ROUND ROCK, Texas (KXAN) – Round Rock officials said Wednesday that crews removed dead fish at a creek in the city.

According to the city, they were notified of the dead fish in Lake Creek in the vicinity of the Round Rock West neighborhood during the week of Sept. 25.

City crews found no evidence, the city said, of wastewater spills, breaks or leaks. The city said staff removed the fish from the creek Sept. 29 to lessen any concerns about odor.

According to the city, one of its contractors is installing a new wastewater line in the area and recently had to evacuate rainwater from the trench they were digging and push the rainwater into the creek. City crews found deceased fish upstream of the construction site, and the city said that indicated the issue was not related to this activity.

The city of Round Rock took water samples and found Lake Creek’s dissolved oxygen levels were significantly low, while bacterial levels were elevated. According to the city, the preliminary assessment suggests natural causes, such as recent rainfall introducing decomposing vegetation into the previously stagnant creek.

The city told KXAN it informed the Texas Parks and Wildlife Department about the situation and also neighbors who asked the city what happened.

P&W told KXAN that recent rain washed organic matter into Lake Creek, and the bacteria breakdown of organic matter led the dissolved oxygen to crash. P&W said this has been pretty common this summer.

According to P&W, Lake Creek was broken into stagnant intermittent pools because of the lack of rain, resulting in very little flow. The department said there was a buildup of organic matter because there had not been rain in a while.