To know the magnitude of sea water intrusion that occurred in Candidasa area need to be mapping by using Geo-electric Method. Geo-electric

This study proposes a new simple procedure for extracting coastline from Synthetic Aperture Radar (SAR) images by utilizing a low-pass filter and edge detection algorithm. The low-pass filter is used to improve the histogram of the pixel value of the SAR image. It provides better distribution of pixel value and makes it easy to separate between sea and land surfaces. This study provides the processing steps using open-source software, i.e., SNAP SAR processor and QGIS application. This procedure has been tested using dual polarization Sentinel-1 (10x10 meters resolution) and single polarization ALOS-2 (3x3 meters resolution) dataset. The results show that using Sentinel-1 with dual polarization (VH) provides a better result than single polarization (VV). In the ALOS-2 case, only single polarization (HH) is available. However, even using only HH polarization, ALOS-2 provides a good result. In terms of resolution, ALOS-2 provides a better coastline than Sentinel-1 data due to ALOS-2 has better resolution. This procedure is expected to be helpful to detect coastline changes and for coastal area management.

This study presents a new simple approach to detect the coastline changes due to the construction of man-made structures. The new approach uses low-pass filter to reduce the speckles errors and Otsu thresholding method the create binary image. Then, a closing morphological operation was conducted to improve the binary image. In the final step, the canny edge detection is used for coastline delineation. The coastlines changes analysis was done by using Digital Shoreline Analysis System (DSAS). In general, the processing steps of this new approach is semi-automatic processes, it does not require manual digitization to extract the coastline. This method was tested using two independent synthetic aperture radar (SAR) satellite images, i.e., ALOS-1 and Sentinel-1 SAR data. The results show that this new approach produced better results than other well-known methods. This new approach detects clearly the man-made structure and its impact to the coastal zone, i.e., abrasion and accretion. The study area is located in Pengambengan Port, Jembrana Regency, Bali, Indonesia. In addition, the result of this study can be used as evaluation parameters for future development of Pengambengan port or re-design of present structures.

Klungkung has a coastline of 113 km out of a total of 5780.06 km2 the coastline in the province of Bali, but about 25 km is eroded. One of the critical areas occurs in Tegal Besar beach which caused erosion of 0.08875 to 3.0915 m/yr. Revetment with scalloped concrete blocks is expected to protect land from the wave attack. Concrete blocks have uniform size and shape, showing the aesthetic aspect so as not damage the beauty of the beach. Analysis of wind, tidal, bathymetry and soil data are carried out to obtain the structure and stability of the revetment. The results of this design can be used to rehabilitate the condition of the Tegal Besar beach. From the analysis, the design wave height with a return period of 25 years (H25) = 0.891 m, while the height with the breaking wave (Hb) = 1.003 m and the breaking wave depth (db) = 1.068 m and the design water level elevation (DWL) = 2.061 m calculated from MSL. The revetment structure has a height of 4.00 m, a peak width of 1.50 m, the weight of the first layer of protection is 300 kg and the second is 30 kg with a thickness of 1.00 m. Toe protection are 1.25 m high, 3.00 m wide and weigh 150 kg. The results showed that the revetment was stable against overturning, shearing, and the bearing capacity of the soil was declared safe with the results of overturning stability 22,075 > 2, slidding stability 2.249 > 1.5 and the bearing capacity of the soil 57,993 > 3 so that the revetment can be eligible to be applied at the site.

Monitoring Coastline changes is a very important task to assess and evaluate the condition of the coastal area. Accurate results of changes in coastline are very useful as a consideration in making decisions for coastal area management and planning for future coastal development. Therefore, coastline changes, both erosion and accretion were examined in this study. Batu Mejan Beach is selected as a study area. It is a tourism destination often visited by foreign and local tourists in North Kuta Beach. Its current condition is very poor because of the erosion that has occurred. The government has tried to build a sea wall for protection, but the structure has failed. Remote sensing is a method that can monitor shoreline changes more efficiently than taking measurements directly into the field. With the remote sensing method, changes in the shoreline at a certain period can be investigated. The remote sensing analysis method is used to extract coastlines from Landsat 7 satellite images in 2002 and Landsat 8 in 2018. Landsat was analyzed using a combination approach of threshold and band ratio methods of infrared bands and green bands. Image processing uses ENVI 5.3 software and ArcGIS 10.4.1 with the Quoted Shoreline Analysis System (DSAS) extension to make transect shoreline calculations. The results of the analysis of the rate of change in the coastline along Batu Mejan Beach showed abrasion of 0.11-5.14 m/year and accretion of 0.29-0.84 m/year.