Volume XLI-B8
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLI-B8, 1397-1401, 2016
https://doi.org/10.5194/isprs-archives-XLI-B8-1397-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLI-B8, 1397-1401, 2016
https://doi.org/10.5194/isprs-archives-XLI-B8-1397-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

  14 Oct 2016

14 Oct 2016

VULNERABILITY ASSESSMENT USING LIDAR DATA IN SILANG-STA. ROSA SUBWATERSHED, PHILIPPINES

M. A. Bragais1, D. B. Magcale-Macandog1, J. L. Arizapa2, and K. M. Manalo2 M. A. Bragais et al.
  • 1Institute of Biological Sciences, University of the Philippine Los Baños, College, Laguna 4031, Philippines;
  • 2College of Human Ecology, University of the Philippines Los Baños College, Laguna 4031, Philippines

Keywords: LiDAR DEM, unsteady flow analysis, disaster and risk adaptation and mitigation, watershed management

Abstract. Silang-Sta. Rosa Subwatershed is experiencing rapid urbanization. Its downstream area is already urbanized and the development is moving fast upstream. With the rapid land conversion of pervious to impervious areas and increase frequency of intense rainfall events, the downstream of the watershed is at risk of flood hazard. The widely used freeware HEC-RAS (Hydrologic Engineering Center- River Analysis System) model was used to implement the 2D unsteady flow analysis to develop a flood hazard map. The LiDAR derived digital elevation model (DEM) with 1m resolution provided detailed terrain that is vital for producing reliable flood extent map that can be used for early warning system.

With the detailed information from the simulation like areas to be flooded, the predicted depth and duration, we can now provide specific flood forecasting and mitigation plan even at community level. The methodology of using 2D unsteady flow modelling and high resolution DEM in a watershed can be replicated to other neighbouring watersheds specially those areas that are not yet urbanized so that their development will be guided to be flood hazard resilient. LGUs all over the country will benefit from having a high resolution flood hazard map.