Thursday, March 25, 2021

Increased Risk of Harmful Algae on Lady Bird, Lake Austin


Increased Risk for Harmful Algae on Lady Bird Lake and Lake Austin

The City of Austin is changing the risk level for harmful algae on Lady Bird Lake and Lake Austin from "low risk" to "increased risk," given the recent discovery by LCRA of harmful algae in the other Highland Lakes. 

Watershed Protection Department staff has observed accumulations of algae in areas of Lady Bird Lake and is arranging to send samples to the University of Texas at Austin for testing. As a precaution, a sample was taken on Lake Austin and sent for testing last week. Results will be posted at

A harmful algae bloom occurs when Cyanobacteria, or blue-green algae, produce toxins. Warm water, low flow through the lake and high levels of nutrients make harmful algae more likely. According to Brent Bellinger, Ph.D. Environmental Scientist Senior, "Blue-green algae proliferate in warmer times of the year. However, the specific ranges in which they can produce toxins is still under investigation. With the exception of the winter storm, we had a fairly warm winter this year, which probably contributed to the toxicity concerns we have seen so far in the Highland Lakes. We will continue to track algae quantity and toxicity through the spring as we get ready for the summer bloom season." 

Dogs appear particularly vulnerable to the harmful algae blooms in Central Texas. At least five dogs died after swimming in Lady Bird Lake during the summer of 2019. The City of Austin is recommending that dog owners be cautious about allowing their dogs in Lady Bird Lake or Lake Austin. If they allow their dogs in the water, it is at their own risk. 

Dog owners should take the following precautions: 

  • Check for the latest information before taking their dogs to the lakes.
  • Do not allow dogs to touch or ingest algae in the lakes.
  • Avoid areas with floating mats of algae or stagnant areas of the lakes. Rinse dogs after contact with the lakes to help prevent them from licking algae off their fur. 

Dog owners should take their pets to a veterinarian immediately if their dogs become sick after swimming in the lakes. Please also report the illness to 3-1-1. Symptoms of exposure may include:  

  • Excessive drooling, vomiting and diarrhea 
  • Foaming at the mouth 
  • Jaundice and hepatomegaly 
  • Blood in urine or dark urine 
  • Stumbling 
  • Loss of appetite 
  • Photosensitization in recovering animals 
  • Abdominal tenderness 
  • Progression of muscle twitches 
  • Respiratory paralysis

There is educational signage at six locations around Lady Bird Lake. If toxins are detected in the algae, additional signage will be placed in the same locations. 

At this time, the risk to people appears low, and people may continue to boat and fish. Swimming has been banned in Lady Bird Lake since 1964. 

There is more information about Lady Bird Lake at and about Lake Travis and other Highland Lakes at