Seems to me we’re just gonna transfer the car problem to boats. People worried about all those sports boats mowing over us poor kayakers and row boaters, and even worse, disregarding paddle boarders crossing at designated points, but it’s our fault because they have big boats that can’t stop, forcing us to row down small canals or risk being stranded on a narrow river arm with a hole in our hull and no flex tape to at least get to a repair shop. But maybe we’ll start getting protected rowing lanes and not just a line of buoys that tell us where to be.

But I do like the idea of the Venetian solution from another comment. Build bridges low enough to block boats from coming through but high enough to let rowers and paddlers through. And if we need a place to pass on foot on busy places, we can always build drawbridges, but those would get pushback due to the danger they’d cause distracted boat drivers.

The future is wet, but not so different.