Optimasi Intensitas Tanam (D.I) Pondok Kabupaten Ngawi Dengan Pengelolaan Air Waduk Serta Pemanfaatan Air Tanah

Safira, Nadiya el (2026) Optimasi Intensitas Tanam (D.I) Pondok Kabupaten Ngawi Dengan Pengelolaan Air Waduk Serta Pemanfaatan Air Tanah. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Daerah Irigasi Pondok Pondok di Kabupaten Ngawi merupakan kawasan pertanian yang sangat bergantung pada pasokan air dari Waduk Pondok, dengan kapasitas tampungan normal berkisar 25 sampai 28 juta m³. Namun, pada musim kemarau volume tampungan dilaporkan menyusut secara signifikan hingga sekitar 7 juta m³, sehingga pasokan air irigasi untuk sawah padi menjadi tidak mencukupi. Kondisi ini menimbulkan ketidaksesuaian antara kebutuhan air tanaman padi dan ketersediaan air irigasi, yang memaksa peralihan pola tanam ke palawija pada Musim Tanam III dan berpotensi menurunkan intensitas tanam serta mengancam produktivitas pertanian di Daerah Irigasi Pondok, Kabupaten Ngawi. Penelitian ini dilakukan melalui tahapan survei lokasi, studi literatur, pengumpulan data sekunder (curah hujan, klimatologi, debit intake, data inflow–outflow waduk, karakteristik tanah, dan pola tata tanam eksisting), serta pengolahan dan analisis data. Analisis meliputi perhitungan curah hujan efektif, evapotranspirasi dengan metode Penman, kebutuhan air irigasi, dan neraca air untuk mengetahui ketersediaan air. Berdasarkan hasil tersebut disusun beberapa alternatif Pola Tata Tanam (PTT), Pola Operasi Waduk (POW), dan sistem rotasi air irigasi, yang selanjutnya dievaluasi kelayakan ekonominya menggunakan metode Benefit Cost Ratio (BCR) untuk menentukan alternatif pengelolaan terbaik. Hasil analisis menunjukkan bahwa dari lima alternatif Pola Tata Tanam yang diuji, Alternatif V dengan pola Padi-Padi-Padi dan awal musim tanam Oktober Periode I terpilih sebagai yang terbaik, dengan luas tanam 9.695 ha dan intensitas tanam meningkat dari 264% (eksisting) menjadi 281%, tanpa mengalami defisit air sepanjang tahun (Faktor K 100% pada seluruh periode). Nilai Benefit Cost Ratio (BCR) meningkat dari 1,8339 menjadi 2,0199 dengan estimasi keuntungan sebesar Rp439.501.713.542,58. Meskipun demikian, simulasi pola operasi waduk pada kondisi tahun kering (debit andalan Q65) menunjukkan keandalan Waduk Pondok yang masih rendah, yaitu 43% (volumetrik) dan 31% (waktu), sehingga diperlukan bantuan debit pompa air tanah sebesar 2,808 m³/detik untuk menutupi kekurangan pasokan air irigasi
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The Pondok Irrigation Area Pondok in Ngawi Regency is an agricultural region highly dependent on the water supply from Pondok Reservoir, which has a normal storage capacity of around 25 to 28 million m³. However, during the dry season the storage volume is reported to decline significantly to approximately 7 million m³, resulting in insufficient irrigation water supply for paddy fields. This condition creates a mismatch between rice crop water demand and irrigation water availability, forcing a shift in cropping pattern to secondary crops (palawija) during Cropping Season III and potentially reducing cropping intensity while threatening agricultural productivity in the Pondok Irrigation Area, Ngawi Regency. This research was carried out through the stages of a site survey, literature study, secondary data collection (rainfall, climatology, intake discharge, reservoir inflow–outflow data, soil characteristics, and existing cropping patterns), followed by data processing and analysis. The analysis included calculation of effective rainfall, evapotranspiration using the Penman method, irrigation water requirements, and water balance to determine water availability. Based on these results, several alternative Cropping Patterns (PTT), Reservoir Operation Patterns (POW), and irrigation water rotation systems were formulated, which were then evaluated for economic feasibility using the Benefit Cost Ratio (BCR) method to determine the best management alternative. The analysis results show that among the five Cropping Pattern alternatives tested, Alternative V with a Rice-Rice-Rice pattern and planting starting in the first period of October was selected as the best alternative, with a planting area of 9,695 ha and cropping intensity increasing from 264% (existing) to 281%, without any water deficit throughout the year (K Factor of 100% in all periods). The Benefit Cost Ratio (BCR) increased from 1.8339 to 2.0199, with an estimated profit of IDR 439,501,713,542.58. Nevertheless, the reservoir operation pattern simulation under dry-year conditions (dependable discharge Q65) showed that the reliability of Pondok Reservoir remains low, at 43% (volumetric) and 31% (time-based), so assistance from a groundwater pump discharge of 2.808 m³/second is required to cover the irrigation water supply shortfall.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Irigasi, Intensitas Tanam, Optimasi, Neraca Air, Pola Tata Tanam, Benefit Cost Ratio (BCR) ======================================================================================================================== Irrigation, Cropping Intensity, Optimization, Water Balance, Cropping Pattern, Benefit Cost Ratio (BCR)
Subjects:	T Technology > TC Hydraulic engineering. Ocean engineering > TC812 Irrigation
Divisions:	Faculty of Vocational > 22301-Civil Infrastructure Engineering (D4)
Depositing User:	Nadiya El Safira
Date Deposited:	04 Aug 2026 07:07
Last Modified:	04 Aug 2026 07:07
URI:	http://repository.its.ac.id/id/eprint/142802

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