They will need to breech another area of the canal or lake to stop this or to slow it down. This means they will have to flood another area on purpose by blowing up another part of the levee. But where would they break it at and could they do it in time? There is no way to fix this current 2 block break in the levee.
that sounds like burning down San Francisco to save it.
Correct - there is no heavy equipment in the area or materials that would be needed to fix a levee break. Maybe they could take a page from a Cussler novel and sink a container ship in the gap - but they'd have to do that NOW.