NEW ORLEANS, Louisiana (CNN) -- The catastrophe caused by Hurricane Katrina in New Orleans could happen again unless the city's hurricane protection system is massively overhauled, an engineering panel said Friday.

"We must place the protection of public safety, health and welfare at the forefront of our nation's priorities. To do anything less could lead to a far greater tragedy than the one we have witnessed in New Orleans," a report issued by the American Society of Civil Engineers External Review Panel said.

More than 150 engineers and scientists contributed to the panel's report analyzing what happened in New Orleans.

"We now have a better understanding of what went wrong and why," the panel wrote. It also issued recommendations, but warned that there is "no quick fix."

Among the findings:

The city's system of levees and floodwalls, "failed catastrophically at over 50 different locations."

Pump stations "were not designed to function in a major hurricane or mitigate flooding if the levees were overtopped or breached."

Politicians and the designers and operators of New Orleans' hurricane protection system did a poor job, "evidenced by the fact that the system took decades to build and remains incomplete yet today."

Some of the panel's recommendations:

Designate one person to coordinate local, federal and state hurricane and flood protections and improve communication between all agencies.

Congress "should establish and fund a program for nationwide levee safety and rehabilitation, much as we do for major dams."

Be sure that levees are designed and maintained at levels appropriate to the threat and the work is reviewed by independent experts. Before Katrina, authorities warned a Category 4 storm could cause flooding; Katrina turned out to be a Category 3 storm at landfall.

Make levees and pump stations able to withstand overtopping. "If this is not done, New Orleans will remain unnecessarily vulnerable," the report said.

The panel also recommended that officials "rethink the whole system, including land use in New Orleans" to put fewer people and less property at risk.