Storm water control is no small job: Chicago has spent over 3 billion on their Tunnel and Reservoir Plan which is a huge underground system of tunnels for holding stormwater and sewage during storms to prevent it from draining into Lake Michigan (Chicago's water source). Similarly, whenever you build something in New York State there are rules created by the DEC governing what you have to do to account for the increased runoff that your buildings and parking lots create (see the New York State Stormwater Design Manual)
Runoff is just what it sounds like, water that runs off land (as opposed to sinking into it) and eventually works its way down the watershed. Fast moving runoff rips up soil, floods rivers too small to handle the extra flow, and is generally harmful. Runoff can also contain chemicals leaking out of cars or pesticides and fertilizer from lawns.
Apparently the big detention basins/ponds are the old way of dealing with runoff. The idea was you would build your subdivision and put a big (and usually ugly) basin at the bottom of it. When it rained the basin would fill up and water would be slowly metered out. While this does slow the water down, it doesn't do much for the build up of chemicals and other compounds. The new trend is to try and get the water to trickle down into the ground or infiltrate as soon as possible. This way the ground filters out some of the nasties while also slowing the water down. One example of this is porous pavement (the Wild Center had it in their parking lot) which is full of holes. Assuming the soil underneath is suitable (e.g. not the golf course or minor field), the holes allow rainwater to infiltrate, and no water runs off the parking lot. Other forms of promoting infiltration are rain gardens and putting downspouts from roofs and parking lots in areas where the water can spread out and sink in.
Effectively, we go to a lot of trouble to try to do what the trees in the Adirondacks already do a good job of: slowing the water down and pushing it into the ground.
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I'm glad you researched this aspect of Colvin's argument; I didn't know anything about it before reading his commission and wanted to know more. It's interesting how humans come up with mechanisms that mimic nature's ways of dealing with its problems. Not only do we try to deal with runoff in a similar way as the trees, but we also create lightning rods that serve a similar purpose as trees for example. I wonder if eventually we will run out of processes to adapt from nature when our problems become increasingly and uniquely manmade.
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