In the past, some researchers have written about rivers as if they work in the same way that a faucet works; that is, researchers assume that the river is determined by its source. Then they worry that problems found in the source will cause problems for the entire length of the river. But the vast majority of rivers are determined by the many watersheds through which they flow. The Nile might be a notable exception because it flows through various degrees of desert for most of its length. By contrast, the Mississippi River flows through varied but rich watersheds for its entire length. If the Mississippi River were obstructed by a dam at Minneapolis the long term impact would not be noticed at St. Louis and would be undetectable at New Orleans.
I hope that the relative importance of watersheds and the relative unimportance of the source have been taken into account by the modelers. I hope that the old error has been fully expunged from today’s research. I regret that I do not have time to do the checking myself.
![\scriptstyle\rule[2.25ex]{0.01pt}{0.01pt}\,\boldsymbol{\overset{\scriptstyle\circ\wedge\circ}{\smile}\,\heartsuit\,{\displaystyle\text{\bfseries!!!}}\,\heartsuit\,\overset{\scriptstyle\circ\wedge\circ}{\smile}}\ \rule[-0.25ex]{0.01pt}{0.01pt}](http://s0.wp.com/latex.php?latex=%5Cscriptstyle%5Crule%5B2.25ex%5D%7B0.01pt%7D%7B0.01pt%7D%5C%2C%5Cboldsymbol%7B%5Coverset%7B%5Cscriptstyle%5Ccirc%5Cwedge%5Ccirc%7D%7B%5Csmile%7D%5C%2C%5Cheartsuit%5C%2C%7B%5Cdisplaystyle%5Ctext%7B%5Cbfseries%21%21%21%7D%7D%5C%2C%5Cheartsuit%5C%2C%5Coverset%7B%5Cscriptstyle%5Ccirc%5Cwedge%5Ccirc%7D%7B%5Csmile%7D%7D%5C+%5Crule%5B-0.25ex%5D%7B0.01pt%7D%7B0.01pt%7D&bg=ddffdd&fg=0033ff&s=2 "\scriptstyle\rule[2.25ex]{0.01pt}{0.01pt}\,\boldsymbol{\overset{\scriptstyle\circ\wedge\circ}{\smile}\,\heartsuit\,{\displaystyle\text{\bfseries!!!}}\,\heartsuit\,\overset{\scriptstyle\circ\wedge\circ}{\smile}}\ \rule[-0.25ex]{0.01pt}{0.01pt}")
