162
5.5 Analisis Intensitas Curah Hujan
Analisis intensitas curah hujan menggunakan rumus yang diberikan oleh DR. Mononobe yaitu:
I = R
24
24 x 24 t
23
dimana: I
= Intensitas Curah Hujan mmjam R
24
= Curah hujan maksimum dalam 1 hari mm t
= Lamanya Curah Hujan jam.
5.5.1 Ruas Hulu
Perhitungan Intensitas Hujan dengan periode ulang tertentu dapat dilihat pada tabel 5.27.
Periode ulang
Intensitas I 2 th
5 th 10 th
25 th 50 th
100 th R24
mm 118.1148 158.2707 189.8464 235.7826 274.8145 318.1683
t mmjam mmjam mmjam mmjam mmjam mmjam
1 40.948 54.869 65.816 81.741 95.273 110.303 2 25.796 34.566 41.462 51.494 60.018 69.486
3 19.686 26.378 31.641 39.297 45.802 53.028 4 16.250 21.775 26.119 32.439 37.809 43.774
5 14.004 18.765 22.509 27.955 32.583 37.723 6 12.401 16.617 19.933 24.756 28.854 33.406
7 11.190 14.994 17.986 22.338 26.036 30.143 8 10.237 13.717 16.454 20.435 23.818 27.576
9
9.464 12.681 15.211 18.892 22.020 25.493 10 8.822 11.821 14.180 17.611 20.526 23.764
11 8.279 11.093 13.307 16.526 19.262 22.301 12 7.812 10.468 12.557 15.595 18.177 21.044
13 7.406 9.924 11.904 14.785 17.232 19.951 14 7.049 9.446 11.330 14.072 16.402 18.989
15 6.732 9.021 10.821 13.439 15.664 18.135 16 6.449 8.641 10.365 12.873 15.005 17.372
17 6.193 8.299 9.955 12.364
14.410 16.684
18 5.962 7.989 9.583 11.901 13.871
16.060 19 5.751 7.706 9.243 11.480
13.380 15.491
20 5.558 7.447 8.933 11.094 12.931
14.970 21 5.380 7.209 8.647 10.739
12.517 14.491
22 5.215 6.988 8.383 10.411 12.134
14.049 23 5.063 6.784 8.138 10.107
11.780 13.639
24 4.921 6.595 7.910 9.824 11.451 13.257
Tabel 5.27 Intensitas Hujan dengan Periode Ulang Tertentu
Sumber : Hasil Perhitungan
163 Grafik Intensitas Hujan dengan periode ulang tertentu dapat dilihat pada
Gambar L.G 5.7.
5.5.2 Ruas Hilir
Perhitungan Intensitas Hujan dengan periode ulang tertentu dapat dilihat pada tabel 5.28.
Periode Intensitas I
ulang 2 th
5 th 10 th
25 th 50 th
100 th R24
mm 111.867 148.894 177.248 217.788 251.575 288.605
t mmjam mmjam mmjam mmjam mmjam mmjam
1 38.782182 51.6187 61.4483 75.503 87.216 100.054
2 24.431244 32.5177 38.71 47.5639 54.9427 63.0298
3 18.644528 24.8157 29.5413 36.2981 41.9291 48.1008
4 15.390719 20.4849 24.3858 29.9634 34.6117 39.7063
5 13.26332 17.6533 21.015 25.8217 29.8275 34.2179 6 11.745317
15.6329 18.6098 22.8664 26.4137 30.3016 7 10.598235
14.1061 16.7923 20.6332 23.834 27.3422 8 9.6955455
12.9047 15.3621 18.8758 21.804 25.0134 9 8.9633543
11.9301 14.202 17.4503 20.1574 23.1244 10 8.3553678
11.1209 13.2386 16.2666 18.7901 21.5559 11 7.8409818
10.4363 12.4236 15.2652 17.6333 20.2288 12 7.399086 9.8481 11.7235 14.4049 16.6396 19.0888
13 7.0146069 9.33637 11.1143 13.6564 15.7749 18.0969
14 6.6764697 8.88631 10.5785 12.9981 15.0145 17.2245
15 6.376339 8.48684 10.103 12.4138 14.3395 16.4502 16 6.1078109
8.12943 9.6775 11.891 13.7357 15.7575 17 5.8658771
7.80742 9.29417 11.42 13.1916 15.1333 18 5.6465594
7.51551 8.94667 10.993 12.6984 14.5675 19 5.4466546
7.24944 8.62993 10.6038 12.2488 14.0517 20 5.2635519
7.00573 8.33981 10.2473 11.837 13.5794 21 5.0951 6.78152 8.07291 9.91939 11.4582 13.1448
22 4.939509 6.57443 7.82639 9.61648 11.1083 12.7434 23 4.7952768
6.38246 7.59786 9.33568 10.7839 12.3713 24 4.6611321
6.20392 7.38531 9.07452 10.4823 12.0252
Tabel 5.28 Intensitas Hujan dengan Periode Ulang Tertentu
Sumber : Hasil Perhitungan
164 Grafik Intensitas Hujan dengan periode ulang tertentu dapat dilihat pada
Gambar L.G 5.8.
5.6 Analisis Debit Banjir Rencana
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