The real world is complex. It's not all like software or taking multiple choice exams. Again the devil is in the details. Pay really close attention to the map legend. It looks like there's nearly 200 feet of distance from the closest water shown on that map and the nearest side of the cathedral. I really doubt that all fire trucks carry 200 feet of hard suction hose, or have pumps designed to draft through 200 feet of hard hose.
"The NFPA 1901, Standard for Automotive Fire Apparatus – Requires pumpers to carry:
15 feet of large soft sleeve hose or 20 feet of hard suction hose"
You would never try to draft through 200 feet of hard suction. In fact, I'm relatively sure it would be impossible, since no matter how well you tighten the connections, there's pretty much always going to be a minute amount of vacuum loss at each coupling. In practice, few fire departments ever draft though more than 20 feet (2 sections) of hard suction, and even then it can be a challenge getting the pump primed, depending on any elevation difference between the water surface and the engine location, etc.
In real life, if you were going to draft in an environment like this, (leaving aside any reference to fire boats for a moment), you'd drive an engine to within 20' or so of the water, have it draft, and then relay water to the fire scene using (usually) 5" LDH. But sometimes even getting an engine to within 20' of the water can be a challenge, based on the geography and circumstances.
If the body of water you're drafting from is (strongly) subject to tides, that adds another complicating factor as your water source is now moving around, which could require constant re-positioning of the apparatus.
Lay people always see fires near large bodies of water and think "Why is water supply a problem, they're surrounded by water?!?" But it's often more complicated than that.
Source: was a firefighter and firefighting instructor for about a decade in a former life.
Also, even if you had a pump by the river, hand-jacking that length of LDH requires a huge amount of physical effort, and would tie up a lot of manpower during a critical phase of the operation.
I don't have to pay close attention to the map. I've been there. It is absolutely close enough to the river to have hoses running directly from it. The fact that they didn't use it suggests it probably wasn't such a good idea, we are only dudes writing on the internet, they are firefighters with experience doing their job.
The real world is complex. It's not all like software or taking multiple choice exams. Again the devil is in the details. Pay really close attention to the map legend. It looks like there's nearly 200 feet of distance from the closest water shown on that map and the nearest side of the cathedral. I really doubt that all fire trucks carry 200 feet of hard suction hose, or have pumps designed to draft through 200 feet of hard hose.
"The NFPA 1901, Standard for Automotive Fire Apparatus – Requires pumpers to carry: 15 feet of large soft sleeve hose or 20 feet of hard suction hose"
http://tkolb.net/tra_sch/FireHose/HoseBasics.html