New research shows higher concentrations of pollution from wastewater discharge in Kihei compared to Lahaina


New research shows higher concentrations of pollution from wastewater discharge in Kihei compared to Lahaina

February 25, 2016

New research from Washington State University analyzed water quality data from the Hawai`i State Department of Health in response to the lawsuit filed against the County of Maui in 2012. Between 1997 and 2008, the County of Maui disposed of about 51 billion gallons of partially treated effluent, including 3.8 million lbs. of nitrogen (equivalent to about 1,000,000 bags of lawn fertilizer), into injection wells connected to the nearshore environment. In January, 2015, a federal judge ruled all four injection wells at the Lahaina wastewater reclamation facility were in violation of the Clean Water Act. In the Maui injection well issue, most of the focus has been on the Lahaina wastewater facility, while the Kihei and Kahului wastewater facilities have received very little attention. However, this recent research shows pollutants in the ocean near Kihei are actually much higher than near Lahaina. The study compared water quality data from 2004-2015 for beach sites near the Lahaina and Kihei wastewater reclamation facilities.

“Focus on the Lahaina facility has brought a lot of attention to the ecological and environmental issues going on in West Maui, which is positive, but after we looked at these data, we were blown away at how much higher the impairments are near Kihei. When looking at these results, it is shocking that so little attention has been paid to Kihei. Hopefully some of the focus will shift in the near future.” Mailea Miller-Pierce, PhD Biology Candidate and National Science Foundation NSPIRE Fellow, Washington State University

The central part of the Kihei effluent plume is at Kalama Beach Park and Cove Park where resurfacing groundwater can contain up to 60-80% partially treated wastewater. The water emerges right near the shoreline where people are most active. The results show Cove Park, Kalama Beach Park, and South Kihei are among the worst in water quality pollution for nitrogen, phosphorous, turbidity, and chlorophyll a (all indicators of water quality). Concentrations of these water quality measures at sites near Kahekili, which is the area of central focus in the lawsuit, were much lower than Cove Park and Kalama Beach Park. Most alarming was Cove Park, which contained over one hundred times the amount of inorganic nitrogen than the EPA standard in 2012.

While the research focused on marine ecology, it did not assess impacts to human health. The Department of Health collects data for micro-biological indicators and monitors risks to human health from such things as enteric bacteria. These same authors have an upcoming paper in preparation to investigate how human health may be influenced in these areas.

“On many days, the plume at Cove Park can be seen from shore and in aerial images. It is difficult to watch people swimming and learning to surf in the middle of the plume, with seemingly no knowledge of what’s going on.” Mailea Miller-Pierce

Water quality indicators like nitrogen and phosphorus are important to monitor because they can encourage algal blooms, kill coral, and harm other sensitive marine species. Coral reefs are declining throughout Hawai`i due to high nutrient levels, algal blooms, and coastal development.

Beaches along the west-facing coast of Maui are inside a National Marine Sanctuary, which requires the state to support conservation of coral reefs, marine life, and recreation.

“I spent summers in Kihei as I was growing up. It hurts my heart to witness the negative ecological changes that have happened on Maui, particularly the coral declines I have seen firsthand on the South Kihei beach where I grew up snorkeling. I only hope that more action is taken, and soon, so that one day my children will be able to enjoy the beauty of the Hawai`ian ocean as I have.” Mailea Miller-Pierce

Overall, the study suggests water quality impairments appear to be a more serious concern in South Maui than previously thought. In light of these results Maui County should take into consideration not only the Lahaina facility but also the Kihei and Kahului facilities when updating wastewater infrastructure and practices. The study calls for stakeholders, managers, and scientists to conduct more research on how the marine ecosystem, particularly the coral reef near Kihei, may be affected. Overall, more ecological, chemical, and human-health related research and attention needs to be paid to South Maui ecosystems, particularly near the Kihei wastewater facility.

“This paper comes at a perfect time. Over the past few years there’s been increasing awareness and concern about the declining quality of near-shore water in Maui County caused by land-based sources of pollution. A lot of people have been asking how they can help collect more data that would be useful to the understaffed Department of Health.” 

“The Mani Nui Marine Resource Council’s turbidity task force has been quite successful documenting brown water coming from construction sites, but the process for identifying other pollutants is taking time. We partnered with 5 other organizations to write a Quality Assurance Project Plan (QAPP) which will allow us to involve volunteers in the process of increasing the amount of usable water quality data available to DOH.” 

“This paper shows that the State has the information but it hasn’t been in useable form until these authors applied such an innovative approach to analyzing data that already exists and thereby pin-pointing where the problems areas are. A big “Mahalo” to the authors for making this information available to the public, County and State officials.”

Robin Newbold, Chair, Maui Nui Marine Resource Council. Robin also serves on the governor’s Natural Area Reserve System Commission and the National Marine Sanctuary Advisory Council.

The scientific paper was published in the Marine Pollution Bulletin on February 15, 2016. It is available for download online until April 10th, 2016 here:

The authors have a web site called where the paper and additional information will be available to the public.