🌍🌎🌏🌎🌍The Aging of the Colorado River 🌍🌎🌏🌎 EarthCache

Determining the age of a river is a very interesting study through the eyes of geology. But first a look at the basics of this river and a little history to current day.

Here at the posted coordinates you can observe the Colorado River, not to be confused with the Colorado River that flows west through Utah and the states west of there.

You will be making these observations on our Texas Colorado River.  The headwaters are northwest of where you stand here, 573 miles up near Lamesa. It flows through and along the borders of 19 counties into Matagorda Bay at the Gulf of Mexico. In its entire length of 862 miles there are 7500 miles of creeks, streams and rivers. Among the latter that contribute are the Concho, San Saba, Llano, James, and Pedernales Rivers'. You might be familiar or have crossed one or two of those as you adventured in Texas so far. This river is the 11th longest river in the USA.

Originally it was referred to as Brazos des Dios - "Arms of God" - and the current day Brazos was called the Colorado. In the early days, the names of each river were interchanged with each other but eventually they were sorted to what they are officially called today. 

As with most major rivers in Texas, there is a River Authority that monitors the health and flow of this river. Currently the Lower Colorado River Authroity- LCRA, has 275 hydromet gauging stations along the Lower Colorado River Basin. These provide real-time weather, water, early warning, and climate information and data.

Age of the River

• Young River - the upper course.

• Middle Aged River - the middle course.

• Old River - the lower course.

River Channel Types

There are three basic types of channels, straight, meandering and braided.

“Straight” channels" happen toward the heads of rivers and at places they cross high ridges. Quite often they are in canyons, though the “canyon” may not be very deep.

"Meadering channels" flow over gradual sloping regions and begin to curve back and forth across the landscape. It flows faster in these deeper sections that are sometimes towards the middle and sometimes towards and edge eroding material from the river bank. 

"Braided channels" are several channels that are separated by small islands that are sometimes temporary called braid bars also called aits or eyots.

River Classifications 

• Ephemeral Rivers existing for a short time.

• Episodic Rivers that have run off channels rarely showing up in areas where it is very dry and desert-like

• Exotic Rivers start in a humid region and run through a dry region

• Intermittent Rivers are temporary, flowing every 2 to 5 years, ceasing to flow every year 

• Mature Rivers low gradient slow moving and spread out

• Periodic Rivers run dry on occcasion, located in areas where evaporation is much more than any rainfall

• Permanent Rivers are those that have water flow all year round, no matter the amount.

• Youthful Rivers are fast flowing and generally have steep sides... they can be found at the headwaters of an old mature river.

Please read carefully the description and answer the following questions.

1. What is the age of this River?

2. What type of channel do you observe at gz?

3. Of the 8 different classifications of River,  what class can you determine this river is? (It is likely you will observe more than one classification here as most rivers do)

4. Please post a photo from gz with the bridge behind  you. (optional)