What was the point you wanted to make, and what did you want me to do. I am not normally this obtuse. What is the relevance of the site to the current situation, other than the elevations, for which I use a more precise terra server topo map?
At this point I've forgotten as I was so focused on finding that damn graphic (which was bookmarked on my other computer which crashed last night).
Overall, my point was that sea level as a point of reference may be misleading if the river levees are breached. Furthermore, I'm not so sure that the lake can't fill most of the city on its own. So to try to repair the breach is futile until the lake and the city are in equilibrium.
How's that?