It would have been a good thing to do, but the real delay imposed by for example the complete destruction of the lochs at any given point would have been to shut down the canal for three months. It is a fairly trivial task to reroute a section of a major canal for a short interval. It basically just entails moving a lot of dirt. By 1940 the US was much better at moving giant quantities of dirt than when the canal was originally constructed.
Tthat really depends on how well they did their homework. Blowing it up at the lake dam that supplies all the water to run the locks would shut her down for a long long time ... blowing it in one of the individual lock sections would be rebuilt fairly quickly.
This is too funny, I see Mogami already replied with exactly this ... can't keep up, must stop eating, takes too much time...