It's not a new issue though, and you're right it shouldn't happen from rain, but it certainly has in the past. The purpose of SELA construction is to ameliorate seasonal rain flooding issues by putting in new higher capacity box drainage culverts below major thoroughfares responsible for carrying water from the lowest parts of the city. The federal funds for it were granted in the late 90s after severe rain flooding in the middle of the decade (likely worse than this past weekend's). The city put off a lot of the construction for years, partly for issues with state/local fund matching and likely can kicking, but now has to implement multiple phases all at once to ensure they don't lose the federal contribution, thus uptown has been ripped up for almost 5 years. Hopefully this will help fix rain flooding issues. However, it would do little to ameliorate a levee breach. The proper inquiry is about SWBNO's rate hikes, failure to clear storm drains and drainage boxes, failure to properly implement SELA in a timely fashion, neglect of infrastructure, and proper management of pumping stations.