Bendung Sekka-sekka meskipun telah dilengkapi dengan kantong lumpur, tetap memerlukan pemeliharaaan rutin akibat akumulasi sedimen yang terjadi di Saluran Primer D.I Maloso. Pemodelan sedimen menjadi pendekatan yang efektif untuk mengidentifikasi area dengan sedimentasi tinggi agar pemeliharaan lebih fokus dan efisien. Penelitian ini bertujuan untuk mengetahui pola sedimentasi yang terjadi, memodelkan angkutan sedimen dasar, serta menganalisis besar angkutan sedimen dasar pada saluran primer D.I Maloso menggunakan perangkat lunak Hec-Ras. Analisis dilakukan dengan menggunakan pendekatan Quasy-Unsteady Flow, dengan input berupa data penampang melintang saluran, debit aliran sebesar 33.81 m3/s, serta karakteristik sedimen dasar. Penelitian berlokasi di saluran primer Bendung Sekka-Sekka, Polewali Mandar, tepatnya diwilayah juru pengairan Masila. Hasil Simulasi menunjukkan adanya proses angkutan sedimen sepanjang saluran dengan dominasi fraksi pasir halus dan pasir sedang. Total angkutan sedimen selama satu bulan di hulu mencapai 14.551 kg/bulan dengan ketebalan sedimen (0.00227 m), ditengah saluran sebesar 35.351 kg/bulan (0.00551 m), dan dihilir sebesar 23.791 kg/bulan (0.00371 m). nilai tegangan geser
masing-,asing berturut-turut sebesar 0.0080 Pa, 0.0078 Pa, dan 0.0076 Pa, dengan kecepatan jatuh (fall velocity) 0.26 m/s di hulu, dan 0.2 m/s di tengah serta hilir. Konsentrasi sedimen rata-rata selama tiga bulan sebesar 0.3 mg/l, dengan konsentrasi tertinggi tercatat di hilir sebesar 4.8 mg/l. pemodelan ini membuktikan adanya distribusi sedimen terangkut di saluran, dengan akumulasi tertinggi dibagian hilir akibat penurunan kecepatan aliran dan tegangan geser. Hasil penelitan ini diharapkan dapat menjadi acuan dalam perencanaan strategi pemeliharaan saluran irigasi yang lebih efektif dasn efisien.
Although the Sekka-Sekka Weir is already equipped with a sedimentation basin, it still requires routine maintenance due to sediment accumulation occurring in the Primary Channel of D.I. Maloso. Sediment modeling becomes an effective approach to identify areas with high sedimentation so that maintenance can be more focused and efficient. This study aims to determine the occurring sedimentation pattern, model the bedload sediment transport, and analyze the amount of bedload transport in the primary channel of D.I. Maloso using HECRAS
software. The analysis was carried out using the Quasi-Unsteady Flow approach, with input data including channel cross-section profiles, a discharge of 33.81 m³/s, and bed sediment characteristics. The research is located in the primary channel of Sekka-Sekka Weir, Polewali Mandar, precisely in the Masila irrigation area. Simulation results indicate the occurrence of sediment transport along the
channel dominated by fine sand and medium sand fractions. Total sediment transport during one month at the upstream reached 14.551 kg/month with a sediment thickness of 0.00227 m, in the middle channel 35.351 kg/month (0.00551 m), and downstream 23.791 kg/month (0.00371 m). The shear stress values were respectively 0.0080 Pa, 0.0078 Pa, and 0.0076 Pa, with fall velocities of 0.26 m/s
at the upstream, and 0.2 m/s in the middle and downstream. The average sediment concentration during three months was 0.3 mg/l, with the highest concentration recorded downstream at 4.8 mg/l. This modeling proves the distribution of transported sediment in the channel, with the highest accumulation occurring in the downstream section due to a decrease in flow velocity and shear stress. The results of this study are expected to serve as a reference in planning more effective and efficient irrigation channel maintenance strategies.