Adelaide coastal waters
The Adelaide coastal waters include the Port waterways and metropolitan beaches, and extend from Sellicks Beach in the south to Port Gawler in the north. They include the waters approximately 20 km offshore. Adelaide’s coastal waters are part of the waters of Gulf St Vincent and include areas of seagrass and subtidal reef environments supporting important feeding grounds and nurseries for fish, crustaceans, molluscs and marine mammals. Maintaining good water quality is essential for the maintenance of these marine habitats and important for industry and the recreational uses of Adelaide's coastal waters and metropolitan beaches.
What are the problems facing Adelaide's coastal waters?
Historically the area of the Port River and the broader area of Adelaide’s coastal waters have been impacted by poor water quality from discharges from industry, wastewater and stormwater. The EPA has previously studied and monitored water quality in this area quite extensively.
The EPA established the Adelaide Coastal Waters Study (ACWS) in 2001 in response to concerns about the decline in coastal water quality and loss of more than 5,000 hectares of seagrass. The ACWS final report found that discharges into Adelaide’s coastal waters from wastewater treatment plants, industry and stormwater outlets are high in nutrients and suspended solids and are causing loss of seagrass along the Adelaide coastline.
Excess nutrients cause algal blooms and epiphyte growth on seagrass leading to loss of seagrass. Discharges of high levels of suspended solids into the Adelaide coastal waters increase turbidity levels contributing to challenges for re-establishing seagrass, poor recreational water quality and may result in beach closures at times after rain events.
Loss of seagrass has implications in terms of sediment instability for the management of Adelaide’s beaches and loss of seagrass results in more carbon released into the atmosphere. The carbon storage value of seagrass beds is greater than equivalent sized terrestrial based carbon stored in areas such as rainforest or woodland.
What is being done to improve water quality in the Adelaide coastal waters?
In order to further the recommendations from the ACWS and provide a long-term strategy to achieve and sustain water quality consistent with community expectations for Adelaide’s coastal waters the Adelaide Coastal Water Quality Improvement Plan (ACWQIP) was released in mid-2013. The plan was a culmination of over 5 years of work on consultation with key stakeholders and the community for the improvement of water quality along Adelaide's coastline.
The ACWQIP was developed in partnership with relevant government agencies, business and industry. A summary overview of the ACWQIP has been provided for your information.
The ACWQIP includes 8 strategies which are underway in partnership with key stakeholders and the community. This work is supported by Australian Government National Landcare Programme funding for the 'Catchment to Coast focus for water quality improvement across urban Adelaide'.
The EPA also completed the Port Waterway water quality improvement plan in 2008 which is focused on water quality improvement for the Port Waterways.
What are the ACWQIP strategies?
In the ACWQIP the EPA is identified as the agency to lead the reduction of nutrients from point source discharges operated by SA Water and Penrice Soda Products (discharges ceased in July 2013). Leadership on addressing stormwater issues involves many more players including the AMLR NRM Board, local governments, a range of state agencies and local communities.
Implementation for many of the strategies in the ACWQIP is well underway with Australian Government National Landcare Programme funding support for 'Catchment to coast focus for water quality improvement across urban Adelaide’ (Catchment to Coast). This is a $2-million project that includes implementing six sub-projects:
Seagrasses form the 'meadows' of coastal waters.
They are vascular, flowering plants with roots, making them quite different from seaweed, which is an alga. Their large root system is essential for the uptake of nutrients and for anchoring them to the sand.
It is estimated that seagrasses cover 5,000 km² of the sheltered waters of Gulf St Vincent. The dominant seagrasses are ribbon-weed (Posidonia spp.) and wire-weed (Amphibolis spp.) and in the shallower regions, paddle-weed (Halophila spp.) and eel-grass (Zostera and Heterozostera spp.).
Seagrass provides habitat for a large variety of marine animals, including fish, and stabilises the sand, reducing erosion. Seagrasses also reduce wave energy, which can help to stop coastal damage during storms.
What is happening to seagrass?
Seagrass is commonly lost when nutrient levels in the water increase.
These nutrients cause a large number of epiphytes to grow on the seagrass leaves, causing them to become too heavy and to break off.
The nutrients also encourage more microscopic algae to grow in the water, reducing the amount of light getting to the seagrass, particularly in the deeper regions.
Over 50 km² of seagrass have been lost from the Adelaide metropolitan coastline. This has been attributed to the effects of discharges such as sewage effluent and sludge and also stormwater.
Water quality monitoring
The EPA's Water Quality Monitoring Program has previously involved monitoring water quality in the Port waterways and along metropolitan beaches, but now is focussed on ecosystem condition monitoring of seagrass and reef habitats in Gulf St Vincent. This condition assessment monitoring can still provide a good indication of what is happening for Adelaide’s coastal waters in terms of water quality and condition of segrass and reef areas along the Adelaide coastline.
Water quality information can be obtained for the following beaches
- Largs Bay
- Henley Beach
- West Beach
- Glenelg North
- Port Noarlunga
- Victor Harbor
- Horseshoe Bay
- Metropolitan Bathing Waters Quality Report No. 1
- Metropolitan Coastal Waters Quality Report No. 2
- Metropolitan Coastal Waters Quality - Community Summary
- Gulf St Vincent metropolitan bathing waters - Report No 1
- Gulf St Vincent metropolitan coastal waters - Report No 2
- Protecting Gulf St Vincent
- Water quality of Adelaide's metropolitan coastal waters - community summary
- Changes in seagrass coverage
- The health of subtidal reefs
- Technical Report No 1 - Audit of the quality and quantity of treated wastewater discharging from Wastewater Treatment Plants (WWTPs) into the marine environment
- Technical Report No 2 - A review of seagrass loss on the Adelaide metropolitan coastline
- Technical Report No 3 - Audit of contemporary and historical quality and quantity data of stormwater discharging into the marine environment, and field work programme
- Technical Report No 4 - Estimation of groundwater and groundwater N discharge to the Adelaide Coastal Waters Study area
- Technical Report No 5 - Distribution of Suspended Matter in Adelaide Coastal Waters Using SeaWiFS Data
- Technical Report No 6 - Remote sensing study of marine and coastal features and
interpretation of changes in relation to natural and anthropogenic processes
- Technical Report No 7 - In-situ field measurements for Adelaide Coastal Waters Study
- Technical Report No 8 - Physical oceanographic studies of Adelaide coastal waters using high resolution modeling, in-situ observations and satellite techniques
- Technical Report No 9 - Responses to reduced salinities of the meadow forming seagrasses Amphibolis and Posidonia from the Adelaide metropolitan coast
- Technical Report No 10 - Reconstruction of Historical Stormwater Flows in the Adelaide Metropolitan Area
- Technical Report No 11 - Elevated nutrient responses of the meadow forming seagrasses, Amphibolis and Posidonia, from the Adelaide metropolitan coastline
- Technical Report No. 12 - Turbidity and reduced light responses of meadow forming seagrasses Amphibolis and Posidonia, from Adelaide metro coastline
- Technical Report No. 13 - Nutrient fluxes in the meadow forming seagrasses Posidonia and Amphibolis from the Adelaide metropolitan coast
- Technical Report No. 14 - Field surveys 2003-2005: Assessment of the quality of Adelaide's coastal waters, sediments and seagrasses
- Technical Report No. 15 - Assessment of the effects of inputs to the Adelaide coastal waters on the seagrasses, Amphibolis and Posidonia
- Technical Report No. 17 - The loads of particulate matter and atmospheric nitrogen deposited from wet and dryfall to Adelaide metro coastal waters
- Technical Report No. 18 - Volumes of inputs, their concentrations and loads received by Adelaide metropolitan coastal waters
- Technical Report No. 19 - An integrated environmental monitoring program for Adelaide's coastal waters
- Technical Report No. 20 - Physical oceanographic studies of Adel coast waters using high-res modelling, in-situ observations and satellite techniques
- Adelaide Coastal Waters Study, Final Report Volume 1
- Adelaide Coastal Waters Study
- Monitoring for coastal protection
- Adelaide coastal waters information sheets
Following the completion of the ACWS, information sheets on Adelaide’s coastal waters and some of the findings of the study are now available:
- Importance of seagrass
- Seagrass health
- Changes in urban environments
- Physical processes
- Inputs to coastal waters
- What can households do?
- Strategies for water quality improvement for Adelaide's coastal waters
- Community vision and environmental values for Adelaide's coastal waters.
- ACWQIP supporting documents
The development of the draft ACWQIP included collation of considerable background information provided as separate consultant reports and statements. These are listed below as reports 1 to 8. Some of this information has undergone minor editing to remove names or other information to protect privacy. Most of the work for these reports was undertaken between 2006 and 2008, and as such, some of the content is not necessarily current for and does not reflect the views of the South Australian Government or current government policy.
- Report 1: Community consultation executive summaries
- Report 2: Draft water quality objectives
- Report 3: Sample of programs and activities relevant to water quality improvement for Adelaide's coastal waters
- Report 4: Modelling the catchments of Adelaide's coastal waters
- Report 5: Adelaide Coastal Water Quality Improvement Plan Monitoring and Assessment Framework
- Report 6: Understanding the possible impacts of climate change and population growth by the year 2030 on nearshore water quality of metropolitan Adelaide
- Report 7: Statutory capacity to implement the Adelaide Coastal Water Quality Improvement Plan
- Report 8: Reasonable assurance statement for the Adelaide Coastal Water Quality Improvement Plan
- Port River Water Quality Report No. 1
- Port River Water Quality Report No. 2
- Port River Sediment Quality Report
- Port River: heavy metals and PCBs in dolphins, fish and sediment
- Port River Water Quality Improvement Plan
- Department of Environment, Water and Natural Resources coastal and marine conservation
- Adelaide and Mount Lofty Ranges Natural Resources Management Board
- Adelaide and Mount Lofty Ranges Natural Resources Management Board
- Water Sensitive SA
- City of Onkaparinga
- City of Marion
- City of Holdfast Bay
- City of West Torrens
- City of Charles Sturt
- City of Port Adelaide Enfield
- City of Salisbury
- City of Playford
- District Council of Malalla