Signs are posted around the Ala Wai Canal urging the public to stay out.
A broken pipe caused sewage to spill into the water.
The state Department of Health says about 4,400 gallons of sewage leaked into the Ala Wai Canal. The flow has since been stopped.
The public is advised to stay out of the water until warning signs have been removed.
A California company is proposing a second wind farm next to the current Kahuku wind farm.
Murder suspect Bryan Suitt made his first court appearance in California on Wednesday. He's accused of killing 34-year-old Alex Gonzales and dumping his dismembered body in a Waipio ravine in September.
The mayor says ad sales would help close a huge budget gap. But at least one group believes the ads would spoil Hawaii's beauty.