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EMP Processes Study

The GRCCC has engaged SMEC Australia to undertake the 2nd and 3rd stages of the Estuary Planning Process.  SMEC will complete a joint Data Compilation and Estuary Processes Study for the Georges River.  These two stages involve:

 

Data Compilation Study:  Identifying, collecting and collating all existing information (i.e. data and reports) on the Georges River Estuary

This part of the study will focus on information that is specific to the study area and identified management issues, some information that is generally applicable to relevant estuarine environments or management should also be included.  It should encompass the principal physical, ecological, social and economic characteristics that are appropriate to the scope of this study.  To gather this information, the consultants will work with Councils and State & Commonwealth Government Departments (for example DECC, DPI, NSW Maritime, RTA, and SES) CSIRO, Australian Museum, academic institutions, voluntary organisations, conservation groups, community interest groups, local historical sources and utilise maps and local newspapers.

Estuary Processes Study Georges River Estuary

This will define the baseline conditions of the various estuarine processes (physical, biological and chemical) and the interactions between them and possible impacts from human uses to enable management options to be meaningfully considered based on the best possible science.  The Georges River Estuary Processes study will also focus on:
 

Estuarine Foreshore Assessment and Prioritisation Studies (Processes Studies) 

The foreshore study area will include the estuary and all tidal tributaries and creeks.  This exercise will require considerable field work, both land based and where necessary by boat.  This exercise shall document the location, type, condition and prioritised actions for the following foreshore asset categories:

Estuarine vegetation  

  • Identify and document threats and pressures on areas of estuarine vegetation at the local site specific scale for the whole study area.  This should include sea level rise as outlined in the attached document pdf icon NSW Govt Draft Sea Level Rise Policy Statement (58.11kB) (e.g. 40cm by 2050, 90cm by 2100);
  • Identify areas where estuarine vegetation may be threatened in the medium term due to sea level rise (e.g. saltmarsh where no possibility of inland migration exists), and where rehabilitation would not be a priority;
  • If other previous mapping is identified as part of the data compilation, or is referred to in recent documentation associated with the mapping that has recently been completed, the consultant should document any changes and/or trends in distribution of estuarine vegetation.
  • Identify specific actions that need to be undertaken in order to protect and rehabilitate existing estuarine vegetation remnants, as well as strategies for present and future sustainable management of these communities and their possible expansion.  These actions will be of sufficient detail to provide councils clear detail on how to proceed without having to rely on further studies and plans from other consultants;
  • For seagrasses, assess how moorings are situated in proximity to them and identify any areas of seagrasses where moorings should be prioritised for conversion to seagrass friendly moorings.  This should be based on size, condition, and permanency of the seagrass patch (i.e. location of patch is unchanged in both historical and current mapping).  GIS data will be obtained by NSW Maritime for mooring locations.  An assessment should also be made of where stormwater outlets (natural creek, culvert or pipe) coincide with seagrass beds and may be causing a problem (via desktop assessment and field inspection), as well as where stormwater outlets coincide with existing modelled suitable seagrass locations that are not currently colonised (if this modelled information is available);
  • Threats, pressures, and specific management actions should be documented in site management summaries for discreet sections of foreshore or individual bays.  Relevant legislation should also be discussed in the light of these management actions; 
  • Estuarine vegetation maps at the local level will also be developed.  These maps will be overlaid with management actions for particular areas or compartments of estuarine vegetation (as well as areas where rehabilitation would not be undertaken due to the threat of sea level rise).   Maps should be of a sufficient scale to identify and portray the specific management areas and discreet site characteristics (in GIS format and printed hard copy) and identify opportunities for protection, rehabilitation and enhancement of habitats and vegetation as highlighted in the example from Canada Bay’s Estuary Vegetation Management Plan.

Riparian Vegetation

Recent vegetation mapping was completed for the whole of the study area and the consultant should utilise this and any other information identified in the data compilation phase for background and supporting information.  The consultant will be required to undertake a more detailed field assessment of the entire foreshore study area up to 40m landward of MHWM to achieve the following:

  • Identify and document threats and pressures (including sea level rise if relevant) on areas of riparian vegetation (all vegetation not covered by the estuarine vegetation mapping component) at the local site specific scale for the whole study area;
  • Identify specific actions that need to be undertaken in order to protect and rehabilitate existing vegetation remnants, as well as strategies for present and future sustainable management of these communities and their possible expansion.  These actions need to be of sufficient detail to provide councils clear detail on how to proceed without having to rely on further studies and plans from other consultants;
  • Threats, pressures, and specific management actions should be documented in site management summaries for discreet sections of foreshore or individual bays.  Relevant legislation should also be discussed in the light of these management actions;
  • Riparian vegetation maps at the local level will need to be developed.  These maps will be overlaid with management actions for particular areas or compartments of riparian vegetation.  Maps should be of a sufficient scale to identify and portray the specific management areas and discreet site characteristics (in GIS format and printed hard copy) and identify opportunities for protection, rehabilitation and enhancement of habitats and vegetation as highlighted in the example from Canada Bay’s Estuary Vegetation Management Plan.

Foreshore Erosion

The following detailed field assessment of the entire foreshore study area will be undertaken:

  • Identify all foreshore areas that are undergoing erosion (both active and past) and the likely causes of the erosion, e.g. boat wash, uncontrolled access.  Map the locations of erosion at the local scale as described in the above section, i.e. Estuarine Vegetation;
  • Document the severity of the erosion (including extent/dimensions, type, causes) and capacity to contribute to ongoing environmental and recreational problems such as water quality pollution, smothering of seagrasses, and foreshore amenity and access;
  • Develop management actions to rehabilitate eroding areas and prioritise these based on the 2nd dot point.  Actions will need to be prioritised both for the whole estuary and for each LGA to determine the key actions using an agreed cost-benefit methodology.  Management actions should also be mapped at the local level.  Management actions should recommend specific techniques for each site to concept stage such as rock revetment, mangroves withGeorges River Estuary wave barriers, coir logs/jute matting and revegetation, rock toe protection with bank re-vegetation, macrophyte reed beds etc.  Softer techniques should be favoured;
  • Erosion severity, ongoing impacts and specific management actions should be documented in site management summaries for discreet sections of foreshore or individual bays to the detail and scale as the above section for estuarine vegetation.

Seawalls

  • Visual assessment of all seawalls lining public areas (solid concrete, sandstone blocks, loose rubble revetment etc) along the foreshore to identify stretches of seawall requiring replacement or upgrading due to obvious signs of degradation in all its forms (e.g. cracking, landward subsidence, collapse).  These will be mapped so they are consistent with the previous sections;
  • Identify and outline options to improve the environmental value of the seawall stretches found to require either replacement or maintenance and/or would be suitable for environmental enhancement (e.g. incorporating boulders, lower slopes, benches with pools and/or estuarine vegetation, landward riparian vegetation).  The consultant will be provided with guidelines that describe environmental seawall improvement options for this purpose.  Seawall management options should also be mapped at the local level;
  • Prioritise stretches of seawalls for environmental enhancement through either replacement or maintenance based on the severity of seawall degradation and the potential to improve the biodiversity value of the seawall.  Actions will need to prioritised both for the whole estuary and for each LGA to determine the key actions using agreed cost-benefit methodology;
  • Seawall degradation and specific management actions should be documented in site management summaries for discreet sections of foreshore or individual bays to the detail and scale as the above sections.

Foreshore Existing Gross Pollutant Traps (GPTs) and Stormwater Outlets

The consultant will liaise with all councils within the study area as well as undertake detailed field assessment of the entire study area to achieve the following:

  • Determine the location of all GPTs and document the GPT type and size.  GPTs should include all proprietary and non-proprietary devices including those located underground, end-of pipe, open channel (fixed and floating) and in-pit.  These details should also be mapped consistent with previous sections;
  • Collect statistics (where available) from asset owner/operators on the volume/weight/type of material removed to date and the current cleaning/maintenance schedule (e.g. triggered after rainfall event of certain magnitude or every X months);
  • Map the location, size and type of all stormwater outlets (natural creek and built infrastructure) for the entire estuary foreshore including delineation for each local government area.  Some of this information may be able to be provided by council but the consultant may also be required to collect this information as part of the field work if not available by councils and allowance should be made for this.

The Estuary Processes study will also document the characteristics/processes/health of the Estuary.  These include:

  1. Estuary and catchment characteristics (e.g. estuary classification and basic description, tributaries, climate statistics, topography, geology, soils vegetation, land use and zoning);
  2. Sedimentary processes (e.g. sediment quality/contamination, bathymetry, dredging/reclamation, erosion, siltation/infilling, acid sulphate soils);
  3. Hydrodynamics (e.g. tides, tidal flushing, freshwater inflows, water levels, climate change/sea level rise, currents, wind/waves);
  4. Water quality (e.g. physical, chemical and biological parameters, point sources of pollution, stormwater, groundwater, environmental flows);
  5. Ecology (e.g. terrestrial, aquatic, intertidal, flora/fauna, threatened species, pests and introduced species);
  6. Human usage, recreation and impacts (e.g. boating, fishing, aquatic industries such as oysters, foreshore usage and infrastructure, illegal dumping, contaminated sites);
  7. Aboriginal and European cultural heritage and values (e.g. Indigenous heritage, significant features, European heritage).

Advantages of an Estuary Management Plan for the entire Estuary

A coordinating Estuary Management Plan (EMP) for the whole estuary involving all councils, as opposed to EMPs for parts of estuaries in individual council areas has many advantages:

  • It is more economical, more efficient and saves replication;
  • Some issues are similar throughout whole estuary, so why investigate them separately each time?
  • Impacts often stem beyond the study area of small local plans and cannot be dealt with properly, e.g. water quality;
  • Avoids ad hoc decision-making that does not fix problems operating at larger spatial scales, e.g. development controls for controlling sedimentation;
  • Creates a single management framework;
  • Fosters co-operation and collaboration between councils in the same catchment;
  • High profile whole-of-estuary EMPs are more likely to attract State Government and CMA grants to help implement them;
  • Helps build contacts and networks with other councils and Government agencies that can assist councils with other issues.

Benefits of an Estuary Management Plan

  • All actions within an adopted estuary management plan are eligible for grant funding up to 50% of the total cost through the Georges River EstuaryEstuary Management Program
  • Actions within a Plan receive top priority as apposed to councils applying for grants who have no estuary management plan
  • DECC provides specialist technical support to councils to prepare and implement actions within an estuary management plan. This extends to helping councils design suitable on-ground projects and the provision of data and information.
  • The scope of what can be funded under the program is quite broad and covers all projects likely to have a positive result for estuaries:
      • GPTs, water quality and stormwater management;
      • Bush regeneration in estuarine foreshore and riparian vegetation;
      • Riparian, creek and foreshore rehabilitation and protection including erosion control;
      • Wetland rehabilitation, protection, management;
      • Foreshore improvement works and related infrastructure to restore vegetation, habitats, improvements to amenity and access to the foreshore e.g. viewing platforms, boardwalks;
      • Estuarine monitoring programs e.g. water quality monitoring;
      • Estuary management plans and related estuarine technical studies;
      • Pre-construction activities for works projects which are eligible for subsidy and likely to proceed to construction e.g. designs and environmental impact assessment;
      • Estuarine educational programs including interpretive signage, brochures etc.