section_path: History/20th century/Drainage and flood control
section_name: Drainage and flood control
paragraph_text: Drainage and flood control
  
  In the 20th century, New Orleans' government and business leaders believed they needed to drain and develop outlying areas to provide for the city's expansion. The most ambitious development during this period was a drainage plan devised by engineer and inventor A. Baldwin Wood, designed to break the surrounding swamp's stranglehold on the city's geographic expansion. Until then, urban development in New Orleans was largely limited to higher ground along the natural river levees and bayous.
  
  Wood's pump system allowed the city to drain huge tracts of swamp and marshland and expand into low-lying areas. Over the 20th century, rapid subsidence, both natural and human-induced, resulted in these newly populated areas subsiding to several feet below sea level.
  
  New Orleans was vulnerable to flooding even before the city's footprint departed from the natural high ground near the Mississippi River. In the late 20th century, however, scientists and New Orleans residents gradually became aware of the city's increased vulnerability. In 1965, flooding from Hurricane Betsy killed dozens of residents, although the majority of the city remained dry. The rain-induced flood of May 8, 1995, demonstrated the weakness of the pumping system. After that event, measures were undertaken to dramatically upgrade pumping capacity. By the 1980s and 1990s, scientists observed that extensive, rapid, and ongoing erosion of the marshlands and swamp surrounding New Orleans, especially that related to the Mississippi River–Gulf Outlet Canal, had the unintended result of leaving the city more vulnerable than before to hurricane-induced catastrophic storm surges.