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C957
Storm-Surge Barriers: Holding Back the Sea

Jeffrey Syken

"God made the World, but the Dutch made Holland"

In the First Century A.D., Pliny the Elder (a Roman author and natural philosopher) visited the Netherlands, characterizing it as a �pitiful country,� where: �Two times in each period of a day and a night, the ocean with a fast tide submerges an immense plain, thereby the hiding the secular fight of the Nature whether the area is sea or land. There this miserable race inhabits raised pieces ground or platforms, which they have moored by hand above the level of the highest known tide. Living in huts built on the chosen spots, they seem like sailors in ships if water covers the surrounding country, but like shipwrecked people when the tide has with-drawn itself, and around their huts they catch fish which tries to escape with the expiring tide�� It was, out of necessity that the Dutch learned to not only survive in this Waterworld-like environment, but also thrive as a nation, taking back what the North Sea claimed as its own; but at great cost in both treasure and lives. With sea-levels rising globally and warming seas spurning superstorms ever more frequently, perhaps the �eternal struggle� of the Dutch against an invading sea is a glimpse into humanity�s shared future when you consider the fact that 90% of the world�s population lives along coastlines.

In 1953, a powerful North Sea storm-surge inundated the east coast of England and the exposed Dutch coast, over 1,800 people perished. Thanks to failed flood defenses downstream, London was spared the full wrath of the storm, but the �clear and present danger� was recognized for what it was and both the Dutch and UK governments were called-to-action. In the UK, the end result would be a beefing-up of flood defenses (i.e. levees, flood walls etc.) and an Act of Parliament authorizing the construction of a storm-surge barrier on the River Thames at Woolwich Reach, a few miles east of Westminster. Inspired by a simple gas tap, the design included massive concrete piers with navigation channels between the piers having �rising sector� gates that lie in a concrete cradle at the bottom of the Thames and, when called upon to block a North Sea storm-surge, rotate (via electro-hydraulic arms) 90-degrees to a defense position. Built between 1927 and 1932, the Zuiderzee (South Sea) reclamation project added an entire province to the Netherlands. However, after the 1953 national disaster, the focus of Dutch engineers would turn to southwest Holland, where the mouths of the Meuse and Rhine River/s break into a complex, treacherous delta. Appropriately named: �The Delta Project,� its crowning achievement would be the Oosterschelde, where tidal waters flow unimpeded below a series of steel gates slung between massive concrete piers.

Founded in 1703 at the eastern-end of the Gulf of Finland, during the +300-year history of St. Petersburg (the former capital of Imperial Russia) the waters of the River Neva rise about 100x a year, and the city�s territory may be flooded up to 10x a year. Begun in 1979 during the Soviet-era and delayed by the collapse of the Soviet Union in 1991, construction of the St. Petersburg Flood Prevention Facility Complex (SPFPFC) was resumed in 2005 and completed in 2011. Consisting of eleven stone-earthen dams, six culverts, two navigable structures, a highway, seven bridges and a road tunnel, the SPFPFC would also complete St. Petersburg�s ring-road (to the delight of the natives). For the larger (C-1) of its two navigation channels, a pair of �Bataports� (French for �Ship Door�) swing into position and meet mid-channel when a storm-surge threatens, retracting into their respective docks when the threat has passed. Perhaps the most dramatic of the pressing need for man-made solutions to the problem of storm-surges can be found in the Venice Lagoon. There, memories of November 4, 1966 are literally written on the low-lying city�s walls. That�s when an �Acqua Alta� (High-Water) of 194cm above mean sea-level was recorded. Flood protection schemes for Venice, including inflatable dams (a/k/a �Fabridams�), have given way to the MOSE Project, which includes a �Bottom-Hinged Buoyant Gate� design whereby 78 gates located at Venice Lagoon�s three inlets deploy when a storm-surge threatens, that�s if they work if/when it�s ever completed.

This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.


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