Analisis Teknis Penggunaan Sumber Daya Air Tanah Untuk Irigasi Tanaman Padi di Kabupaten Jembrana
Authors: Hendrayana  S Angga , . Sumiyati , Madrini Ida Ayu Gede Bintang 
Published: April 2021

Air tanah merupakan salah satu sumber daya air yang dapat digunakan untuk memenuhi kebutuhan irigasi. Dengan keterbatasan ketersediaan air, maka diupayakan dengan memanfaatkan air tanah dengan menggunakan sumur pompa. Penggunaan sumur pompa belum maksimal dalam memenuhi kebutuhan air irigasi maka diperlukan penelitian lebih lanjut. Tujuan dari penelitian ini adalah : (1) mengetahui teknis penggunaan sumber daya air tanah untuk irigasi menggunakan sumur pompa, dan (2) menganalisis kemampuan sumur pompa pada subak sampel di Kabupaten Jembrana terhadap kebutuhan air irigasi. Penelitian ini menggunakan analisis deskriptif kuantitatif melalui metode survey. Data ini diperoleh menggunakan data primer dan sekunder. Data debit tersedia diperoleh melalui metode survei langsung ke lapangan dan perhitungan kebutuhan air irigasi dilakukan dengan bantuan software CROPWAT 8.0. Berdasarkan analisis neraca air irigasi dari selisih antara kebutuhan air irigasi dengan ketersediaan air irigasi terhadap 3 sampel subak, diperoleh hasil pada Subak Sari Merta terjadi kekurangan air pada selama 2 periode yaitu periode Juni I sebesar 171.900 l/hari, Januari I 149.700 l/hari, pada Subak Brawantangi terjadi kekurangan air sebanyak 4 periode yaitu periode Agustus I sebesar 123.900 l/hari, Agustus II 99.200 l/hari, Maret I 98.000 l/hari, Maret II 78.200, dan pada Subak Tegal Badeng terjadi kekurangan air sebanyak 8 periode yaitu periode Juni II sebesar 64.600 l/hari, Juni III 178.500 l/hari, Agustus III 35.600 l/hari, September I 35.100 l/hari, September II 38.400 l/hari, September III 32.900 l/hari, November I 48.400 l/hari, November III 149.700 l/hari. Defisit air terjadi karena pada periode bulan tersebut dilakukan pengolahan tanah sehingga kebutuhan air irigasi cenderung tinggi. Untuk dapat memenuhi kebutuhan air irigasi yang diperlukan untuk pengolahan tanah, pada 3 sampel subak dilakukan sistem giliran memakai air irigasi supaya aktifitas pertanian dapat berjalan baik.
The Ground water is one of water resources that can be used to fullfill the needs of irrigation. With the limited availability of water, it is attempted by utilizing ground water using pump wells. The use of pump wells has not been maximal in fulfilling the irrigation water requirement so further research is needed. The objectives of this research are: (1) To know the technical use of groundwater resources for irrigation using pump wells, and (2) to analyze the ability of pump wells in subak samples in Jembrana Regency to irrigation water needs. This research uses descriptive analysis through survey method, taking data using primary and secondary data. Available discharge analysis is obtained through direct survey method of spaciousness and analysis of irrigation water needs carried out with the help of CROPWAT 8.0 software. Based on the irrigation water balance analysis, there is a reduction between the irrigation water demand and the availability of irrigation water to 3 subak samples. In Subak Sari Merta it is known that there is water shortage 2 periods that is the period of June I equal to 171.900 l / day, January I 149.700 l / day. Subak Brawantangi is known that there is water shortage as much as 4 periods that is the period of August I equal to 123.900 l / day , August II 99.200 l / day, March I 98,200 l / day, March II 78.200 l / day. Subak Tegal Badeng is known that there is water shortage for 8 periods that is June II period is 64.000 l / day, June III 178.500 l / day, August III 35.600, September I 35.100 l/day, September II 38.400 l/day, September III 32.900 l/ day, November I 48,400 l / day, November III 149.700 l / day. Water deficit occurs because in the period of the month is done so that the processing of irrigation water needs tend to be high. To be able to meet the needs of irrigation water needed for the processing of the soil, the Subak Sari is done by the turn system using irrigation water so that agricultural activities can run well.