Farouk Maricar

Irrigation channels are a vital component of an agricultural system, functioning to distribute water to agricultural land and support food security. The Saddang irrigation area, one of the main irrigation regions in Indonesia, plays a crucial role in enhancing agricultural productivity. However, the sediment accumulation in irrigation channels can significantly impact water distribution efficiency and environmental quality. The current research aims to analyze the influence of flow parameters during the rainy and dry seasons, examine the relationship between seasonal changes and sediment transport, and assess the impact of sediment discharge in the primary channel of the Saddang irrigation area. The tests conducted included sieve analysis, specific gravity, sediment concentration, and hydrometer analysis. Based on the research results, the average sediment discharge during the rainy season in the primary channel of the Saddang irrigation area is 2,702 tons/day, while during the dry season, the average sediment discharge is 100 tons/day. The ratio of the average sediment discharge between the rainy and dry seasons is 27:1. Additionally, linear equations were obtained to predict sediment discharge in the primary channel of the Saddang irrigation area. For the rainy season, the linear equation used is y = 857.67x - 1618.3, while for the dry season, it is y = 38.811x - 79.937. These equations have a validation rate of 98% between the linear equation and the actual calculation results, indicating high accuracy in modeling sediment discharge in the channel.

The Citarum Watershed is indeed a critical water resource in Indonesia, playing a significant role in providing water to Jakarta and other areas in West Java. However, it faces severe environmental stress due to land use changes and climate changes. The Upper Citarum Watershed, considered to be a conservation area, has experienced rapid development due to human activities and economic growth. Climate change not only affects the rainfall value but also the rainfall patterns and sediment flow. The sedimentation process significantly impacts the soil characteristics around the river body. Several factors such as topography, flow velocity, and soil texture influence the sediment characteristics. Given the critical condition of climate and land use change, this study aims to analyse the impacts of the hydrological response of land use and climate change on the sediment rate in the Upper Citarum Watershed. The land use change analysis was conducted by comparing the land use data in 2000, 2010, and 2023 in the Upper Citarum Watershed. The deposition process of solid particles such as sand, silt, and gravel that are transported in the Upper Citarum River were examined in a soil investigation. The sediment rate and deposition by river flow were analysed using HEC-RAS quasi-unsteady flow. The impact of climate change in this study was assessed by simulating the discharge in three conditions, with the first simulation using the discharge from 2000 to 2010, the second simulation using the discharge from 2011 to 2023, and the last simulation using the discharge from 2000 to 2023. Due to the land use change, the developed area increased from 4% to 24% between 2000 until 2023. The magnitude of low flow during the simulation step for three discharge gauges (Majalaya, Dayeuhkolot, and Nanjung) decreased up to 48%, but, on other hand, the sediment rate increased by 20% in Dayeuhkolot.

A flood forecasting and early warning system is critical for rivers that have a large flood potential, one of which is the Gilireng watershed, which floods every year and causes many losses in Wajo Regency, Indonesia. This research also introduces an integration model between UH SUH and HEC-RAS in flood impact analysis, as a reference for flood forecasting and early warning systems in anticipating the timing and occurrence of floods, as well as GIS in the spatial modeling of flood-prone areas. Broadly speaking, this research is divided into four stages, namely, a flood hydrological analysis using UH SUH, flood hydraulic tracing using a 2D HEC-RAS numerical model, the spatial modeling of flood-prone areas using GIS, and the preparation of flood forecasting and early warning systems. The results of the analysis of the flood forecasting and early warning systems obtained the flood travel time and critical time at the observation point, the total time required from the upstream observation point to level 3 at Gilireng Dam for 1 h 35 min, Mamminasae Bridge for 4 h 35 min, and Akkotengeng Bridge for 8 h 40 min. This is enough time for people living in flood-prone areas to evacuate to the 15 recommended evacuation centers.

Perubahan kecepatan aliran di dalam alur tidak sama arah horisontal maupun arah vertikal. Dengan kata lain kecepatan aliran pada tepi alur tidak sama dengan tengah alur, dan kecepatan aliran dekat permukaan air tidak sama dengan kecepatan pada dasar alur. penelitian Perubahan kecepatan aliran banyak dilakukan pada saluran terbuka dengan dimensi penampangnya yang kecil dan sama. Penelitian ini ditujukan untuk mengetahui perubahan kecepatan pada berbagai titik baik horizontal maupun vertikal pada saluran terbuka. Hasil penelitian menunjukkan bahwa Posisi ¼ B dan ¾ B aliran fluida akan terpisah dari pilar, yang dapat mengakibatkan kecepatan aliran meningkat karena tidak ada gangguan signifikan dari pilar. Namun, di tengah pilar atau posisi ½ B, aliran akan bersentuhan dengan pilar dan mengalir di sekitarnya, yang dapat menyebabkan kecepatan aliran berkurang. seiring bertambahnya debit maka kecepatan akan semakin meningkat. Perubahan kecepatan aliran pada tanpa pilar tidak memberikan perubahan signifikan, sedangkan pada aliran dengan model pilar di tengah perubahan kecepatan aliran pada titik pengamatan D sampai dengan G melambat kemudian berangsur normal pada Titik pengamatan H

ABSTRAK: Dalam rangka peningkatan kinerja pelayanan irigasi, pengembangan dan pengelolaan irigasi dengan melakukan kegiatan kinerja irigasi untuk mendata dan menilai fungsi aset daerah irigasi. Agar aset jaringan irigasi dapat dimanfaatkan secara berkelanjutan, maka perlu terus didayagunakan melalui penyelenggaraan Operasi dan Pemeliharaan (OP) secara baik dan benar, sehingga dapat memberikan pelayanan irigasi sebaik mungkin kepada para petani dalam mendukung program ketahanan pangan. Dalam hal ini dilakukan penilaian indeks kinerja irigasi menggunakan software PDSDA-PAI Versi 1.0 yang bertujuan untuk mengetahui bagaimana kondisi fisik indeks kinerja jaringan irigasi pada Daerah Irigasi Selli Coppobulu Kabupaten Bone, (Kondisi Exsisting saat ini), dan juga untuk mengetahui besar indeks jaringan pada Daerah Irigasi Selli Coppobulu Kabupaten Bone. Metode yang digunakan dalam penelitian ini adalah menggunakan metode survey langsung di lapangan. Berdasarkan dari hasil survei dan pengambilan data dilapangan, seluruh daerah irigasi yang berada di Kab. Bone masih berfungsi semuanya. Salah satunya adalah D.I Selli Coppobulu yang memiliki luas baku 1238 Ha dan panjang saluran induk ± 9.200 m, saluran sekunder ± 2.900m. Berdasarkan hasil survei jumlah aset (PAI) berupa 383 bangunan. Berdasarkan hasil analisa software PDSDA-PAI Versi 1.0 hasil penilaian indeks kinerja Prasarana Daerah Irigasi Selli Coppobulu Kabupaten Bone didapatkan nilai sebesar 33,44%, dimana menurut Peraturan Menteri Pekerjaan Umum Nomor 32/PRT/M/2007 hasil indeks kinerja tersebut masuk pada kondisi daerah irigasi kurang dan perlu perhatian. Oleh karena itu daerah irigasi Selli Coppobulu memerlukan penanganan dengan cara melakukan rehabilitasi prasarana jaringan irigasi terutama pada saluran dan bangunan yang kondisi rusak sedang dan rusak berat, dan melaksanakan pemeliharaan rutin dan berkala.

Sedimentasi merupakan proses pengendapan material yang terjadi di sungai. Krib merupakan bangunan yang dibuat melintang sungai guna mengatur arus sungai dan mengurangi gerusan. Tujuan penelitian ini yaitu mengetahui pengaruh krib permeable terhadap karakteristik aliran dan mengetahui berapa besar laju angkutan sedimen dasar akibat krib permeable menggunakan metode Duboys dan Einstein. Penelitian ini dilakukan di Laboratorium Teknik Unhas menggunakan flume akrilik sepanjang 900 cm dengan krib permeable dari kayu bulat dan bahan uji tanah pasir lolos ayakan 20. Hasil penelitian ini diketahui bahwa terjadi penurunan bilangan Froude sekitar 18 % dan kenaikan bilangan Reynolds sekitar 14,56 % pada pengaliran menggunakan krib kerapatan (ak1) 0,9 cm. Laju angkutan sedimen dasar tertinggi ada pada Q3S3ak1 dan yang terendah pada Q1S1. Menurut Einstein didapatkan qb sebesar 7,564 m3/hari dan 0,358 m3/hari sedangkan menurut Duboys sebesar 0,4096 m3/hari dan 0,0058 m3/hari.

ABSTRAK: Bendung bettu merupakan salah satu dari beberapa bendung yang ada di DAS Sungai Bialo, Desa Dampang, Kecamatan Gantarang, Kabupaten Bulukumba, Provinsi Sulawesi Selatan. Bendung Bettu adalah bangunan bendung yang dibangun melintang di sungai Bialo untuk mengaliri Daerah Irigasi (DI) Bettu dengan luas areal 1.817 Ha dan panjang saluran irigasi untuk Saluran induk 1.007 m dengan 3 saluran sekunder dengan panjang 11.000 m dan saluran tersier 940 m. Sumber air utama yang digunakan untuk megairi areal irigasi Bettu berasal dari bendung Bettu mengairi 5 Desa dan 1 Kelurahan pada Desa Dampang, Barombong, Bialo, Paenre lompoe, Bontosunggu dan Kelurahan caile. Untuk menganalisa kriteria penilaian fungsi dan kondisi bendung bettu berdasarkan struktur bangunannya. Analytic Hierarchy Process (AHP) adalah suatu metode pengambilan keputusan yang dikembangkan oleh Prof. Thomas L. Saaty. Metode Analytic Hierarchy Process (AHP) adalah metode yang digunakan untuk mendapatkan suatu keputusan (decision maker) dari beberapa parameter yang bersifat kualitatif maupun kuantitatif. Komponen kinerja bendung sebagai indikator kondisi bendung dibagi menjadi tujuh komponen, yaitu Debit, Sedimen, Mercu, Bangunan Pengambilan, Bangunan Pembilas, Kantong Lumpur, dan Bangunan Penguras. dari ketujuh Komponen bendung didapatkan bobot kondisi bendung Bettu sebesar 25.33% dan kondisi bendung mengalami Kerusakan Sedang. Fungsi bendung bettu sebesar 65,40% dan keberfungsian bendung dalam Kondisi Cukup. Kata kunci: Bendung, Irigasi, Ketersediaan air

Flood historical data from the Kelara River in the last 10 years shows that the river has often overflowed, and the worst floods happened on January 22, 2019. One of the efforts to minimize the negative impact of a flood disaster is to conduct flood tracking. Flood tracking is an analysis of the flood along the river, or also known as flood propagation, which can be used as a reference in the preparation of a flood early warning system. This study aims to determine the propagation of the Kelara River flood which can be used to determine flood-prone areas and as a reference in the preparation of a flood early warning system. This research was carried out in 3 stages, namely flood hydrology analysis using the HEC-HMS program, numerical simulation of 2D floods using the HEC-RAS program, spatial modeling of flood-prone areas using the ArcGIS program, and preparation of a flood early warning system. The results of this study showed that the flood that occurred on January 22, 2019, was a 100-year return period flood, and determined that 10 points of residential areas/villages must be alerted when the intensity of rain is high, with the fastest time to be alerted being 52 minutes.

A sluice gate is a controllable barrier that controlling the elevation of the water at the channel. Generally, energy change occurs at the upstream and downstream of watergate, caused by the impact of the water flow at watergate upstream. This study aims to analyze the energy change at Watergate and to compare the value of energy change that occurs at the channel with or without sediment. This research was carried out by the Civil Engineering Hydraulics Laboratory of the Faculty of Engineering, Hasanuddin University, which runs from December 2018 to March 2019. In this research, we use some variables that are channel bed condition, flume slope, debit, and watergate openings. The result of this research shows that debit and watergate openings really affect the value of the energy change, while the flume slope is not really affected it. The energy change that occurs at the flume without sediment is bigger than the energy change that occurs at the flume with sediment in it.