Hui O Ka Wai Ola

The Hui adds to the data collected by the Department of Health and our testing keeps a close eye on changing water quality conditions that can harm local coral reefs. Our data also provides the community with information to make resource management decisions and is shedding light on the impact of the Lāhainā wildfire on nearby marine ecosystems. Every two years, the Hui distills its most recent findings and data in its water quality report that covers trends, concerns, and insights into conditions around the island. A copy of the most recent report can be found here

What We Test For

Turbidity

How it is measured: We gather samples at knee depth, then use a turbidity meter onsite to measure the amount of sediment (turbidity) in the water.

How changes are caused: Sediment carried from the land to the ocean (by streams, flooding, storm runoff) can cause ocean water to become brown or murky.

Why it is a concern: Sediment blocks sunlight from reaching reefs and can smother corals.

What we can do: When we find areas with high levels of turbidity, we can address upslope issues such as grading or clearing of land that caused sediment to flow into the ocean.

Ocean chemistry

How it is measured: We measure pH, salinity and water temperature onsite using portable, handheld equipment.

How changes are caused: Changes in ocean chemistry can be caused by climate change and other local factors. Salinity can be changed by freshwater flowing into the ocean. Water temperature can fluctuate by season and can also be caused by climate change. Ocean acidity can be increased warming ocean temperatures. Warmer water also holds less dissolved oxygen (needed for aquatic plants and animals to survive).

Why it is a concern: Corals are very sensitive to changes in ocean chemistry, including increased ocean water acidity. Corals bleach when water temperature increases; collecting water temperature can help track localized variations between sites.

What we can do: We can monitor changes in reef health against changes in ocean water quality and continue to advocate for ways to reduce greenhouse gases and reverse climate change.

Nutrients (nitrogen and phosphorous)

How they are measured: Water samples are gathered, refrigerated and shipped on ice to the SOEST Analytical Laboratory on Oahu for analysis of nitrogen and phosphorous.

How changes are caused: High levels of nitrogen and phosphorous can indicate pollution from wastewater, run-off from agriculture, landscaping and/or golf courses.

Why it is a concern: Too much nitrogen can cause an increase in invasive algae (limu), which is damaging to coral reefs.

What we can do: When we identify ocean areas with high levels of nutrients, we can pinpoint and address up-slope areas that are sources.