Global sea level rise has rapidly increased as the result of climate change which indicated by the expansion of marine heat and ice melting as the indicator, including: in Indonesia. It was identified as one of the most contributing factors which threatens coastal communities, even national economy, especially in the research area at Jabon District Sidoarjo Regency. The combination of groundwater flooding and coastal flood was reported to make a total loss of at least 5 billion rupiah with respect to crop failure of tons of seaweed as well as fish lost in a month production.

The aim of this research is to construct the topography and bathymetry using Unmanned Aerial Vehicles (UAV) / drone series DJI Phantom 3 Advanced, which can further be used to justify an adaptation method in the vicinity of the research area. The UAV is selected as a data logger to record topographical and bathymetry data. Furthermore, the recent advanced technology of UAV is used amongst researchers around the world, because it has many advantages, including considerably more accurate with accuracy as precise as 7-10 cm. Although, it has been confirmed in the previous research that the results provided by UAV is accurate, it is important to compare the result to other reference. In order to produce the accurate and realistic measurement data, some instruments are needed to deploy including: geodetic station, weather station, total station, waterpass station and sonar.  This research method requires drones to take pictures that will be processed later using open source software, including:  ArcGis, Menci, Quick Grid.

The analysis data for initial research can be seen in Figure 1a which shows the result of contour map in the vicinity of the research area (Sidoarjo Coast). Some area on the land has light green and light blue in color which indicate the elevation is similar to or lower than sea level. The elevation in the vicinity of the coastal is higher compared to the upstream elevation. It makes overflow water which resulted from coastal flood was traped in the upstream, thus the area was submerged for at least four months.

Furthermore, the UAV has been used to construct a topography and bathymetry map in Kenjeran Coast, Surabaya (See Figure 1 b). The UAV has been launched to scan the area around Kenjeran Coast, which has a total area circa 10 Ha. The scanning time consumed about 10-15 minutes. The output from this observation of the UAV can be used to construct a topography and bathymetry contour map around Kenjeran Coast. It can be seen that the elevation is higher on the west side and lower on the east side. This is appropriate to the evidence that the sea is on the East side of Kenjeran Coast.

From the previous result, it can be concluded that the data obtained from UAV scanning can be used to construct a topography and bathymetry map in Kenjeran Coast. This assure that the method analogously applicable to the research area: Sidoarjo Coast. The bathymetry map is in ongoing process and will be discussed in detail in the full manuscript. By referring to the constructed topography and bathymetry maps, appropriate action can be made to take suitable design of coastal construction for adaptation to climate change effects in the vicinity of Sidoarjo Coast.

Keywords: Climate Change, Coastal Flood, Topography and Bathymetry Map, Sidoarjo, Unmanned Aerial Vehicles.

Acknowledgment: The authors would like to express appreciation for the support of the sponsors of Directorate General of Higher Education Indonesia and Kopertis VIII, project number: 002/SP2H/LT/K7/KM2017.