What's that in the water?
This page contains a simple guide to aquatic phenomena in the Wingecarribee area and details about who you should notify if you suspect water pollution is occurring.
Clear water
Photo: An example of clear water at a local waterway.
Clear water has less dissolved and suspended material.
Mountain creeks are often clear because they run over bare rock without sediment or vegetation.
Shallow water also tends to be clear because there is not enough depth for the long, blue wavelengths of light to travel and be reflected.
Clear brown or reddish water
Photo: Clear brown or reddish water at a local waterway.
Sometimes water is clear but brown like tea.
The colour is the result of dissolved organic material from the breakdown of plants and animals.
The material leaches into slow moving streams and lakes from surrounding forests, and wetlands, and stains the water brown or reddish brown.
Green water
Photo: An example of green water at a local waterway.
Suspended particles of living material can impart a green hue to the water. Green water probably has a large population of algae (microscopic plants).
Algae and other microscopic organisms have coloured pigments. When they grow in large numbers ("bloom"), they can colour certain areas or entire waterways.
Blooms of an organism called Euglena may appear red. A bloom of diatoms - a kind of algae - can look brown.
Turbid water (sometimes grey or brown)
Photo: An example of turbid water at a local waterway.
Turbidity in open water may be caused by growth of phytoplankton.
Human activities that disturb land such as construction can lead to high sediment levels entering water bodies during rainstorms due to storm water run-off.
Areas prone to high bank erosion rates as well as urbanised areas also contribute large amounts of turbidity to nearby waters, through storm water pollution from paved surfaces such as roads, bridges, and parking lots.
If you suspect turbid water is not from a natural cause you should let us know.
Slime or fluff
Photo: Orange slime at a local waterway.
Orange slime or fluff
Orange fluff is produced by a group of bacteria that use iron as an energy source. This is the same group of bacteria that create oily sheens.
The masses of bacteria excrete slimy or fuzzy-looking material as they grow and reproduce and the slime becomes coated with rusty iron hydroxide. This is usually a natural phenomenon and is generally associated with acidic soils.
In some areas, iron-rich groundwater may seep to the surface, and the iron drops out as it becomes exposed to air. In this case, the iron will appear as an orange crust or stain and will not be fuzzy looking.
Iron Bacteria Fact Sheet(PDF, 270KB)
Algae
Green hair-like strands and green clumps are formed by filamentous algae. These colonies of microscopic plants live in shallow water on the bottom near shore or on submerged objects.
Blue-green algae can present like a paint-like presence or strong colour in the water.
Blue-green algae can pose a health risk to humans and animals. If you suspect you have an algae bloom do not drink the water.
More information from the NSW Department of Primary Industries:
Farm water quality and treatment: Algae
Should I be concerned about algae?
The presence of algae in a waterway does not necessarily mean the water is polluted.
A diverse community of algae is healthy. Algae are an important source of food and oxygen for other plants and animals in the water.
Sometimes, certain conditions might favour a species that is normally rare in a waterway. With the right temperature, light, and nutrients in the water, the rare organism might multiply rapidly, forming a bloom.
When an algae bloom is persistent or occurs routinely, too many nutrients may be entering the water. Nutrients, especially phosphorus, fertilise a waterway just as they fertilise your lawn or garden, causing microscopic plants in the waterway to grow.
Identifying algal blooms
WaterNSW has information to help identify different types of algae in waterways.
Blue-green algae can pose a health risk to humans and animals. If you suspect you have an algae bloom do not drink the water and let us know.
WaterNSW Algae Alerts Map
Managing Blue Green Algae in Farm Dams(PDF, 53KB)
NSW Health Recreational Water Quality
WaterNSW Algae Contacts
Pollen, oily sheens, and foam
Pollen
A yellowish powder or dust on the surface of water in spring and early summer is probably pollen from trees.
Pollen can also collect in clumps or blobs.
After becoming water-logged, the pollen sinks to the bottom or may collect in shallows along the banks. Lines of pollen may be left on rocks as water levels drop.
Oily sheens
Photo: Natural oily sheen fracturing when broken with a stick.
An oily sheen that reminds you of rainbow puddles in an asphalt parking lot might be from spilled petroleum.
A minor spill is usually enough to form a film across the surface of large waterway.
Oily sheens can also come from natural sources. Some bacteria (Leptothrix discophora) that live in waterlogged places get their energy from iron and manganese, and as these harmless bacteria grow and decompose, the iron may appear oily or form red or orange films, fluffs, and coatings.
If you suspect an oily sheen at a local waterway is not from a natural source you should let us know.
What is the difference between petroleum spills and natural oil sheens?
Photo: Natural oily sheen fractured and brown fluffy evidence of iron bacteria.
Poke the sheen with a stick.
If the sheen swirls back together immediately, it's petroleum.
If the sheen breaks apart (shatters, or forms many sided fragments) and does not flow back together quickly, it is from bacteria or another natural source.
Foam
Photo: An example of foam at a local waterway.
Foam is often seen along lake shores and on streams and rivers. Most foam is natural and does not indicate pollution.
Foam forms when water is mixed with air, such as by a waterfall or waves breaking against shore.
Plants and animals release organic compounds as they decompose, and these compounds lessen the surface tension of water and create bubbles. Biodegradable detergents and reduction of pollution from wastewater treatment plants have reduced the occurrence of pollution-related foam.
If the foam smells fragrant or perfume, it may be from a nearby spill or waste discharge pipe. Natural foam may smell fishy or earthy, and may be white, off-white, or brownish, and breaks apart easily when disturbed.
If you suspect foam at a local waterway is not from a natural source, you should let us know.
Should I notify Council?
If you suspect water pollution is occurring in a local waterway, or are unsure of the cause of aquatic phenomena in a waterway, please let us know.