UH researchers create model to track Oahu water quality

HONOLULU (HawaiiNewsNow) - University of Hawaii researchers have created a model that tracks water quality on Oahu's south shore, by predicting the flow of brown water from the Ala Wai Canal.

Five sensors have been in place since 2007 from Ala Moana to Hawaii Kai to create the online models.

The data confirms on most days, Hawaii's water is a clear deep blue.

But, when it rains, the ocean can turn murky.

How many times have you seen debris clogging the Ala Wai Canal and harbor after a storm?

Oceanography Professor Margaret McManus says, "It's when you have 2-3 days of rain that produces a plume. Those are the ones we track."

The Pacific Islands Ocean Observing System or PacIOOS at the UH Manoa School of Ocean and Earth Sciences and Technology tracks turbidity. That's a measure of water clarity.

The sensors provide real time data about brown water or storm runoff. They follow the plume carried into the Ala Wai Canal from Manoa and Palolo streams.

Oceanography Associate Professor Brian Powell explained, "What we're measuring is the amount of sediments collected in those streams that are discharged now into the Ala Wai."

McManus added, "We take that information and put it into a model and predict where that sediment is going to go."

Light blue on the model signifies clear water. After a rain event in December, the model demonstrates the flow with a growing brown blob.

The website also charts surf conditions, wave predictions and tiger shark sightings.

Powell says, "We're the only ocean state so knowing what's happening on our coasts is very important for us."

McManus checks the site daily, saying "If I want to take my kids to the beach, I look at which way the plume is going and make my decisions based on that."

In the past five years, researchers have counted 4 days total when plumes are present.

The trend is for the brown water to migrate west, away from Waikiki.

To check out the website, visit pacioos.org.

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