Flood barrier Manila

Leslie Mooyaart, Wouter de Hamer, Peter de Vries, Ronald Stive

Friday 3 july 2015

11:00 - 11:15h at Oceania (level 0)

Themes: (T) Managing deltas, (ST) Impacts of urbanization and land reclamation

Parallel session: 15K. Managing deltas - Impacts

The Integrated Flood Control and Coastal Defense Project of Manila Bay has multiple purposes. First, a coastal barrier protects the coastline against flooding from the ocean. Furthermore it is a city waterfront providing an attractive urban development, areas for industrial growth like an airport and seaport, and it connects Metro-Manila with Bataan Province via an expressway. This paper presents the design of the flood protection of the first of the five intended islands of this project, located most eastern and closest to Metro-Manila. The main objective of the first island is to protect Navotas City against flooding from the ocean. This is achieved by constructing a City Flood Barrier, which consists of a 10 km long coastal dike and two flood gates of 50 m length. During normal conditions the floodgates are opened to allow tidal circulation to preserve sufficient water quality and navigation by local fishermen. During an extreme storm surge or exceptional high tide the flood gates can be closed to prevent water from overflowing the existing city flood protection structures. The paper will address both the functional and structural design aspects of the flood gates. During a typhoon it is likely that next to surges also high river run-off will occur, leading potentially to flooding of the area. Therefore, a retention pond behind the flood gates has been designed to store this river discharge during a storm surge. In the study the size of the retention pond has been optimized, considering water level reduction in the hinterland compared to the size of the retention pond. The optimizations and trade-off’s for other aspects of the retention pond (e.g. water quality, navigation) are addressed in the paper.