PERHITUNGAN PERENCANAAN SISTEM DRAINASE

Data : Lo (m) L (m) io CC rata2 V R24 B

m/det mm B1 B2

1. Waktu Kosentrasi Tc1 = To + Tf Tc2 = #DIV/0! 3. Debit Rencana

#DIV/0! jam QR1 = 0,278 . B . C . It . A#DIV/0! m3/det

To1 = 0,0195 (Lo/io^0,5)^0,77 QR2 = #DIV/0! m3/det#DIV/0! menit = #DIV/0! jam Q TOT = #DIV/0!

To2 = #DIV/0! menit = #DIV/0!4. A1 ( Luas basah perlu ) =

Tf = L/V #DIV/0!#DIV/0! #DIV/0! detik

#DIV/0! menit = #DIV/0! jam 5. A2 0

2. Intensitas hujan (it) 6. A1 = A2It1 = R24/24 * (24/Tc)^0,66667 #DIV/0!

#DIV/0! mm/Jam It2 = #DIV/0! 7. V2 = #DIV/0!

V1=V2 = #DIV/0!

8. QS = A2 x V2 >/= QR

#DIV/0!

Luas Lahan Kemiringan

A1 (Km2) A2 (Km2) Data : ke n B m Y123 0

n rata #DIV/0!

A (m2) P Simetris1 P2Simetri 0 0 0

QR/V1 n =

- R jari Hdrolis = #DIV/0!#DIV/0!

- V2 Teoritis = #DIV/0!#DIV/0!

T Simetri P1 02 03 0

P tot 00

No Simetri P1

3P tot

3

0.666667

Permasalahan 1 :

DIKET :Io = 0.0006 I = 0.001V = 0.8 m/det (Rencana)

500 m C = 0.57R24 = 120 mm

C1 = 0.6C2 = 0.8C3 = 0.3

L = 700 m Kondisi :Permukiman 0.4 A1 = 350000Fas. Umum 0.3

Lahan terbuka 0.3Plesteran (n) 0.018

Penyelesaian :1. Tc = To + Tf 6. Rencana dimensi (Sal. Bentuk Trapesium)

1.050654 Jam QR = 2.233 m3/detTo = 0,0195 (Lo/io^0,5)^0,77 Vr = 0.8 m/det

52.62255 menit 0.87704 Jam A = 2.79066 m2Tf = L/V Direncanakan =

625 Detik 0.17361 Jam m = 1b = 1.5 m

2. Intensitas Hujan R = A/PIt1 = R24/24 * (24/Tc)^0,66667 A = (b + m.Y).Y P = b + 2y*(1+m^2)^0,5

40.254 mm/Jam 2.79066 = ( 1.5 + 1 y ).Y

3. Luas Lahan = 0.35 Km2 2.790659 = 1.5 Y + 1 Y2B = 1 1 Y2 + 1.5 Y - 2.7906586

4. Debit Rencana b= 1.5 c = 2.7906586QR1 = 0,278 . B . C . It . A a = 1

2.233 m3/dety = 1.081163 -2.5812

7. Kontrol A = (b + m.Y).Y

2.79066 OKR = 0.6122562

P = b + 2y*(1+m^2)^0,54.557991 m

Permasalahan 2 :

DIKET :Io = 0.0005 I = 0.001V = 1 m/det (Rencana)

418 m C = 0.635R24 = 120 mm

C1 = 0.75 n = 0.025C2 = 0.85

818 m C3 = 0.25kondisi :

Permukiman 0.35 A = 341924Fas. Umum 0.35

Lahan Terbuka 0.3

Penyelesaian : 5. Rencana dimensi (Sal. Bentuk Trapesium)QR = 2.77723526 m3/det

1. Tc = To + Tf Vr = 1 m/det0.859759 A = 2.77723526 m2

To = 0,0195 (Lo/io^0,5)^0,77 Direncanakan =37.95219 menit 0.632537 Jam m = 1

Tf = L/V b = 1.5 m818 Detik 0.227222 Jam

A = (b + m.Y).Y2. Intensitas Hujan 2.777235It1 = R24/24 * (24/Tc)^0,66667 2.777235

46.01131 mm/jam A = (b + m.Y).Y2.777235 = ( 1.5 + 1 y ).Y

3. Luas Lahan = 0.341924 km2 1.5 Y2 + 1 Y2B = 1 1 Y2 + 1.5 Y - 2.777235

4. Debit Rencana b = 1.5 c = 2.777235QR1 = 0,278 . B . C . It . A a = 1

2.777235 m3/dety = 1.077494 -2.577494

8. Kontrol V 6. Kontrol V2 = 0.910497 NOT OK A = (b + m.Y).YV1 = 1 2.777235 OK 2.777235

9. Kontrol Q P = b + 2y*(1+m^2)^0,5 R= 0.610702Qs = A2 x V2 Q1 4.547614 m

2.5287 2.777235 NOT OK

Soal : Diketahui saluran sekunder AB dengan bentuk penampang trapesium simetris, Lebar dasar b=5m, kedalaman aliran y=1,5m

koefisien n = 0,02 miring talud m=0,5 . Miring dasar saluran I=0,0005. saluran tersebut bermuara kesaluran primer dimana kondisi saluran primer dalam keadaan banjir. Elevasi dasar muara +55,60 dan elevasi muka air banjir +58,10.Hitung pengaruh back water yang terjadi dan gambar profil aliran ? !

X = Back water58.1 MAB

Y = 1.52.5

AI = 0.005 55.6

B Q = 30m = 0.5

α = 1n = 0.02

B= 5 m

Tabel Perhitungan : 1.333333333

Y A P R V E ΔE If ΔX X

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

2.5 15.625 10.590 1.475 1.680 1.920 0.188 2.688 0.000 0.001 0.000 0.000 0.000 0.000 2.5002.5 15.251 10.478 1.455 1.649 1.967 0.197 2.647 0.041 0.001 0.001 0.004 9.939 9.939 2.5502.4 14.880 10.367 1.435 1.619 2.016 0.207 2.607 0.040 0.001 0.001 0.004 9.935 19.874 2.5992.4 14.511 10.255 1.415 1.589 2.067 0.218 2.568 0.039 0.001 0.001 0.004 9.931 29.805 2.6492.3 14.145 10.143 1.395 1.558 2.121 0.229 2.529 0.039 0.001 0.001 0.004 9.927 39.732 2.6992.3 13.781 10.031 1.374 1.527 2.177 0.242 2.492 0.038 0.001 0.001 0.004 9.922 49.654 2.7482.2 13.420 9.919 1.353 1.496 2.235 0.255 2.455 0.037 0.001 0.001 0.004 9.917 59.572 2.7982.2 13.061 9.808 1.332 1.465 2.297 0.269 2.419 0.036 0.001 0.001 0.004 9.912 69.484 2.8472.1 12.705 9.696 1.310 1.434 2.361 0.284 2.384 0.035 0.002 0.001 0.004 9.906 79.390 2.8972.1 12.351 9.584 1.289 1.402 2.429 0.301 2.351 0.033 0.002 0.002 0.003 9.900 89.290 2.9462.0 12.000 9.472 1.267 1.371 2.500 0.319 2.319 0.032 0.002 0.002 0.003 9.893 99.183 2.9962.0 11.651 9.360 1.245 1.339 2.575 0.338 2.288 0.031 0.002 0.002 0.003 9.886 109.069 3.0451.9 11.305 9.249 1.222 1.307 2.654 0.359 2.259 0.029 0.002 0.002 0.003 9.878 118.947 3.0951.9 10.961 9.137 1.200 1.275 2.737 0.382 2.232 0.027 0.002 0.002 0.003 9.869 128.816 3.1441.8 10.620 9.025 1.177 1.242 2.825 0.407 2.207 0.025 0.003 0.002 0.003 9.860 138.675 3.1931.8 10.281 8.913 1.153 1.210 2.918 0.434 2.184 0.023 0.003 0.003 0.002 9.849 148.524 3.2431.7 9.945 8.801 1.130 1.177 3.017 0.464 2.164 0.020 0.003 0.003 0.002 9.838 158.362 3.2921.7 9.611 8.690 1.106 1.144 3.121 0.497 2.147 0.017 0.003 0.003 0.002 9.826 168.188 3.3411.6 9.280 8.578 1.082 1.111 3.233 0.533 2.133 0.014 0.004 0.004 0.001 9.812 178.000 3.3901.6 8.951 8.466 1.057 1.077 3.351 0.573 2.123 0.010 0.004 0.004 0.001 9.797 187.797 3.4391.5 8.625 8.354 1.032 1.043 3.478 0.617 2.117 0.006 0.005 0.004 0.001 9.780 197.578 3.488

m3/det

R4/3 α V2/2g Ifrat I0-IfratElv. Dasar

Saluran

Jadi, panjang back water yang terjadi = 197.578 m (dari muara ke hulu saluran) .