Determination of the original coastline on Semarang city and Demak district using remote sensing approach

¹ Department of Civil Engineering, Faculty of Engineering, Diponegoro University, Semarang, Indonesia
² Department of Civil Engineering, Faculty of Engineering, Ndejje University, Kampala, Uganda
³ Member of Watershed Coordination Forum in Central Java Province, Central Java, Indonesia

^* Corresponding author: sriyana@live.undip.ac.id

Abstract

Development of the coastal area without environmental consciousness is disrupting coastline equilibrium, thus triggering erosion and accretion. This results in the obscurity of the border area due to coastline change. The objective of this study is to determine the original coastline of Semarang city and Demak district. The method used is remote sensing using Landsat satellite imagery data dating from 1984 to 2018. The results showed that the length of the coastline in Semarang and Demak border coast shows a continuous increase from 48.2, 57.9, 63.7, and 73.5 km in 1984, 1992, 2000, and 2008, respectively to 92.6 km in 2018, and the average annual change rate from 1984 to 1992, 1992 to 2000, 2000 to 2008, and 2008 to 2018 is 1.2 km per year, 0.7 km per year, 1.2 km per year, and 2.1 km per year, respectively. It was concluded that the current coastline condition of Semarang city and Demak district has had an increase of 29.8 km in length and shifted inwards by 0.5-2 km in 2000 – 2018 compared to the original coastline. This shows a deviation of 5-15% from Government Regional Spatial Plan. The study recommends a sustainable coastal management and action plan to be prepared by the government, as it is vital in preserving the coastal regions.