John Anderson also began testing for E.coli bacteria in Lake Travis in late August. Elevated levels of bacteria are usually found after heavy rain so it was reassuring that none were detected in his initial samples. E.coli analysis takes much longer than the other water quality measurements because the bacteria have to be cultured in a Petrie dish inside an incubator held at a constant 35 Celsius. After 24 hours of feeding on a sugar-based solution called Coliscan Easygel, the bacteria form colonies or clusters easy to see with the naked eye. E.coli colonies show up as a deep purple color which is absent from the Travis Landing results, although other coliform bacteria are clearly present.

 

Water contaminated by E coli bacteria can cause gastrointestinal illness, skin, ear, respiratory, eye, neurologic and wound infections. Outbreaks of E coli may be the result of untreated human sewage, failing septic tanks, livestock agriculture, pets, wildlife and illegal connections from home sewer systems. One of the reasons why the River Watch program was set up about 30 years ago was Austin’s rapid growth. Pressure from the increased population coupled with inadequate effluent treatment resulted in high levels of bacteria being released into the Colorado River during the 1980s. Levels were reduced over time once monitoring commenced through improved wastewater treatment.