Prediksi Keandalan Alokasi Air Waduk Bendungan Cabean terhadap Berbagai Pola Tanam dan Air Baku

Cahyono, Bisma Hendra Dwi (2026) Prediksi Keandalan Alokasi Air Waduk Bendungan Cabean terhadap Berbagai Pola Tanam dan Air Baku. Other thesis, Teknologi Sepuluh Nopember.

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Abstract

Waduk memiliki peran strategis dalam menampung kelebihan air pada musim hujan dan mendistribusikannya kembali pada musim kemarau untuk memenuhi kebutuhan irigasi dan air baku. Optimalisasi pemanfaatan potensi air waduk menjadi sangat penting, khususnya pada wilayah yang rawan kekeringan seperti Bendungan Cabean yang terletak di Desa Karanganyar dan Desa Todanan, Kabupaten Blora. Peningkatan kebutuhan air tidak sebanding dengan debit Sungai Galuk yang relatif kecil, sementara kebutuhan air Kabupaten Blora mencapai 55,61 liter/detik dan Kabupaten Pati sebesar 100,92 liter/detik.Proyek akhir ini bertujuan untuk menganalisis ketersediaan air kondisi eksisting, merumuskan optimasi potensi air Waduk Bendungan Cabean dalam memenuhi kebutuhan irigasi dan air baku, serta mengevaluasi peran waduk dalam mereduksi banjir.Metodologi yang digunakan meliputi studi literatur dan pengumpulan data sekunder berupa data teknis bendungan, hidrologi, dan klimatologi. Analisis yang dilakukan mencakup analisis hidrologi berupa uji kualitas data hujan, perhitungan curah hujan rata-rata dengan metode Poligon Thiessen, curah hujan efektif, distribusi hujan jam-jaman menggunakan metode Mononobe dan PSA 007, perhitungan debit banjir rencana dengan Hidrograf Satuan Sintetik Nakayasu, serta debit andalan. Analisis klimatologi dilakukan dengan menghitung evapotranspirasi potensial menggunakan metode Penman termodifikasi. Selanjutnya, analisis kebutuhan air meliputi perhitungan kebutuhan air irigasi (penyiapan lahan dan konsumtif tanaman) serta kebutuhan air baku berdasarkan proyeksi jumlah penduduk dengan metode aritmatika, geometrik eksponensial.Hasil penelitian menunjukkan bahwa kebutuhan air irigasi eksisting rata-rata sebesar 59,12 l/detik, sedangkan untuk kebutuhan air baku untuk Kecamatan Todanan dan Kecamatan Puncakwangi masing-masing sebesar 55,61 l/detik dan 100,73 l/detik. Pola operasi waduk yang paling optimal tercapai dengan awal masa tanam pada bulan Oktober periode II menggunakan pola tanam Padi-Padi-Palawija dengan intensitas tanam 300%. Simulasi menunjukkan bahwa dengan pola tersebut, waduk mampu memenuhi seluruh kebutuhan air dengan keandalan 100% pada tahun 2025 sampai 2035 (10 tahun) kedepan. Selain itu, Waduk Bendungan Cabean sebagai pengendali banjir, mampu mereduksi debit banjir kala ulang 50 tahun sebesar 45%, banjir kala ulang 100 tahun 44%, dan banjir (PMP) sebesar 42%.
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Reservoirs play a strategic role in storing excess water during the rainy season and redistributing it during the dry season to meet irrigation and raw water demands. Optimizing the utilization of reservoir water potential is crucial, especially in drought-prone areas such as the Cabean Dam, located in Karanganyar and Todanan Villages, Blora Regency. The increasing water demand is disproportionate to the relatively small discharge of the Galuk River, while the raw water demand for Blora Regency reaches 55,61 liter/sec and Pati Regency requires 100,92 liter/sec.This final project aims to analyze the existing water availability, formulate the optimization of the Cabean Dam's water potential to meet irrigation and raw water demands, and evaluate the reservoir's role in flood reduction.The methodology used includes literature studies and secondary data collection in the form of technical dam specifications, hydrology, and climatology data. The analysis conducted encompasses hydrological analysis, including rainfall data quality tests, average rainfall calculation using the Thiessen Polygon method, effective rainfall, hourly rainfall distribution using the Mononobe and PSA 007 methods, design flood discharge calculation using the Nakayasu Synthetic Unit Hydrograph, and dependable flow. Climatological analysis is carried out by calculating potential evapotranspiration using the Modified Penman method. Furthermore, the water demand analysis includes calculating irrigation water requirements (land preparation and crop consumptive use) and raw water demands based on population projections using arithmetic and exponential geometric methods.The research results indicate that the average existing irrigation water requirement is 59.12 L/sec, while the raw water requirements for Todanan District and Puncakwangi District are 55.61 L/sec and 100.73 L/sec, respectively. The most optimal reservoir operation pattern is achieved by starting the planting season in the second period of October, using a Rice-Rice-Palawija (secondary crops) cropping pattern with a cropping intensity of 300%. Simulations show that with this pattern, the reservoir is able to meet all water demands with 100% reliability for the next 10 years, from 2025 to 2035. Furthermore, functioning as a flood controller, the Cabean Dam Reservoir is capable of reducing the 50-year return period flood discharge by 45%, the 100-year return period flood by 44%, and the Probable Maximum Precipitation (PMP) flood by 42%.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Waduk, Irigasi, Air Baku, Program Linier, Keandalan, Reservoir, Irrigation, Raw Water, Linear Programming, Reliability
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) T Technology > TC Hydraulic engineering. Ocean engineering T Technology > TC Hydraulic engineering. Ocean engineering > TC167 Dams, reservoirs T Technology > TC Hydraulic engineering. Ocean engineering > TC812 Irrigation
Divisions:	Faculty of Vocational > 22301-Civil Infrastructure Engineering (D4)
Depositing User:	Bisma Hendra Dwi Cahyono
Date Deposited:	04 Aug 2026 07:41
Last Modified:	04 Aug 2026 07:41
URI:	http://repository.its.ac.id/id/eprint/143060

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