Many of the greatest threats to the reefs come from land-based sources of pollution, including sediment, nutrients, cesspools, sewer treatment plant overflow, and road run-off. Excess nutrients promote the growth of algae that compete for space on the benthic reef surfaces and affect the ability of coral to establish and grow. Another threat to the health of reefs is grounded vessels.
Climate change impacts on coral include effects from ocean warming, coral bleaching, and ocean acidification. Coral bleaching is becoming more frequent as the oceans warm, with predictions that by 2050 many of the reefs of the Pacific will bleach annually. Increased acidification of the ocean is caused by rising levels of carbon dioxide absorbed by sea water. With ocean acidification, less carbonate is available for coral reefs to build their calcium carbonate skeletons, causing coral loss. Coral cover throughout the Pacific is expected to decline 15% to 35% by 2035.
Benchmark - Where we are now
- The Department of Land and Natural Resources Division of Aquatic Resources (DLNR-DAR) finalized the Hawai‘i Coral Reef Strategy: 2010-2020 (2010) and has begun implementing place-based management in two selected priority sites: in South Kohala on the Island of Hawai‘i, utilizing The South Kohala Conservation Action Plan (2012) that was developed by local experts and stakeholders to address impacts to coastal resources; and on the Island of Maui, using both the West Maui Ridge to Reef Initiative to begin watershed planning in 2012 and the Kahekili Conservation Action Plan (2013).
- DLNR-DAR, with support from partners, is developing and expanding community-based stewardship and co-management efforts.
- The Department of Transportation (DOT)-Harbors Division is working with federal agencies to improve and streamline mitigation efforts for planned impacts, such as harbor improvements, necessary for the state’s economy.
Target - Where we would like to be
- As pilot projects are implemented, they are evaluated so that the most effective ones can be applied, as appropriate, in additional areas.
- Education is a key strategy to address coral threats as residents and visitors are aware of the significance of the coral reefs and how easily they can be damaged.
- An effective day use mooring program is in place, which reduces boating impacts to reef ecosystems, improves public access to resources, and helps to reduce user conflicts.
Decrease in number of impaired coastal waters listed
Every two years the Department of Health publishes an Integrated Report to the US Environmental Protection Agency (EPA) and the US Congress in adherence to the Clean Water Act (CWA). The Integrated Report contains valuable information for the assessment of coastal waterbody health, including testing for attainment and non-attainment of Water Quality Standards (WQS). Conventional pollutants tested for in Hawaiʻi are bacteria, nutrients, turbidity, and chlorophyll.
The graph below displays the variable number of marine waterbody segments tested and found to be impaired every two years, as compared to the total marine waterbody segments in the state (575). In 2016, 60% of listings were attributed to chlorophyll, whereas in 2014, 86% of exceedances were due to turbidity. In 2016, attainment of bacterial WQS indicators of recreational health, accounted for over 96% of marine water bodies assessed on Kauaʻi, Oʻahu, and Hawaiʻi.
For more information, please review the State of Hawaiʻi Water Quality Monitoring and Assessment biennial reports and the U.S. EPA WQS regulations for Hawaiʻi.
For daily monitoring results from the Clean Water Branch, please view the Water Quality Data page.
Agency: Department of Health
Decrease in number of shoreline postings due to sewage or other water pollution
A brown water advisory is a type of health advisory issued by the Department of Health to stay out of coastal waters in specified areas. This type of advisory is usually given when the National Weather Service issues a Flash Flood Warning or upon recommendation from Clean Water Branch staff. Coastal waters may become polluted from flood waters and storm water runoff that may possibly contain any combination of matter from overflowing cesspools, pesticides, animal fecal matter, dead animals, chemicals, and associated flood debris. The graph below displays the number of brown water advisories issued per island and state wide from 2010-2016.
Real time advisories can be found on the Clean Water Branch Webpage.
Agency: Department of Health