See the ‘Mornington Catchment’ page for a detailed description of the catchment.
The Report Card for the Mornington catchment has generated water quality index scores for the period July 2012 to June 2013. These scores are generated using a combination of standard indicators: nutrients, water clarity (turbidity), dissolved oxygen, salinity (conductivity), pH and metals.
These are sampled monthly across five sites as part of catchment monitoring programs.
The following section ‘Changes over time’ compares these annual index scores and indicators with the catchment's scores from 2000.
Results can also be compared to other catchments in the section below ‘Compared to other catchments’.
Site-specific details about indicators can be found via the site lists or can be accessed directly from the map.
Summary Table: The table below shows area-weighted distribution of site scores based on subcatchments. Scores are averaged in subcatchments with multiple sites. See scoring method for more information.
Small tributaries in the urbanised beach suburbs
Rural drainage to small tributaries in urbanised beach suburbs
The routine monthly monitoring across five sites accounts for 94 per cent of the catchment. The remaining 6 per cent of unmonitored catchment is urban and typically scores as Poor for this region.
Urban and industrial inputs from coastal towns contribute to poor scores, especially metals from road and industrial runoff. The sites that are sampled in the Mornington catchment are situated along the coastal edge where the water quality depends on the quality of the runoff from the upper rural areas, as well as contributions from the urban areas along the coast.
Although water quality index scores were generally Poor to Very Poor in the small waterways of the Mornington Peninsula, some of the index's individual components, such as water clarity and pH, were rated Fair to Very Good.
Levels for nutrients, salinity and metals are higher than ideal, and are due to low flows and intensive agriculture within the catchment.
The levels of dissolved oxygen required to support aquatic life are not being achieved in the smaller waterways and may be a consequence of low flows.
The Report Card's water quality index is based on monthly sampling which can mean short-lived environmental and weather events that can impact water quality are not always captured. This section highlights events for the 2012-13 reporting period.
There were no significant environmental or weather events recorded for the period in this catchment that would have significantly affected water quality.
Overall, ‘Very Poor’ to ‘Poor’ water quality has been a consistent trend in the Mornington catchment over the past 13 years.
Improvements in water quality can be difficult to achieve in catchments with heavy urban or agricultural land use where the source of pollutants is diverse and widely spread across the catchment. Therefore, the installation of rainwater tanks, raingardens and roadside swales serve an important role in reducing the transport of these pollutants via stormwater runoff.
The ‘Actions’ section below outlines projects and initiatives that will contribute toward addressing the issues outlined above.
Driven by the key water quality issues identified for the region, major projects were implemented to improve waterway health in the Mornington catchment and included the following initiatives:
Management objectives across the Mornington Catchment over the next 20 years include:
The following figures show a comparison of scores for each identified water quality indicator in the catchments and Port Phillip Bay.