Estimasi Laju Pengendapan Sedimen di Perairan Muara Sungai Silugonggo Kabupaten Pati

Abstract

Muara Sungai Silugonggo merupakan sungai yang berada di Kabupaten Pati yang bermuara di Laut Jawa. Muara Sungai Silugonggo menjadi daerah penting karena menjadi alur pelayaran bagi nelayan di TPI Bajomulyo yang berada di sekitar muara sungai. Masalah yang sering terjadi adalah sedimentasi di muara sungai yang menyebabkan pendangkalan dan mengganggu kegiatan nelayan. Penelitian ini bertujuan untuk mengetahui kondisi arus dan laju sedimentasi di perairan muara Sungai Silugonggo. Penelitian menggunakan metode deskriptif dan lokasi pengambilan sampel ditentukan dengan metode purposive sampling, dengan jumalah 7 stasiun. Pengambilan data lapangan dilakukan pada tanggal 16 - 28 Mei 2022. Data primer berupa sampel sedimen, material suspensi, debit sungai, debit suspensi dan kecepatan arus, sedangkan data sekunder berupa data pasang surut dari BMKG Maritim Semarang. Hasil penelitian diperoleh nilai rerata laju pengendapan sedimen di perairan muara Sungai Silugonggo berkisar 0,965 kg/m²/hari sampai 1,121 kg/m²/hari. Laju pengendapan sedimen terkecil ditemukan daerah muara yang lebih menjorok ke laut dengan nilai 0,951 kg/m²/hari, sedangkan laju pengendapan sedimen terbesar ditemukan di mulut sungai dengan nilai 1,128 kg/m²/ hari. Jenis sedimen di lokasi penelitian didominasi oleh sedimen silt. Proses angkutan partikel sedimen terjadi secara suspensi yang pada akhirnya mengendap di dasar perairan ketika kecepatan aliran sungai melemah. Faktor yang mempengaruhi proses laju pengendapan sedimen di perairan muara sungai Silugonggo adalah, debit sungai, debit suspensi, pasang surut dan arus pasang surut.

Kata kunci: Muara Sungai Silugonggo, Pendangkalan, Laju Pengendapan Sedimen

The estuary of the Silugonggo River is a river in Pati Regency that empties into the Java Sea. The mouth of the Silugonggo River is an important area because it is a shipping channel for fishermen at TPI Bajomulyo, which is around the river mouth. The problem that often occurs is sedimentation at the mouth of the river, which causes siltation and disrupts fishing activities. This study aims to determine current conditions and sedimentation rates in the waters of the Silugonggo River estuary. The research used the descriptive method, and the sampling location was determined by the purposive sampling method, with a total of 7 stations. Field data collection was carried out on May 16–28, 2022. Primary data consisted of sediment samples, suspension material, river discharge, suspended discharge, and current velocity, while secondary data consisted of tidal data from the Semarang Maritime BMKG. The results showed that the average rate of sediment deposition in the waters of the Silugonggo River estuary ranged from 0.965 kg/m²/day to 1.121 kg/m²/day. The smallest sediment deposition rate was found in the estuary, which was more indented into the sea, with a value of 0.951 kg/m²/day, while the highest sediment deposition rate was found in the mouth of the river with a value of 1.128 kg/m²/day. The type of sediment in the study site is dominated by silt sediments. The process of transporting sediment particles occurs in suspension, which eventually settles to the bottom of the water when the river flow velocity weakens. Factors that influence the rate of sediment deposition in the estuary of the Silugonggo River are river discharge, suspension discharge, tides, and tidal currents.

Keywords: Silugonggo River Estuary, Shallowing, Sediment Deposition Rate