Scenarios of Flooding Water Level Using Digital Elevation Model based on Unmanned Aerial Vehicle System Case Study: Tha Wanga Pha District, Nan Province

Abstract

The study is focused on scenarios of flood water level using Digital Elevation Model (DEM) from Unmanned Aerial Vehicle System (UAVs), a case study of Tha Wang Pha District, Nan Province. The main objectives of research are to; 1) create DEM using UAVs; and 2) to estimate flood water level in different scenarios using DEM from UAVs. The authors conducted survey in the study area using UAVs and integration with Global Navigation Satellite Systems (GNSS), Post-Processing Kinematic (PPK). By using photogrammetry process could derive Orthophoto with 10 cm spatial resolution. The Orthophoto results showed the horizontal tolerance in a x-axis and a y-axis of 5.0725 cm, and 7.8635 cm, respectively, and a vertical tolerance in a Z-axis of 14.3460 cm. Using orthophoto, contour line was constructed to estimate flood water levels. Thailand extreme flood event in 2006 (2549 BC) was applied to simulate a flood situation. The results showed that with a flood level of 5 m, the affected areas approximately 7,710 rai. This study also examined the effect of land use type. The results showed the top three most affected areas were paddy field and village area at 54.06 and 22.27 percent, respectively.