Wt At t K - PowerPoint PPT Presentation

 Wt At  t K H Nt Ht  Robert Whittier 1&2 Adaptive Management Symposium on Groundwater Dependent Ecosystems at Kaloko- Honokhau National Historical Park (KHNHP) November 9, 2018 1 – Hawaii Dept. of Health 2 – Water Resources Research Center

 Wt At • Coastal groundwater discharge is the primary contaminant transport vehicle • Zone of Contribution (ZOC) ● That land area under which groundwater travels to coastal discharge areas ● Activities within the ZOC may contribute contamination to the Kaloko-Honokhau National Historical Park (KHNHP) • Delineate the ZOC using a groundwater model • Inventory the potential contamination sources within the ZOC • Wastewater disposal has the greatest contamination potential Nitrogen isotope data indicate wastewater impact to the KHNHP is not severe • compared to other coastal areas of West Hawaii

tt   Ctt ● Primary Potential Contaminants Wastewater disposal ● Light industrial ● ● USGS sampling Found only trace levels of ● contaminants Data Sources: ● Hunt, 2014, Baseline water-quality ● at Kaloko-Honokhau National Historical Park, USGS Scientific Investigations Report 2014-5158, 52 p Hawaii Dept. of Health, Safe ● Drinking Water Branch Contaminant Data Base 3

tt tt Ctt ● Wastewater Sources Septic/Cesspool disposal ● Municipal Disposal ● ● Nitrogen Isotopic Composition of Algae Hawaii Coral Reef Initiative, 2013, ● Survey of the Nitrogen Isotopic Composition of West Hawaii Coastal Algae Potential wastewater contribution when ● δ 15 N >4 o / oo ● Septic/Cesspools within the ZOC 2 yr. – 75 septic, 45 cesspools ● 10 yr. – 21 septic, 67 cesspools ● Upland – 53 septic, 82 cesspools ● Total nitrogen load ● 26 kg(N)/d ● ● Wastewater Disposal ~1.5 mgd ● 3.8 mg/L (N) ● Hunt, 2008 ● N Load – 20 kg(N)/d ● Likely discharge to the small boat harbor? ● 4