Water Coverage and Aquifers

Questions and Answers

What percentage of Earth's water is freshwater?

97%

71%

20%

3% (correct)

What is the primary purpose of flood control in water management?

To prevent damage from excess water (correct)

To irrigate crops

To supply water for drinking

To generate hydroelectric power

What is a characteristic of 'major' aquifers?

They are only found in urban areas

They produce a small amount of water over a small area

They are only used for irrigation

They produce a large amount of water over a large area (correct)

What is the characteristic of brackish aquifers?

They have a high level of dissolved solids Signup and view all the answers

How is surface water managed in Texas?

Through a permit system based on 'first in time, first in right' Signup and view all the answers

What is the proportion of groundwater in Texas' total water use?

55% Signup and view all the answers

Which water right holder has the most diversion amount?

The Dow Chemical Company Signup and view all the answers

What is the main purpose of Groundwater Conservation Districts?

To balance the conservation and development of groundwater Signup and view all the answers

What is the Rule of Capture in Texas groundwater law?

A doctrine that considers groundwater as a property right Signup and view all the answers

What is a limit to the Rule of Capture in Texas?

Maliciously taking water for the sole purpose of injuring a neighbor Signup and view all the answers

What governs surface water in national and international boundary waters?

Interstate and international treaties Signup and view all the answers

What can happen to groundwater rights in Texas?

They can be severed and then reserved or conveyed like mineral rights Signup and view all the answers

What is the effect of senior water rights holders on junior water rights holders?

Senior water rights holders have priority over junior water rights holders Signup and view all the answers

What is the purpose of the priority date in water rights?

To prioritize water rights holders in times of scarcity Signup and view all the answers

Study Notes

Water Coverage and Types

71% of Earth's surface is covered with water
97% of the water is saltwater, and 3% is freshwater
80% of the freshwater is frozen, and 20% is liquid
Examples of large water reservoirs: Toledo Bend (4.47 million acre-feet) and others (5,000 acre-feet)

Aquifers

9 major aquifers: underground layers of water-bearing permeable rock, rock fractures, or unconsolidated materials
These aquifers provide a large amount of water over a large area
22 minor aquifers: provide a minor amount of water over a large area or a large amount of water over a small area
Important source of water for rural communities
Brackish aquifers: geologic zones within major or minor aquifers with a Total Dissolved Solids of 1,000 to 10,000 parts per million

Water Use in Texas

Total water use in Texas: 14.17 acre-feet
Breakdown: 55% groundwater, 42% surface water, and 3% other sources

Texas Water Policy

Surface water is owned by the state
Prior Appropriations Doctrine and 1967 Water Rights Adjudication Act
Permit system based on 'first in time, first in right'
Administered through Texas Commission on Environmental Quality

Surface Water Rights Holders

Largest surface water rights holders:
- The Dow Chemical Company (4,209,000 acre-feet)
- Entergy Texas, Inc. (1,590,820 acre-feet)
- City of Clyde (1,534,000 acre-feet)
- others

Groundwater in Texas

Groundwater is owned by property owners
Foundational Doctrine: Rule of Capture
Considered a property right
'Law of the biggest pump'
Groundwater rights can be severed and then reserved or conveyed

Limitations to the Rule of Capture

Malicious taking of water to injure a neighbor
Willful or wanton waste of groundwater
Negligent drilling or pumping causing subsidence
Pumping from a contaminated well
Trespassing to pump groundwater

Groundwater Conservation Districts

Purpose: protect property rights, balance conservation and development of groundwater
Use the best available science in conservation and development of groundwater
Rules developed, adopted, and promulgated by a district

National and International Boundary Waters

Surface water governed by interstate and international treaties
Rio Grande Treaty of 1944

Description

Learn about the percentage of water coverage on Earth, types of water, and underground water reservoirs known as aquifers. Discover the distribution of freshwater and saltwater, and explore examples of large water reservoirs.