Studi Karakteristik Sedimen Dasar Perairan Tanjung Pasir Banten menggunakan Metode Gradistat

Abstract

Program NCICD (National Capital Integrated Coastal Development) merupakan program strategis nasional untuk menangani permasalahan di Teluk Jakarta. Salah satu rencananya adalah dengan membangun waduk lepas pantai (WLP) di Perairan Tanjung Pasir, Banten. WLP selain berfungsi sebagai tanggul laut juga sebagai penyedia air baku. Dalam perencanaan WLP salah satu pertimbangan utama adalah permasalahan sedimentasi. Proses sedimentasi di perairan sangat terkait dengan karakteristik sedimen. Tujuannya penelitian ini adalah untuk mengetahui pola sebaran karakteristik sedimen dasar seperti kadar air, berat jenis, gradasi, tekstur sedimen, ukuran d50 butir sedimen dan analisis statistik sedimen dasar sehingga dapat mendukung rencana pembangunan WLP NCICD. Metode yang dipakai adalah pengambilan sampel sedimen di lapangan, pengujian sampel sedimen di laboratorium, analisis sedimen secara statistik dan analisis deskriptif karakteristik sedimen dasar menggunakan metode Gradistat. Berdasarkan hasil kajian diketahui nilai kadar air 39,657 % - 413,83 %, berat jenis 1,633 g/cm3 – 2,557 g/cm3, ukuran butir 0,085 mm – 2,0 mm, ukuran rerata butir 261,1 µm - 2657,5 µm, sortasi sedimen very poorly sorted (terpilah sangat buruk) dan poorly sorted (terpilah buruk), analisis statistik sedimen tipe very platykurtic, jenis lithologi didominasi oleh pasir, sedikit berukuran lanau dan pasir halus hingga pasir sedang. Sedimen dasar di perairan ini mempunyai daya dukung tanah yang baik untuk dibangun WLP.   The NCICD (National Capital Integrated Coastal Development) is a national strategic program to deal with problems in Jakarta Bay. One of the plans is to build a sea dike (WLP) in Tanjung Pasir, Banten. In addition to functioning as a sea wall, WLP is also a raw water provider. In WLP planning, one of the primary considerations is the problem of sedimentation. The sedimentation process in the waters is closely related to the characteristics of the sediment. This study aimed to determine the distribution pattern of bottom sediment characteristics such as water content, specific gravity, gradation, sediment texture, d50 sediment grain size, and statistical analysis of bottom sediments to support the NCICD WLP development plan. The method used is taking sediment samples in the field, testing sediment samples in the laboratory, statistical analysis of sediments, and descriptive analysis of bottom sediment characteristics using the Gradistat method. Based on the results of the study, it is known that the water content is 39.657% - 413.83%, the specific gravity is 1.633 g/cm3 – 2.557 g/cm3, the grain size is 0.085 mm – 2.0 mm, the average grain size is 261.1 µm - 2657.5 µm, Sediment sorting is very poorly sorted and poorly sorted, statistical analysis is classified as very platykurtic type, lithology type dominated by sand, slightly silt, and fine sand to medium sand. The bottom sediments in these waters have good soil-carrying capacity for WLP construction.