Haiku Stream Data: In Situ Data
April 2 Field Comments:
Turbidity (water clarity) was low (clear) for Kailua Stream Dog Pond (3.32 NTU), medium for Na’ili’ili’haele Stream Bamboo Forest (6.12 NTU), Ho’olawa Stream Cave (8.54 NTU) and Honopou Stream (9.76 NTU), and high for Ho’olawa Stream Bridge (13.07 NTU) and Ho’olawa stream Twin Falls (12.08 NTU) which was Approximately 400 percent higher than the lowest turbidity stream, Kailua Stream Dog Pond (3.32 NTU).
Dissolved Oxygen was approximately within the ideal range for healthy Hawai’i stream ecosystems, with Ho’olawa Stream Twin Falls and Na’ili’ili’haele Stream Bamboo Forest coming in at over slightly over (8.2 MG/L) the ideal maximum of 8 MG/L.
Both enterococcus and E. Coli seem to rise and fall with each other in varied proportions/ratios, but overall the enterococcus levels were much lower than E. coli. Enterococcus ranged from 0 CFU/100ml (Ho’olawa Stream Bridge) to a high of 37.8 CFU/100ml (Kailua Stream Dog Pond, Ho’olawa Stream Twin Falls), All seven streams measured were all well-below the EPA recommended levels of concern. The relative proportions of E. coli to enterococcus on the high side ranged from approximately 15 to 1 for Ho’olawa Stream Cave (44 CFU E.coli:3 CFU enterococcus) to approximately 2 to 1 for Kailua Stream Dog Pond (17.1 CFU E. coli to 37.8 CFU enterococcus.
Turbidity
Turbidity is a measure of water clarity. Higher turbidity indicates cloudier water due to suspended particles like sediment (for example silt and clay) organic matter, or algae
Dissolved Oxygen
Dissolved oxygen (DO) is vital for the survival of fish, aquatic plants, and other organisms. Just like humans need air to breathe, aquatic life depends on dissolved oxygen for survival. Healthy high dissolved oxygen levels indicate a well-functioning ecosystem, while low dissolved oxygen levels can signal pollution and poor water quality. Low dissolved oxygen levels can also lead to the proliferation of harmful bacteria and algae, making the water unsafe for swimming, fishing, and other water activities. While a single “typical” dissolved oxygen (DO) level isn’t applicable across all Hawaiian streams, a generally desirable range for healthy streams falls between 6 milligrams per liter (mg/L) and 8 mg/L, because this range supports a variety of aquatic life.
Conductivity
While not a standalone indicator of safety for swimming, long-term trends in conductivity and specific conductivity can help identify water quality concerns and potential pollution sources. This information can be used to guide efforts to protect stream health. Possible sources of increased conductivity include:
- Natural Mineral Content: Streams flowing through areas with naturally high mineral content may have higher baseline conductivity [1].
- Pollution Sources: Human activities like road runoff, fertilizer application, or wastewater discharge can introduce dissolved salts and minerals, raising conductivity [2].
Elevated conductivity levels can suggest contamination by pollutants such as heavy metals, which pose health risks to those swimming, fishing, or engaging in other water activities.
Water pH
pH is a measure of acidity (or basicity) on a scale from 0 to 14, with 7 being neutral. Freshwater streams should ideally have pH levels between 6.5 and 8.5 to support aquatic life and be safe for recreational use (U.S. Environmental Protection Agency [EPA], 2022). Deviations from this range can indicate the presence of pollutants or other environmental issues that may harm aquatic organisms and pose risks to human health.
Enterococcus and E. Coli
Hawaii’s freshwater streams present unique challenges: enterococci and E. coli fecal (excrement/doo doo) bacteria can proliferate (multiply) in tropical environments, including soils and vegetation; which, when measured in freshwater streams, may not always indicate direct fecal contamination from an animal, which is a concern due to other diseases that could accompany animal waste. It is important to understand that E. coli and Enterococcus are indicator bacteria, and do not always directly cause the illnesses. They indicate the potential presence of other, more dangerous pathogens, including:
- Gastrointestinal Illnesses: These are the most common risks. Pathogens associated with fecal contamination can cause diarrhea, vomiting, nausea, and stomach cramps.
- Infections: Exposure can lead to ear, eye, and skin infections.
- More Serious Illnesses: In some cases, more severe illnesses like hepatitis A or other viral infections can be present.
Animal waste, particularly from livestock or wild animals, can significantly contribute to bacterial contamination. This can introduce pathogens like: 1) Salmonella; 2) Campylobacter; and 3) Leptospira (which can cause leptospirosis).
