THE EFFECTS OF THE CHANGING LANDSCAPE ALONG THE MANDULOG RIVER TO LOWLAND FLOOD RISK Julius Noah H. Sempio 1 Czar Jakiri S. Sarmiento 1 and Enrico C. Paringit 2 1 Geosimulation Research Laboratory, Department of Geodetic Engineering, University of the Philippines, Diliman, Quezon City 1101 julius.sempio@gmail.com 2 Applied Geodesy and Space Technology Research Laboratory, Geodetic Engineering Department, University of the Philippines, Diliman, Quezon City 1101 ABSTRACT The area surrounding the Mandulog River in northern Mindanao has been experiencing changes due to both conversion of forestland to agricultural lands and due to infrastructure and community development in the area. This changing landscape, and the possible effects of a changing climate in Mindanao, may have been factors to the destructive flooding suffered by the lowland areas during the rage of tropical storm Washi (“Sendong”) particularly in Iligan City. This article pieces together observations and researches on the general state of the Mandulog River from the past and the present. Keywords: remote sensing, land cover change, flooding INTRODUCTION Over the past few years, the island of Mindanao has experienced some of the worst flood incidences in the country. The first of a string of events, the arrival of tropical storm Washi (better known as “Sendong” as per the PAGASA naming convention), was especially shocking. The massive losses in life, property and financing caused in the cities of Cagayan de Oro and Iligan rattled media headlines and shocked the world even if it was already bracing for the dangers of a changing climate. There were even unreported events of the storm-brought rainfall devastating areas surrounding Lake Lanao (Mero, 2013). These once far-flung realities of ruin made the tell-tale notion of the South’s safety from weather hazards totally devoid of meaning. The Mandulog River was one of the four rivers that were involved in the Sendong crisis. Over the years prior to the event, its surrounding landscape has experienced changes that possibly contributed to the disaster. Figure 1. An eroded section of the incomplete Bukidnon-Iligan road along the Mandulog River taken in April 2, 2013. If the 20-m easement for rivers in urban areas as required by PD1067 was observed for the project, it will mean the river has already eaten through it during the Sendong event.