The Ala Wai Canal was a chocolate brown mess Tuesday complete with floating trees, natural debris and trash.

Hurricane Lane was downgraded to a tropical storm Friday, but the buildup of brown water in the canal was a reminder that it remains vulnerable to heavy rain, which has the potential to cause pollution and flooding.

Despite its off-color appearance, the canal was not listed among the 11 sites statewide that the state’s Clean Water Branch was monitoring Tuesday for active brown-water and wastewater discharge concerns.

Janice Okubo, state Department of Health spokeswoman, said that’s because the canal is permanently posted with warning signs advising the public not to enter the water due to bacteria levels.

“We do not test the Ala Wai because it is always above the EPA threshold,” Okubo said.

But the Clean Water Branch did issue a warning Tuesday that the water quality at nearby Moana Beach Park exceeded an acceptable level of enterococci. The public was warned that they could become ill if they swim at beaches where potentially harmful microorganisms such as bacteria, viruses, protozoa or parasites may be present in the water.

Gastroenteritis and ear, nose and throat infections are the most common illnesses associated with swimming in water polluted by fecal pathogens, the branch said.

Longtime Waikiki resident Stephany Sofos said current conditions at the Ala Wai Canal are unacceptable, although she acknowledged it could have been worse if a hurricane had hit Oahu on Friday as forecast.

“All of that brown water from the canal flows into the ocean. I usually swim every day, but I’m taking a break for another five to seven days after the rain stops. The kupuna warned me that it’s not safe to swim with all that garbage, which sometimes include dead animals that cause the sharks to come down and feed,” Sofos said.

Dan Dennison, a spokesman for the state Department of Land and Natural Resources, said the debris trap at the foot of the canal next to the Ala Moana bridge was cleaned Tuesday. If there is corresponding debris in the Ala Wai Small Boat Harbor, Dennison said DLNR’s Division of Boating and Ocean Recreation or one of its contractors would typically clean it up.

While cleanup after a storm is important to the health of the Ala Wai Canal, some stakeholders, such as the Waikiki Improvement Association (WIA) and the Ala Wai Watershed Collaboration, are calling for longer-term debris and flood prevention efforts.

Rick Egged, WIA president, said, “I feel like the latest hurricane warning is a real wake-up call. If we received the kind of rain that was being forecast over Oahu, we would have had a real crisis. This event should be an alarm bell that we need to move forward to clean up the Ala Wai Canal and make additional modifications to control potential flooding.”