Figure 4-3: Albany Rainfall 1991. Much of the year's rain fell during a three-day period in July
The water quality of Albany's waterways
The Albany area, compared to other areas of Western Australia, has a long history of European settlement and land use which has led to a lot of pressure on the waterways. Industry, residential development, clearing, agriculture, recreation and port activities have all taken their toll on the land and water. Pollutants normally found only in cities can be found in the Albany area, too. Monitoring all the pollutants is relatively new, with studies being done only since the 1970s.
The Albany waterways are mainly affected by high levels of nutrients. These are causing excessive growth of algae in the harbours, and algal blooms in the rivers.
Nutrients, such as phosphorus and nitrogen, are attached to particles of soil. They get into the rivers when the river banks (which are enriched by farm fertilisers) erode, and from farm drains. The nutrient-enriched soil is washed downstream and settles in deeper river pools or the harbours.
Erosion is made worse by removing trees and other plants from along the river banks and drains. Livestock also damage the banks when they walk on them. Clearing trees on farms and farming crops that don't use much rainwater increases how much rain gets into the rivers as run off. This is because not as much rain is taken up by the crops as the original trees. The more water that runs off the land, the more soil it tends to take with it. This means there can be more water in a river after rain, which increases its flow and its ability to erode the banks. It can also carry more of the soil it eroded and more nutrients downstream.
Applying a lot of fertiliser to crops that don't use all of it can increase the amount of nutrients that get into rivers or the groundwater. The excess fertiliser is washed into the waterways by the run off.
Pollution of Oyster Harbour is mainly cumulative, caused by broadacre farming and catchment clearing over a long time. Point source pollution (such as from piggeries) is increasing, however.
Princess Royal Harbour and its catchment is polluted mainly by point source pollution from urban areas. Over the years industrial waste, rubbish, sewage, stormwater and run off from the town, as well as run off and drainage from agricultural areas, have all ended up in the harbour.
However, the condition of both harbours and their catchments is improving. Pollution sources are being tackled and the levels of many pollutants are being reduced to environmentally acceptable levels.
The Water and Rivers Commission and the Albany Waterways Management Authority (AWMA) coordinate monitoring of Albany's waterways. The monitoring identifies pollution sources and guides the management of the waterways and any land use or other activity. Monitoring is also used to gauge the effectiveness of pollution management.
The monitoring focuses on the most important problems, particularly nutrient levels and point sources of pollution.
Pollution monitoring of Albany's waterways includes:
On average, the salinity of the waters of both Princess Royal Harbour and Oyster Harbour is close to that of the sea (around 35 000 parts per million). Salinity tends to be higher in the harbours in summer owing to increased evaporation and less fresh water flowing into them than in winter. These seasonal changes aren't as big in Princess Royal Harbour owing to its small catchment and the lack of fresh water from rivers.
| For more about stratification in Albany's waterways see section 2.5 and section 4.4 - Salinity |
This stratification probably is important to bottom-dwelling macroalgae because it controls the availability of nutrients, restricting growth.
The King and Kalgan rivers drain into Oyster Harbour on its northern shore. They have the characteristics of an estuarine ecosystem for seven and nine kilometres upstream respectively. The tides affect the two rivers in these reaches.
The riverine reaches (further upstream than the estuarine reaches) of the King and Kalgan rivers have similar seasonal changes to many other rivers in the high rainfall areas of south-western Western Australia. The waters can be fresh, or nearly so, in winter and saltier when flow slackens in the summer months. This summer process of increasing saltiness is called `developing a salinity gradient'. The rivers waters often become stratified, with heavier sea water coming in under the slow-flowing and less dense river water in summer and going a long way upstream. This is known as a `salt wedge'. Both rivers carry nutrients, especially at times of high river flow after rain, which come from agricultural land adjacent to Oyster Harbour.
The Kalgan River is brackish, containing 1500-5000 mg/L of salts. The King River is considered fresh, with 650 mg/L of salts. Records haven't been kept long enough to tell if the changes in the rivers salinity is recent, but it is accepted that clearing trees throughout the catchment, and the increasing groundwater levels, have contributed to the rivers state.
The Water and Rivers Commission and AWMA actively manage pollution in the Albany waterways. Both organisations advise the Department of Environmental Protection about conditions to put on licences allowing discharges into the waterways. They also advise local government authorities about the best ways to reduce pollution from development and land uses. The Commission and AWMA work with landowners, Landcare groups and Agriculture WA on fencing and vegetation and river rehabilitation programmes to tackle pollution from agricultural nutrients. AWMA investigates and reports on individual pollution incidents and takes measures to make sure that the pollution is unlikely to happen again.
The temperatures of the three harbours were monitored in 1988-89 during research coordinated by the Environmental Protection Authority. Temperatures in King George Sound varied the least, because of its size, greater depth, bigger exchange of water with the open ocean and less influence from the surrounding land. Sea surface temperatures varied between 15°C in July to a maximum of 21°C in February.
Temperatures in Princess Royal and Oyster harbours were higher in summer and lower in winter than in King George Sound. Patterns were similar in both harbours, with a maximum of about 22°C in February and a minimum of 12°C in July.
Temperatures are affected by seasonal and yearly patterns and will also be subject to more general climate change.
Local variations in water temperature in the harbours can be caused by fresh water from the rivers or run off. Discharge from the Albany Spinning Mills can cause local heating, with discharge waters averaging 27°C.
The rivers are expected to have wider variations in temperature, although these haven't been monitored yet. In summer, water flow can be reduced or stopped altogether, and water in small pools can be quite warm. Blooms of the blue-green algae Nodularia commonly occur in the upper reaches of the Kalgan River in February or March because there are more nutrients available, less river flow and warmer water temperatures.
Nutrient pollution is the main problem in the Albany harbours. Both Princess Royal and Oyster harbours are nutrient-enriched (or `eutrophic').
The excessive amounts of nutrients cause microscopic and larger algae to grow a lot. This reduces the clarity of the water and smothers seagrasses. Eventually the seagrasses die and are replaced by a couple of dominant forms of algae.
In recent years the amount of nutrients entering the harbours has been reduced. Surveys show that the amount of algae has stabilised or been reduced. Seagrasses have started to grow back and water clarity has improved.
The Environmental Protection Authority (EPA) researched the pollution and wrote about it in a series of bulletins, the most important of which was Bulletin No. 442, in 1990. The EPA made 12 recommendations to help reduce nutrient levels. The Authority set limits on the amount of nutrients that each harbour should receive, and how much was allowed from the different sources, including each industry. AWMA's job is to oversee the recommendations and make sure they're carried out properly.
Nutrients getting into the harbour have mainly come from a small number of point sources. The most important is a fertiliser factory (CSBP Farmers Ltd) north-west of the harbour. The factory, established in 1958, put about 20 t of phosphorus per year into the harbour during the 1970s. It also probably added most of the nutrients during the 1960s and through to the early 1980s. Other point sources have included two vegetable and fish processing factories, a woollen mill, a meatworks and a sewage treatment works.
Sewage is no longer discharged into the harbour and the meatworks has closed. The other companies, particularly CSBP, have dramatically reduced the amount of nutrients and other pollutants they discharge into the harbour. The foreshore industries have met, or are close to meeting, the target limits set by the EPA. Together they now add only one quarter of all the nutrients getting into the harbour.
Other nutrient pollution sources include stormwater and agricultural drains, the port, a landfill site and urban land uses (including septic tanks). All of these together are now the major sources of nutrients. They are being monitored and managed.
Figure 4-3: Albany Rainfall 1991. Much of the year's rain fell during a three-day period in July
Nutrients flow into Oyster Harbour mainly in rivers from the catchment (where there has been broad-scale use of phosphate fertilisers). The nutrients are mostly attached to soil particles. Urban sources such as septic tanks also put nutrients into the harbour. The stream flow and phosphorus loads to Oyster Harbour from the catchment vary greatly from year to year depending on how much rain there's been.
The EPA target for annual phosphorus load to Oyster Harbour (14 t) was exceeded in both 1988 and 1991. Phosphorus input from the Kalgan River was lower in 1992 (about 10 t) than in 1991 (more than 35 t) even though total annual stream flow was similar in both years. This was because there were different amounts of rainfall and varying river flow in each year. In 1991, much of the total annual stream flow occurred over a three-day period during a big rain. A lot of phosphorus was washed into the river from agricultural land then. In 1992, stream flow was spread over a greater period and there weren't as much nutrients washed into the river. Also, over 70% of the phosphorus load entering Oyster Harbour from the Kalgan River catchment in 1992 was attached to soil particles. If erosion can be prevented and run off slowed down (for example by planting trees and other plants where rain runs into the rivers and creeks, and by building compensating basins), then nutrient loads can be reduced even further.
There's been a dramatic reduction in the amount of solid waste getting into Princess Royal Harbour since the 1980s.
The EPA's research in 1988 showed that over 1000 t of solids were being discharged into the harbour, mainly from industry. This has been reduced to 14 t, in 1996, largely owing to the meatworks and wastewater treatment works closing and improved management by the other discharging industries.
Water clarity in Princess Royal Harbour has improved. This has been recorded using Secchi discs and also noted from comments by people who use the harbour.
Toxic contamination of Princess Royal Harbour was identified in 1983. The sediments, plants and animals of the western end of the harbour were contaminated with lead and mercury well in excess of the National Health and Medical Research Council's maximum permissible levels.
The main source of the problem was discovered to be industrial effluent discharged by the CSBP fertiliser works resulting from the processing of rock phosphate.
All forms of fishing, including the taking of molluscs, were banned from the whole of the western end of Princess Royal Harbour. The ban was effected under the Fisheries Act in 1984 and was strictly enforced by Fisheries inspectors in Albany. Although direct discharge of effluent ceased in 1984, mercury levels in certain fish species remained above the health limit for a number of years and the western end of the harbour remained closed to fishing until mid-1992.
Recent fish surveys show that there has been a gradual decrease in mercury levels in most fish species. Only two species are still recording levels in excess of the food standard. This isn't thought to be a human health problem because of the sorts of fish and the amount that would have to be eaten.
CSBP and AWMA continue to monitor heavy metals in sediments and shellfish. An extensive survey in 1997 showed contamination in the sediments, cockles and mussels was insignificant. Razorshells had higher levels of mercury and lead in their waste system, probably because razorshells store their waste for a long time.
In 1979 the bacteriological quality of some areas of Princess Royal Harbour and King George Sound was thought to be poor. Occasional high faecal coliform levels were recorded at Middleton Beach, along with Salmonella spp. at various outfalls.
Sampling in the 1980s showed no improvement near the outfalls. The discharges from the wastewater treatment works and the meatworks were both thought to be serious health risks. Other contaminated discharges into King George Sound in January 1995, and from the meatworks in 1993, have led to improvements in these areas. Other industries have improved the quality of their discharges and the Albany Cattle Saleyards, the main input into the Robinson Road drain, no longer washes directly into the drain or harbour.
Bacteria levels in the harbours are no longer thought to be a significant issue or health concern and they're no longer monitored.
Industrial discharges into the harbour contain oil and grease, mainly from the fish processing plant and the woollen mills. Industry was reported to put in over 200 t in 1988, but this was cut to 3 t in 1995 and 600 kg in 1996. Further improvements are being made.
Dyes used in the woollen mills have, at times, discoloured the water in the harbour. The frequency of these discharges has been reduced and will be stopped completely once the factory is connected to the sewerage system.
Litter, from boats or stormwater drains, is confined to the town of Albany. Putting sediment and litter traps at the bottom of York Street will probably solve a lot of the problem.
Oil spilling into stormwater drains, or directly into the harbour from boats, happens regularly, but isn't a big problem.