02 Hidrograf Contoh Soal HSS Nakayasu.xls

Contoh Soal Metode HSS Nakayasu Diketahui: - Luas Daearh Aliran Sungai - Panjang sungai utama - Data Data inten intensit sitas as huja hujan n:

2400 km2 75 km

A= L =

waktu (jam) intensitas (mm"jam)



2

!

20

40

0

Ditanya: - #itung #itung $e%it $e%it maks maksimu imum m& - 'am%ar 'am%ar hi$rg hi$rgra ran*a n*a & Dijawab: a+ ,enghitu ,enghitung ng $e%it $e%it un.ak un.ak L tg

tr

= 75 km / 5 km = 012 6 L 017 = 4+!224044

jam

waktu kelambatan

!+2!42!0!!

jam

satuan lama hujan (antara 0,5 tg s/d tg, diambil 0,75 tg)

= tg 3 01 tr   = +00525447

jam

waktu puncak 

=  6 tg = +2550

jam

waktu saat debit sama dengan 0,3 kali debit puncak (jam), koefisien α diambil nilai  

= 0175tg =

t

t01!

15t

= ("!+) 6 A 6 ;0 6 ("(0+!t 3 t01!)) debit puncak  = 2+!2777 m!"$et 8a$i $e%it un.akn*a () = 2+!2777 

m!"$et

%+ ,enggam%ar graik hi$rgra  bagian lengkung naik   puncak 

0 9 t 9 t



=

 6 (t"t)214

 

=

("!+) 6 A 6 ;0 6 ("(0+!t 3 t01!))



t

bagian lengkung turun !

t 9 t 9 (t3t01!)





=

 6 01!<((t-t)"t01!)

bagian lengkung turun  

(t3t01!) 9 t 9 ((t3t01!) 3 15t01!)





=

 6 01!<((t-t3015 6 t01!)"(15 6 t01!))

bagian lengkung turun 3

((t3t01!) 3 15t01!) 9 t





=

 6 01!<((t-t315 6 t01!)"(2 6 t01!))

t3t01!

5+52225

15t01!

2+!452!

t3t01!315t01!

2+4474

untuk selanjutn*a lihat Tabel Perhitungan

Tabel Perhitungan 

t (jam)

 (m!"$et)

20 mm

aki%at hujan 40 mm

0 mm

0+0000 2+05

0+0000 0+0000

0+0000 0+0000

 ttal (m!"$et)

 2

0 

0+0000 0+045

0+0000 2+40

!

2

!+04

!+07

24+70

0+0000

4 5  7   0  2 ! 4 5  7   20 2 22

! 4 5  +00525447 7   0  2 ! 4 5 5+52225  7   20

+4425 +!2 2+777 44+555 2+!27 +4702 5!+42 4+472 40+4!7 !5+7! !0+5! 2+042 2!+!! 20+2! + 7+24 +!025 4+540 !+5!4 2+!!5

+4 !!+742 575+!547 +0 24+5! 22+404 0+245 2+440 0+7! 70!+42 +74 5!2+047 42+74 402+47 !7!+7 !57+474 !2+050 27+074 270+2! 24+!07

27+7! !!7+2 7!+5! 50+705 72+! 24!+7 245+02 2!+4! 5+ 7+57 40+5!2 22!+5727 04+4 25+5!27 04+572 04+572 747+5 75+4 52+05 54+5

+0447 !+04! 4+4245 +!2 27+774 445+554 2!+2 4+702! 5!4+20 44+720 404+! !5+7!! !05+!2 2+0424 2!+!!2 2!+!!2 20+2!! +0 7+2!7 !+0254

!0+5! 72!+225 !2+54 2254+5 !!7+22 422+57! 4204+0 !72+2 !24!+742! 22+57 245!+25 2!!+750 55+7! 4+77 42+07! 42+00 2+547 24+7! 5+247 0+45

2! 24 25

2 22 2!

+2!5 0+2!75 +!27

224+7! 204+740 +550

54+!4 4!+25 44+4!2

4+5!7 !5+!42 2!+!54

25+54 4!+5 7+!7

+7 lengkung naik

un.ak

lengkung turun >

lengkung turun >>

2

2

7+0557

4+44

!!+50

!+270

5+4070

2 !0 ! !2 !! !4 !5 !

27 2 2+4474 2 !0 ! !2 !! !4

+42 5+575 5+07 5+4040 5+0!7 4+ 4+!! 4+077 !+2

2+575 7+50 2+!4 0+07 00+7!4 !+ 7+24 +75!0 7+2420

!0+75 22+227 257+52 224+! 2+52 20+5 7+7 75+!247 !+500

4+7 77+4!0 70+5572 5+5755 5+07 54+0! 50+!7 4+4 4!+!2

52+745 42+752 445+54 !+4454 !7+00 !54+!252 !!0+4400 !0+4 27+!!

!7 !

!5 !

!+555 !+!55

7+025 +!04

52+440 42+204

40+75 !+20

2+0 24+50

! 40

!7 !

!+020 2+!5

+!5 57+70

!2+ 2!+7

!5+552 !!+547

2!!+05 27+!0

4 42

! 40

2+2 2+507

5!+7!2 50+577

5+!47 07+54

!0+7 2+!54

202+7!! +074

4! 44 45

4 42 4!

2+!! 2+2 2+0!4

4+775 4!+2!! 40+2

00+!5! !+55!0 7+245

2+ 25+07 2!+!2

7+!222 4+4!2 5!+!55

4

44

+70

!7+402

+!52

2+

4!+040

47

45

+7

!5+!2

75+0!

20+!4!

!!+!7!!

4 4 50 5 52 5! 54 55 5 57 5

4 47 4 4 50 5 52 5! 54 55 5

+4 +5!7 +4!4 +!!2 +240 +! +054 +022 0+440 0+04 0 20

!2+74 !0+77! 2+ 2+740 24+5 2!+277! 2+702 20+244 +0 7+074  4205

70+752 5+4 +54 57+!7! 5!+52 4+7 4+554 4!+4! 40+4 !7+702 !5 24

+70 7+! +47 5+!5 4+!4! !+!20 2+47 +!7 0+54 0+224  4400

24+!2 5+7 0+74 00+0 4+052 7+742 +2 7+!20 7+7 +!70!  !

lengkung turun >>>

Grafik Hidrograf HSS Nakayasu 4500+0000

4000+0000

   )    t   e    $    "    !   m    (    7    t    i    %   e    D

 (m!"$et) aki%at hujan 20 mm aki%at hujan 40 mm aki%at hujan 0 mm  ttal (m!"$et)

!500+0000

!000+0000

2500+0000

2000+0000

500+0000

000+0000

500+0000

0+0000 

2

!

4

5



7





0  2 ! 4 5  7   20 2 22 2! 24 25 2 27 2 2 !0 ! !2 !! !4 !5 ! !7 ! ! 40 4 42 4! 44 45 4 47 4 4 50 5 52 5! 54 55 5 57 5 5 0

?aktu t (jam)