SACRAMENTO, Calif. (KTXL) — Several points in the lower section of the American have shown to be containing higher levels of E. coli , and the majority of the fecal matter comes from birds and dogs, according to the California State Water Resources Control Board.

This study focused on three miles of the lower American River between Sutter’s Landing Regional Park and the confluence of the American River with the Sacramento River.

The study took place during the summer of 2021 and through summer 2022 with 30 sampling events. This summary information was collected during 13 sample events in 2021.

The bacteria water quality objectives were used to evaluate whether E. coli levels were too high in this section of the river to be safe for human recreation.

The study found that six of the 12 monitoring stations along this 3-mile section of river exceeded the bacteria water quality objectives more than half the time.

Those stations included:

  • Tiscornia Left
  • Jibboom Bridge Left
  • Discovery Left
  • North 5th left
  • North 10 left
  • Camp Rock Right

Samples that indicated elevated E. coli levels were submitted for microbial source tracing (MST) analysis.

Fecal sources were analyzed and results showed that birds were the most consistent source of contamination.

Around 55 percent of bird fecal samples had a detected quantity of E. coli, the fecal matter from dogs had less than 20 percent and the fecal matter from humans had less than five percent.

The study found that humans did not even produce a significant or consistent source of contamination.

Phase one of this study also found that birds were the largest source of contamination, however the area of tested between the upstream end of Paradise Beach, near Sacramento State, and Sutter’s Landing Regional Park did not indicate any E. coli levels that exceed the bacteria water quality objectives.