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NILAI K DISTRIBUSI LOG PEARSON TIPE III

Kemencengan Periode Ulang (Tahun)

(Cs) 2 5 10 15 20 25 50 100 200 500 1000

3 -0.36 0.42 1.18 1.729 1.912 2.278 3.152 4.051 4.97 5.825 7.25

2.5 -0.36 0.518 1.25 1.756 1.924666667 2.262 3.048 3.845 4.652 5.3825 6.62.2 -0.33 0.574 1.284 1.762 1.921333333 2.24 2.97 3.705 4.444 5.1025 6.22 -0.307 0.609 1.302 1.7605 1.913333333 2.219 2.912 3.605 4.298 4.9025 5.91

1.8 -0.282 0.643 1.318 1.7555 1.901333333 2.193 2.848 3.499 4.147 4.714375 5.661.6 -0.254 0.675 1.329 1.746 1.885 2.163 2.78 3.388 3.99 4.515 5.391.4 -0.225 0.705 1.337 1.7325 1.864333333 2.128 2.706 3.271 3.828 4.30875 5.11

1.31626749 -0.2124401 0.716304 1.33825599 1.72454541 1.853308553 2.1108348355 2.672507 3.21992317 3.7580834 4.219522544 4.9885878611.2 -0.195 0.732 1.34 1.7135 1.838 2.087 2.626 3.149 3.661 4.095625 4.821 -0.164 0.758 1.34 1.6915 1.808666667 2.043 2.542 3.022 3.489 3.883125 4.54

0.9 -0.148 0.769 1.339 1.6785 1.791666667 2.018 2.498 2.957 3.401 3.77375 4.3950.8 -0.132 0.78 1.336 1.667 1.777333333 1.998 2.453 2.891 3.312 3.66375 4.250.7 -0.116 0.79 1.333 1.65 1.755666667 1.967 2.407 2.824 3.223 3.55375 4.1050.6 -0.099 0.8 1.328 1.6335 1.735333333 1.939 2.359 2.755 3.132 3.4425 3.960.5 -0.083 0.808 1.323 1.6165 1.714333333 1.91 2.311 2.686 3.041 3.33125 3.8150.4 -0.066 0.816 1.317 1.5985 1.692333333 1.88 2.261 2.615 2.949 3.219375 3.670.3 -0.05 0.824 1.309 1.579 1.669 1.849 2.211 2.544 2.856 3.106875 3.5250.2 -0.033 0.842 1.282 1.5165 1.594666667 1.751 2.054 2.326 2.576 2.76875 3.090.1 -0.017 0.836 1.27 1.5155 1.597333333 1.761 2 2.252 2.482 3.0325 3.950 0 0.842 1.282 1.5165 1.594666667 1.751 2.054 2.326 2.576 2.76875 3.09

-0.1 0.017 0.85 1.258 1.469 1.539333333 1.68 1.945 2.178 2.388 2.97375 3.95-0.2 0.033 0.85 1.258 1.469 1.539333333 1.68 1.945 2.178 2.388 2.54625 2.81

-0.29 0.0483 0.8527 1.2463 -1.5079231 1.513233333 1.6467 1.8955 2.1114 2.3034 2.4478125 2.6885-0.3 0.05 0.853 1.245 1.444 1.510333333 1.643 1.89 2.104 2.294 2.436875 2.675-0.4 0.066 0.855 1.231 1.4185 1.481 1.606 1.834 2.029 2.21 2.33375 2.54-0.5 0.083 0.856 1.26 1.4135 1.464666667 1.567 1.777 1.955 2.108 2.2175 2.4

-0.543 0.090 0.856 1.234 1.392215 1.445 1.550 1.752 1.923 2.068 2.173 2.346

-0.6 0.099 0.857 1.2 1.364 1.418666667 1.528 1.72 1.88 2.016 2.113125 2.275-0.68455612 0.113 0.857 1.186 1.340 1.391 1.494 1.672 1.817 1.940 2.026 2.169

-0.7 0.116 0.857 1.183 1.3355 1.386333333 1.488 1.663 1.806 1.926 2.01 2.15-0.8 0.132 0.856 1.166 1.307 1.354 1.448 1.606 1.733 1.873 1.93375 2.035

-0.81689035 0.13470246 0.855662 1.16279083 1.30193289 1.348313581 1.4410749557 1.5963725 1.72067004 1.852056 1.912742625 2.01388706-0.9 0.148 0.854 1.147 1.277 1.320333333 1.407 1.549 1.66 1.749 1.809375 1.91-1 0.164 0.852 1.128 1.247 1.286666667 1.366 1.492 1.588 1.664 1.715 1.8

-1.01225499 0.16590 0.85151 1.12543 1.24313968 1.28238 1.36085 1.48508 1.57948 1.65401 1.70474 1.78928

-1.2 0.195 0.844 1.086 1.184 1.216666667 1.282 1.379 1.449 1.501 1.5475 1.625-1.4 0.225 0.832 1.041 1.1195 1.145666667 1.198 1.2701 1.318 1.351 1.39375 1.465-1.6 0.254 0.817 0.994 1.055 1.075333333 1.116 1.166 1.197 1.216 1.24 1.28-1.8 0.282 0.799 0.945 0.99 1.005 1.035 1.069 1.087 1.097 1.109375 1.13-2 0.307 0.777 0.895 0.927 0.937666667 0.959 0.98 0.99 1.995 1.621875 1

-2.2 0.33 0.752 0.844 0.866 0.873333333 0.888 0.9 0.905 0.907 0.908125 0.91-2.5 0.36 0.711 0.771 0.782 0.785666667 0.793 0.798 0.799 0.8 0.80075 0.802

-3 0.396 0.636 0.66 0.663 0.664 0.666 0.666 0.667 0.667 0.667375 0.668

BAB IIIIPERHITUNGAN CURAH HUJAN

3.1. Data Curah Hujan

No. TahunCurah Hujan

Sta B Sta D Sta F

1 1977 190

2 1978 200 160

3 1979 210 145

4 1980 210 195 210

5 1981 205 160 90

6 1982 150 90 170

7 1983 90 230 190

8 1984 195 200 205

9 1985 180 160 175

10 1986 165 175 240

11 1987 125 225 210

12 1988 175 175 160

13 1989 130 210 190

14 1990 205 150 130

15 1991 195 235 175

16 1992 95 165 180

17 1993 140 135 220

18 1994 135 160

19 1995 170 95

20 1996 185 225

21 1997 145 250

No.Tahun Curah Hujan

x (x-x ̅�)Sta B Sta D Sta E

1 1980 210 195 210 205.000 30.952 958.050 29653.925 917859.585

2 1981 205 160 90 151.667 -22.381 500.907 -11210.776 250907.852

3 1982 150 90 170 136.667 -37.381 1397.336 -52233.736 1952546.782

4 1983 90 230 190 170.000 -4.048 16.383 -66.313 268.410

5 1984 195 200 205 200.000 25.952 673.526 17479.605 453637.377

6 1985 180 160 175 171.667 -2.381 5.669 -13.497 32.137

7 1986 165 175 240 193.333 19.286 371.939 7173.105 138338.453

8 1987 125 225 210 186.667 12.619 159.240 2009.462 25357.493

9 1988 175 175 160 170.000 -4.048 16.383 -66.313 268.410

10 1989 130 210 190 176.667 2.619 6.859 17.965 47.052

11 1990 205 150 130 161.667 -12.381 153.288 -1897.851 23497.205

12 1991 195 235 175 201.667 27.619 762.812 21068.135 581881.829

13 1992 95 165 180 146.667 -27.381 749.717 -20527.953 562074.910

14 1993 140 135 220 165.000 -9.048 81.859 -740.633 6700.963Ʃ 2260 2505 2545 2436.667 0.000 5853.968 -9354.875 4913418.457

n = 14 Koefisien Skewness:

Cs ̅=n Ʃ

x ̅� =x ̅�

n

Cs ̅=-130968.253968253

x ̅� =2436.667 1333853.3665

14Cs = -0.09818789

x ̅� = 174.04762

Koefisien cartesius:

Simpangan BakuCk ̅=

Ʃ

s = (Ʃ

n-1

Ck ̅=963030017.636685

s = (5853.968 300028104.339241

13Ck = 3.20979936115514

s = 20.448486

syarat Gumbel : syarat Distribusi Log Normal : syarat Log Pearson III :Cs = 1.14 Cs=0 tak ̅ada ̅syaratCk = 5.40

(x-x ̅�)2 (x-x ̅�)3 (x-x ̅�)4

Ʃx (n-1)(n-2)S3

n2

)1/2 (n-1)(n-2)(n-3)S4

)1/2

(x-x ̅� )^2

(x-x ̅� )^3

(x-x ̅� )^4

3.2.3 METODE LOG PEARSON III

Tabel 1.15

No Tahun Xi (mm) Log Xi

1 1981 205.000 2.3118 0.0541 0.01262 1982 151.667 2.1809 0.0103 0.00113 1983 136.667 2.1357 0.0032 0.00024 1984 170.000 2.2304 0.0229 0.00355 1985 200.000 2.3010 0.0492 0.01096 1986 171.667 2.2347 0.0242 0.00387 1987 193.333 2.2863 0.0429 0.00898 1988 186.667 2.2711 0.0368 0.00719 1989 170.000 2.2304 0.0229 0.003510 1990 176.667 2.2472 0.0282 0.004711 1991 161.667 2.2086 0.0167 0.002212 1992 201.667 2.3046 0.0508 0.011513 1993 146.667 2.1663 0.0076 0.0007

Jumlah 29.1090 0.3698 0.0704

n= 14

Log X =29.1090

= 2.07921714

Sx = Cs =(n - 1)

=0.3698

=14 . 0.0704

13 13 . 12 . 0.169 3

= 0.16864946 = 1.3162674896554

Berdasarkan nilai Cs = 1.316267 maka diperoleh nilai K untuk setiap periode ulang (tabel 3)

Log Xi = Log X + K . Sx

Tabel 1.16T (tahun) K Log X Sx Xi (mm)

2 -0.212 2.0792 0.16865 110.5075 0.716 2.0792 0.16865 158.49710 1.338 2.0792 0.16865 201.79615 1.725 2.0792 0.16865 234.455

T (TAHUN) Curah hujan2 110.5075 158.497

10 201.79615 234.455

(Log Xi - Log X)2 (Log Xi - Log X)3

S (Log Xi - Log X)2 n . S (Log Xi - Log X)3

(n - 1)(n - 2)(Sx)3

xi=10logx+k.Sx

3.3 PERHITUNGAN INTENSITAS CURAH HUJAN

1. Intensitas Curah Hujan Rencana Dengan Metode Mononobe

I =R

X (5

5 t

Diketahui :

= 110.507 mm

= 158.497 mm

= 201.796 mm

= 234.455 mm

Untuk t = 1 jam

110.507x (

5= 64.625 mm/jam

5 1

158.497x (

5= 92.690 mm/jam

5 1

201.796x (

5= 118.011 mm/jam

5 1

234.455x (

5= 137.110 mm/jam

5 1

Untuk t = 2 jam

110.507x (

5= 40.711 mm/jam

5 2

158.497x (

5= 58.391 mm/jam

5 2

201.796x (

5= 74.342 mm/jam

5 2

234.455x (

5= 86.374 mm/jam

5 2

)2/3

R2

R5

R10

R15

I2 = )2/3

I5 = )2/3

I10 = )2/3

I15 = )2/3

I2 = )2/3

I5 = )2/3

I10 = )2/3

I15 = )2/3

Untuk t = 3 jam

110.507x (

5= 31.068 mm/jam

5 3

158.497x (

5= 44.561 mm/jam

5 3

201.796x (

5= 56.734 mm/jam

5 3

234.455x (

5= 65.916 mm/jam

5 3

Untuk t = 4 jam

110.507x (

5= 25.646 mm/jam

5 4

158.497x (

5= 36.784 mm/jam

5 4

201.796x (

5= 46.833 mm/jam

5 4

234.455x (

5= 54.412 mm/jam

5 4

Untuk t = 5 jam

110.507x (

5= 22.101 mm/jam

5 5

158.497x (

5= 31.699 mm/jam

5 5

201.796x (

5= 40.359 mm/jam

5 5

234.455x (

5= 46.891 mm/jam

5 5

I2 = )2/3

I5 = )2/3

I10 = )2/3

I15 = )2/3

I2 = )2/3

I5 = )2/3

I10 = )2/3

I15 = )2/3

I2 = )2/3

I5 = )2/3

I10 = )2/3

I15 = )2/3

Tabel Intensitas Hujan

t Intensitas (mm/jam)

(jam)

1 64.625 92.690 118.011 137.1102 40.711 58.391 74.342 86.3743 31.068 44.561 56.734 65.9164 25.646 36.784 46.833 54.4125 22.101 31.699 40.359 46.891

I 2 I 5 I10 I15

1 2 3 4 50.000

20.000

40.000

60.000

80.000

100.000

120.000

140.000

160.000

Chart Title

2 tahun 5 tahun 10 tahun 15 tahun

0 1 2 3 4 5 60

20

40

60

80

100

120

140

160

Grafik Intensitas Curah Hujan Metode Mononobe

TAHUN ̅10

TAHUN ̅5

TAHUN ̅2

TAHUN ̅15

Waktu Konsentrasi (menit)

Inte

nsi

tas

(mm

/jam

)

8.5 8 7.5 7 6.5 6 5.5 5

ib c d

A0 A1 A2 A3 A4 A5 A6 A7

hI B II C III D

C4 C1 C49 IV

jB0 B1 B2 B3 B4 B5 C2

C0 C1 C2 C3

D0 D1

gV

C19.5 E0 E1

F0 F1 VIm

A C3VII

kG0 G1 G2 G3 C2

f

VIII IX H0 H1 H2 H3

C3 C3 F

10

I0 I1 I2 I3

lX XIJ0 J1 J2 J3 J4 C4 J5 J6 C1 J7

E

ea

Q3

Q1 Q2

Diketahui :

Q1 = 0.5 C1 = 0.45 C4 = 0.6

Q2 = 0.6 C2 = 0.9

Q3 = 0.7 C3 = 0.71

a = 500 m f = 1000 m k = 900 m

b = 1000 m g = 600 m l = 300 m

c = 400 m h = 500 m m = 1280 m

d = 1000 m i = 100 m

e = 100 m j = 900 m

Lebar Jalan + Trotoar :

Jalan ̅A = 10 m = 0.8

Jalan ̅B = 10 m

Jalan ̅C = 10 m

Jalan ̅D = 10 m

Jalan ̅E = 10 m

Jalan ̅F = 10 m

m3/detik

m3/detik

m3/detik

Cjalan

BAB IV

PERHITUNGAN DAN PERENCANAAN 4 2

4.1 DATA DASAR

4.1.1 Data Curah Hujan

No TahunCurah Hujan (mm)

Sta B Sta D Sta E

1 1982 - - 250

2 1983 - - 215

3 1984 - - 100

4 1985 210 - 180

5 1986 205 160 240

6 1987 150 90 130

7 1988 90 230 175

8 1989 195 200 200

9 1990 180 160 235

10 1991 165 175 180

11 1992 125 225 140

12 1993 175 175 220

13 1994 130 210 265

14 1995 205 150 110

15 1996 195 235 175

16 1997 95 165 190

17 1998 140 135 235

18 1999 - 230 -

19 2000 - 90 -

20 2001 - 190 -

21 2002 - 190 -

22 2003 - 240 -

23 2004 - 215 -

24 2005 - 240 -

4.1.2 Data TopografiRumus perhitungan Elevasi, Panjang Lahan Terjauh, dan kemiringan lahan

n

m

Perhitungan Elevasi Awal dan Akhir

R=

X P = Jarak areal ke garis berikutnya (m)

P r R = Jarak antar kontur (m)r = Interval antar kontur yang membatasi titik

Sehingga tinggi elevasi = Kontur -X

Perhitungan panjang lahan terjauh

= +

Kemiringan Lahan

StE awal - E akhir

x 100%Lt

Mencari Luas lahanA = m x n

Perhitungan Luas Areal

PETAKPanjang Lebar Luas

(m) (m) (Ha)

I 490 500 24.5

II 500 500 25

III 400 500 20

IV 1000 900 90

V 1000 600 60

VI 400 1280 51.2

VII 1000 900 90

VIII 490 1000 49

IX 500 1000 50

X 400 300 12

XI 1000 300 30

Lt2 m2 n2

110109

108

P

R

Lt

Dengan mengacu pada denah, dapat dibuat tabel data topografi sebagai berikut :

No PetakLuas Areal Elevasi ( m ) Panjang lahan ( Lt ) Kemiringan

( Ha ) Awal Akhir ( m ) Saluran (%)

1 I 24.50 8.33 7.42 700.07 0.12999

2 II 25.00 7.87 6.50 707.11 0.19375

3 III 20.00 6.91 5.85 640.31 0.16554

4 IV 90.00 6.78 5.27 1345.36 0.11224

5 V 60.00 8.78 7.00 1166.19 0.15263

6 VI 51.20 8.38 6.50 1341.04 0.14019

7 VII 90.00 8.00 6.50 1345.36 0.11149

8 VIII 49.00 9.58 8.42 1113.60 0.10417

9 IX 50.00 9.08 8.00 1118.03 0.09660

10 X 12.00 8.85 8.19 500.00 0.13200

11 XI 30.00 8.43 7.74 1044.03 0.06609

Jumlah 501.70

3.1.3 Data Saluran

No SaluranElevasi ( m ) Panjang Kemiringan

Awal Akhir Saluran ( m ) Saluran (%)

1 7.90 7.42 490 0.09796

2 7.37 6.50 500 0.17400

3 6.32 5.85 400 0.11750

4 6.24 5.27 1000 0.09700

5 7.92 7.42 500 0.10000

6 6.87 6.50 500 0.07400

7 6.50 5.85 500 0.13000

8 6.26 5.27 900 0.11000

9 8.40 7.00 1000 0.14000

10 6.88 6.50 400 0.09500

11 7.84 7.00 600 0.14000

12 8.17 6.50 1280 0.13047

13 6.86 6.50 1000 0.03600

14 7.69 6.50 900 0.13222

15 8.78 8.42 790 0.04557

16 8.38 8.00 500 0.07600

17 9.12 8.42 1000 0.07000

18 8.80 8.00 1000 0.08000

19 8.39 8.19 400 0.05000

20 8.11 7.74 1000 0.03700

21 8.50 8.19 300 0.10333

22 8.13 7.74 300 0.13000

23 9.53 9.34 490 0.03878

24 9.05 8.75 500 0.06000

25 8.70 8.50 400 0.05000

26 8.45 7.65 1000 0.08000

A0 - A1

A2 - A3

A4 - A5

A6 - A7

B1 - A1

B3 - A3

B5 - A5

D1 - A7

C0 - C1

C2 - C3

F1 - C1

H1 - C3

E0 - E1

H3 - E1

G0 - G1

G2 - G3

J1 - G1

J3 - G3

I0 - I1

I2 - I3

J5 - I1

J7 - I3

J0 - J1

J2 - J3

J4 - J5

J6 - J7

4.2 PERHITUNGAN DEBIT RENCANA

4.2.1 Rumus Perhitungan Debit

Qs = 0,00278 . Cs. Cr. I.A

Cs =2 tc

tc = to + td2 tc + td

td =Lsv

Cr =

to = 0.0197LtSt

ket. :A = Luas areal (Ha)Ls = Panjang Saluran (m)Lt = Panjang lahan terjauh (m)St = Kemiringan lahan (%)to = Waktu untuk mengalir dari permukaan lahan ke saluran terdekat (menit)td = Waktu pengaliran dalam saluran (menit)tc = Waktu pengumpulan air (menit)Cs = Koefisien penampunganCr = Koefisien pengaliran rata-rataI = Intensitas curah hujan (mm/jam)v = Kecepata rencana (m/dtk)

(diasumsikan, v = 0.4 m/dtk)

4.2.2 Contoh Perhitungan Debit

= 0.7

diketahui data-data sbb :

49.00 Ha = 490000

0.49 Ha = 4900Ls = 490 mLt = 1113.60 mSt = 0.001042Cj = 0.8

0.71

to = 0.0197 xLt 0.77St

to = 0.0197 x1113.5978 0.77

0.0323

to = 61.4640 menit

Cjalan . Ajalan + Clahan . Alahan

Ajalan + Alahan

Saluran J0 - J1

Q3 m3/dtk

AL = m2

AJ= m2

CL=

td =Ls

v = 0.4 m/detv

td =490

= 20.4167 menit0.4 x 60

tc = to + tdtc = 61.4640 + 20.4167tc = 81.8807 menit

Cs =2 tc

=163.7614

2 tc + td 163.7614 + 20.4167

= 0.8891

Cr =

=### 0.49 + ### 49.00

0.49 + 49.00 = 0.711

Periode ulang 2 tahun untuk Saluran TersierPeriode ulang 5 tahun untuk Saluran SekunderPeriode ulang 10 tahun untuk Saluran Primer

dimana : tc = 81.8807 menit= 4912.843 dtk= 0.1105 m .....Tabel curah hujan maximum

=0.1105

(5

= 0.00022 m/dtk5 ###

Qs = 0.00278 x Cs x Cr x I x AQs = 0.00278 x 0.889 x 0.711 x 0.00022 x 490000

Qs = 0.1925

+= 0.7 + 0.1925

= 0.8925


49.00 Ha = 490000

1 Ha = 10000Ls = 1000 mLt = 1113.60 mSt = 0.0007Cj = 0.8

0.71

to = 0.0197 xLt 0.77St


Ajalan + Alahan

Penentuan Intensitas dengan Metode Mononobe Untuk periode ulang T = 2 tahun

R2 Thn

I2 )2/3

m3/dtk

Qkomulatif = Q2 Q (J0-J1)

m3/dtk

Saluran J1 - G1

AL = m2

AJ= m2

CL=

to = 0.0197 x1113.5978 0.77

0.0265

to = 71.6282 menit

td =Ls

v = 0.4 m/detv

td =1000

= 41.6667 menit0.4 x 60


Cs =2 tc

=226.5898

2 tc + td 226.5898 + 41.6667

= 0.8447

Cr =

=### 1.00 + ### 49.00

1.00 + 49.00 = 0.712



=0.1585

(5

= 0.00026 m/dtk5 ###


Qs = 0.2115

+= 0.8925 + 0.2115

= 1.1041


Ajalan + Alahan


R5 Thn

I5 )2/3

m3/dtk

Qkomulatif = Q (J0-J1) Q (J1-G1)

m3/dtk


20.00 Ha = 200000

0.4 Ha = 4000Ls = 400 mLt = 640.31 mSt = 0.001175Cj = 0.8

0.6

to = 0.0197 xLt 0.77St

to = 0.0197 x640.3124 0.77

0.0343

to = 38.3198 menit

td =Ls

v = 0.4 m/detv

td =400

= 16.6667 menit0.4 x 60


Cs =2 tc

=109.9730

2 tc + td 109.9730 + 16.6667

= 0.8684

Cr =

=### 0.40 + ### 20.00

0.40 + 20.00 = 0.604



=0.2018

(5

= 0.00053 m/dtk5 ###


Qs = 0.1553

Saluran A4 - A5

AL = m2

AJ= m2

CL=


Ajalan + Alahan


R10 Thn

I2 )2/3

m3/dtk

4.2.3 TABEL PERHITUNGAN DEBIT (Q) CURAH HUJAN UNTUK PERIODE ULANG 2 TAHUN, 5 TAHUN, DAN 10 TAHUN

Tabel 4.2.3.1. Debit Rencana Untuk Periode Ulang 2 Tahun (Saluran Tersier)

No

Aliran Permukaan Aliran dalam salurantc

Cs Cr

Curah HujanLuas (A)

Lt St to Ls V td T I

(m) menit (m) m/dtk menit menit Thn m/dtk

1 700.071 0.0010 44.022 490 0.40 20.417 64.439 0.863 0.604 2 0.00026 245000 0.0932 0.0932

2 700.071 0.0010 43.674 500 0.40 20.833 64.508 0.861 0.604 2 0.00026 245000 0.0929 0.0929

3 1166.19 0.0014 56.835 1000 0.40 41.667 98.502 0.825 0.456 2 0.00020 600000 0.1240 0.1240

4 1341.04 0.00095 73.481 400 0.40 16.667 90.147 0.915 0.711 2 0.00021 512000 0.1942 0.1942

5 1345.36 0.00036 107.028 1000 0.40 41.667 148.694 0.877 0.899 2 0.00015 900000 0.2964 0.2964

6 1113.60 0.0004557 84.500 790 0.40 32.917 117.417 0.877 0.711 2 0.00018 490000 0.1495 0.1495

7 500.00 0.0005 44.012 400 0.40 16.667 60.679 0.879 0.606 2 0.00027 120000 0.0486 0.0486

8 1044.03 0.00037 87.120 1000 0.40 41.667 128.787 0.861 0.461 2 0.00017 300000 0.0548 0.0548

9 1113.60 0.0003878 89.919 490 0.40 20.417 110.336 0.915 0.711 2 0.00018 490000 0.1625 0.8625

10 1118.034 0.0006 76.241 500 0.40 20.833 97.074 0.903 0.711 2 0.00020 500000 0.1781 0.1781

11 500.000 0.0005 44.012 400 0.40 16.667 60.679 0.879 0.606 2 0.00027 120000 0.0486 0.0486

12 1044.031 0.0008 64.742 1000 0.40 41.667 106.409 0.836 0.461 2 0.00019 300000 0.0604 0.0604

Nama saluran

Q Rencana (m3/det)

Q Kumulatif (m3/det)m2

A0 ̅- ̅A1

A1 ̅- ̅B1

C0 ̅- ̅C1

C2 ̅- ̅C3

E0 ̅- ̅E1

G0 ̅- ̅G1

I0 ̅- ̅I1

I2 ̅- ̅I3

J0 ̅- ̅J1

J2 ̅- ̅J3

J4 ̅- ̅J5

J6 ̅- ̅J7

Tabel 4.2.3.2 Debit Rencana Untuk Periode Ulang 5 Tahun (Saluran Sekunder)

No


Cs Cr

Curah HujanLuas (A)



1 707.107 0.0017 35.560 500 0.40 20.833 56.393 0.844 0.457 5 0.00041 250000 0.1102 0.2962

2 707.11 0.0007 49.421 500 0.40 20.833 70.255 0.871 0.457 5 0.00036 250000 0.0982 2.8196

3 640.31 0.0013 36.857 500 0.40 20.833 57.690 0.847 0.605 5 0.00041 200000 0.1154 1.2143

4 1345.36 0.0011 69.620 900 0.40 37.500 107.120 0.851 0.899 5 0.00027 900000 0.5133 1.5779

5 1166.19 0.0014 56.835 600 0.40 25.000 81.835 0.867 0.453 5 0.00032 600000 0.2105 2.5973

6 1341.04 0.0013 65.032 1280 0.40 53.333 118.365 0.816 0.712 5 0.00025 512000 0.2075 0.9047

7 1345.36 0.0013 64.859 900 0.40 37.500 102.359 0.845 0.899 5 0.00028 900000 0.5254 0.7683

8 1113.60 0.0007 71.628 1000 0.40 41.667 113.295 0.845 0.712 5 0.00026 490000 0.2115 1.0740

9 1118.03 0.0008 69.609 500 0.40 20.833 90.442 0.897 0.711 5 0.00030 500000 0.2660 1.4895

10 1118.034 0.0008 68.248 1000 0.40 41.667 109.914 0.841 0.712 5 0.00026 500000 0.2192 0.8974

11 500.000 0.0010 33.281 300 0.40 12.500 45.781 0.880 0.605 5 0.00047 120000 0.0839 0.6486

12 1044.031 0.0013 53.704 300 0.40 12.500 66.204 0.914 0.453 5 0.00037 300000 0.1277 0.1881

Tabel 4.2.3.3 Debit Rencana Untuk Periode Ulang 10 Tahun (Saluran Primer)

No


Cs Cr

Curah HujanLuas (A)



1 640.31 0.001175 38.320 400 0.4 16.667 54.986 0.868 0.604 10 0.00053 200000 0.1553 3.2711

2 1345.362 0.00097 73.074 1000 0.40 41.667 114.741 0.846 0.899 10 0.00038 900000 0.7212 5.2066

= += 5.2066 + 1.5779

= 6.7845

Nama saluran

Q Rencana (m3/det)


A2 ̅- ̅A3

B3 ̅- ̅A3

B5 ̅- ̅A5

D1 ̅- ̅A7

F1 ̅- ̅C1

H1 ̅- ̅C3

H3 ̅- ̅E1

J1 ̅- ̅G1

G2 ̅- ̅G3

J3 ̅- ̅G3

J5 ̅- ̅I1

J7 ̅- ̅I3

Nama saluran

Q Rencana (m3/det)


A4 ̅- ̅A5

A6 ̅- ̅A7

Q total Q (A6-A7) Q (D1-A7)

m3/dtk

Qtotal dipakai untuk perencanaan Outfall (Saluran Pembuang)

4.3 Perhitungan Dimensi Saluran

Dimensi saluran bentuk trapesiumDimana:

- Kecepatan rencana (v) = 0.4 m/dtk- Koefisien kekasaran Manning (n)= 0.0178- Kemiringan talud rencana (m : n = 1 : 2

T

w

1 h 2 h

m

b

Penampang Ekonomisb = 1.5 h

Luas penampang trapesium (A)

A =Q

, dimana : A = (b + m.h).hv

Keliling basah (p)

p =

Jari-jari Hidrolik ( R )

R =AP

=(b + m.h).h

Dengan menggunakan rumus Manning, maka v (kecepatan) :

v =

Dimana:

v =Q

; R =A

A p

ket:

Q =

A =

p = keliling basah (m)R = jari-jari hidrolisS = kemiringan saluran

1/n . R2/3 . S1/2

debit (m3/dtk)

Luas (m2)

b+2h .√1+m2

b+2h .√1+m2

Q=

1.

A. S

A n p

=

= n . Q................................................... ( 1 )

=

Untuk trapesium dimana b = 1.5 h, didapat:

A = (b + m.h).h , misal m = 1

= ( 1.5h + 1 . h ) .h

= 2.5

p ==== 4.328 h

Dari persamaan 1, didapat :

= n . Q

=

=n . Q

; n= 0.0178

97.656=

### Q 3

18.732

5.2135 = 0.0000056Q 3

= 0.00000108Q 3

h = 0.17958Q

.............................. ( 2 )

2/3 1/2

n . Q . P2/3 A5/3 . S1/2

A5/3

p2/3 S1/2

h2

1.5h + 2h.√1 ̅+ ̅12

1.5 h + 2h . √2

A5/3

p2/3 S1/2

( 2.5.h2 )5 1/3

(4.328.h)2 S1/2

h10

h2 S1/2

h8

S1/2

h8

S1/2

3/8

S1/2

b+2h .√1+m2

Tabel Perhitungan Dimensi Saluran Tersier

No. saluranQ maks v

Dimensi Saluran

n m P R Sw V saluranQ saluran

A h b

m/dt m m m m/dtk

1 0.09315 0.40 0.18269 0.27033 0.40549 0.0178 1 1.16998 0.15615 0.00098 0.36758 0.50988 0.09315

2 0.092852 0.40 0.18085 0.26896 0.40344 0.0178 1 1.16406 0.15536 0.00100 0.36724 0.51342 0.09285

3 0.124048 0.40 0.19809 0.28149 0.42224 0.0178 1 1.21829 0.16260 0.0014 0.37037 0.62621 0.12405

4 0.194207 0.40 0.32065 0.35813 0.53720 0.0178 1 1.54999 0.20687 0.00095 0.38953 0.60567 0.19421

5 0.296361 0.40 0.63347 0.50338 0.75507 0.0178 1 2.17861 0.29077 0.00036 0.42584 0.46784 0.29636

6 0.149468 0.40 0.34704 0.37258 0.55887 0.0178 1 1.61253 0.21522 0.000456 0.39315 0.43069 0.14947

7 0.048574 0.40 0.14427 0.24022 0.36033 0.0178 1 1.03968 0.13876 0.0005 0.36006 0.3367 0.04857

8 0.054753 0.40 0.17669 0.26585 0.39877 0.0178 1 1.15058 0.15356 0.00037 0.36646 0.30989 0.05475

9 0.862468 0.40 1.37269 0.74100 1.11149 0.0178 1 3.20703 0.42802 0.00039 0.48525 0.62831 0.86247

10 0.178147 0.40 0.35707 0.37792 0.56689 0.0178 1 1.63566 0.21830 0.00060 0.39448 0.49892 0.17815

11 0.048574 0.40 0.14427 0.24022 0.36033 0.0178 1 1.03968 0.13876 0.00050 0.36006 0.3367 0.04857

12 0.060413 0.40 0.14245 0.23871 0.35806 0.0178 1 1.03312 0.13788 0.00080 0.35968 0.4241 0.06041

m3/dt m2 m3/dtk

A0 ̅- ̅A1

A1 ̅- ̅B1

C0 ̅- ̅C1

C2 ̅- ̅C3

E0 ̅- ̅E1

G0 ̅- ̅G1

I0 ̅- ̅I1

I2 ̅- ̅I3

J0 ̅- ̅J1

J2 ̅- ̅J3

J4 ̅- ̅J5

J6 ̅- ̅J7

Tabel Perhitungan Dimensi Saluran Sekunder

No. saluranQ maks v

Dimensi Saluran


A h b

m/dt m m m m/dtk

1 0.29623 0.40 0.39126 0.39560 0.59341 0.0178 1 1.71218 0.22851 0.00130 0.3989 0.75711 0.29623

2 2.81961 0.40 2.61911 1.02354 1.53532 0.0178 1 4.42990 0.59123 0.00074 0.55589 1.07655 2.81961

3 1.21430 0.40 1.12717 0.67147 1.00720 0.0178 1 2.90611 0.38786 0.0013 0.46787 1.0773 1.21430

4 1.57793 0.40 1.46056 0.76434 1.14652 0.0178 1 3.30808 0.44151 0.0011 0.49109 1.08037 1.57793

5 2.59734 0.40 1.93897 0.88068 1.32101 0.0178 1 3.81156 0.50871 0.0014 0.52017 1.33954 2.59734

6 0.90470 0.40 0.90269 0.60089 0.90134 0.0178 1 2.60067 0.34710 0.001305 0.45022 1.00223 0.90470

7 0.76830 0.40 0.79457 0.56376 0.84564 0.0178 1 2.43996 0.32565 0.001322 0.44094 0.96694 0.76830

8 1.07402 0.40 1.29664 0.72018 1.08027 0.0178 1 3.11693 0.41600 0.0007 0.48004 0.82831 1.07402

9 1.48945 0.40 1.60671 0.80168 1.20251 0.0178 1 3.46965 0.46308 0.00076 0.50042 0.92702 1.48945

10 0.89736 0.40 1.07780 0.65660 0.98490 0.0178 1 2.84176 0.37927 0.0008 0.46415 0.83258 0.89736

11 0.64857 0.40 0.76754 0.55409 0.83114 0.0178 1 2.39811 0.32006 0.00103 0.43852 0.845 0.64857

12 0.18812 0.40 0.27833 0.33367 0.50050 0.0178 1 1.44411 0.19274 0.00130 0.38342 0.67587 0.18812

Tabel Perhitungan Dimensi Saluran Primer

No. saluranQ maks v

Dimensi Saluran


A h b

m/dt m m m m/dtk

1 3.27110 0.40 2.46167 0.99230 1.48846 0.0178 1 4.29470 0.57319 0.00118 0.54808 1.32881 3.27110

2 5.20656 0.40 3.74841 1.22449 1.83673 0.0178 1 5.29957 0.70730 0.00097 0.60612 1.389 5.20656

m3/dt m2 m3/dtk

A2 ̅- ̅A3

B3 ̅- ̅A3

B5 ̅- ̅A5

D1 ̅- ̅A7

F1 ̅- ̅C1

H1 ̅- ̅C3

H3 ̅- ̅E1

J1 ̅- ̅G1

G2 ̅- ̅G3

J3 ̅- ̅G3

J5 ̅- ̅I1

J7 ̅- ̅I3

m3/dt m2 m3/dtk

A4 ̅- ̅A5

A6 ̅- ̅A7

4.5 Perhitungan Dimensi Gorong-gorong dan Kehilangan Energi

Perhitungan Gorong-gorong A1 - A2

Data-data ̅sbb:

Bangunan ̅pelintas ̅gorong-gorong ̅bentuk ̅Segi ̅empat

= 0.186

= kecepatan ̅di ̅hulu ̅saluran = 0.40 m/s

= kecepatan ̅didalam ̅gorong-gorong = 1.5 m/s

= kecepatan ̅di ̅hilir ̅saluran = 0.4 m/s

g = perc. ̅Gravitasi = 9.81

n = Koefisien ̅kekasaran ̅Manning = 0.018

Luas ̅penampang ̅Gorong-gorong ̅

A =Q

=0.186

= 0.1240031.5

Tinggi ̅permukaan ̅air ̅gorong-gorong ̅(h) ̅dapat ̅dihitung ̅:

A ̅ = (Asumsi ̅h ̅= ̅b)

0.124 =

d = 0.40 m

Jadi, ̅diameter ̅gorong-gorong ̅

d = 0.40 m

Keliling ̅Basah ̅

P = b + 2d

= 0.39727 + 2 ̅. 0.40

= 1.1918 m

Jari ̅- ̅jari ̅Hidrolis

R =A

P

=0.124

= 0.104046 m1.192

Kemiringan ̅Dasar ̅Saluran

S =2

=1.5 . ̅0.018 2

= 0.0146 = 1.46 ̅%0.221

Qsaluran m3/s

v1

v2

v3

m/s2

v2

m2

(d2 ̅x ̅π)/4

(d2 ̅x ̅π)/4

v2 ̅x ̅n

R2/3

Kehilangan ̅Energi ̅:

1. Akibat ̅pemasukan

hc = 0.502 ̅. ̅g ̅ ̅

= 0.50( 1.5 - 0.40

= 0.0308 m2 x 9.81

2. Akibat ̅gesekan

Nilai ̅koefisien ̅kekasaran ̅Strickler ̅(k) ̅untuk ̅beton ̅70

hf = Cf =1

R1/6

=1

0.1041/6

= 0.010 ̅m2 ̅. ̅g ̅ k 70

=0.0098 x ̅ ̅1.5 2

= 0.0011 m2 x 9.81

3. Akibat ̅pengeluaran

ho = 0.112 ̅. ̅g ̅ ̅

= 0.11( 1.5 - 0.40

= 0.0068 m2 x 9.81

4. = hc ̅+ ̅hf ̅+ ̅ho

= 0.0308 + 0.0011 + 0.0068

= 0.0387 m

Sketsa Penampang Gorong-Gorong A1 - A2

0.40 ̅m

=h

b = 0.40 m

(v2 ̅- ̅v1)2

)2

Cf ̅. ̅v22

(v2 ̅- ̅v3) ̅2

) ̅2

Htotal

Tabel Perhitungan Dimensi Gorong-gorong (Bulat)

SKETSA PENAMPANG GORONG-GORONG

d ̅( ̅m ̅)

b ̅( ̅m ̅)

No Nama Gorong-Gorong

Kecepatan Aliran Dimensi KoefisienP R S

A d b Manning

m/dt m/dt m/dt m m ( n ) m m %

1 A1 ̅- ̅A2 0.19 0.40 1.5 0.40 0.1240 0.40 0.40 0.0178 1.19 0.10 1.457

2 A3 ̅- ̅A4 3.12 0.40 1.5 0.40 2.0772 1.63 1.63 0.0178 4.88 0.43 0.223

3 A5 ̅- ̅A6 4.49 0.40 1.5 0.40 2.9903 1.95 1.95 0.0178 5.85 0.51 0.175

4 C1 ̅- ̅B3 2.72 0.40 1.5 0.40 1.8143 1.52 1.52 0.0178 4.56 0.40 0.244

5 C3 ̅- ̅B5 1.10 0.40 1.5 0.40 0.7326 0.97 0.97 0.0178 2.90 0.25 0.446

6 E1 ̅- ̅D1 1.06 0.40 1.5 0.40 0.7098 0.95 0.95 0.0178 2.85 0.25 0.455

7 G1 ̅- ̅G2 1.22 0.40 1.5 0.40 0.8157 1.02 1.02 0.0178 3.06 0.27 0.415

8 G3 ̅- ̅F1 2.39 0.40 1.5 0.40 1.5912 1.42 1.42 0.0178 4.27 0.37 0.266

9 I1 ̅- ̅H1 0.70 0.40 1.5 0.40 0.4648 0.77 0.77 0.0178 2.31 0.20 0.604

10 I3 ̅- ̅H3 0.24 0.40 1.5 0.40 0.1619 0.45 0.45 0.0178 1.36 0.12 1.219

No Nama Gorong-GorongKehilangan Energi

hc hf hom m m m

1 A1 ̅- ̅A2 0.0308 0.0011 0.0068 0.03872 A3 ̅- ̅A4 0.0308 0.0014 0.0068 0.03903 A5 ̅- ̅A6 0.0308 0.0015 0.0068 0.03914 C1 ̅- ̅B3 0.0308 0.0014 0.0068 0.03905 C3 ̅- ̅B5 0.0308 0.0013 0.0068 0.03896 E1 ̅- ̅D1 0.0308 0.0013 0.0068 0.03897 G1 ̅- ̅G2 0.0308 0.0013 0.0068 0.03898 G3 ̅- ̅F1 0.0308 0.0014 0.0068 0.03909 I1 ̅- ̅H1 0.0308 0.0013 0.0068 0.0389

Q1V1 V2 V3

m3/det m2

S H

10 I3 ̅- ̅H3 0.0308 0.0011 0.0068 0.0388

4.4 Perhitungan Inlet pada Trotoar

Definisi ̅Inlet ̅Lubang-lubang ̅di ̅sisi ̅jalan ̅yang ̅berfungsi ̅untuk ̅menampung ̅dan ̅menyalurkan ̅

limpasan ̅air ̅hujan ̅yang ̅berada ̅di ̅sepanjang ̅jalan ̅menuju ̅ke ̅dalam ̅saluran.

Diketahui ̅data-data ̅sebagai ̅berikut:

A6 ̅- ̅A7

= 1000 m

= 8 m

= 1 m

= 10 m

D =280

x S £ 50 ̅mw

dimana: w = lebar ̅jalan ̅(m)

s = kemiringan ̅jalan ̅(%) ̅= ̅2%

D = jarak ̅antara ̅sreet ̅inlet ̅(m)

Q=

L

dimana ̅:

Q =

L = lebar ̅bahan ̅inlet ̅(m)

g = kecepatan ̅grafitasi

d = kedalaman ̅air ̅(m)

A6 ̅- ̅A7

Dik: w = 8 m

S = 0.02 = 2%

g = 9.8

· ̅Jalur ̅Trotoar ̅yang ̅direncanakan

· ̅Panjang ̅Saluran

· ̅Lebar ̅jalan

· ̅lebar ̅trotoar ̅

· ̅jalan ̅+ ̅trotoar ̅

· ̅Jarak ̅antara ̅Sreet ̅Inlet ̅( ̅D ̅)

· ̅Kapasitas ̅untuk ̅inlet ̅tegak ̅

0,36 ̅x ̅g ̅x ̅d3/2

kapasitas ̅inlet ̅(m3/det)

m/det2

* ̅Perencanaan ̅inlet ̅pada ̅jalur ̅trotoar

m/det2

Jarak antara Sreet Inlet ( D )

D =280

x S £ 50 ̅mw

280x 2 £ 50

8

49.50 £ 50 ( Oke !!! )

Selanjutnya ̅jumlah ̅inlet ̅tegak ̅yang ̅dibuat ̅di ̅sepanjang ̅jalan ̅A

N =Ltot

=1000

= 21D 49.50

Luas 1 inletA =A = 0.5 x 8 x 49

A = 0.02 Ha

Kapasitas inlet tegak (Curb Inlet)

Data-data ̅:

A ̅ = 0.02 Ha st ̅ = 2.0 ̅%

Lt ̅ = 4.001 ̅m C = 0.8

Ls ̅ = 1000

Perhitungan:

to = 0.0197 (Lt

)1

( st ) 0.5

= 0.0197 (4.000799920016

)0.77

= 0.0439 menit( 2.000 ) 0.5

td =

Ls Untuk ̅kemiringan ̅0-1% ̅= ̅0.4

v Untuk ̅kemiringan ̅1-2% ̅= ̅0.6

Untuk ̅kemiringan ̅2-4% ̅= ̅0.9 ̅

=1000

= 2500.00 detik = 41.67 menit0.4

tc = to + td

= 0.043876 + 41.667 = 41.71 menit

Cs ̅ =2 ̅. ̅tc

=2 x 41.711

= 0.672 ̅. ̅tc ̅+ ̅td ( 2 x 41.711 ) + 41.67

Gunakan ̅Curah ̅Hujan ̅Maksimum ̅antara ̅periode ̅ulang ̅2, ̅5, ̅10 ̅dan ̅15 ̅tahun

I15 =R

x24 2/3

24 tc ̅/ ̅60

=234.4555

x24 2/3

= 103.58 mm/jam24 41.711 / 60

1/2 x w x D

Tinggi Genangan Air

d = 0.046

= 0.046 ( 49 . 103.58 ( ̅1 ̅/ 2

= 2.8673023554769 mm

dimana ̅tinggi ̅genangan ̅maksimum ̅yang ̅diijinkan ̅untuk ̅jalur ̅jalan ̅yang ̅lurus ̅= ̅6.5 ̅mm

( modul perencanaan drainase permukaan, teknik sipil unhas, hal.2-12 )

Q = 0.36

dimana ̅: ̅ Q =

g = = 9.81

L = Lebar ̅bukaan ̅curb ̅( ̅m ̅)

diambil ̅l ̅= ̅ 20 cm = 0.2 m

d = kedalaman ̅air ̅dalam ̅curb ̅(m)

diambil ̅d ̅= ̅ ̅ 10 cm = 0.1 m

Q = 0.36 x 9.81 x 0.03162 x 0.2

= 0.0223358

= 22.3358 lt/det

Sketsa ̅Inlet ̅:

d = 0.10 ̅m

L

0.20 ̅m

( ̅D ̅. ̅I ̅) ̅0.5 ( ̅1 ̅/ ̅S ̅) ̅0.2

) ̅0.5 ) ̅0.2

g. d3/2. L

kapasitas ̅inlet ̅tegak ̅( ̅m3/det ̅)

percepatan ̅gravitasi ̅( ̅m/det2 ̅) ̅ m/det2

m3/det

BAB VIII

PERHITUNGAN OUTFALL KE SUNGAI

8. Perhitungan Outfall ke sungai

Outfall ke sungai yang digunakan adalah bentuk trapesiumDiketahui data sebagai berikut :

Debit Rencana ( Q ) = 6.7845Kecepatan air dalam outfall = 0.4 m/detKoefisien manning (n) = 0.018

8.1. Luas penampang basah ( A )

A =Q

=6.7845

= 16.9612V 0.4

8.2. Mencari lebar saluran dan kedalaman air

A = ( b + ( m x h )) x h Asumsi b = 1.5 hA = ( 1,5 h + ( 1,0 x h )) x hA = ( 1,5 h + 1,0 h ) h

A = 2.5

16.96 = 2.5

h =16.96 0.5

2.5

h = 2.60 m b = 3.91 m

8.3. Keliling basah ( P )

P =

= 3.9 + 2(2,13) + 1 0.5P = 11.27 m

8.4. Jari-jari Hidrolis ( R )

R =A

=16.9612

= 1.5044 mP 11.27

m3/det

m2

h2

h2

b + 2 h ( m2 + 1 )0,5

(1)2

D22

Imm@n'K : Lihat 0.33 dari " m "

8.5. Tinggi Jagaan

fb = (1.5. Q. h

60

= (1.5 6.784 2.60

60

= 0.6647 m

8.6. Kemiringan Saluran ( S )

S =Q x n 2 6.7845 x 0.018 2

16.9612 x 1.50

S = 0.0000301

S saluran = S rencana

0.00003007 = 0.000030 …… OK !!!

8.7. Kontrol Debit

Q = 1n

Q = 116.9612 x 1.50 x 0.00003007

0.50.018

Q = 6.7845

Q saluran = Q rencana 6.7845 = 6.7845 …… OK !!!

8.8. Kehilangan tingkat energi ( z )

Q = f. A. 2. g. z6.784 = 0.8 1.5044 2 9.8 z

z = 0.2876 m

dimana : f = koefisien debit = 0.8

)0.5

)0.5

A x R2/3 2/3

A x R2/3 x S0.5

2/3

GAMBAR OUTFALL KE SUNGAI

fb 0.66 m

h 2.60 m

b = 3.91 m

Documents

drainase umum bulat.xls