Kauai Ocean Safety Report - Polluted waters – 2015 Annual water quality review
In 2015 Kauai’s streams and canals are often polluted with fecal indicating bacteria, yet only the Hanalei River at Weke Rd. boat launching ramp is posted with warning signs. Surfrider feels that more polluted streams need to be posted with warning signs and has been supplementing the Hawaii Department of Health’s water quality monitoring data with its own.
Water quality monitoring data is collected weekly by the Hawaii Department of Health at ocean beaches around the island and monthly samples are collected by the Blue Water Task Force of the Surfrider Foundation – Kauai Chapter at surfbreaks, streams and canals around the island. The BWTF is a national program of The Surfrider Foundation and the Kauai chapter has been monitoring water quality since 2007. Most of the time the beach and ocean waters are clean. The exception is when heavy rains cause runoff from the land to turn the waters brown. The DOH then usually issues a “Brown Water Advisory” to stay out because the runoff can contain sewage and other pollutants. Most of the time the streams and canals are polluted, but there are no warning signs.
During water quality monitoring, water samples are collected and the bacteria Enterococcus, an indicator of fecal contamination, are cultured and counted in a 100 ml water sample. In a single sample the count must not exceed a Statistical Threshold Value of 130 bacteria per 100 ml. The percentage of samples that exceed the STV is listed, as it indicates the percentage of time the area is considered polluted.
The geometric mean (average) of 5 samples should not be more than 35 bacteria per 100 ml. What is reported here are geometric means for the entire year 2015, indicating chronic levels of pollution for each area.
The DOH data for 2015 was collected by DOH staff in approximately mid-calf deep water on the beaches. A total of 39 different sites were sampled over the course of 2015; only 5 sites were sampled approximately twice a week over the course of the full year, another 14 once a week for just half a year. Special sampling was done at Mahaulepu and 6 other sites. DOH data for frequently collected sites is presented in Table 1. If no bacteria were detected, the sample was given a numerical value of 2.3 in order to do geometric mean statistics. The sites are listed from cleanest down to most polluted. Most are polluted less than 6% of the time and those values are caused by sampling on rainy days. Only Waimea Bay landing had a high mean value and was polluted 39.1% of the time. Four polluted sites in the DOH 2014 study (Hanalei River, Hanalei Pier, Koloa Landing, and Hanamaulu Beach) were not sampled by DOH in 2015 and no new warning signs were put up.
The DOH has a secondary guidance, the indicator bacterium Clostridium perfringens. Concentrations greater than 50 per 100 m indicate human fecal matter may be present. DOH data for 2015 shows that C. perfringens was present above guidance levels only once, at Kalapaki Bay, but were at lower levels of concern occasionally at other beach parks. There is great concern where two indicator bacteria concentrations surpass state and EPA standards.
Note that not all of the County Parks on Kauai are tested regularly (e.g. Niumalu) and neither are popular surf sites like Pakalas. The most recent values from the DOH are posted on their website at: http://emdweb.doh.hawaii.gov/CleanWaterBranch/WaterQualityData/default.aspx
Table 2 lists the 28 offshore surfbreaks, streams and canals that the Blue Water Task Force (BWTF) volunteers of The Surfrider Foundation – Kauai Chapter sampled on a monthly basis and tested for Enterococcus bacteria; the same test used by Hawaii Department of Health. Hurricane warnings, storms, and high surf caused missed monthly samples and higher than normal counts. All sites are different from the DOH sites. The sites are listed from cleanest down to most commonly polluted.
The most important thing to note is that most surf sites had very low geometric means and never exceeded Hawaii STV of 130, i.e. they were really clean. Since they were sampled only monthly, even one rainfall event could account for a 10% exceedance.
The areas of most concern are those 10 streams and canals that were polluted more than 50% of the time and had geometric mean values 3X – 287X times Hawaii state rules. Pakalas surfbreak, off the stream area, also has a high geometric mean count. The levels of pollution in the canals are important as the Hawaiian monk seals feed and rest in them. The stream mouths are important because our children always play in them. Waiopili stream empties out at Gillin’s beach at Mahaulepu and is so polluted that it pollutes the beach water. It is perhaps the most polluted stream being monitored in the state. Both tourists and local children play in that area, but the DOH, although it has known of the high bacteria counts for 2 years, has failed to post warning signs. Surfrider is working hard to get the DOH to post warning signs at our chronically polluted places. Remember to rinse off whenever you go in dirty ocean or stream water.
The values for Surfrider Foundation – Kauai samples taken on the second Saturday of each month can be found at: http://kauai.surfrider.org/what-we-do/blue-water-task-force/
Dr. Carl J. Berg, Marine Biologist
Blue Water Task Force
The Surfrider Foundation – Kauai Chapter