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equally well to floods resulting from increased sea level. While 

 overcoming precedent to change design criteria for traditional flood events 

 may be impossible, applying these concepts to sea level rise damages may 

 be an opportunity for a different approach. 



Drainage structure effectiveness will be compromised by higher sea 

 level. Responding to this effect will require modifications to such 

 structures and perhaps addition of pumping capacity. 



Locks are frequently used to limit salinity intrusion in navigable 

 waterways. Rising sea level can endanger the gates of locks, requiring 

 gate replacement and perhaps raising of the lock walls. Limiting 

 freshwater loss and saltwater intrusion through locks is a major design 

 concern that will certainly grow worse with higher sea levels. 



As climate changes and precipitation and runoff patterns change, river 

 floods could become worse or better. Hurricanes could become more or less 

 common at a particular site. Thus these changes could affect structure 

 design requirements as much as or more than sea level rise. 



Research Needs 



Structure design and evaluation procedures can be revised to account 

 for accelerated sea level rise, but they are practical only if reliable and 

 precise estimates of future sea level rise rates are commonly agreed to. 

 Then economically sound decisions can be made. The present broad range of 

 possible rates of rise does not encourage design engineers to begin 

 including any of them; therefore, additional work is needed to refine the 

 estimates and obtain a consensus on them. 



Design criteria such as damages related to specific rates of sea level 

 rise and specific probabilities of occurrence are needed. Better 

 mathematical descriptions of the processes by which earth mound structures 

 are overtopped and eroded will be needed if the methods of setting 

 protection criteria are changed. 



Geotechnical and structural research is needed to develop ways to more 

 economically raise protection levels. 



Designs are needed to reduce flanking of perpendicular structures such 

 as groins and dikes. 



