The Interagency Drinking Water System Team (IDWST) finalized the plan last week, in consultation with the Hawaii Department of Land and Natural Resources, University of Hawaii, and other community stakeholders. The IDWST includes Hawaii Department of Health (DOH), the U.S. Environmental Protection Agency, Army and Navy.

The plan includes actions to pump and filter contaminated groundwater from the Navy’s Red Hill Shaft to reduce spread of contamination and protect plants and wildlife. It will also help the IDWST better understand movement and contamination of groundwater.

Each day, the Navy is pumping up to 5 million gallons of groundwater from the Red Hill Shaft. This creates a capture zone within the aquifer to reduce the spread of groundwater contamination. To remove contaminants inside the well, the Navy will use skimming pumps and an array of booms and absorbent pads. The Navy’s goal is to contain contamination near the Red Hill Shaft and prevent further contamination of the aquifer.

After the water is pumped from the well, it passes through the GAC filtration system before being discharged into Halawa Stream. The purpose of the GAC filtration system is to filter (or clean) the discharged water so it does not pose a threat to human health or the environment. As the water passes through the GAC filtration system, it is closely monitored for contaminants in real time. The Navy will also send water samples to a certified laboratory for testing. The maximum daily amount of water to be discharged into Halawa Stream will be less than 1% of the amount of water in the stream during peak rainwater flow.

The Hawaii Department of Health (DOH) approved a National Pollutant Discharge Elimination System (NPDES) permit Jan. 27, allowing these operations to take place. The NPDES permit includes strict requirements to test the water at each step of the GAC filtration system. If contaminant levels exceed DOH’s acceptable limits, operations will be stopped. DOH staff will be on-site to monitor NPDES permit compliance.

The Red Hill Shaft Recovery and Monitoring Plan also includes Navy commitments to reuse treated water and undertake projects to improve the upper watershed and recharge the aquifer.

Click here to download a copy of the plan. Click here to download a copy of the NPDES permit.