Against a bleak backdrop of surging COVID-19 and the resulting shutdowns of public sports and exercise venues on Oahu, there remain a couple of bright spots for ocean exercisers.

Swimmers, paddlers and surfers are allowed to cross the city’s and state’s closed beach parks and beaches to get in the ocean for active exercise, fishing or traditional gathering activities.

And lately, the water quality at several popular Oahu beaches has been good, from a public health perspective — at least as of August 9, when volunteers from Surfrider Foundation’s Oahu Chapter tested beachwaters at 13 sites around the island, and found that levels of bacterial contamination in waters from all but two sites were below the threshold for higher risk of waterborne illness, as reported on the chapter’s Facebook page.

Enterococcus is a fecal indicator bacterium commonly found in the presence of pathogens that can cause illnesses such as gastroenteritis, according to the website of the Hawaii state Department of Health Clean Water Branch, which conducts routine monitoring of water quality at beaches statewide.

Like the Clean Water Branch, Surfrider uses an EPA-recommended threshold value, called the Beach Action Value or BAV, of 130 enterococci per 100 mL of water sampled. The illness rate associated with the BAV has been determined to be 36 illnesses per 1,000 swimmers or waders, and enterococci levels higher than the BAV mean that there is an increased probability of risk of illness, particularly for infants, the elderly and people with compromised immune systems.

Surfrider’s Oahu Chapter volunteers collect water samples and take them to University of Hawai‘i at Manoa’s Kewalo Marine Laboratory to be processed, according to the Surfrider’s Blue Water Task Force website, which states that the task force’s tests are meant to supplement and complement routine beachwater monitoring conducted by state health departments nationwide.

The two Oahu beaches from which Surfrider’s samples showed high levels of enterococci were Kahaluu, with 301 enterococci per 100 mL, and Kuliouou Stream, with 644 per 100 mL.

Fewer than 10 enterococci per 100 mL were detected in samples from Black Point – Kaikoo, Black Point – Cromwells, Kalama Beach Park, Magic Island Bowls, Magic Island Canoe Launch, Point Panic – Stairs, Pua’ena Point, Pupukea Tidepools, Waialae Beach Park and Waimanalo Bay Beach Park; South Kaneohe Bay, with 31 per 100 mL, was also low.

However, this can change quickly, both Surfrider’s and the Clean Water Branch’s website warned: enterococcus levels can rapidly spike during or after heavy rains, which can wash pollution from flooding streams and overflowing cesspools and storm drains into the sea.

Surfrider’s website advises keeping out of the ocean for up to 72 hours after a heavy rainfall.

A summary of Surfrider’s local beachwater test results going back several years (with a hiatus during the March – June COVID shutdown) can be viewed at bwtf.surfrider.org/report/.

The Clean Water Branch publishes advisories of beach bacterial exceedances at eha-cloud.doh.hawaii.gov/cwb, where you can also sign up to receive beachwater bacteria, brown water and sewage spill advisories via email.