Regulate Ocean Pollution from the Mānā Plain Drainage Ditch System

Polluted drainage ditch water is being released into the ocean along West Kaua‘i, which poses serious risks to coastal waters including public health and the reefs. For many years, the Kauaʻi Chapter has led the charge in addressing pollution sources that impact coastal waters of Kauaʻi. One area of particular concern is the Mānā Plains area on West Kauaʻi. 

For decades, the Mānā Plain Drainage Ditch System has discharged polluted waters into the ocean from seven outfalls spanning the entire West Kauaʻi shoreline (from Kīkīaola Harbor to Barking Sands). The outfalls are: Kīkīaola Harbor Drain (operated by the County) and Cox Drain, First Ditch, Second Ditch, Dry Ditch, Kawai‘ele Outfall/Kinikini Ditch, and Nohili Drain (all operated by the state Agribusiness Development Corporation (“ADC”)).

The flows from these drainage ditches pick up pollution from agricultural, livestock, and shrimp farm operations, the Waimea wastewater treatment plant, Kekaha landfill, a military base, and a gravel and asphalt plant. The outfalls are located along beaches that are popular for surfing, swimming, diving, fishing, limu gathering, and other cultural, recreational, and subsistence activities. 

Studies show these discharged waters contain pesticides, petroleum products, diesel, sediment, nutrients, and bacteria that are harmful to humans and the environment, all of which can smother and kill reefs, cause algal blooms, and contaminate the ocean waters. At the main outfall, Kinikini Ditch, which discharges 24/7, ADC’s discharge waters mix with the Shrimp Farm’s discharge waters before entering the ocean. This has led to massive fish kills along the shoreline.

The Surfrider Foundation Kaua’i Chapter along with community group Nā Kiaʻi Kai, represented by Earthjustice, sued ADC for failure to renew its National Pollution Discharge Elimination System (“NPDES”) permit. The lawsuit came about after the Kauaʻi Chapter conducted  pesticide testing , which led to another pesticide study by the Hawai‘i Department of Health (“DOH”), which both confirmed pesticide pollution in the Mānā Plain Drainage Ditch System. As a result of our lawsuit, the DOH is required to regulate the pollutant discharge through a  NPDES permit..

Unfortunately, the proposed NPDES permit, as drafted, is not strong enough to sufficiently safeguard our coastal waters. We will urge the DOH to issue a stronger permit. 

Surfrider Kauaʻi Chapter goals are for DOH to make the following revisions to the proposed NPDES permit: 

• Require testing for harmful contaminants such as pesticides, petroleum products, and vibrio bacteria that are present in the ditch waters.
• Require a limit on discharge at Kinikini Ditch to reduce the amount of pollution entering the ocean. Currently there are no limits on the amount of discharge flowing to the ocean.
• Require ADC and the County to clean up pollution in the ditches by using constructed wetlands, UV filtration, and erosion control measures.
• Require clear protocols to prevent further fish kills at Kinikini Ditch.