8/17/2019 Sanjaya Shah 1
1/14
Assignment
of
Engineering Hydrology
Assignment no: 01
SUBMITTED TO:
SUMBITTED BY:
Mr. Bharani Dharan
Sanjaya Bikram Shah
Dept. of CE B-
Tech Civil 7th sem
AP!"#!"!!$"%%
8/17/2019 Sanjaya Shah 1
2/14
Q.No.2.13
Following are the data of storm as recorded in the self-recording rain gage rain gage at station:
!ime from
the
"eginningof #torm
$%in&
10 20 30 '0 (0 (0 )0 *0 +0
,mlati
e ainfall
$mm&
1/ '1 '+ )+ /1 12' 1(2 1)0 1))
a& lot the hyetograh of the #torm. "& lot the maimm intensity-dration cre of the #torm.
#oltion:
a& !he ntensity of the rainfall at arios time dration is calclated as shown "elow:
!ime since
start $min&
10 20 30 '0 (0 )0 *0 +0 /0
,mlatie
ainfall $mm&
1/ '1 '+ )+ /1 12' 1(2 1)0 1))
ncremental
deth of
ainfall in
interal $mm&
1/ 22 * 20 23 33 2+ + )
ntensity
$mm4hr.&
11' 132 '2 120 13+ 1/+ 1)( '+ 3)
8/17/2019 Sanjaya Shah 1
3/14
!" $" %" &" '" (" 7" )" #""
!""
$""
%""
"
!!& !%$
&$
!$" !%)!#) !()
&) %(
hyetograph of storm
Time since start *min+
,ainfall ntensity *mmhr+
"& !he maimm ntensity-dration cre of the storm is:
ncremental deth of rainfall $mm& in arios drations
5rations$min&
!ime
$min&
,m.
ainfall$mm
&
10 20 30 '0 (0 )0 *0 +0 /0
0 0 0
10 1/ 1/
20 '1 22 '1
30 '+ * 2/ '+
'0 )+ 20 2* '/ )+(0 /1 23 '3 (0 *2 /1
)0 12' 33 () *) +3 10( 12'
*0 1(2 2+ )1 +' 10' 111 133 1(2
+0 1)0 + 3) )/ /2 10) 11/ 1'1 1)0
/0 1)) ) 1) '2 *( /+ 112 12( 1'* 1))
And6
5ration
in min.
10 20 30 '0 (0 )0 *0 +0 /0
%a.
deth
$mm&
33 )1 +' 10' 111 133 1(2 1)0 1))
%a.
ntensity
$mm4hr.&
1'+ 1+3 1)+ 1() 133.2 133 130.3 120 110.*
8/17/2019 Sanjaya Shah 1
4/14
8/17/2019 Sanjaya Shah 1
5/14
ncremental 1epth of rainfall *mm+ in vario/s 1/rations
D/ration in min Time*Mi
n+
C/m.
,ainf
all
*mm+
!" $" %" &" '" (" 7" )" #"
" "!" ) )
$" !' 7 !'%" $' !" !7 $'
&" %" ' !' $$ %"
'" &( !( $! %! %) &((" '' # $' %" &" &7 ''
7" (" ' !& %" %' &' '$ (")" (& & # !) %& %# %# '( (&
#" (7 % 7 !$ $! &$ &$ &$ '# (7
And6
D/ratio
n *min+
!" $" %" &" '" (" 7" )" #"
Ma0.
1epth
!( $' %! &" &7 '' (" (& (7
8/17/2019 Sanjaya Shah 1
6/14
" !" $" %" &" '" (" 7" )" #" !"""
!"
$"
%"
&"
'"
("
7"
)"
!(
$'
%!
&"
&7
''
("(&
(7
Ma0 Depth-1/ration c/rve
time *min+
ma0 septh *mm+
Q.No. 2.1(
!he mass cre of the rainfall in a storm of total dration /0 mintes is gien "elow.
a& lot the hyetograh of the storm at 10 mintes ste. "& lot the maimm intensity dration
cre for this storm. c& lot the maimm deth dration cre for the storm.
!ime
$%intes&
0 10 20 30 '0 (0 )0 *0 +0 /0
,mlati
e rainfall
$mm&
0 2.1 ).3 1'.( 21.* 2*./ 33.0 3(.1 3).2 3*.0
8/17/2019 Sanjaya Shah 1
7/14
#oltion:
a+ The ntensity of the rainfall at vario/s time 1/ration is calc/late1 as sho4n 3elo45
Time since
start *min+
!" $" %" &" '" (" 7" )" #"
C/m/lative
,ainfall*mm+
$.! (.% !&.' $!.7 $7.# %% %'.! %(.$ %7."
ncremental
1epth of
,ainfall in
interval
*mm+
$.! &.$ ).$ 7.$ (.$ '.! $.! !.! ".)
ntensity
*mmhr.+
!$.( $'.$ .$ &%.$ %7.$ %".( !$.( (.( &.)
!" $" %" &" '" (" 7" )" #""
!"
$"
%"
&"
'"
("
!$.(
$'.$
.$
&%.$
%7.$
%".(
!$.(
(.(&.)
hyetograph of storm
time 1/ration in min/tes
,ainfall ntensity *mmhr+
3+ an1 c+
ncremental 1epth of rainfall *mm+ in vario/s 1/rationsD/ration in min
Time*Mi
n+
C/m.
,ainf
all
*mm+
!" $" %" &" '" (" 7" )" #"
" "!" $.! $.!
8/17/2019 Sanjaya Shah 1
8/14
$" (.% &.$ (.%%" !&.' ).$ !$.& !&.'&" $!.7 7.$ !'.& !#.( $!.7'" $7.# (.$ !%.& $!.( $'.) $7.#(" %% '.! !!.% !).' $(.7 %".# %%7" %'.! $.! 7.$ !%.& $".( $).) %% %'.!)" %(.$ !.! %.$ ).% !&.' $!.7 $#.# %&.! %(.$#" %7 ".) !.# &." #.! !'.% $$.' %".7 %&.# %7."
And6
D/ration
*min+
!" $" %" &" '" (" 7" )" #"
Ma0. 1epth
*mm+
).$ !'.& $!.( $(.7 %".# %% %'.! %(.$ %7
Ma0.ntensity *mmhr.+ .$ &(.$ &%.$ &"."' %7.") %%." %".") $7.!' $&.(7
" !" $" %" &" '" (" 7" )" #" !"""
!"
$"
%"
&"
'"
("
.$&(.$
&%.$&"."'
%7.")%%
%".")$7.!'
$&.(7
ma0 intensity 1/ration c/rve
Time in min/tes
Ma0. ntensity in mmhr
8/17/2019 Sanjaya Shah 1
9/14
" !" $" %" &" '" (" 7" )" #" !"""
'
!"
!'
$"
$'%"
%'
&"
).$
!'.&
$!.($(.7
%".#%%
%'.! %(.$%7
Ma0. 1epth 1/ration c/rve
Time in min/tes
Ma0. Depth in mm
Q.N7. 2.1)
!he record of annal at a lace is aaila"le for 2( years .lot the cre of recrrence interal s
annal rainfall magnitde and "y sita"le interolation estimate the magnitde of rainfall at the
station that wold corresond to a recrrence interal of $a&(0 years8 and $"&100 years
9ear Annal ainfall
$cm&
9ear Annal ainfall
$cm&
1/(0 113.0 1/)3 )+.)1/(1 /'.( 1/)' +2.(
1/(2 *).0 1/)( /0.*
1/(3 +*.( 1/)) //.+
1/(' /2.* 1/)* *'.'
1/(( *1.3 1/)+ )).)
1/() **.3 1/)/ )(.0
1/(* +(.1 1)*0 /1.0
1/(+ 122.+ 1/*1 10).0
1/(/ )/.' 1/*2 102.0
1/)0 +1.0 1/*3 +*.0
1/)1 /'.( 1/*' +'.01/)2 +).3
8/17/2019 Sanjaya Shah 1
10/14
#oltion:
,alclation of retrn eriod $N2( year&
m Annal ainfall $cm& ro"a"ility
m4$N;1&
etrn eriod
!14
1 122.+ 0.03+ 2)
2 113 0.0*) 13
3 10).+ 0.11( +.))*
' 102.2 0.1(3 ).(
( /+.+ 0.1/2 (.2
) //.( 0.230 '.333
* /' 0.2)/ 3.*1'
+ /2.* 0.30* 3.2(
/ /1 0.3') 2.++
10 /0.* 0.3+' 2.)
11 +*.( 0.'23 2.3)
12 +* 0.')1 2.1))13 +).3 0.( 2.00
1' +(.1 0.(3+ 1.+(*
1( +' 0.(*) 1.*33
1) +2.( 0.)1( 1.)2(
1* +1 0.)(3 1.(2/
1+ **.3 0.)/2 1.'''
1/ )/.' 0.*30 1.3)+
20 *'.' 0.*)/ 1.3
21 *1.3 0.+0* 1.23+
22 )/.' 0.+') 1.1+1
23 )+.) 0.++' 1.1302' )).) 0./23 1.0+3
2( )( 0./)1 1.0'
8/17/2019 Sanjaya Shah 1
11/14
! !" !"""
$"
&"
("
)"
!""
!$"
!&"
f*0+ 6 !7.!' ln*0+ 7".7
,ec/rrence interval 8s Ann/al ,ainfall
,et/rn perio1 T in years
Ann/all ,ainfall in cm
Form the grah6
1*.1(ln $!& ; *0.)//
A) For T=50 year 1*.1(ln $(0& ;*0.)//
13*.*/ cm
"& For !100 year
1*.1(ln $100& ;*0.)//
1'/.)** cm
8/17/2019 Sanjaya Shah 1
12/14
Q.N7: 2.1*
!he annal rainfall ales at a station for a eriod of 20 years are as follows:
9ear Annal ainfall$cm&
9ear Annal ainfall$cm&
1/*( 120.0 1/+( 101.0
1/*) +'.0 1/+) 10/.0
1/** )+.0 1/+* 10).0
1/*+ /2.0 1/++ 11(.0
1/*/ 102.0 1/+/ /(.0
1/+0 /2.0 1//0 /0.0
1/+1 /(.0 1//1 *0.0
1/+2 ++.0 1//2 +/.0
1/+3 *).0 1//3 +0.0
1/+' +'.0 1//' /0.0
5etermine
$a& !he ale of annal rainfall at with a recrrence interal of 1( years.
$"& !he ro"a"ility of occrrence of an annal rainfall of magnitde 100 cm at station .$c& *(< deenda"le annal rainfall at the station.
#oltion:
,alclation of retrn eriod $N2( year&
m Annal ainfall $cm& ro"a"ility
m4$N;1&
etrn eriod
!14
1 120 0.0'* 21.2*
2 11( 0.0/( 10.(2
3 10/ 0.1'2 *.0'2
' 10) 0.1/0 (.2)
( 102 0.23+ '.201
) 101 0.2+( 3.(0+
* /( 0.3+0 2.)31
+ /2 0.'*) 2.100
/ /0 0.(*1 1.*(110 +/ 0.)1/ 1.)1(
11 ++ 0.))* 1.'//
12 +' 0.*)1 1.31'
13 +0 0.+0/ 1.23)
1' *) 0.+(* 1.1))
1( *0 0./0' 1.10)
1) )+ 0./(2 1.0(
8/17/2019 Sanjaya Shah 1
13/14
! !" !"""
$"
&"
("
)"
!""
!$"
!&"
f*0+ 6 !!.#' ln*0+ )'.%
Ann/al rainfall 8s ret/rn perio1 chart
,et/rn perio1 in T years
Ann/al ,ainfall in Cm
9rom the a3ove chart
p6!(.$7'ln *T+ 7(.))
a+
the val/e of p at rec/rrence interval of !' years5
P6!(.$7'ln *!'+ 7(.))
P6!$".# cm
3+
Pro3a3ility of occ/rrence of an ann/al rainfall of ma2nit/1e !"" cm at station P is
P 6 !(.$7'ln *T+ 7(.))
!"" 6 !(.$7'ln *T+ 7(.))
*!""-7(.))+!(.$' 6 ln *T+
T 6&.") year
c+
9or pro3a3ility of e0ce1ence 6 ".7'
T6 !p6!".7'6!.%%% year
3y /sin2 the e:/ation from the 1erive1 tren1 line
8/17/2019 Sanjaya Shah 1
14/14
pr 6!(.$7'ln *!.%%%+ 7(.))
6 )).'( cm
Q.N7: 2.20
A one-day rainfall of 20.0 cm at a lace at a lace = was fond to hae a eriod of 100 years.
,alclate the ro"a"ility that a one-day rainfall of magnitde e>al to or larger than 20.0 cm:
a& ?ill not occr at station = dring the net (0 years.
"& ?ill occr in the net year.
#oltion:
Here8
141000.01
Q $1-& 1-0.010.//
i&
r8n Qn $1&n
08(0 0.//(0 0.)0(year
ii&
1822 !
1 !∗2! @0.012@0.//2-1
0.01