Great Lakes Shire Council: Water Quality Improvement Plan

Great Lakes Council is implementing an estuary and catchment management program for the coastal Great Lakes system – including the Wallis, Smiths and Myall Lakes - of NSW (pictured below).
 
A central guiding framework for this program is a Water Quality Improvement Plan, developed after council won funds from the national Coastal Catchments Initiative (CCI) in 2005. The Plan guides council and its partners on the required steps to reduce the impact of sediments, nutrients and faecal coliforms on the water quality and health of the Great Lakes.

Activities and projects to develop the WQIP are now described. A schematic of the plan's components is provided at the bottom of the page.

Community and Stakeholder engagement

Council worked with urban and rural residents and organisations (such as neighbouring councils, the Catchment Management Authority and water supply authorities) to identify community values for the waterways. An economic analysis on the cost and benefit of improving the Lakes’ water quality helped communicate the case to develop and implement the plan.

Catchment, ecological and hydrodynamic modelling

A number of inter-related modelling exercises were used to assess the current ecological condition of the Lake system, and predict how this condition was influenced by activities and land use in the Lakes’ catchments. Catchment models were used to predict possible stormwater pollutant loads from Rural land and urban land. The estuary's response to these loads was modelled separately.

These investigations determined the nutrient and sediment levels required to ensure the Lakes are in an ecological condition that is consistent with the waterway values identified through community and stakeholder engagement.

Decision Support System

A custom made decision support system took the data from the various models and provided a simple computer interface that helped people understand:
• Where the Lake system is most impacted by catchment activities on urban and rural land;
• Where nutrient loads need to be capped and;
• Where development control and catchment rehabilitation efforts were best placed to reduce pollutant lands entering the Lakes.

The decision support system was also used to explore the possible effects of various pollution prevention actions on both rural and urban land at different scales across the catchment. This helped those involved to select the most suitable policy recommendations and actions to include in the Great Lakes Water Quality Improvement Plan (WQIP).

The Water Quality Improvement Plan and its implementation

The final WQIP provides an ongoing framework for council and the community to better coordinate a range of management, protection and rehabilitation measures to maintain and improve water quality in the Lakes system.

It helps council and the community to more effectively prioritise their efforts to make a difference to water pollution. The modelling and studies that were used to develop the plan also provide a scientific basis for council’s water quality objectives and targets.

The findings and actions arising from this nationally significant project of potential interest to other councils are now described in brief. For more information on any of the items below or to locate a copy of the plan for downloading, refer to the urbanwater.info summary of the WQIP and related resources.

• Council has set a stormwater objective of ‘no net increase in nutrients’ for land rezoning and greenfield developments. To meet this objective, developers and council undertake a staged negotiation process to produce a Masterplan for the site, using MUSIC modelling to test that proposed changes to land use will not generate additional pollution to the Lakes.
• For larger re-developments within existing urban areas, best practice stormwater quality pollutant load reduction targets are to be achieved: (Total Nitrogen: 45%, Total Phosphorous 60%; Total Suspended Solids 80%). For smaller redevelopment sites, a WSUD DCP is being developed to provide a ‘recipe based’ deemed to comply set of tools.
• Water Sensitive Urban Design retrofits are being installed in catchments that are critical to rehabilitating degraded and at-risk areas of the Lake. These retrofits have been informed by MUSIC modelling at the catchment scale.
• Modelling identified that unmanaged erosion from a range of construction sites can release pollutants into waterways at a rate two orders of magnitude higher than bushland. In response, Great Lakes Council has worked to improve sediment and erosion control of roadworks.

Source: Great Lakes Council (2009), Water Quality Improvement Plan