How to plan for sea level rise
What to consider in developing seaside settlements
Architects, engineers and planners should take scientific data and practical information on water-related natural phenomena (tides, wave action, typhoons, storm surges, tsunamis) into consideration when developing settlement areas, according to Dr. Laura David, Deputy Director for Instruction of the University of the Philippines Marine Science Institute. She emphasizes that the Philippines is an island country where land is not limitless and 67 percent of Filipinos live close to the seas and ocean, and that consequently, these have implications on how we develop our built environment. Dr. David presents the following practical guidelines for designers, planners and developers:
- Tides are actually related to earth’s distance from the sun and moon. This means that when doing site assessment, the best time to visit a site is during a full moon in the period between the late December to early January because the tides are at its highest level.(January is the month when the sun is closest to the earth.) One can see the effects of tide especially in coastal areas at full moon.
- Wave action creates areas of embayment and protrusion in coastal land forms. It is considered better to locate a building site at the area of protrusion since embayment areas are constantly eroded by wave action.
- Consider historical and scientific data on typhoons and storm surges, especially the significant wave height data because this can give us an indicator on how high above the sea level a structure should be built. A factor of three times the biggest wave height can be considered safe. (The house-on-stilts concept is actually a suitable design for coastal settlements because it allows waves to pass underneath a house.)
- Monitor the El Niño and La Niña cycles because these affect the soil condition of a site. If soil verification is done during an El Niño state, soil may appear consolidated or compacted but during normal weather condition or the rainy season it may turn loose and muddy.
- Occurrence of tsunamis cannot be predicted but scientists can compute the lag time before a tsunami can hit the coast to give people proper warnings. Tsunamis are common within the South China Sea and the Philippines – most recent tsunami experience was in 1994 at Mindoro. (It caused damage to some houses but notable was that the mangroves area served as a barrier and minimized its disastrous impact.) Appropriate responses to tsunami hazards are emergency evacuation and building structural barriers (like in Japan and Maldives) but which are rather costly.
Dr. David urges designers, planners and developers to a) respect nature by taking nature’s cue on when best to look at a site, where best to locate on a site, and how high above sea level a structure should be built; b) take into consideration the need for long-term historical data before making decisions as well as the possible need to employ/develop new and innovative technology; and c)be cognizant and adaptable to the issues that crop up due to increasing and local human pressures.
(These tips were taken from “Implications of Natural and Human-triggered Hazards in Human Settlements Development”,a lecture presented by Dr. Laura T. David during the 2006 YP Workshop on Social Housing, 17 October 2006, Antipolo City. Illustration above is from Intergovernmental Panel of Climate Change (IPCC), Response Strategies Working Group, Global Climate Change and the Rising Challenge of the Sea, 1992, p.9)
Climate Change, Disaster Risk Management | rp | 28 November 2007 |
