PERENCANAAN JARINGAN IRIGASI AIR TANAH SISTEM PERPIPAAN SALURAN BERCABANG TERBUKA PADA DAERAH ONCORAN SDMJ 619 DI KABUPATEN MOJOKERTO

Abstract

ABSTRAK: Sebagian besar lahan pertanian di Desa Sumber Karang, Kecamatan Dlanggu, Kabupaten Mojokerto merupakan daerah yang kekurangan air irigasi pada saat musim kemarau. Salah satu  upaya untuk mengatasi masalah tersebut pada tahun 2016 Kegiatan Pendayagunaan Air Tanah SNVT PJPA Brantas, Balai Besar Wilayah Sungai Brantas membangun sumur produksi SDMJ 619 di Desa Sumber Karang dengan potensi debit sebesar 40,11 liter/detik dan direncanakan akan mengairi seluas 39,9 ha. Namun hingga saat ini manfaatnya belum dirasakan masyarakat, dikarenakan belum dibangun jaringan irigasinya. Sehingga diperlukan suatu alternatif perencanaan jaringan irigasi air tanah yang dapat mengairi lebih luas dan lebih optimal dalam pembagian air ke petak petak sawah. Dalam studi ini dilakukan perhitungan luas daerah oncoran, perencanaan jaringan irigasi air tanah, pengaturan pola operasi dan menghitung rencana anggaran biaya. Luas daerah oncoran yang mampu diairi oleh sumur SDMJ 619 sebesar 51 ha. Perencanaan jaringan irigasi air tanah menggunakan sistem perpipaan saluran bercabang terbuka meliputi: 1 buah sumur produksi, 8 buah outlet, 1 bangunan rumah pompa, 1 buah pipa pengontrol tekanan, 8 buah alat ukur Thompson, pipa PVC berdiameter 8 inchi dengan total panjang 2141 meter, dimana dalam analisis hidraulik dengan menggunakan Paket Program WaterCAD V8i dan dinyatakan mengalir sesuai dengan syarat pengaliran. Pola operasi menggunakan sistem rotasi dengan debit pompa sebesar 40,11 liter/detik selama 8 jam pengaliran dimulai dari pukul 07.00 sampai pukul 15.00. Pengoperasian pompa ini hanya pada musim kemarau atau pada saat tidak ada hujan. Biaya yang dibutuhkan untuk pembangunan dan pengembangan sistem irigasi air tanah sumur produksi SDMJ 619 adalah sebesar Rp. 1.102.765.000,00 (Satu Milyar Seratus Dua Juta Tujuh Ratus Enam Puluh Lima Ribu Rupiah).

 

Kata Kunci: Irigasi air tanah, jaringan irigasi, sistem perpipaan

 

ABSTRACT: Most of agricultural land in Sumber Karang Village, Dlanggu Sub-district, Mojokerto District are located in areas that lacked of water irrigation supply during the dry season. An effort has been taken to address this problem in 2016 through the establishment of groundwater utilization system in Brantas SNVT PJPA, Balai Besar Wilayah Sungai Brantas, by digging SDMJ 619 production well in Sumber Karang Village that would potentially provide water supply up to 40.11 litre/second. The well was expected to supply water to a total of 39.9 ha agricultural land. Unfortunately, the community around had not yet obtained the benefits of this project due to unavailability of irrigation channels. Therefore, it was considered necessary to build groundwater irrigation channels with  higher elevation channels along the sides. Farmers also expected that this well production could supply water to broader area. The total area of water channel that could be supplied by SDMJ 619 well reached 51 ha. The needs for the establishment of the open-branch water channel piping system included; 1 production well, 8 outlets, 1 pump house, 1 pressure controlling pipe, 8 Thompson measuring equipment, 2141 meter-long PVC pipe with a diameter of 8 inches. Hydraulic analysis was administered using WaterCAD V8i program, which results showed that all the water successfully flowed through all junctions and pipes. The operational pattern of the system was rotation-based system, employing water pumps with a debit capacity of 400.11 liter/second which were turned on at 07.00 to 11.00, and at 11.00 to 15.00. The pumps were only used in dry seasons or when the rainfall was low. The total cost for the establishment and maintenance of the SDMJ 619 groundwater production well for irrigation system was Rp. 1.102.765.000,00 (One Billion One Hundred Two Million Seven Hundred Sixty Five Thousand Rupiah).

Keywords: Groundwater irrigation, irrigation network, operational pattern