12-08-2005, 09:19 PM
AUSTIN — For the first winter in six years LCRA will not need to lower Lake Austin to help control hydrilla and other nuisance aquatic plants in the lake.
This is because the hydrilla appears to be well under control in the lake for the first time since the fast-growing water weed was initially spotted in 1999.
As a result, the City of Austin will not be requesting a winter lake drawdown, said Mary Gilroy, environmental scientist with the City of Austin’s Watershed Protection and Development Review Department.
In recent surveys of Lake Austin, Texas Parks and Wildlife Department scientists found only about nine acres of hydrilla in September and 13 acres in November. This compares to nearly 250 acres in September 2004. At the highest point in 2002, hydrilla covered more than 300 acres of Lake Austin, which is one of six reservoirs in the Highland Lakes chain and a popular recreational waterway.
“The winter drawdowns have been one of the tools used to help control the hydrilla, along with the introduction of sterile grass carp and limited mechanical harvesting,” Gilroy said. “We believe the grass carp will be able to control the limited amount of hydrilla that is remaining.”
LCRA has lowered the lake by 12 feet annually in the winter since 2001 to help control hydrilla growth. In the past, LCRA had lowered the lake, usually every other year, since the 1950s at the City of Austin’s request to help curb the growth of duckweed (milfoil) and to allow lakeside residents to perform construction and maintenance. That schedule would continue in the future if the City of Austin requests it.
Hydrilla – which is not native to Texas waters – can quickly overtake a lake or river channel, crowding out other aquatic life and affecting water quality and recreation. Lowering Lake Austin has been one component of a comprehensive plan carried out by the City of Austin, LCRA, Texas Parks and Wildlife Department and lakeside residents to fight hydrilla.
The lake drawdowns were aimed at controlling hydrilla by exposing some of the plants to the air and killing off the leaves and stems by dehydration, providing temporary relief, particularly in the shallower areas where the plants are exposed.![[Image: spacer.gif]](http://www.lcra.org/images/general/spacer.gif)
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This is because the hydrilla appears to be well under control in the lake for the first time since the fast-growing water weed was initially spotted in 1999.
As a result, the City of Austin will not be requesting a winter lake drawdown, said Mary Gilroy, environmental scientist with the City of Austin’s Watershed Protection and Development Review Department.
In recent surveys of Lake Austin, Texas Parks and Wildlife Department scientists found only about nine acres of hydrilla in September and 13 acres in November. This compares to nearly 250 acres in September 2004. At the highest point in 2002, hydrilla covered more than 300 acres of Lake Austin, which is one of six reservoirs in the Highland Lakes chain and a popular recreational waterway.
“The winter drawdowns have been one of the tools used to help control the hydrilla, along with the introduction of sterile grass carp and limited mechanical harvesting,” Gilroy said. “We believe the grass carp will be able to control the limited amount of hydrilla that is remaining.”
LCRA has lowered the lake by 12 feet annually in the winter since 2001 to help control hydrilla growth. In the past, LCRA had lowered the lake, usually every other year, since the 1950s at the City of Austin’s request to help curb the growth of duckweed (milfoil) and to allow lakeside residents to perform construction and maintenance. That schedule would continue in the future if the City of Austin requests it.
Hydrilla – which is not native to Texas waters – can quickly overtake a lake or river channel, crowding out other aquatic life and affecting water quality and recreation. Lowering Lake Austin has been one component of a comprehensive plan carried out by the City of Austin, LCRA, Texas Parks and Wildlife Department and lakeside residents to fight hydrilla.
The lake drawdowns were aimed at controlling hydrilla by exposing some of the plants to the air and killing off the leaves and stems by dehydration, providing temporary relief, particularly in the shallower areas where the plants are exposed.
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