site of the breach, had been reporting their front yards flooding from persistent seepage from the canal for a year prior to Hurricane Katrina to the Sewerage and Water Board of New Orleans. However, no data exists confirming that the water was coming from the canal. Other studies showed the levee floodwalls on the 17th Street Canal were "destined to fail" from bad Corps of Engineers design, saying in part, "that miscalculation was so obvious and fundamental," investigators said, they, "could not fathom how the design team of engineers from the Corps, local firm Eustis Engineering, and the national firm Modjeski and Masters could have missed what is being termed the costliest engineering mistake in American history." Dr. Robert Bea, chair of an independent levee investigation team, has said that the New Orleans-based design firm Modjeski and Masters could have followed correct procedures in calculating safety factors for the flood walls. He added, however, that design procedures of the Corps may not account for changes in soil strength caused by the changes in water flow and pressure during a hurricane flood. Dr. Bea has also questioned the size of the design safety margins. He said the corps applied a 30% margin over the maximum design load. A doubling of strength would be a more typical margin for highway bridges, dams, off-shore oil platforms and other public structures. There were also indications that substandard concrete may have been used at the 17th Street Canal. In August 2007, the Corps released an analysis revealing that their floodwalls were so poorly designed that the maximum safe load is only of water, which is half the original design. A report released in August 2015 in the official journal of the World Water Council concluded the following: Overtopping of levees in the Eastern New Orleans According to Professor Raymond Seed of the University of California, Berkeley, a surge of water estimated at 24 feet (7 m), about 10 feet (3 m) higher than the height of the levees along the city's eastern flank, swept into New Orleans from the Gulf of Mexico, causing most of the flooding in the city. He said that storm surge from Lake Borgne travelling up the Intracoastal Waterway caused the breaches on the Industrial Canal. Aerial evaluation revealed damage to approximately 90% of some levee systems in the east which should have protected St. Bernard Parish. National Academy of Sciences