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Understanding Groundwater Supplies in Central Texas
By Forefront Editor

What is water?

It seems like a silly question, but it’s worth understanding:

  • In this article, we are referring to freshwater, whether underground or on the Earth’s surface. If it is on the surface, water is owned by the State of Texas. The Texas Commission on Environmental Quality grants water rights to people, cities and organization like LCRA so that they can use the state’s surface water. Groundwater can be pumped by whoever owns the land above it, and it can be pumped wherever it is needed subject to regulations by local districts in most areas.
  • When floodwaters are kept in a reservoir behind a dam, they become “stored water.” LCRA built the dams that form the Highland Lakes and has been given the right by the state to manage all of its stored water. Lakes Travis and Buchanan hold nearly 500 billion gallons.
  • When water flows naturally through tributaries and the Colorado River, it is called “run-of-river water.” LCRA has purchased from private companies the rights to use much of the run-of-river water in the lower Colorado River system.  Here’s a critical fact:  Run-of-river water is not guaranteed to be there when you need it.  It’s only available when there is sufficient rainfall and runoff.

Editors Note:

Everybody’s heard the clichés:

“Water is precious.”

“Is water the new oil?”

“We’ll be fighting over water in the future.”

Water is definitely of supreme importance for Central Texas.  Winter 2011 was the driest winter season in 44 years.  With El Nina, we are looking at another hot and dry summer. 

The Lower Colorado River Authority (LCRA)manages water supplies and floods in the lower Colorado River basin, develops water and wastewater utilities, in 58 Central Texas counties.  The LCRA is developing long-range plans to manage and provide water for Central Texas through the rest of the 21st century.

Below are excerpts from an LCRA publication that answers the following questions:

  • Is there enough today (the short answer is yes.
  • Will our uses of water change? (Undoubtedly)
  • Will there be enough for the future? (Yes, if we all work together.)

See the complete publication from which these excerpts were compiled.

How much water is needed for Texas and where will it come from?
The 2007 Texas State Water Plan projects that groundwater and surface water supplies can more than meet demands, at least until 2030. Surface water is projected to provide about 77 percent of supplies and groundwater about 23 percent in 2010. The principal surface water supply sources are the Colorado River and its tributaries, including the Highland Lakes system.

How much surface water is available for LCRA to supply Central Texas water needs?
LCRA has the right to use nearly 700 billion gallons of water per year, but some of it is run-of-river so it will not be available during droughts. The City of Austin owns the right to use 107.5 billion gallons of run-of-river water per year. Total surface water use in 2006 (a drought year) was about 160.5 billion gallons, far less than is available.

What could happen during a drought?
Although there is much more water available than is being used, our region still experiences problems during the inevitable droughts:

  • The more people who live in the region, the more likelihood that farmers’ water supply will be partially interrupted or reduced during severe, multiyear droughts. The first reduction, which applied to rice and row crops in Colorado, Wharton and Matagorda counties, was ordered last year, but had little impact on production.
  • In some areas, there is not enough groundwater to get through droughts and people and communities experience poor-quality groundwater and dry wells.
  • During droughts, the levels of lakes Travis and Buchanan drop such that recreation and access is more difficult. While this is not a water supply problem, it is a consequence of our climate and greater use of the Highland Lakes.

What impact does population growth have on water availability?

Along the Colorado River basin lie three of the 100 fastest-growing counties in the United States:

  • Travis County: 3.5 percent per year
  • Hays County: 6.3 percent per year
  • Parts of Williamson County: 6.4 percent per year

American population growth is about 1 percent per year, but the rate of growth in Texas is twice that.

The population in this region is expected to more than double between 2010 and 2060 to more than 2.7 million, according to state projections. Population growth means more water is needed for people and businesses.

That’s not all. We have a state-approved water plan for this region. However, we are seeing population growth in some counties that is outpacing the projections in the plan.

All told, we will need more water supplies in the next 50 to 100 years to serve growing populations. Even before a shortfall might occur, water will have to be physically moved from place to place within the basin to meet specific needs. Agriculture could be limited, especially during severe drought years. Many expect that more groundwater may be shifted from agricultural to municipal use in the future. These actions will create conflicts.

When the environment, jobs and a community’s vitality are on the line, people want to know whether there is enough water for them. They also may demand that “their” water not be used elsewhere. The problem is, surface water does not belong to specific cities or counties. Surface water belongs to all Texans and is regulated by the Texas Commission on Environmental Quality. On the other hand, groundwater belongs to whoever pumps it, sometimes with local regulation and sometimes without. The challenge is to plan for everyone, to move water where it is needed and to balance the claims of diverse users to the water they need. These are the reasons that LCRA is preparing the Water Supply Resource Plan, which was initiated in 2007 by the LCRA Board of Directors.

Is the water safe for people to use and drink, and is the river a healthy environment for fish and other wildlife?
The Colorado does well on both counts. The river, with routine water treatment, is an excellent source of drinking water. Unlike other river basins, the Colorado River basin has only one major metropolitan area and few industries that discharge treated waste into the river. Those are well-managed and comply with specific discharge standards. Except after major floods, the water quality upstream of Austin is excellent and the water quality downstream, which carries nutrients from cities’ wastewater treatment plants, is considered good. Usually, bacteria levels in the river are low enough to be appropriate for swimming and other water-related activities. The water downstream used for irrigation is certified as "organic" for purposes of raising organic crops.

From the standpoint of sustainable habitat, the river itself is home to rare and threatened species such as the American bald eagle and the blue sucker fish. Dissolved oxygen is generally high enough for healthy fish and diverse aquatic life. The river is an important source of freshwater for Matagorda Bay, which is a vital nursery for finfish and shellfish along the Gulf Coast. LCRA manages water from the river to help meet specific environmental needs of the bay throughout the year.

What types of water supplies are available to meet Central Texas needs?
LCRA manages water supplies as a comprehensive system. In identifying supplies for this system, we consider the potential consequences of the use of any source, including cost, water rates, social and environmental impact and effect on other existing water users.

LCRA Water Supplies
Lakes Buchanan and Travis are our water supply reservoirs. Their total volume is more than 651 billion gallons. Based on the drought of record (the worst drought on record) LCRA can provide 145 billion gallons of firm water per year from the lakes.

An important part of the system includes significant run-of-river water rights located downstream. These rights allow LCRA to take water from the river downstream and can provide between 65 billion and 163 billion gallons of water each year for firm water users. The Highland Lakes combined with the run-of-river water rights can provide a firm yield between 210 billion and 308 billion gallons per year.

LCRA’s commitments for water total about 149 billion gallons per year. The LCRA Board also has reserved more than 16.2 billion gallons of water per year for future uses.

What types of water supplies should be considered to meet our future needs?
Other communities in Texas and throughout the southwestern United States rely on multiple sources of supply to meet their needs, including:

  • Desalination—removing salt from groundwater or ocean water
  • Reservoirs—dams and infrastructure can be built to store water so it is available for use during droughts
  • Rivers and streams—also known as surface water, are the primary source of water supply in our region
  • Conservation—using water wisely and reducing waste can be the least expensive way to extend existing water supplies
  • Groundwater—pumping water from underground is used in many communities for cities, industry and agriculture

About the Lower Colorado River Authority
The Lower Colorado River Authority was created in 1934 by the Texas Legislature to “control, store, and preserve, within the boundaries of the authority, the waters of the Colorado River and its tributaries…and may use, distribute, and sell those waters.” It receives no appropriation from the state; it sells electricity and water and makes no profit. LCRA has worked with members of the state water planning group to develop a plan that takes us, with some changes, to the year 2060. However, because the Colorado River basin includes several of the fastest-growing counties in the state, LCRA foresees a time when its current supplies are exhausted, if not in our lifetime then within 100 years. LCRA is not required to plan for 100 years, but the Board of Directors of LCRA thinks it is prudent to do so. It is not the responsibility of LCRA to provide for all of the water needs of the region, but it is LCRA’s responsibility to make available to the public the water that it manages.