03 Jun '11, 10pm

Lay of the Land Between Old River and the Mississippi: This model of the land elevation between the Mississip...

The Mississippi River is highly “engineered,” as major rivers go. The battle between human civilization and the river is perhaps best exemplified by the Old River Control structures in central Louisiana. Completed in the 1960s, the system of levees, locks, floodgates, and canals has so far successfully kept the Mississippi River from meandering westward, as it has done several times over the centuries. If left to natural processes, the Mississippi might migrate to the west and merge with the Atchafalaya River, taking a more southerly route toward the Gulf of Mexico. The process is known to geologists and hydrologists as “avulsion.” The accumulation of sediments in a channel reduces its slope, slows the flow, and leads the river to look for a steeper downward slope and faster flow. Human “control” of the river continues in spite of land topography that is working in nature'...

Full article: http://earthobservatory.nasa.gov/IOTD/view.php?id=50824&s...

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NASA scientists produce first global map of lan...

e360.yale.edu 07 Jun '11, 3pm

07 Jun 2011: Global Land Fluorescence Is Mapped For the First Time Click to enlarge NASA Global land plant fluorescence NA...