OK, maybe I'm getting a little carried away here, but in the spirit of 'what ifs' since crossing that water is vital to travels home. I see on Google maps what appear to be numerous small-boat slips scattered along the canal. Are you familiar with the area? Any sense of likelihood a small boat -- not necessarily powered -- might be available to 'borrow' in emergency situation (even a serviceable rowboat), or is that area likely to be a high-visibility beehive of activity post-earthquake?

As an afterthought -- speaking to the 'should I attempt to swim' question -- have you decided on a water-tight bag for your gear-pack? Is the likely crossing-point narrow enough that a water-tight bag would be a viable flotation device? How are the currents there? Water temperature? Lot of boat travel (especially in emergency situation) that would make water-crossing even more perilous?