LAPORAN HASIL PENELITIAN DISERTASI DOKTOR TAHUN ANGGARAN 2010

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1 BIDANG ILMU: PERTANIAN LAPORAN HASIL PENELITIAN DISERTASI DOKTOR TAHUN ANGGARAN 2010 Judul Peneliti : Model Alat Ukur Debit Saluran Irigasi Dengan Modifikasi Parshall Flume dan Drempel : Ir. Endang Purwati, MP. Dibiayai Oleh Direktorat Jenderal Pendidikan Tinggi, Kementerian Pendidikan Nasional sesuai dengan Surat Perjanjian Penugasan Dalam Rangka Pelaksanaan Penugasan Penelitian Disertasi Doktor Tahun Anggaran 2010 Nomor : 492/SP2H/PP/DP2M/VI/2010, tanggal 11 Juni Universitas Brawijaya Malang 2010

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4 RINGKASAN Alat ukur debit dibutuhkan pada saluran tersier bertujuan memberi air irigasi pada petak sawah secara tepat. Alat ukur Parshall Flume dan Drempel merupakan alat ukur dengan pelimpah berambang lebar. Parshall Flume memiliki keunggulan membersihkan sedimen secara sendiri (self-cleaning capability). Akan tetapi masalah di lapangan pada alat ukur dengan pelimpah berambang lebar adalah terjadinya sedimentasi di lokasi alat ukur. Adanya sedimentasi tersebut menyebabkan kesalahan penentuan dalam pengukuran debit sehingga berakibat pemberian air irigasi tidak tepat, sehingga menurunkan produktivitas tanaman di sawah (padi). Tujuan penelitian ini adalah memodifikasi alat ukur debit Drempel dengan Parshall Flume menjadi alat ukur modifikasi (AUMOSI). Modifikasi diharapkan lebih baik dari aslinya dan memiliki beberapa keunggulan yaitu lebih akurat, sederhana dan didapatkan mode debit yang sederhana. Kajian karakteristik aliran dilakukan melalui empirika maupun hidrolika dengan simulasi, dibantu paket program Surface-wter Modelling System (SMS), untuk hidrolika dan aliran sedimen. Kajian ini akan mencari slope (kemiringan = m) hulu dan hilir banguan ukur yang sedimentasi = 0 atau equilibrium (setimbang), di titik tinjau 1 sampai 5, yaitu hulu, ambang dan hilir alat ukur. Hasil simulasi diperoleh bentuk fisik AUMOSI bahwa m = 2.5 dan 3, akan diuji pada model tes hidrolika dengan skala 1 : 1 dan dicari pula model debit AUMOSI. Selain itu AUMOSI dalam saluran diperlakukan sebaga model dengan prototipenya adalah sungai dengan skala model 1 : 30. Hal ini dikarenakan menurut Parshall, flumenya dapat digunakan di sungai, sehingga adalah kemungkinan AUMOSI juga dipasang di sungai. Pelaksanaan odel tes dilaksanakan di Laboratorium Hidrolika Model Test.

5 SUMMARY The usage of a discharge measurer is needed for a tersier channel to distribute the irrigation water to the rightrice field. The Parshall Flume and Drempel is a measurer with a broad crested weir. The Parshall Flume has a capability to clean the sediment by itself (selfcleaning capability). But in the field, a sedimentation occurred, which is the problem of the practical use of the broad crested weir. The sedimentation caused an inaccurate measurement of the discharge, which leads to inaccuracy of the distribution of the irrigation water. The inaccuracy decreases the productivity of the rice field. The goal of this experiment is to modify the Parshall Flume and Drempel measurer into a modified measurer (AUMOSI). The modification is expected to have a better feature as the original with a better accuracy, a simple form, and a better discharge mode. The study of the characteristic of the channel is done by empirical and hydraulical simulation, with a support of Surface-water Modeling System program (SMS), for the study of the hydraulic and sediment channel. The purpose of the study is to find the slope (in meter) of the upstream and downstream of the measurer building with a number of sedimentation = 0 or equilibrium, in (titik tinjau) 1 to 5, which is upstream, (ambang), and the downstream of the measurer. The result of the simulation is a physical form of AUMOSI which is a meter = 2,5 and 3. The result will be tested by the hydraulic testing model with a scale of 1 : 1. Another purpose of the simulation is also to find the discharge model of AUMOSI. AUMOSI in the channel is used as a model with the prototype in the river with the model scale of 1: 30. It s due to the Parshall,which the flume can be used as the river, so there s a possibility to use AUMOSI in a river. The simulation of the model test is carried out at the Hydraulical Model test Laboratory.

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