<P> For most of the city to the west of the Industrial Canal, the flood levels were much the same as those reached in mid-19th century storms when, like Katrina, major hurricanes created a "lake flood" by pushing Lake Pontchartrain up into the South Shore . At the time of these earlier storms the lower lying areas of the city had little development, so effects on life and property were much less severe . </P> <P> West of the Industrial Canal, the parts of the city unflooded or minimally flooded largely corresponded with areas of the city developed on naturally higher ground before 1900 . </P> <P> On August 31, flood levels started to subside . The water level in the city had reached that of Lake Pontchartrain, and as the lake started to drain back into the Gulf, some water in the city started to flow into the lake via the same levee breaches they had entered through . In 19th century lake floods, the water soon flowed back into the lake as there were no levees on that side . In 2005, while the levees proved inadequate to keep the lake out of the city, even in breached form they were sufficient to keep much of the flooding from flowing back out . As breaches were gradually filled, some city pumps were reactivated, supplemented by additional pumps brought in by the United States Army Corps of Engineers . Some of the city's pumps which survived could not be reactivated because of the failures of the canals that they pumped flood waters into . The combined task of closing breaches and pumping the flood waters out took weeks and was compounded by a setback in late September due to further flooding from Hurricane Rita . </P> <P> By the start of October 2005, only a few small areas of flood waters remained within the city, but the disastrous flooding in the aftermath of Katrina left the majority of the city's houses and businesses so damaged as to be unusable until major renovations or repairs could be made . An article in the New Orleans Times - Picayune on 30 November 2005 reported that studies showed the 17th Street Canal levee was "destined to fail" as a result of fundamental design mistakes by the United States Army Corps of Engineers . </P>

How did they get rid of the water from hurricane katrina