It is human nature to think of everything in linear terms -- going another 10% requires 10% more effort. Budgets are always like this, anybody who doesn't do math or physics wallows in it. Oklahoma will soon learn the power of exponentials, and so will these guys by the river.
Today, they are tinkering with lowering a mini-excavator into the quicksand pit. They think they can work their way around the sewer. But the hydraulic head increases linearly, and the permeability with quicksand drops exponentially. This gives a big exponential for total water flowing in. In other words, they try to go an extra foot, the water comes in like a torrent.
I would like to say that this is only confined to 'handyman specials' but it isn't. Many engineers are caught up in this. Look at seismic 'upgrading'. It only goes up one intensity level (double PGV), but the uncertainties are 3 intensity levels. Upgrading is useless, but it looks good. Put everything on screw piles! :) These are lessons only learned by body count. :(
**The exponent aspect of water flow was my big objection with the Bruce Black Hole, now thankfully in Liberal Limbo.
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