1.1 Introduction
Floods are natural events that have always been an integral of the geologic history of Earth. Flooding occurs along rivers, streams and lakes and coastal areas in alluvial fans, in ground failure areas, such as subsidence, in areas influence by structural measures and in areas that flood due to surface run-off and locally inadequate drainage (Ways, 2011).
The damages caused by floods in terms of loss of life, property and monetary loss due to disturbance of economic activity are too well known (Subramanya, 2009). Floods have been the number one catastrophe that the Philippines are facing even from the early times. Furthermore, the Philippine’s geographical structure, being an archipelago, increases the potentials of storm formation that produces heavy rains and eventually lead to flash floods. Another factor contributing floods is the lack of discipline of the Filipinos in disposing their garbage; hence, clogging drainages and sewerage systems leads to worse scenario.
One of the highest death tolls has reached to 1268 during the flood that has occurred in the Philippines caused by Tropical Storm Sendong on 2011 and another is the 2006 Southern Leyte Mudslide that has killed 1144 people due to heavy rain. Widespread flooding occurred in the eastern part of the Philippines since late December 2010. The Visayas and the Bicol and Caraga regions have been mainly affected by unusually heavy rains. The floods have banished 452,999 persons in 19 provinces, and have