Testing the Waters: Hawaii

Hawaii has almost 400 public beaches stretching along nearly 300 miles of Pacific Ocean coastline. Its beachwater monitoring program is administered by the Clean Water Branch of the Hawaii Department of Health (DOH).

Identifying Sources of Contamination in Nawiliwili Bay and Hanalei Bay

In 2012, DOH will work with Stanford University and the U.S. Geological Survey to identify the sources of fecal indicator bacteria in the waters of Nawiliwili Bay. In addition to using a genetic technique called quantitative polymerase chain reaction (qPCR) to identify the species responsible for bacteria found in bay waters, water samples will be analyzed for two human pharmaceuticals, carbamazepine (an anticonvulsant) and sulfamethoxazole (an antibiotic). These pharmaceuticals are present in wastewater but are not destroyed during wastewater treatment, so detecting them indicates the presence of wastewater effluent. As part of this project, the Kauai chapter of the Surfrider Foundation will assist with bimonthly water sampling for nutrients and weekly sampling for fecal indicator bacteria in the Hanalei Bay watershed. This organization has been collecting samples from nine sites in the watershed, and its data will be used to complement the pharmaceutical data and the information gathered about the species responsible for fecal indicator bacteria in the bay.1

Correcting Water Quality Problems Around Mokauea Island

Several homes on Mokauea Island, located in Ke'ehi Lagoon, were directly discharging sewage into the ocean. All of the homes that are currently occupied now have a dry compost system, and beachwater sampling around the island has verified that these systems are working properly. Hawaii does not list the beach on this island as a BEACH Act beach because of accessibility constraints.1

Investigating Wastewater Disposal in Injection Wells as a Suspected Source of Contamination in Mauai Waters

The Lahaina Wastewater Reclamation Facility, operated by Maui County, uses injection wells to dispose of sewage that has been through secondary treatment. Solids, dissolved organic matter, and residual suspended matter are removed from this treated wastewater, but the water is not disinfected. It is suspected that the wastewater injected into these wells is making its way to the ocean through underwater seeps. In January 2012, the Clean Water Branch and the University of Hawaii began gathering monthly water samples at these underwater seeps. Samples are analyzed for nutrients, metals, volatile organic compounds, bacteria, chlorine residuals, and turbidity. Samples have also been collected for qPCR analysis in order to detect the species responsible for fecal indicator bacteria in the water and to detect pharmaceuticals that signal the presence of human waste. In addition to samples collected at the underwater seeps, samples are collected at ocean sites near the seeps for comparison with the water from the seeps. The results of this project so far indicate that there is a hydrologic connection between the Lahaina Wastewater Reclamation Facility injection wells and the ocean seeps, and that wastewater being injected into the wells is finding its way to the ocean.1

What Does Beachwater Monitoring Show?

In 2011, Hawaii reported 467 coastal beaches and beach segments. Of these, 51 (11%) were assigned a monitoring frequency of more than once a week, 16 (3%) a frequency of once a week, 82 (18%) every other week, 8 (2%) once a month, and 4 (1%) less than once a month; 296 (63%) were not assigned a monitoring frequency, and there was no monitoring assignment information for 10 (2%) beaches. In 2011, 4% of all reported beach monitoring samples exceeded the state's daily maximum bacterial standard of 104 colonies/100 ml. The beaches with the highest percent exceedance rates of the state standard in 2011 were Hanalei Beach Park (22%), Kalihiwai Bay (20%), and Ke'e Beach (18%) in Kauai County; Honoli'i Beach Park (16%) and Pelekane Bay (13%) in Hawaii County; and Nawiliwili Harbor (13%) and Lumaha'i Beach in Kauai County (13%). Beaches in Kauai County had the highest exceedance rate of the state standard in 2011 (9%), followed by Hawaii (4%), Honolulu (2%), and Maui (2%) counties. NRDC considers all reported samples individually (without averaging) when calculating the percent exceedance rates in this analysis. This includes duplicate samples and samples taken outside the official beach season, if any.

* Please note that only samples from a common set of beaches monitored each year from 2007-2011 are included in the bar chart.

What Are Hawaii's Sampling Practices?

The monitoring season in this tropical state is year-round.

Sampling practices, locations, standards, and notification protocols and practices are uniform throughout the state. Samples are taken 1 foot below the surface in water that is knee to waist deep. Hawaii's beach monitoring program prioritizes sampling efforts based on the risk of illness to swimmers and the frequency of use. Tier 1 beaches are Hawaii's important and threatened beaches; all (except those on Oahu) were monitored two times a week in 2011. Tier 2 beaches are moderate-use beaches and were sampled once or twice a week for 6 months at a time. If a Tier 2 beach shows periodic elevated counts for no obvious reason, it is sampled once or twice a week for another 6 months or is elevated to Tier 1 status. If a beach is unlikely to be contaminated and has consistently low fecal indicator counts, then it is assigned Tier 3 status and is sampled at least once every 6 months. Circumstances such as inaccessibility, sampler illness or vacation, or lab closure may prevent these frequencies from being maintained. For instance, because of reductions in budget and manpower, the beaches on Oahu were not sampled at these frequencies in 2011. Instead, Oahu's Tier 1 beaches were sampled at least once a week, and Tier 2 and 3 beaches were unmonitored.2

If a warning is issued, daily monitoring is performed until bacteria levels no longer exceed action levels, after which the beach is reopened. States that monitor more frequently after an exceedance is found will tend to have higher percent exceedance rates and lower total warning/advisory days than they would if their sampling frequency did not increase after an exceedance was found.

How Many Beach Warnings and Advisories Were Issued in 2011?

Total warning/advisory days for 741 events lasting six consecutive weeks or less increased 11% to 4,696 days in 2011 from 4,215 days in 2010. For prior years, there were 2,352 days in 2009, 2,766 days in 2008, 4,134 days in 2007, 6,507 days in 2006, and 2,228 days in 2005. There were no permanent or extended events in 2011. Extended events are those in effect more than six weeks but not more than 13 consecutive weeks; permanent events are in effect for more than 13 consecutive weeks. For the 741 events lasting six consecutive weeks or less, almost all (4,691) were preemptive due to heavy rainfall; less than 1% (5) were preemptive to due known sewage spills or leaks.

How Does Hawaii Determine When to Warn Visitors About Swimming?

Hawaii's Department of Health does not have the authority to close beaches. Instead, it issues warnings (for bacterial exceedances), sewage advisories (for known and suspected sewage spills), and stormwater advisories. In 2009, Hawaii began using a single-sample maximum standard of 104 cfu/100ml (for beaches that are not sampled at least five times a month) and a 30-day geometric mean standard of 35 cfu/100ml (for beaches that are sampled at least five times a month).1 Hawaii also uses quantitative information about the presence of Clostridium perfringens (a tracer for human sewage) when making beach warning decisions.1

At beaches that are monitored at least five times a month, a warning is posted on the Internet when enterococcus exceeds the geometric mean standard and the Clostridium perfringens count surpasses its level of action.1 When these two things occur, the rule is absolute: No overriding factors can be taken into account before a warning is issued. At beaches that are monitored less frequently than five times a month, as with all beaches, an exceedance of the single sample standard is noted on the program's website as soon as sampling results are available, whether or not a warning is issued.1 By themselves, exceedances of the single sample standard (including repeat exceedances of the single sample standard) rarely result in a warning.

Preemptive rainfall advisories (brown water advisories) are issued when the National Weather Service issues a flash flood warning and the beach monitoring program determines that stormwater will cause water quality problems.1 When there is a storm event that does not generate a flood warning but creates turbid waters with debris and possibly dead animals in near-shore waters, a preemptive rainfall advisory may be issued.1 Brown water advisories can be issued statewide, island-wide, or for specific areas of one island.

If a sewage spill is suspected or if there are indications of human fecal contamination, a sign is posted at the beach immediately and a sample is taken.1

Notes

1. Watson Okubo, Hawaii Department of Health, personal communication, May 2012.
2. Hawaii Department of Health. "Beaches Environmental Assessment and Coastal Health Act: 2011 Notification Report to EPA," not dated.