Water and Bridges

More than 80,000 miles of waterway stretch across Texas: about 92 major waterways.  Streams in East Texas usually move slowly in the jungle-like landscape.  Streams in Central Texas tend to flow faster, carving their own paths and often becoming white water.  The streams in West Texas flow more randomly over arid landscapes, cutting and flowing through deep canyons.

Major waterways of Texas

Geographers find the Guadalupe Arroyo particularly interesting.  It is an ephemeral stream (one that flows in response to precipitation events) found on the eastern side of Guadalupe Mountain National Park.

Guadalupe Mountain National Park--The arid landscape of the park allows for little vegetation, but it also creates beautiful views.  Pictured is a section of the Guadalupe Mountains.

The "A" indicates the Guadalupe Arroyo.  The stream runs down the pictured canyon and causes major problems for highway 62-180.

The Guadalupe Arroyo starts in the mountains and disappears several miles later in a dry lake.  It usually flows due to severe flash flooding.  When it does flow, it transports materials ranging from silt to boulders.  This load routinely washes against the bridge on highway 62-180.  This often causes the stream to dam and in turn erode the sidewalls and widen its path.  Maintenance crews routinely clean out the sediment load to keep the bridge in the best possible condition.  They even built barriers to keep the boulders from smashing into and destroying the bridge.  One day a huge flash flood may completely wash out the small bridge.

McKittrick Canyon--Located in Guadalupe Mountain National Park near Guadalupe Arroyo, this canyon shows similar landscape to the Guadalupe Arroyo.  Past streams cut the giant v-shaped valleys in the sides of the mountain.  

An example of a dry stream bed from an ephemeral stream.  Left over bed load appears lighter-colored than the rest of the rock around it.  (This is not the Guadalupe Arroyo)

An example of sediment transported by a stream ranging from very small to large boulders.  The stream carries the sediment and rocks and deposits them where it pleases.  (This is not the Guadalupe Arroyo)

Images: http://geology.com/lakes-rivers-water/texas.shtml
http://www.exploring-america.com/pics/guadalupe-mountains-national-park-texas.jpg
maps.google.com
http://rpmedia.ask.com/ts?u=/wikipedia/commons/thumb/f/f5/McKittrick_Canyon_from_a_distance_2006.JPG/180px-McKittrick_Canyon_from_a_distance_2006.JPG
http://thegeographyspot.files.wordpress.com/2011/03/wadi-dry-bed-from-stream.jpg
http://www.sleepingdogstudios.com/Network/Earth%20Science/ES_6.2_files/slide0009_image020.jpg
Information: http://www.tpwd.state.tx.us/publications/pwdpubs/pwd_rp_t3200_1047/03_introduction.phtml
http://trid.trb.org/view.aspx?id=1083145