.'(31/2

) 1.2*4 for grain sie 0'(

) (.'( mm

0s ) 1.6( 1.2*43

) 1.4* mELE-. +F C+UR ) 24.;2 1.4'

) 2.2( ?#:erefore$ >oGr >annot be eJe>te0


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Design of Drainage Structures(Culverts)

Required Design Data


70/72

A. Field Sur6e" Infor5ation

'. To$ogra$hic Sur6e"

*. Crosssection Sur6e"

,. Terrain Infor5ation and Descri$tion

!. ;"drologic Data

'. Nearest Rainfall Gauging Station

*. Discharge

Design Criteria and Standards


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Design Fre8uenc"

RC!C *B "ears 2B?7 9i$e Cul6ert 'B "ears 2*B7

Road Side Ditch * "ears

LM" $eo$le are destro"ed fro5 lac3 of 3no%ledge.


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" $ $ " g

;osea

(et "our hearts &e /ooded %ith lo6e and let it &ee5inent# o6er/o%# and in/uence others for the5 tothe &eaut" of life in this %orld.

Than3 "ou for "our attention and 5a" God &less "o

Documents

Design of FC and Other Drainage Structures