Lagoon certainly looks big enough, could sail some F18s in there:
And a nice pic of the slough they would use... but it is at low tide in this picture so it isn't obvious. Seems it would actually be easy to have a crane pick it up, drive across the parking lot and crane it into the lagoon.
The problem with that idea is where do you find a mobile crane that can pick up 20 tons at a reach of about 60 feet and then drive across the car park ???
No disrespect intended, but you obviously have never had to move heavy equipment. Cranes are available to do hundreds of tons. We used to move extrusion presses from the rail spur to the factory floor across some pretty interesting features. These things weigh 100s of tons. Remember, a standard container crane routinely does 20 tons and is often driven around the hard like a cowboy herding cattle... at least in 3rd world countries where I come from.
And I don't think DZ weighs 20 tons, but don't want to bother to look it up.
If the features to be traversed are too "interesting", then you lift the load, rotate the crane, place the load, move the crane, repeat... as many times as necessary. As for the comment about it being as large as an infield, check the vid I posted above. Seems about the size.
But for kicks, I just looked at the google image to refresh my memory of the place, and I would guess they would float it all the way to Marine Parkway where we would offload, Put their crawler crane on Marine Parkway at 1AM (with permit in hand)... Hoist it, slowly drive down until parallel with the lagoon and drop it in. There may be trees in the way so this may not be possible, but barring that, technically it would be pretty straightforward. If not, pick and plant across their own parking lot.
Anyway, I assure you, a good rigger can do it. You just gotta pay.
Link below is of the google image to show you have straightforward the path could be. Just don't know the obstacles. Big square of water across the street is the final 500m of the rowing racecourse. But rowing hasn't the intrigue to talk about. And remember, the pic is at low tide.