WAIMEA, Kauai— Kauai officials have allowed treated sewage mixed with storm water to flow into Kikiaola Small Boat Harbor to prevent flooding.

The Kauai Department of Public Works said in a statement it opened the Kikiaola irrigation ditch Monday morning.

The department said warning signs were posted at the harbor to inform the public that treated wastewater is present.

Residents and tourists were advised to avoid contact with surface or storm water at the harbor and nearby coastal areas.

The department said the water could contain harmful microorganisms that can cause illness.