Flood Control and Drainage, Water Supply and Sewerage: Managing Water in Both Excess and Scarcity
Authors:   National Academy of Science and Technology, Philippines, DOST Complex,  Bicutan, Taguig City 1631, Philippines  Institute of Civil Engineering, University of the Philippines Diliman, Quezon  City, Philippines, Liongson Leonardo 
Published: March 2024

The first part of this paper draws the lessons for flood management from the experience of the recent major flooding events of 2009 TS Ketsana (Ondoy), 2009 TS Panna (Peping) in Luzon, and the adverse impacts of 2011 TS Sendong on Visayas and Mindanao. NDRRMC data are analyzed in terms of the relative intensities and distribution of population impacts (killed, injured, missing) and economic damages reported among the different storms and regions of impacts. The paper emphasizes the need for implementing structural mitigation measures in poor unprotected towns and regions in the country, as part of an adaptation strategy, under the challenge and threat posed by growing population and anticipated climate change. Likewise, non-structural mitigation measures (which have shorter gestation periods of months and few years only, compared to decades for major structural measures) must also be provided under the imperative or necessity implied by the quantified "structural gap" of existing structures to adequately reduce and effectively manage the increasing flood hazard risks caused by growing population and climate change. In the second part of this paper dealing with water supply and sewerage (sanitation), recent NEDA and ADB reports were cited which make very clear the necessity that the Philippines has to achieve a faster rate of providing access to improved sanitation facilities, at a rate at par with that of providing access to improved drinking water, in the quest of the country to attain the "early achiever" status before 2015 in both water supply and sanitation targets. After all, the improvement of water supply facilities brings in the potential for producing higher volumetric rates of wastewater. The needs for wastewater treatment (and possible reuse of treated water) are met in the medium term by septage truck-collection and septage plant treatment (in Metro Manila, for example), but better in the longer term with piped sewerage collection networks and sewage treatment plants in both developed and developing communities and towns nation-wide. It is strongly recommended that new programs and projects in water supply development be accompanied with parallel and coupled sewerage (sanitation) programs and projects. This two-part article deals with the two important sub-sectors of the water sector: namely, flood control & drainage (flood management), on one hand, and water supply & sewerage (or sanitation) on the other hand. The article aims to explain and share with the general reading public the results of a long series of round-table discussions (RTDs), research studies, and annual scientific meetings held in the period 2009-2012, organized by the National Academy of Science & Technology (NAST) of the Philippines in pursuit of its policy-making and advisory mission and function to the nation. These fora and activities were done also with the cooperation and support of the UNESCO National Commission, national government agencies (NGAs such as NEDA, NWRB, DPWH, DENR and DOST), NGCCs (MWSS, water districts, etc.), NGOs (PWP and professional societies), the academe (UP Diliman, Mapua (MIT) and Manila Observatory-Ateneo), and representatives of certain LGUs and the private sector (such as MWCI, MWSl, and consulting firms). In addition lo the consensus established and recommended in the various water fora, the personal views and recommendations of the author are also indicated where they help in clarification of issues or demonstration of solutions. The other major sub-sectors of irrigation, hydropower and other water uses may be covered in future articles by other writers among the academicians of NAST.