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Water for ALL Texans: Enough for Both Humans and Wildlife?
Contributed by Tom
New Laws Debated
rise in years when salinity in their feeding areas is low because the
blue crabs they eat need low salinity. Good freshwater inflow keeps salinity
at healthy levels.
have known for a long time that the fresh water flowing into Aransas National
Wildlife Refuge is critical for Whooping Cranes and other species that
live in the estuary. Ten years ago (before some Journey North participants
were born!) there was a report in the San Antonio Light newspaper (Nov
16, 1992) about the water needs of Whooping Cranes and how their needs
sometimes conflict with human uses of water. The article stated that whoopers,
just like San Antonians, depend on water from the Edwards Aquifer.
This aquifer is a source of spring water that feeds the Guadalupe
and San Antonio Rivers. Of course, rainwater and runoff also provide fresh
water for the rivers; but during dry spells, aquifer springs may contribute
than 80 percent of the fresh water entering the bay. When people remove
this aquifer water for individuals, farmers, ranchers, and manufacturers,
the estuary ecosystem can be damaged.
Powell, director of the bays and estuaries program for the Texas Water
Development Board, said "The bay needs between 1 and 2 million acre-feet
of water per year to maintain a productive life." (An acre-foot is
the amount of water needed to cover an acre of land 1 foot deep, or 325,851
gallons.) "If it drops below1 million acre-feet, the quality of bay
water would drop, which could hurt marine life along the coast. San Antonio
Bay receives an average of about 2.3 million acre-feet of water each year."
During some droughts, the annual freshwater in-flow into the bay may be
only 275,000 acre-feet. Comal Springs in New Braunfels, which normally
spews 206,928 acre-feet of water a year, went dry in 1956, during a severe
Shortages Threaten Cranes
years when not enough fresh water flows from the rivers into the estuary,
Whooping Crane winter deaths increase. "We found when salinity in
the marshes reach 23 parts per 1,000 (and sea water is 35 parts per 1,000),
the whooping cranes have to fly to fresh water to drink at least twice
a day. And we find there's more crane mortality when the salinity is at
23 parts or higher," said Tom Stehn, Whooping Crane coordinator at
the Aransas National Wildlife Refuge. Also, cranes reproduce more poorly
once they reach their breeding grounds in years when salinity is high,
because they are lacking the basic nourishment their bodies normally get
from blue crabs.
Needs Fresh Water
not only Whooping Cranes that depend on the fresh water inflows to the
estuary. Other endangered or threatened species that live in the bay include
Ridley sea turtle, the most endangered of all the sea turtles.
scientists determine exactly how much fresh water is needed to maintain
the ecosystem and the species that live in San Antonio Bay and Guadalupe
River estuary, regulations could affect how much water people are allowed
to pump. The human population of Texas is expected to double
in the next 50 years (2002 projection). Do you think it's possible
for humans to meet our own needs AND those of Whooping Cranes?
This! Activity and Journaling Question
editorials and articles to work out your position about water rights.
One valuable resource is Tom Stehn's Document
about Freshwater Inflows.
how you feel about water rights and Whooping Cranes. Try our activity,
Exposing All Sides, to
make sure you've thought it all the way through.
Do you feel that the freshwater needs of wildlife should be protected
by law in places where water shortage is a problem?
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