Hawaii 2012 Beachwater Quality Summary
Reported Sources of Beachwater Contamination
(number of closing/advisory days)
- 720 (98%) stormwater runoff
- 16 (2%) sewage spills/leaks
Hawaii has almost 400 public beaches stretching along nearly 300 miles of Pacific Ocean coastline. The beachwater monitoring program is administered by the Clean Water Branch of the Hawaii Department of Health (DOH).
What Are the Water Quality Challenges and Improvements in Hawaii?
Extremely Dry Weather
2012 was a very dry year for Hawaii. As the state continued to suffer a multiyear drought, the U.S. Department of Agriculture declared the entire state a federal drought disaster area. Part of the reason for the drought is the continuing of El Niño conditions, a warming of the waters in the equatorial Pacific, which usually results in less rainfall in Hawaii. While agriculture and drinking water supplies suffer during droughts, beachwater quality tends to improve because less rain results in less pollution reaching the ocean in stormwater runoff.
Identifying Sources of Contamination in Nawiliwili Bay and Hanalei Bay
In 2012, the DOH worked with Stanford University and the U.S. Geological Survey to identify the sources of fecal indicator bacteria in the waters of Nawiliwili and Hanalei Bay on the island of Kauai. In addition to using a genetic technique called quantitative polymerase chain reaction (qPCR) to identify the species responsible for the bacteria found in bay waters, water samples will be analyzed for pharmaceutical and waste indicator compounds using USGS Schedule 2080 and 4433 respectively. With emphasis on two human pharmaceuticals, carbamazepine (an anticonvulsant) and sulfamethoxazole (an antibiotic)that has shown up at other beaches in Hawaii. 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 has assisted with biweekly water sampling for nutrients and weekly sampling for fecal indicator bacteria in the Hanalei Bay watershed. Surfrider 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 fecal indicator bacteria in Nawiliwili Bay. Pharmaceutical sampling has been completed and data received from USGS. Genetic sampling has been completed and should be receiving final sampling genetic data soon. A report will be completed in February 2014.
Investigating Wastewater Disposal in Injection Wells as a Source of Contamination in Maui Waters
The Lahaina Wastewater Reclamation Facility, operated by Maui County, uses injection wells to dispose of sewage that has undergone secondary treatment. Solids, organic matter, and residual suspended matter are removed from this treated wastewater, but the water was not disinfected. It was suspected that the wastewater injected into these wells was making its way to the ocean through underwater seeps. In 2011, the EPA required Maui County to increase wastewater disinfection prior to injection. Maui is on schedule to achieve full ultraviolet disinfection of all wastewater at the Lahaina facility by December 2013.
The U.S. Army Corps of Engineers, University of Hawaii, and DOH have studied the effluent flow from Lahaina's injection wells to nearshore ocean waters since July 2011. 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. However, the DOH has detected bacterial indicators at very low levels (detectability levels). The University of Hawaii final draft tracer study report has been completed in June 2013 and a final is due shortly. DOH seep sampling will continue through December 2013 and a report will be completed in February 2014.
What Does Beachwater Monitoring Show?
In 2012, Hawaii reported 470 coastal beaches and beach segments, of which 39 (8%) were assigned a monitoring frequency of more than once a week, 108 (23%) once a month, and 2 (<1%) less than once a month; 321 (68%) were not assigned a monitoring frequency. In 2012, 3% 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 daily maximum standard in 2012 were Hanamaulu Beach Park in Kauai County (75%); Waiulaula in Hawaii County (42%); and Kalihiwai Bay (21%), Anini Beach (17%), and Wailua Beach (13%) in Kauai County. Kauai County had the highest exceedance rate of the daily maximum standard in 2012 (7%), followed by Honolulu (3%), Hawaii (2%), and Maui (2%). 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.
Hawaii Percent of Samples Exceeding the State's Daily Maximum Bacterial Standard for 104 Beaches Reported 2008-2012*
* Please note that only samples from a common set of beaches monitored each year from 2008-2012 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 on the basis of risk of illness to swimmers and frequency of use. Tier 1 beaches are Hawaii's important and threatened beaches; all (except those on Oahu) are monitored twice a week. Tier 2 beaches are moderate-use beaches and are sampled once or twice a week for 6 month rotation. If a Tier 2 beach shows periodic elevated counts for no obvious reason, the Kualoa Protocol (multitracer waste water and nutrient source tracking methodology) is initiated to determine the source of the bacteria levels. 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.
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 Closings and Advisories Were Issued in 2012?
Total closing/advisory days for 74 events lasting six consecutive weeks or less decreased 84% to 736 days in 2012 from 4,696 days in 2011. For prior years, there were 4,215 days in 2010, 2,352 days in 2009, 2,766 days in 2008. In addition, there were no permanent or extended events in 2012. 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 74 events lasting six consecutive weeks or less, 98% (720) of closing/advisory days were preemptive due to heavy rainfall, and 2% (16) 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. Warnings and advisories are posted online on the DOH website.
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). Hawaii also uses quantitative information about the presence of Clostridium perfringens (a tracer for human sewage) when making beach warning decisions.
At beaches that are monitored at least five times a month, a warning is posted online when enterococcus exceeds the geometric mean standard and the Clostridium perfringens count surpasses its level of action. When these two things occur, no overriding factors can be taken into account before a warning is issued. At beaches that are monitored less 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. By themselves, exceedances of the single-sample standard (including repeat exceedances of the 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. When there is a storm event that does not generate a flood warning but creates turbid waters with debris and possibly dead animals in nearshore waters, a preemptive rainfall advisory may be issued. 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.
Hawaii 2012 Monitoring Results and Closing/Advisory Days