DAFTAR ISI
HALAMAN JUDUL ...................................................................................... i HALAMAN PENGESAHAN ........................................................................ ii BERITA ACARA BIMBINGAN TUGAS AKHIR ..................................... iii ABTRAK......................................................................................................... iv ABSTRACT .................................................................................................... v MOTTO DAN PERSEMBAHAN ................................................................. vi KATA PENGANTAR .................................................................................... viii DAFTAR ISI ................................................................................................... x DAFTAR GAMBAR ...................................................................................... xiv DAFTAR TABEL........................................................................................... xvi DAFTAR GRAFIK ........................................................................................ xvii DAFTAR ISTILAH ....................................................................................... xviii DAFTAR NOTASI ......................................................................................... xx
BAB I
PENDAHULUAN 1.1. Latar Belakang Masalah ...................................................... 1 1.2. Rumusan Masalah ................................................................ 2 1.3. Batasan Masalah .................................................................. 2 1.4. Maksud dan Tujuan ............................................................. 2 1.5. Metode Penyusunan Tugas Akhir ........................................ 3 1.6. Sistematika Penulisan Tugas Akhir ..................................... 3
BAB II
STUDI PUSTAKA 2.1. Gambaran Umum................................................................. 5 2.2. Lokasi Studi ......................................................................... 5 2.3. Drainase ............................................................................... 7 2.3.1.
Definisi Drainase ................................................... 7
2.3.2.
Jenis-Jenis Drainase ............................................... 7
2.3.3.
Fungsi Drainase ..................................................... 9
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2.4. Hidrologi .............................................................................. 10 2.4.1.
Pengertian Hidrologi.............................................. 10
2.4.2.
Daur Hidrologi (Siklus) ......................................... 10
2.5. Curah Hujan ......................................................................... 13 2.5.1.
Pengertian Curah Hujan......................................... 13
2.5.2.
Curah Hujan Daerah Aliran Sungai ....................... 15
2.5.3.
Metode Perhitungan Curah Hujan ......................... 20
2.6. Curah Hujan dan Periode Ulang ......................................... 26 2.6.1.
Frekuensi Curah Hujan .......................................... 26
2.6.2.
Pengukuran Dispersi .............................................. 27
2.6.3.
Distribusi Curah Hujan dan Periode Ulang (Return Period) ...................................................... 29
2.7. Daerah Pengaliran (Chatchment Area) ................................ 30 2.8. Debit Banjir.......................................................................... 33 2.8.1.
Pengertian Debit Banjir ......................................... 33
2.8.2.
Debit Banjir Maksimum Menggunakan Metode Gumbell .................................................... 33
2.8.3.
Debit Banjir Maksimum Menggunakan Metode Rasional .................................................... 34
2.8.4.
Debit Banjir Maksimum Menggunakan Metode Weduwen .................................................. 36
2.8.5.
Debit Banjir Maksimum Menggunakan Metode Hasper ....................................................... 37
2.9. Perhitungan Hidrograf Inflow .............................................. 38 2.9.1.
Metode Nakayasu .................................................. 39
2.10. Perhitungan Pasang Surut .................................................... 40 2.11. Perhitungan Dimensi Saluran .............................................. 41 2.9.1.
Metode Strickler .................................................... 41
2.9.2.
Metode Manning.................................................... 42
2.12. Analisa Limpasan Permukaan Dimensi Saluran .................. 43
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2.13. Kolam Penampungan ........................................................... 44 2.13.1. Kolam Retensi (Retention Basin) .......................... 44 2.13.2. Pembuatan Polder .................................................. 45 2.14. Perencanaan Pompa Drainase (Storm Water Pump)............ 46
BAB III
METODOLOGI PENELITIAN 3.1. Data yang Dibutuhkan ......................................................... 50 3.2. Peralatan yang Digunakan ................................................... 51 3.3. Bagan Alir Pelaksanaan ....................................................... 51 3.4. Tahapan Pelaksanaan Studi ................................................. 53 3.5.1. Survey ...................................................................... 53 3.5.2. Perumusan Maslah ................................................... 53 3.5.3. Studi Pustaka............................................................ 54 3.5.4. Pengumpulan Data ................................................... 54 3.5.5. Analisis Data ............................................................ 54 3.5.6. Penyusunan Laporan TA.......................................... 55
BAB IV
ANALISIS HIDROLOGI 4.1. Uraian Umum ...................................................................... 56 4.2. Penentuan Dareah Aliran Sungai ......................................... 57 4.3. Analisis Curah Hujan Rata-Rata DAS ................................. 57 4.4. Data Curah Hujan Harian Maksimum ................................. 58 4.5. Analisis Curah Hujan Rata-Rata .......................................... 60 4.5.1. Analisis Curah Hujan Rata-Rata Metode Thiesen ... 60 4.5.2. Analisis Curah Hujan Rata-Rata Metode Aljabar .... 60 4.6. Analisis Frekuensi Curah Hujan Rencana ........................... 61 4.6.1. Pengukuran Dispersi ................................................ 61 4.6.2. Pemilihan Jenis Sebaran .......................................... 63 4.7. Analisis Curah Hujan Periode Ulang Tertentu .................... 64 4.9.1. Analisis Curah Hujan Periode Ulang Tertentu Metode Log Person Type III .................................... 64
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4.9.2. Analisis Curah Hujan Periode Ulang Tertentu Metode Gumbel ....................................................... 65 4.9.3. Analisis Curah Hujan Periode Ulang Tertentu Metode Log Normal ................................................. 66 4.8. Analisis Pasang Surut .......................................................... 67 4.9. Analisis Perhitungan Debit Banjir Rencana ........................ 69 4.9.1. Metode Rasional ...................................................... 69 4.9.2. Metode Weduwen .................................................... 70 4.9.3. Metode Hasper ......................................................... 71 4.10. Analisis Perhitungan Hidrograf Inflow Metode Nakayasu ................................................................ 73 4.11. Analisis Perhitungan Hidraulic Existing ............................. 74 4.11.1 Metode Strickler....................................................... 74 4.11.2 Metode Manning ...................................................... 76 4.12. Analisis Limpasan Penampang Permukaan Saluran ............ 77 4.13. Analisis Kapasitas Tampungan Polder, Kapasitas Pompa dan Simulasi Pemompaan ................................................... 78
BAB V
KESIMPULAN DAN SARAN 5.1. Kesimpulan .......................................................................... 83 5.2. Saran .................................................................................... 83
DAFTAR PUSTAKA ..................................................................................... xxii LAMPIRAN
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DAFTAR GAMBAR
Gambar 2.1. Lokasi Kegiatan Studi ................................................................. 6 Gambar 2.2. Daur Hidrologi (Siklus) ............................................................... 10 Gambar 2.3. Metode Aljabar............................................................................ 16 Gambar 2.4. Metode Thissen ........................................................................... 17 Gambar 2.5. Metode Isohet .............................................................................. 18 Gambar 2.6. Kurva distribusi frekuensi normal ............................................... 25 Gambar 2.7. Koefisien Kurotis ........................................................................ 29 Gambar 2.8. Daerah Pengaliran Berbentuk Bulu Burung ................................ 30 Gambar 2.9. Daerah Pengaliran Menyebar ...................................................... 31 Gambar 2.10. Daerah Pengaliran Sejajar (Paralel) .......................................... 31 Gambar 2.11. Hidrograf Satuan Sintetik Nakayasu ......................................... 40 Gambar 2.12. Penampang Saluran ................................................................... 41 Gambar 2.13. Kolam Penampung .................................................................... 45 Gambar 2.14. Rumah Pompa ........................................................................... 46 Gambar 2.15. Pengaliran Air dengan Pompa ................................................... 47 Gambar 3.2. Bagan Alir Pelaksanaan .............................................................. 52 Gambar 4.1. Luas Pengaruh Stasiun Hujan ..................................................... 58
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DAFTAR TABEL
Tabel 2.1. Derajat Curah Hujan dan Intensitas Curah Hujan ........................... 14 Tabel 2.2. Keadaan Curah Hujan dan Intensitas Curah Hujan ........................ 15 Tabel 2.3. Ukuran, Masa dan Kecepatan Jatuh Butir Hujan ............................ 15 Tabel 2.4. Reduced Mean (Yn) ......................................................................... 21 Tabel 2.5. Reduced Standart Deviation (S) ...................................................... 22 Tabel 2.6. Reduced Varains (Yt) ...................................................................... 22 Tabel 2.7. Harga K untuk Distribusi Log Pearson III...................................... 23 Tabel 2.8. Koefisien Kemencengan Periode Ulang (Tahun) ........................... 26 Tabel 2.9. Koefisien Limpasan ........................................................................ 36 Tabel 2.10. Harga K (Koefisien Strickler) ....................................................... 42 Tabel 2.11. Harga Rata-rata n ......................................................................... 43 Tabel 2.12. Jenis-jenis Pompa.......................................................................... 48 Tabel 4.1. Luas Pengaruh Stasiun Hujan Terhadap DAS Kali Banger ............ 57 Tabel 4.2. Data Curah Hujan Harian Maksimum Bulan Februari 2012 Stasiun Genuk/Karang Roto ........................................................... 58 Tabel 4.3. Data Curah Hujan Harian Maksimum Bulan Februari 2012 Stasiun Tlogosari ............................................................................. 59 Tabel 4.4. Data Curah Hujan Harian Maksimum Bulan Februari 2012 Stasiun Genuk/Karang Roto ............................................................ 59 Tabel 4.5. Perhitungan Curah Hujan Rata-rata Maksimum dengan Metode Thissen ............................................................................................. 60 Tabel 4.6. Perhitungan Curah Hujan Rata-rata Maksimum dengan Metode Aljabar ............................................................................................. 61 Tabel 4.7. Parameter Statistik Curah Hujan ..................................................... 61 Tabel 4.8. Parameter Pemilihan Distribusi Curah Hujan ................................. 63 Tabel 4.9. Parameter Pemilihan Logaritmik Distribusi Curah Hujan .............. 64 Tabel 4.10. Curah Hujan Periode T Tahun Distribusi Log Pearson Type III .. 65 Tabel 4.11. Curah Hujan Periode T Tahun Distribusi Gumbel ........................ 65 Tabel 4.12. Curah Hujan Periode T Tahun Distribusi Log Normal ................. 66
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Tabel 4.13. Rekapitulasi Perhitungan Curah Hujan Periode T Tahun ............. 66 Tabel 4.14. Rekapitulasi Pengamatan Pasang Surut Per Jam pada Bulan Februari 2012 Stasiun Meteorologi Maritim Semarang................ 67 Tabel 4.15. Perhitungan Debit Banjir Metode Rasional .................................. 70 Tabel 4.16. Perhitungan Debit Banjir dengan Metode Wedowen .................... 71 Tabel 4.17. Perhitungan Debit Banjir dengan Metode Haspers ...................... 72 Tabel 4.18. Rekapitulasi Perhitungan Debit Banjir ......................................... 72 Tabel 4.19. Hidrograf Inflow Metode Nakayasu .............................................. 73 Tabel 4.20. Perhitungan Penampang Saluran Existing Metode Strickler ........ 76 Tabel 4.21. Perhitungan Penampang Saluran Existing Metode Manning........ 77 Tabel 4.22. Rekapitulasi Perhitungan Kapasitas Penampang Saluran Existing .......................................................................................... 77 Tabel 4.23. Perhitungan Debit Limpasan Permukaan ...................................... 78 Tabel 4.24. Hasil Analisa Simulasi Routing Tandon Polder Kali Banger VPolder= 186.750,1677 m3 .............................................................. 81 Tabel 4.24. Hasil Analisa Simulasi Routing Tandon Polder Kali Banger VTotal= 320.723,8384 m3 ................................................................ 82
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DAFTAR GRAFIK
Grafik 4.1. Total Pasang Surut Bulan februari 2012 ........................................ 68 Grafik 4.2. Rata-rata Maksimum dan Minimum Pasang Surut Bulan Februari 2012 ................................................................................ 68 Grafik 4.3. Unit Hidrograf Satuan Metode Nakayasu Kali Banger ............... 74 Grafik 4.4. Simulasi Routing Tandon Polder Kali Banger Semarang VPolder=186.750,1677 m3 ............................................................... 81 Grafik 4.4. Simulasi Routing Tandon Polder Kali Banger Semarang VPolder=320.723,8384 m3 ............................................................... 82
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