AUSTIN (KXAN) — The uncharted depths of Lady Bird Lake are a little less mysterious now.
Since the early 2000s, scientists at UT have been testing underwater surveying instruments and sediment sampling apparatus in the lake, using SONAR equipment that studied the terrain.
“It’s very powerful at giving us an image of the topography or the shape of the bottom of the lakebed, so we can see a lot of detail just in the topography down there…it’s not flat,” said Marcy Davis, Engineering Scientist at UT’s Institute for Geophysics.
That data largely went unused until a collaboration was formed with the Austin Watershed Department just last year.
Knowing how our lakes are changing can be vital in keeping them healthy at a time when more of us are worried about toxic algae.
“Rivers are conduits for sediments historically, they bring it in and move it downriver pretty quickly. Lakes, on the other hand, tend to be repositories, places where sediments are deposited,” said Brent Bellinger, Environmental Scientist Sr. with the City of Austin Watershed Department.
Sediments are usually small deposits made up of rocks and minerals worn down by erosion and weather.
The various dams along the Colorado River prevent those sediments from reaching the ocean and that can cause problems.
“The sediments that are being moved into the reservoirs are carrying a lot of nutrients and as those nutrients accumulate and build up those become fuel for excessive algae or plant growth so there’s very likely a connection there,” said Bellinger.
To reduce the influx of sediment or nutrient runoff, the city has created buffer strips — or plant grow zones — to act as a barrier to protect the lakes.
In the meantime, these studies of the lake terrain hope to look to create a baseline for future surveys.
“Part of what this survey is about is seeing how the vegetation, extent of the vegetation grows and shrinks over the course of the year due to seasonal changes,” said Davis.
Knowing where and how quickly the sediments are depositing could eventually help to predict toxic algae blooms in the future.