This undated photo made available by the Texas Medical Center shows submarine type flood doors which were installed throughout the Texas Medical Center tunnel system in Houston after se

 

              This undated photo made available by the Texas Medical Center shows submarine type flood doors which were installed throughout the Texas Medical Center tunnel system in Houston after se
This undated photo made available by the Texas Medical Center shows submarine type flood doors which were installed throughout the Texas Medical Center tunnel system in Houston after severe flooding from tropical storm Allison in 2001. The floods caused a blackout, inundated medical center streets with up to 9 feet of water, and forced evacuations of patients from the district's 6,900 hospital beds. If metropolitan New York is going to defend itself from surges like the one that overwhelmed the region during Superstorm Sandy, decision makers can start by studying how others have fought the threat of fast-rising water. (AP Photo/Texas Medical Center)