Texas Aquifers Lecture Notes

Groundwater Overview

• Groundwater exists below the Earth's surface almost everywhere.
• More than 2 million cubic miles of fresh water is stored in the Earth.
• Half of this groundwater is within half a mile of the surface.
• 50% of the U.S. population relies on groundwater for daily needs.
• Groundwater is vital for irrigation.

Major Aquifers in Texas

Edwards Aquifer

• Stretches across ten counties in Texas.
• 180 miles long, width varies between 5 and 40 miles.
• Composed mainly of Edwards limestone.
• Known for its permeability and productivity.
• Comprises three segments:
  • Drainage Zone
  • Recharge Zone
  • Artesian Zone
• Supports approximately 1.7 million people.
• Has supported civilization for over 12,000 years.

Ogallala Aquifer

• One of the largest aquifer systems in the world.
• Extends across parts of eight states: South Dakota, Nebraska, Wyoming, Colorado, Kansas, Oklahoma, New Mexico, and Texas.
• Covers about 174,000 square miles.
• Located in the Texas Panhandle.

Activity Instructions

1. Use the Texas Water Development Board website to:
   • Color and label major Texas aquifers on a map: Ogallala, Gulf Coast, Edwards BFZ, Edwards-Trinity Plateau, Trinity, Carrizo-Wilcox.
   • Create a legend for the map.

Aquifer Related Questions

1. Water Supply Aquifer

   • Trinity Aquifer supplies our water.

2. Location of Ogallala Aquifer in Texas

   • Located in the Panhandle.

3. Source of Springs in Austin and San Antonio

   • Edwards Aquifer is the source.

Definitions and Comparisons

Definitions (Pages 106-113)

• Zone of Aeration: Pores and cracks in rocks are filled with air.
• Zone of Saturation: Pores and cracks in rocks are filled with water.
• Water Table: The line that separates the Zone of Aeration and Zone of Saturation.

Springs vs. Aquifers

• Springs: Water flows naturally from an aquifer to the Earth's surface.

Artesian Wells vs. Aquifers

• Artesian Wells: Man-made wells where water flows without the need for a pump.