The analysis of d90 and d50 sediment grain size in Alue Naga estuary, Banda Aceh City

Abstract

The study of d50 and d90 sediment grain size in the Alue Naga estuary of Banda Aceh City, which was taken in December-March 2017 was completed. The purpose of the study is to determine the size of d50 and d90 sediment diameters and how it was dispersed along the estuarial area. The study used 15 stations sampling which was determined by purposive random sampling. The results of 15 sediment samples were then analyzed at the Marine Science Laboratory using a multilevel sieve method and evaluated using the Wentworth sieve analysis method. The results of the analysis showed that the largest particle size of d50 was 1.44 mm at station 14, and the biggest particle size of d90 of 3.5 mm was also obtained at station 14. The results attained were due to the dynamics of the ocean currents and the flow of the river interacting at station 14. This could happen because during the high tide, the dominant flow is coming from the sea, it causes a large size of d90 grained size sediment while during the low tide the dominant flow is from upstream of river so that the size of 50% sediment is also dominant.