EXECUTIVE SUMMARY

The 2015 Annual Ocean, Harbor and Bay Water Quality Report provides an updated analysis of bacteriological water quality data for Orange County’s recreational waters and includes data on sewage spills and related ocean, harbor and bay water closures. The annual report also describes year-to-year variability and trends representing the 16-year period (2000 – 2015) that Assembly Bill 411 (AB 411) Ocean Water-Contact Sports Standards for bacteriological water quality have been in place. In addition, the annual report incorporates historical sewage spill and associated ocean, harbor and bay water closure information during the most recent 29-year period from 1987 – 2015.

Major findings of the 2015 Annual Ocean, Harbor and Bay Water Quality Report:

Sewage Spills and Ocean, Harbor and Bay Water Closures

• The total number of sewage spills reported to the Ocean Water Protection Program in 2015 was 133, continuing a steady decline and down 67.4% from the peak record of 408 spills set in 2002.

• During 2015, the total number of sewage spills resulting in beach closures (10) remained 53% below the 29-year average of 19 beach closures per year

• The total number of Beach Mile Days (BMD’s) due to sewage spill closures was 18.9 and is 33% below the 17-year average of 28.2 BMD’s from 1999 through 2015.

• Pipeline blockages continue to be responsible for the majority of sewage spills resulting in beach closures. Since 1999, blockages have resulted in 62% of all closures and over half of these blockages (56.5%) were caused by infiltration of roots or deposition of grease.

Posted Warnings Due to Bacteriological Standards Violations

• A new unified regional monitoring plan was implemented at south county beaches at the beginning of the 2015 AB 411 period (April 1 to October 31). The plan requires “point zero” monitoring at locations where urban runoff physically enters the ocean. First year monitoring results during the AB 411 period showed 20 out of the 28 point zero stations were in 100% compliance with ocean water health standards. See Appendix 6 for additional information about point zero monitoring results.

• Total Beach Mile Days posted due to bacteriological water quality standards violations during the AB 411 period (April 1 to October 31) were 36.2 which is 90.1% below the record high of 366 recorded in 2002. The continuing trend of record lows over the last 3 years is likely due to drought and less runoff impacting the beach.

• During the summer of 2015, HCA/Environmental Health partnered with Stanford University and Heal the Bay for a Predictive Modeling pilot study One of the three chosen pilot locations in Southern California was at San Juan Creek in Doheny State Beach. The pilot used a daily computer model to determine if water quality at selected beach locations would exceed state health standards and require posting. Sixty (60) samples were collected during the period to track the accuracy of the daily predictions, also known as “nowcasts,” and results showed that the model accurately predicted water quality the majority of the time. A continuation of the pilot study is planned.

• Beach Mile Days at the mouth of the San Gabriel River in Seal Beach have increased over the last 4 years exceeding the last high point recorded in 2000. The increase coincides with recent drought years and might be interrelated, however, additional study is required.