The controlled river indicates

[Image: Photo by Matt York for the Associated Press (via)].

"A torrent of water was released into the Colorado River from the Glen Canyon Dam in Arizona on Tuesday, in a disputed effort to improve the environment for fish in the Grand Canyon," the New York Times reports.
The sheer volume of water released is extraordinary:

The water poured out of the dam as if pumped through a gigantic fire hose, at the rate of 41,500 cubic feet per second – enough to fill the Empire State Building in 20 minutes. This release, which engineers call “high flow,” was meant to scour the river bottom and deposit silt and sediment to rebuild and extend sandbars and create new, calm backwater areas where the fish can spawn.

The BBC adds that "the Colorado river rose quickly after the flood was released."

[Images: The water guns are opened. Photos by Matt York for the Associated Press (via)].

1) It would actually be quite fun to do that – to fill the Empire State Building with water in 20 minutes. It would be a performance art piece called Modernism after the Flood.
2) These timed releases are also a means of "calibrating" the river to the West's urban hydroelectric needs: the waters will now "rise and fall for six months in a pattern that the United States Geological Survey is calibrating to match the demand for hydroelectric power in cities like Las Vegas." The waters will "rise and fall," that is, not because of lunar tides or upstream rainfall, but because U.S. cities need more hydroelectric power.
So while it may be obvious to this point out, the implication is that the whole river is a machine now – and what appears to be a "river" is really a kind of liquid chart, graph, or diagram from which we can read the electrical needs of contemporary U.S. urbanism.
The river, then, is a sign – it is information-bearing. It is textual, graphic, communicative. The controlled river, with its unnatural floods and valved reservoirs, indicates.

(Earlier on BLDGBLOG: N.A.W.A.P.A.)