The Lena River DeltaIn one of our previous posts we talked a little bit about meandering stream syst

The Lena River DeltaIn one of our previous posts we talked a little bit about meandering stream systems as the most common breed of rivers. Another major class of streams is braided streams, a system most commonly seen in deltas. A delta is a shoreline protrusion where a flowing stream enters a basin of water such as an ocean, lake, or even a mud puddle. Its distinct branching pattern is due to greater sediment deposition by the in-flowing river than sediment erosion by the basin of water.Deltas are landforms that are constantly in flux, as one can envision by looking at this false-color composite image (used in this image to monitor degree of flooding) of the Lena River Delta in Siberia taken by the Landsat 7 satellite. Sediment and water are constantly fed to the delta by the Lena River. That sediment eventually builds tiny levees that hold the flowing water in channels until they are breached as can happen during floods. Any gap in the levee can become a mini stream of water, and because the river mouth has such a low slope, these mini streams are constantly breaching other tiny levees to find the flow path of least resistance. This back-and-forth between building and breaching of levees results in the characteristic braided stream pattern of a delta.Deltas can form across incredibly wide areas, and the Lena River Delta is no exception, which is about 400 km wide and extends almost 100 km into the Arctic Ocean. The Lena River and delta are surrounded by frozen tundra that transforms into a verdant wetlands during the spring seasons, creating an environment that is home to many nature reserves. The wetlands become home for many different species of nesting and migrating birds, and the rivers also support a variety of fish populations.-DCPhoto credit: http://1.usa.gov/1GDAkPlLearn more about the Lena River Delta and its ecological importance:http://bit.ly/1MYrQYohttp://bit.ly/1zxR05Whttp://bit.ly/1aClGwcThe previous times we have talked about deltas:http://on.fb.me/1PcqXKkhttp://on.fb.me/1HHU5UoMore on deltas:http://bit.ly/1HHTQZDhttp://abt.cm/1abegiuhttp://bit.ly/1F6ksWHHow to interpret false-color images from NASA:http://1.usa.gov/1CvGMSmPlan your next vacation:http://bit.ly/1NXXOB8 -- source link

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