He was working from more limited information than we have now, and may have firmly believed what he said. I've stated earlier in this thread that the raw numbers have the reservoir filling up with sediment in about 700 years, but that's the entire reservoir filling up. He and David Brower reportedly got into a shouting match about how fast the reservoir would get filled by sediment.'The main reason is that they would likely get blocked by sediment somewhat early in the life of the reservoir ...'
Floyd Dominy thought the sediment build-up could be a problem sometime around the year 2960.
Are you calling him out as a liar, drew?
Sediment build-up is already causing problems in the San Juan Arm (raising the river grade at Clay Hills Crossing), and the sediment delta from the San Juan Arm will reach the main channel confluence before the sediment delta in the main channel reaches the confluence. It's already eliminated the use of the Hite Marina for lower water levels, and would/will soon eliminate the use of Hite Marina for even full pool levels if the water stays at that same level for longer.
I think way the sediment distributes as it fills in will be much more of an issue than the total time.