Abstract. Indonesia has experienced several tsunamis triggered by seismic and non-seismic (i.e., landslides) sources. These events damaged or destroyed coastal buildings and infrastructure and caused considerable loss of life. Based on the Global Earthquake Model (GEM) guidelines, this study assesses the empirical tsunami fragility to the buildings inventory of the 2018 Sunda Strait, 2018 Sulawesi–Palu, and 2004 Indian Ocean (Khao Lak–Phuket, Thailand) tsunamis. Fragility curves represent the impact of tsunami characteristics on structural components and express the likelihood of a structure reaching or exceeding a damage state in response to a tsunami intensity measure. The Sunda Strait and Sulawesi–Palu tsunamis are uncommon events still poorly understood compared to the Indian Ocean tsunami (IOT), and their post-tsunami databases include only flow depth values. Using the TUNAMI two-layer model, we thus reproduce the flow depth, the flow velocity, and the hydrodynamic force of these two tsunamis for the first time. The flow depth is found to be the best descriptor of tsunami damage for both events. Accordingly, the building fragility curves for complete damage reveal that (i) in Khao Lak–Phuket, the buildings affected by the IOT sustained more damage than the Sunda Strait tsunami, characterized by shorter wave periods, and (ii) the buildings performed better in Khao Lak–Phuket than in Banda Aceh (Indonesia). Although the IOT affected both locations, ground motions were recorded in the city of Banda Aceh, and buildings could have been seismically damaged prior to the tsunami's arrival, and (iii) the buildings of Palu City exposed to the Sulawesi–Palu tsunami were more susceptible to complete damage than the ones affected by the IOT, in Banda Aceh, between 0 and 2 m flow depth. Similar to the Banda Aceh case, the Sulawesi–Palu tsunami load may not be the only cause of structural destruction. The buildings' susceptibility to tsunami damage in the waterfront of Palu City could have been enhanced by liquefaction events triggered by the 2018 Sulawesi earthquake.

Abstract. This research aimed to assess the tsunami flow velocity and height reduction produced by a planned elevated road spanned parallel to the coast of Banda Aceh called Banda Aceh Outer Ring Road (BORR). Cornell Multi-Grid Coupled Tsunami Model (COMCOT) was used to simulate eight scenarios of the tsunami. One of them was based on the 2004 Indian Ocean tsunami. Two magnitudes of earthquake were used, that is, 8.5 and 9.15 Mw. Both the earthquakes were generated from the same source location as in the 2004 case, around the Andaman Sea. Land use data of the innermost layer of the simulation area were adopted based on the 2004 condition and the land use planning of the city for 2029. The results of this study reveal that the tsunami flow depths and flow velocities can be reduced by about 9 % by using the elevated road for earthquake magnitude 9.15 Mw and about 22 % for earthquake magnitude 8.5 Mw. Combined with the land use planning 2029, the elevated road could reduce the maximum flow velocities behind the road by about 72 %. Notably, the proposed land use for 2029 will not be sufficient to deliver any effects on the tsunami mitigation without the elevated road structures. We recommend the city to construct the elevated road as this could be part of the co-benefit structures for tsunami mitigation. The proposed BORR appears to deliver significant reduction of impacts in the smaller intensity tsunamis compared to the 2004 Indian Ocean tsunami.

The provision of clean water in Takengon City, Aceh Tengah Regency is provided by PDAM Tirta Tawar, one of which is through the water network of Oregon Mendale Water Treatment Plant (IPA). However, a preliminary survey at the Oregon Mendale IPA source suggested inadequate water for the community. The aim of this research is to know the factors that must be fulfilled so that a clean water network system can run smoothly. This includes water flow, pressure and flows continuity, maximum daily factor (Fmax) and real peak factor (Fpeak) of the existing network. This study is also to understand the clean water distribution network in the Oregon Mendale IPA resource area. This research uses a descriptive method and field observation. This study suggests the following: the average water consumption is 0,426 m3/customer/day, the maximum water pressure is 1.517 m and the continuity of flow is 6 hours every day. The maximum daily factor value (Fmax) in Kecamatan Kebayakan is 1.13-1.39 and the peak hour factor (Fpeak) is 1.13-1.41. These results suggested that the existing Oregon Mendale IPA is not running optimally.

A coastal area has important and vital influences on community’s lives due to the natural resource availability. The coastal area occurs any changes over time affecting the changes in the community and in the ecological perspectives. Banda Aceh is one of the coastal areas that has experienced several significant changes especially after earthquake and tsunami on December, 26th 2004. Due to the condition, it is required to analyze coastal vulnerability in Banda Aceh and neighbor. This research was aimed to investigate the influences of physic parameters consisting of hydrodynamic and morphology parameters on determining Coastal Vulnerability Index (CVI). The analysis will determine the coastal vulnerability index in one year period. The analysis was carried out in the northern coast of Aceh Province, between Ujong Pancu and Ujung Batee by dividing the areas into 5 (five) cells bordered by natural morphology feature such as inlet, headland, river estuary, and lagoon. Based on 6 (six) physical parameters used on coastal vulnerability index (CVI) determination, it is obtained that 2 cells have low risk potential (green), which are Cell 1 and Cell 3 with the CVI values are 2.45 and 3.0, respectively. Cell 2 has moderate risk potential (yellow) with CVI value is 4.24. Meanwhile, Cell 4 and Cell 5 have high risk potential (red) with CVI values are 5.20

The massive tsunami of December 26, 2004 has had a huge impact on the life of the coastal region. The effects of the tsunami caused damage to occupation settlements, loss of waterside land and destruction of marine biota ecosystems. The coastal region of Aceh Province in Indonesia is the area that has the worst impact followed by the State of Malaysia, Thailand and as a coastal area of India. As a result of a large amount of coastal land experiencing a loss of land mass, erosion is very significant. As a step towards handling coastal areas from greater erosion prevention, the Government of Indonesia in 2005 adopted a policy of handling rehabilitation and reconstruction through the ANTERP (Aceh Nias Tsunami and Earthquake Response Program) program under the BRR (Rehabilitation and Reconstruction Agency) in collaboration with Ministry of Public Work. One of the steps to handling erosion is to protect the coast using the hard structure method such as the construction of a revetment and jetty made from rock armor. This study aims to assess the level of damage and priority of handling of coastal protective structures that have been built in 2009, 2016 and how changes in shoreline occur on the beach location of Alue Naga - Neuheun, which is a coastal area that was greatly affected by the tsunami. Assessments were carried out in three different coastal structures, namely CS-1 locations in the Alue Naga area, CS-2, Lambada Lhok coastal area and CS-3 Neuheun beach area. Guidelines for assessing structure damage and changes in shoreline in the study using the Ministry of Public Work Regulation No. 08/SE/M/2010. The rate of change in shoreline is obtained through computational calculations of the DSAS (Digital Shoreline Analysis System) program using the EPR (End Point Rate) method and NSM for change distance (Net Shoreline Movement).

The process of changing the coastline has always been a challenge for coastal communities. Beach erosion has been a threat with the coastline withdrawing from its previous position. Coastal protection buildings are needed to overcome coastal erosion problems, and alternative construction also needs to be developed. The zig-zag type porous breakwater is quite effective in reducing erosion based on several small-scale physical models that have been developed. Therefore a prototype was built and tested to observe its usefulness, and how it was applied in the field. This study aims to assess the effect of installing zigzag type porous breakwaters on coastline changes. This research began with the installation of construction and continued with observing changes in the coastline. Observations are carried out periodically at any time, to see changes in the contour of the beach that occurs. Observations were made by leveling the beach surface against several transverse profiles. Changes in coastline due to construction will be analyzed by looking at the relation to the wind direction. The results obtained from several observations show that the construction of a zig-zag type porous breakwater has a positive effect in reducing erosion, as long as the breakwater distance with the coastline does not exceed the breakwater length.

Daerah Irigasi (D.I.) Baro has a total area of 11.950 ha which consists of Baro Kanan area of 8,920 Ha and Baro Kiri area of 3.030 Ha. Maximum cropping intensity indeks of D.I. Baro ranged between 183%-213%. This shows that D.I. Baro is unable to meet the water needs for his extensive irrigation services. One of the factors that influence the planning and regulation of irrigation water is cropping pattern. The aims of this research is to get the best cropping pattern, so that the distribution of irrigation water discharge available in D.I. Baro can be done optimally, knowing the need of irrigation water in D.I. Baro, knowing the maximum plantable area that irrigation can irrigate, and knowing the maximum profit that can be achieved by optimization. Compilation of mathematical models to get the maximum benefit that can be achieved by optimizing land area. The data collected in this study is secondary data. The method used is an optimization method using a linear program.

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