LAPORAN HASIL PENELITIAN DISERTASI DOKTOR

TAHUN ANGGARAN 2010

Judul : Model Alat Ukur Debit Saluran Irigasi Dengan Modifikasi Parshall Flume dan Drempel

Peneliti : 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 2010.

Universitas Brawijaya Malang 2010

BIDANG ILMU: PERTANIAN

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.

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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