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TEXAS' MAJOR AND MINOR ESTUARIES
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Source: Texas Water Development Board, "Water for Texas 1990" (1990), 1-11
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Perhaps the single biggest policy issue related to the use of water is the question of the appropriate amount
of fresh water needed to maintain the state's bays and estuaries located along 367 linear miles of gulf coastline. An estuary occurs where a river meets the
sea and fresh and saltwater mix. The estuary and its adjacent wetlands-coastal vegetative areas with inundated or saturated soils-serve as important
spawning grounds for many species of marine life. The state's 2.6 million acres of coastal habitat, which include 1.5 million acres of open bays, 1.1 million acres of
wetlands, and about 250,000 acres of submerged aquatic vegetation, are also home to 400 species of native and migratory birds. These estuaries and their
adjacent wetlands depend greatly upon the inflow of fresh water from rivers and streams, including associated sediments and nutrients. As river water
winds its way down to the gulf and is used and reused for industry, irrigation, and municipalities, both its quality and quantity are altered, affecting bays and estuaries.
Estuaries, bays, and related aquatic habitats contribute
significantly to the state's economy. They are used for navigation and provide a base for recreational and commercial fishing and boating, contributing around
$2.9 billion annually to the state economy.* In addition, preserving these wetlands and estuarine systems helps
ensure water quality, since they act as a natural filtering system for many pollutants.
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FYI
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The longest river in Texas?
The Rio Grande, which begins in Colorado and covers 1,896 miles, second only to the Missouri-Mississippi.
The second longest?
The Red River, which forms the border between Texas and Oklahoma and Texas and Arkansas.
The shortest river?
The Comal, which is only two and a half miles long.
What's the biggest aquifer?
The Ogallala, which covers four states and in 1974 had more than 281.7 million acre-feet of recoverable groundwater. By 2031, this total will have been reduced to 76.1 million acre-feet in Texas.
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In 1985, the Texas Legislature directed the Texas Water Development
Board and Texas Parks and Wildlife Department to develop freshwater inflow studies for all major Texas estuaries and determine how much
water, sediment and nutrients were needed to maintain healthy ecosystems. Over 15 years, The TPWD, in conjunction with the TWDB
and later the TNRCC (now the TCEQ), has developed estimates of the quantities of fresh water needed to maintain flows to meet different
defined paramaters for seven major estuaries: San Antonio Bay, Aransas Bay, Sabine Lake, Galveston Bay, Matagorda Bay, Nueces Bay and the Laguna Madre.* In addition, the Lower Colorado River Authority, with oversight by the state agencies, has developed a working model of inflow
needs for Lavaca-Colorado Estuary.* The detailed study results do not provide a single number, but instead give inflow recommendations on a
monthly basis and also account for low and high inflow years based upon precipitation.
In theory, the agencies will use these "beneficial inflows" to determine
how much flow must be allowed to pass through any new reservoirs or direct diversion located within 200 miles of the bay or estuary, as well as
how much flow is required to be set aside in new and amended water rights permits.* Since 1985, all new surface water use permits and all
amendments to existing use permits may contain provisions to reserve water for public purposes. The TCEQ can set
conditions in the permit so that water rights holders are required to limit their diversion of water from rivers and streams when streamflows are below a certain level.
It is important to note, however, that most water rights -- some 92 percent-- were issued before 1985. Thus, water
rights for rivers like the Rio Grande have been fully appropriated without any water having been reserved for environmental and public purposes.* Most water rights in Texas have no environmental flow conditions established in
the permit, and thus conditions placed in new permits do nothing to correct problems caused by existing permits.*
Since 1985, the state has also required new reservoirs that are within 200 miles of the coast to dedicate at least 5
percent of their firm yield for in-stream needs of aquatic habitat and the inflow needs of the bays and estuaries.
Proposals to construct reservoirs or dam rivers require both a state and a federal permit. The federal permit process
also requires applicants to consider effects upon streamflow and habitat. However, it is still unclear how exactly the
inflow studies will be used in the TCEQ permitting process for water rights or during possible reservoir construction.
The studies establish different levels of monthly water and sediment flows, but do not define whether these flows must
be maintained every year, or what happens if they are not. Still, the development of inflow studies provides a scientific basis for protecting the natural resources of the state.
INSTREAM FLOWS
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FYI
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Only Missouri, Alabama, Georgia, Tennessee, Kentucky, and Arkansas - all connected
to the immense drainage basin of the Mississippi River - have more native freshwater fishes than Texas
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Source: Texas Water Development Board, "Water for Texas 1997"
(1997), 3-17
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In addition to the bays and estuaries, Texas's 191,000 miles of rivers and streams
provide habitat for 150 native and 247 total species of fishes, as well as a variety of aquatic flora and fauna. In addition, riparian areas, playa lakes, and
hardwood-bottomlands wetland ecosystems also depend upon natural flow conditions of rivers and streams. Diminished flows cause losses in habitat diversity,
reduce stream productivity, and degrade water quality. Estimating the amount of fresh water needed for in-stream habitat viability is also problematic. There is
considerable controversy, for example, about whether the federal government's in-stream flow methodology, which was developed using cold, mountainous Western
rivers as models, can be applied to Texas's slow, meandering, warm water streams.* Only Missouri, Alabama, Georgia, Tennessee, Kentucky, and Arkansas-all
connected to the immense drainage basin of the Mississippi River-have more native freshwater fishes than Texas.*
A few intensive studies to determine instream water flows have been conducted, including a study of springflow
requirements in the San Marcos River. In 2001, the Texas Legislature enacted Senate Bill 2, and established an
instream flow program jointly adminstered by the TWDB, TCEQ and TPWD. The purpose of the program is to perform
studies to determine flow conditions needed to support a sound ecology in the river basins of Texas. As a first step, the
three agencies have signed a memorandum of understanding and published a preliminary technical guide, as well as
prioritized rivers for study. Under the program, these priority studies are to be completed by the end of 2010.
(Footnote.....)> Because these larger, intensive studies will take many years, a number of "desktop" methods have
been developed to estimate instream flow needs as a way of including special conditions in water rights permits.
Mainly, these efforts are focussed on minimizing the extent to which streams flow below historical levels. Still, the more
intensive studies will be needed to determine in-stream flows when major diversions or reservoirs are considered.
One way to protect instream and inflow needs of rivers and bays would be to obtain a water rights permit that is
designed to keep water in, rather than divert water out of, a river or stream. Recently, the San Marcos River
Foundation attempted to do just that, applying for a water right from the TCEQ to guarantee that water would be
maintained -- and flowing -- in the San Marcos and Guadalupe Rivers and into the San Antonio Bay. Nevertheless, the
TCEQ and a court rejected the permit application, arguing that they did not have the authority to keep water in rivers through a permit process.
ENVIRONMENTAL FLOWS AND WATER PLANNING
Under Senate Bill 1, language was added to the Texas Water Code which called upon the state water plan to not only
protect the economy of the state but also to "protect .. the natural resources of the entire state." Senate Bill 1 also
provides a directive that regional water plans consider the environmental water needs and the impact of the
development upstream on bays, estuaries and the Gulf of Mexico. Thus, in theory, the new regional water plans and
overall state water plan should address both environmental water needs and assess the environmental impact of
proposed water development recommendations. SB 1 also allowed regional planning groups to designate ecologically unique river or stream segments where most development would be prevented.
In the initial water plans, however, these three issues -- environmental flows, the impacts of proposed
recommendations and unique rivers and streams-- were for the most part not addressed. For example, only Regions H
and K listed environmental flow needs as an important water user in their regions -- although they didn't recommedn
how such needed flows could be maintained -- and only Region H actually took the step to designate so-called
"ecologically unique river and stream segments," identifying six such segments. Region L -- the South Central Texas
Region -- did take a detailed look at how their proposed recommendations -- including off-channel dams -- would
impact environmental flow and other environmental needs, assessing and comparing the potential effects of 77 water supply options*. Still, even these regions fell far short in making environmental water use an equal partner with
irrigation, municipal and other water demands.
In 2001, the Legislature in passing SB 2 required the TWDB to only approve plans for the next round of planning that
protected the state's natural resources. Unfortunately, the TWDB has not yet adopted rules or guidelines to clarify to
what extent environmental flows needed to protect natural resources must be considered.* The legislation also clarifies
the designation of ecologically unique stream segments, which should help regions have more guidance about that process.
SB 1 also required TCEQ to produce water availability models for all major river basins by 2001. The TCEQ must use
these models to estimate water availability during a drought, the amount of effluent available for reuse, and the
amount of water available if unused water rights cancellation procedures were instituted. Finally, SB 1 establishes a
Texas Water Trust, where unused water rights can be deposited by interested individuals for the purpose of
maintaining environmental flow in rivers and into the bays. Thus far, however, the Texas Water Trust has not been
used for this purpose, and an attempt by the San Marcos Foundation to reserve flows in the San Marcos and Guadalupe Rivers through a water rights permit failed.
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