Hydrilla lookalike takes over lake

AUSTIN (KXAN) - If you've seen Lady Bird Lake lately, you might be wondering what plant is taking over the waters.

A lot of people think it's hydrilla, but it's not. And in fact, the city doesn't plan to do anything about it.

The plant is called cobamba, and environmental scientists with the city said it is actually a really good thing for the lake and creatures that live in it.

And if you've been thinking to yourself, "I've never seen it this bad," you're right.

When you look down on the lake between Lamar Boulevard and Barton Creek, some areas are so thick with weeds that t looks like you could walk on it.

"This is an unusual year," said Mary Gilroy, environmental scientist with the city of Austin.

You can blame the drought, and the weed actually comes from Barton Springs Pool -- where it grows naturally.

When crews clean up the pool, they put the cobamba in Barton Creek to naturally dispose of it.

But with less water flow from Lake Travis coming into Lady Bird Lake -- and practically nothing falling from the sky -- the conditions have been ripe for the weed to grow.

"When you have water that is stiller, it will be easier for plants to get attached on the bottom and grow. There won't be a flow that will move the plants downstream," said Gilroy.

Yet, unlike hydrilla this weed is good. It's good for fish and turtles to hide and breed and also good for the water quality.

That means the city isn't planning to do anything about it and instead let Mother Nature take her course.

"Come fall as the days get shorter, that thick, dense canopy will break down and fall apart," said Gilroy.

So the thought is, it will go away in a few months. There is a second weed in there called milfoil. That's mainly what you find in Barton Creek because it lives on cold water.

But if you ever go down to the section where the lake meets Barton Creek, you will see how overgrown it has become because the two weeds have combined forces.