Leeward Maui Coastal Water Quality Report Released

New 2016 – 2021 report released by Hui O Ka Wai Ola community-based water quality monitoring program

MĀ‘ALAEA, HI – A comprehensive report detailing findings about coastal ocean water quality at dozens of leeward Maui locations over a six-year period was released this week by Hui O Ka Wai Ola, a citizens’ ocean water quality monitoring program.

The 32-page Coastal Water Quality Report 2016-2021 focuses on data gathered by more than 60 volunteers and staff in coastal waters from Honolua Bay to Pāpalaua and from Mā’alaea to ‘Āhihi-Kīna’u Natural Area Reserve. The report reveals high levels of turbidity and nitrates in many areas along the coast and includes recommendations for reducing these pollutant levels.

Hui O Ka Wai Ola is a program conducted by scientists and highly trained community volunteers who monitor water quality every three weeks. The program is coordinated by Maui Nui Marine Resource Council (MNMRC), The Nature Conservancy (TNC), and West Maui Ridge to Reef Initiative (R2R). The group shares the data it collects with the Hawai’i Department of Health (DOH) to improve understanding of coastal waters.

“Since 2016, we have collected and analyzed over 3,200 water quality samples from 48 sites,” reports Tova Callender, R2R’s Watershed and Coastal Management Coordinator. “In a nutshell, what we’ve found is that these coastal waters are often degraded by land-based pollutants, including sediments, fertilizers, and wastewater. Sadly, these pollutants – which can cause brown water events and algae blooms – impact the quality of our lives and can smother, weaken and kill coral reefs.”

“The data in this report can help the community focus its efforts on reducing pollutant levels in areas that need it most,” says Amy Hodges, Programs and Operations Manager at MNMRC. “At Maui Nui Marine Resource Council, this data has led us to focus on efforts to reduce sediment and nitrate pollution in Māʻalaea Bay and sediment runoff along the North Kihei coast.”

“Though there are many areas of concern, there are also some bright spots,” notes Kim Falinski, TNC’s Coastal and Estuarine Scientist. “Most notably at Kapalua, nitrate levels have dropped in the last two years, and the turbidity levels have declined at Keālia Pond, likely due to the wetlands’ ability to filter and absorb pollutants before they reach the ocean.”

Hui O Ka Wai Ola testing protocols align with DOH standards so data collected can be combined with DOH data for an expanded understanding of coastal waters. The data is also available to researchers, advocacy groups, and the public at www.huiokawaiola.com (https://www.huiokawaiola.com/) , PacIOOS, and Zenodo.

To download a free copy of the Hui O Ka Wai Ola Coastal Water Quality Report 2016-2021, please visit https://www.huiokawaiola.com/findings.html

Some findings included in the Coastal Water Quality Report 2016-2021:

• The highest nitrate levels of all the monitored sites were found at Kīhei’s Cove Park, where levels are more than 2x higher than any other leeward Maui site. Studies show wastewater influence from the Kīhei Wastewater Reclamation Facility (WRF) is a likely driver of elevated nitrates near Cove Park [Dailer 2010, Hunt 2007]. Surprisingly, nitrate levels at Cove Park have been consistent from 2017 to 2021, including during the COVID-19 pandemic.

• Second to Cove Park are the nitrate levels from Mā‘alaea to North Kīhei.

• Nitrate levels at two sample sites within the ‘Āhihi-Kīna‘u Natural Area Reserve appear to be increasing, and there is evidence of pharmaceuticals at the south site, possibly from swimmers or from the large cesspool there.

• Nitrate levels far exceed DOH standards at Kapalua, Ka‘ōpala, Nāpili, Pōhaku, and Hanakaʻōʻō Canoe Beach. However, nitrate levels at Kapalua have dropped significantly in the last two years.

• Elevated nitrate levels at leeward Maui sites are associated with fertilizers and wastewater that seep into groundwater systems and emerge through springs on the ocean floor. Elevated nitrate levels can cause algae blooms and smother, weaken, and kill coral reefs.

• Turbidity and nitrate levels were consistently low in the coastal waters adjoining Keālia Pond, likely due to the wetlands’ ability to filter nitrates and sediment from freshwater flows including stormwater runoff.

• Ulua Beach in Wailea has turbidity levels that are so low that on average a snorkel partner 10 feet away will almost always be visible. Unfortunately, Ulua Beach also has elavated levels of nitrates. Contaminated groundwater is the likely source of the nitrates at Ulua Beach.

• Turbidity is a measure of water clarity. High turbidity diminishes water quality and threatens coral reefs. The report notes that high turbidity levels in leeward Maui are associated with coastal erosion, rains that carry sediments to coastal waters, and resuspension.

For additional information, download a free copy of the Hui O Ka Wai Ola Coastal Water Quality Report 2016-2021 at www.huiokawaiola.com.

Hui O Ka Wai Ola Sponsors and Funders

Hui O Ka Wai Ola (Association of Living Waters) is a Maui-based program, whose work is funded by generous individuals, businesses, and organizations.

Lab space provided by:
Lāhainaluna High School, Hawaiian Island Humpback Whale National Marine Sanctuary, Da Hawaiian Store and Pineapple Properties Maui, LLC.

Past and current sponsors and grant funders who made this report possible include:
Bayside Catering, County of Maui, Coastal Planners LLC, Duke’s Maui LLC, Flatbread Company, Hawaii Community Foundation, Hawaiian Paddle Sports, Hawaii Tourism, Host Hotels and Resorts, Jersey Mike’s Subs, Ka’anapali Ocean Resort Charitable Trust, Lilly Pulitzer, Lush Fresh Handmade Cosmetics – Charity Pot, Honua Kai – West Maui Community Fund, Inc, Marty Dread, Maui Sky Diving, Maui Brewing Company, Maui Classic Charters, Maui Ku’ia Estate Chocolate Inc., Maui Marathon & Maui Half Marathon, Maui Ocean Center, Napili Bay and Beach Foundation, National Fish and Wildlife Foundation, North Beach-West Maui Benefit Fund Inc., Pacific Whale Foundation, Plaza Home Mortgage, Pride of Maui, Robert F. Orr Foundation, The GoodCoin Foundation/Target, The Makana Aloha Foundation, The EACH Foundation, Media TheFoundation, Vitalitea Hawaii, and Westin Ka’anapali Ocean Resort Villas,

We thank the individuals and families whose contributions support our community-based ocean water quality monitoring program. Mahalo — we couldnʻt do it without you!