Namoi Catchment Action Plan

The Namoi Catchment Action Plan provides strategic directions for natural resource management in the Namoi river basin. The Namoi Catchment Action Plan aims to provide a pathway for managing stressors to ensure that the economic and natural resource requirements are balanced. The vision of the Namoi Catchment Action Plan is to deliver on ‘Resilient communities and landscapes for the future’.

The action plan is divided into four themes: biodiversity, land, water and people. Critical thresholds are identified along with related targets and actions in each theme. The long-term targets are aimed at avoiding critical thresholds. These thresholds are identified using expert input, thus the action plan provides a summary of key processes and assets to be protected into the future, and will provide valuable context for assessing the impacts of mining on the Namoi subregion. Biodiversity theme

The Biodiversity theme is defined as ‘the variety of all life forms; different plants, animals, the genes they contain and the ecosystems in which they live’ (Namoi CMA, 2013a, p.16). Overall, biodiversity is in decline in the Namoi. Figure 48 shows priority subcatchments close to biodiversity thresholds. The action plan seeks to address the decline in biodiversity through additional reserved habitats and on-ground conservation projects. The Namoi Catchment Action Plan identifies ten assets which depend on biodiversity. These are discussed in more detail in Section .

The plan identifies four key biodiversity targets that are designed to avoid crossing eight key thresholds. The four key biodiversity targets are:

  • By 2020 there is an increase in native vegetation extent and vegetation does not decrease to less than 70% in less cleared subcatchments and 30% in over-cleared subcatchments, and no further Regional Vegetation Community decreases to less than 30% extent as identified by the 2010 baseline.
  • By 2020 maintain sustainable populations of a range of native fauna species by ensuring that no further Regional Vegetation Community decreases to less than 30% extent as identified by the 2010 baseline.
  • By 2020 contribute to the recovery of priority viable threatened species, species and communities.
  • By 2020 no new invasive species are established in the river basin and the spread of key emerging invasive plants and animals is limited.

To achieve these biodiversity targets a number of key thresholds have been defined for the Namoi. These include:

  • woody vegetation cover maintained at 30% in cleared subcatchments
  • woody vegetation cover at 70% in intact subcatchments
  • 61% of the Regional Vegetation Communities maintain 30% extent.

Figure 48

Figure 48 Priority subcatchments close to biodiversity thresholds based on 2010 mapping in the Namoi Land theme

High priority catchments are those that are close to land biodiversity targets. Dark green is a high priority for vegetation restoration as the subcatchment is approaching the 30% extent remaining threshold. Light green represents a priority for maintenance and the subcatchment is above the 70% threshold. Note that an updated version is under consideration in the revised Catchment Action Plan (Namoi CMA, 2013b) Land theme

The Land theme is defined as ‘healthy soil and functional landscapes that are managed in a way that maintains optimal choices for future generations’ (Namoi CMA, 2013a, p. 17) and is based on the premise that land and soils underpin native vegetation, water and economic activity. In the Namoi, deep productive soils underpin economic activity across the river basin. The Namoi Catchment Action Plan defines healthy soils as an asset and soil health is currently variable across the river basin. The major target for the land theme is: ‘by 2020 there is an improvement in soil health as measured by an increase in groundcover at the paddock, subcatchment and catchment scales’.

Groundcover is chosen as an indicator of soil health in the Namoi Catchment Action Plan because it plays a major role in soil structure, organic matter content and permeability. Land assets are discussed in more detail in Section . Water theme

The Water theme is defined as ‘surface and groundwater systems consisting of the riverine zone made up of stream bed and banks, wetlands and floodplain together with aquifers both confined and unconfined. It also includes riparian vegetation, aquatic biota and water quality and covers access to water, both for people and environmental values’ (Namoi CMA, 2013a, p. 18). The Namoi Catchment Action Plan identifies 15 water assets. These are addressed in more detail in Section .

Targets for the maintenance of water assets include:

  • By 2020 there is an improvement in the condition of those riverine ecosystems that had not crossed defined geomorphic thresholds as at the 2010 baseline.
  • By 2020 there is an improvement in the ability of groundwater systems to support groundwater-dependent ecosystems and designated beneficial uses.
  • By 2020 there is an improvement in the condition of regionally important wetlands, and the extent of those wetlands is maintained.

These targets are designed to avoid crossing several thresholds including:

  • Surface water flow quantity is at 66% of natural (pre-development) condition with sensitivity to natural frequency and duration.
  • Geomorphic condition is good (against benchmark condition).
  • Recruitment of riparian vegetation is higher than attrition of individual trees, shrubs or groundcover species.
  • Agricultural and urban water supply aquifers do not cross into lower levels of beneficial use regarding quality.
  • Alluvial aquifers are not drawn down below long-term historical maximum drawdown levels.
  • Groundwater levels do not drop below the rooting depth of groundwater dependent vegetation ecosystems.
  • Wetland is not drained, dammed or otherwise physically modified. People and communities theme

The People and Communities theme is defined as ‘the social and economic elements of the catchment in relation to how they are underpinned by natural resources, an asset for increasing resilience and a driver of system changes’ (Namoi CMA, 2013a, p. 18). People and communities represent an important component of the natural systems of the Namoi river basin. The people theme recognises the intricate linkages between humans, society and the natural world. The Namoi Catchment Action Plan sets targets where:

  • Natural resource management decisions contribute to social wellbeing.
  • There is an increase in the adaptive capacity of the community.
  • There are no clearly-defined thresholds relating to people. However, the plan recognises building resilient communities by increasing adaptive capacity and sustaining or improving wellbeing as important priorities (Namoi CMA, 2013a).

The Namoi Catchment Action Plan identifies a range of assets grouped into the four areas of capital – human, social, manufactured and financial – although these assets are not directly water dependent.

Last updated:
5 January 2018