Responding to Changes in Sea Level Engineering Implications (1987) / Chapter Skim
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7 Assessment of Response Strategies for Specific Facilities and Systems
7 Assessment of Response Strategies for Specific Facilities and Systems
Pages 96-116
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From page 96... ...
However, functional needs change, facilities wear out, and equipment becomes obsolete. Using the three scenarios for relative mean sea level rise discussed in Chapters 1 and 2 of this report results in a range of rise during the next 50 years of about 6 in.
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From page 97... ...
Some preliminary studies have examined the effects of a rise in relative mean sea level. For example, the Hawaii Coastal Zone Management Program (1985)
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From page 98... ...
A study by the Hawaii Coastal Zone Management Program (1985) concluded that a lift rise in relative mean sea level would result in temporary disruptions of transportation at Honolulu International Airport; a 4.8-ft rise would cause frequent and proTonged disruptions if no remedial works such as levees were emplaced.
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From page 99... ...
Source: California Department of Water Resources (1983b)
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From page 100... ...
It appears that a 1-ft increase In relative mean sea level could have a major impact on the protective capabilities of the levees. Increases in levee elevations (and base widths)
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From page 101... ...
as any increase in relative mean sea level. Gates are an integral component of some levees in the United States; examples mclude the Fox Point Barrier in Narragansett Bay, the New Bedford Hurricane Barrier, the hurricane barrier system at New OrIeans, Louisiana, and the Texas City Hurricane Protection System.
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From page 102... ...
Each has its unique set of conditions of topography, bathymetry, tides, current and wind variations, temperature and climate, salinity and turbidity, ~d sediment transport regimes, which, with the man-made developments, result in a different situation for each case. Changes in tidal and other currents wall occur with changes in relative mean sea level, and changes in tide range and phase may occur.
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From page 103... ...
103 This statement was made for the case of no sea level rise. What would be the effect of a rise in relative mean sea level?
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From page 104... ...
The elevation of the marsh surface rises rapidly, gradu~ly slowing as the increasing elevation reduces the frequency and duration of flooding by the tide. Depending on the rate of sea level rise and the supply of suspended sediment, the marsh surface tends to maintain its level relative to the tide as sea level rises.
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From page 105... ...
Whether in an estuarial environment or not, coastal harbors will experience different effects of a change in relative mean sea level, depending on shoreline and bay bathymetry configuration. These changes can be quite complex, but estimates of them can be made with appropriate physical and/or mathematical models.
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From page 106... ...
It is possible that the change in climate, with the resulting change in numbers ant} intensity of storms, will be more important than a small change In relative mean sea level. For example, during the winter of 1982-1983, when an E!
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From page 108... ...
HIGHWAYS, RAIIROADS, BRIDGES, AND VEHICULAR TUNNELS As sea level rises, highways and railroads across lowlands near tidal water wiD experience more frequent flooding during high tides and storms. This effect may be especially severe in certain estuaries where the rise in sea level will be amplified, the more so because these same estuaries are more vulnerable to storm surges as water funnels into a gradually narrowing arm of the sea.
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From page 109... ...
The "design lifer of a power plant is about 40 years, a period over which mean sea level could vary from a few inches to almost 1-ft, considering the scenarios used in this report. Engineering changes required in those aspects of operation most affected by a 1-ft rise in relative mean sea level, such as cooling water intake and discharge systems, would be handled as normal changes.
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From page 110... ...
Pipe sections buried under the beaches and current surf zone might become exposed, while discharge ports could become covered with sand. FLOODING AND STORM DRAINS Flooding could be a major problem ~ many low-ly~ng portions of coastal cities with a sea level rise.
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From page 111... ...
An increase in relative mean sea level could result in higher flood waters upstream, with the possibility of levee overtopping. In addition, he states that the flood control systems of many areas presently rely on storage of flood waters and gravity releases at low tide.
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From page 112... ...
Many mass and hotels in the United States become "aged" in a few decades and undergo major and extensive renovation. It Is likely that measures to accommodate small rises ~ relative mean sea level would be taken as a part of the renovation.
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From page 113... ...
If the surface of the freshwater table is X feet above mean sea level, under static conditions, the freshwater-seawater interface would be about 40X It below mean sea level. As sea level rises, this "bubbles of fresh water should simply float In the salt water at an elevation that is higher by the amount of sea level rise.
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From page 114... ...
A possible rise of mean sea level of between 0.5 and 1.5 m by the year 2100 could have an important imp act on the structures and methods necessary to maintain water quality standards. According to Kennedy (1986)
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From page 115... ...
They should not be affected very much by eustatic rise in mean sea level In that time span. The problem of relative rise in mean sea level owing to subsidence can be of much greater importance.
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From page 116... ...
116 RESPONDING TO CHANGES IN SEA LEVEL classification society, Det Norske Veritas, that several platforms on the field would be total losses in the event of a major storm. An article in the Financial Times of London (April 11, 1986)
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