Week Three - Running Water - Taylor Mills

Considered the chief tributary of the Colorado River, the Green River is located in the western United States.  Interested in seeing it in person, my mom and I decided to take a trip to Wyoming since its drainage basin, or watershed, is known as the Green River Basin and extends across not only Wyoming but also Colorado and Utah as illustrated in Figure 1 below.

Figure 1. Green River Basin Watershed (Edwards, 2018).

We noticed that the Green River Valley cuts through mountains as well as various canyons and plateaus.  Though there didn't seem to be a clearly discernible valley shape, Green River is a large, deep, and powerful river with floodplains and surrounding terraces due to an apparent drop in base level.  Ranging from 100 to 300 feet wide in its upper course to 300 to 1,500 feet wide in its lower course, Green River was an obviously meandering river.  Apparent by its s-shaped curves, Green River meanders because of the continuous occurrence of erosion and sediment deposition along its banks.  Within this meandering river, the majority of sediment carried is silt.  Because of this, I explained to my mom that Green River carries a suspended load which makes sense due to its murky appearance.  However, as I explained to my mom, Green River is a special case of a perennial system of running water.  Though the basin is located in an arid landscape with a flow that varies from year to year, it still has water flowing year-round.  In fact, Green River is susceptible to flooding and actually has a dam that runs its entire length in the hopes of controlling any flooding.  Personally viewed by me and my mother, there were also artificial flood-control levees in place as any flooding could cause lots of widespread damage (i.e. road closures, utility interruptions, etc.).  Nonetheless, I made sure I showed my mom an oxbow lake created by the meandering of the Green River near Bronx, Wyoming.  As depicted in Figure 2, oxbow lakes are created when a meander has been abandoned.  Though my mom didn't understand the majority of geological facts and features I was explaining to her, she had a wonderful time spending time with me and the beautiful western landscape.

Figure 2. Oxbow Lake Created by the Meandering of the Green River (American Geosciences Institute, 2016).