The condition of the Goulburn Broken Catchment is summarised in this secton. Further details are supplied in the supplement Assets of the Goulburn Broken Catchment. Catchment condition is also reported in Goulburn Broken CMA’s Annual Report (GB CMA 2012b).
The general rating of biodiversity condition across the Catchment is poor (Table 1), which is based on comparison with pre-European settlement condition and considers vegetation quality and extent, threatened species population trends, water regimes of environmental features, and the management systems in place (GB CMA 2012b). At a finer scale, biodiversity condition varies from poor to good condition (VCMC 2007), with some aspects improving and some declining (GB CMA 2010b).
Native vegetation extent, including diversity, is particularly important because it underpins most of the Catchment’s species diversity. Variation in biodiversity condition across the Catchment is usually related to past activities, especially the clearing of vast tracts of native vegetation for agriculture in the plains and valleys.
Most remaining native vegetation is on public land, which covers one-third of the Catchment and is largely sloping or prone to flooding, although it is mainly regrowth following land uses such as mining and timber harvesting.
About 10 per cent of native vegetation remains on private land (GB CMA 2010c).
Progress against long-term targets listed in Goulburn Broken CMA strategies is on target (Table 1).
Because land is used and valued in many ways (and often in ways that are not complementary) and there is no precise description of what is needed from soils in the future, it is extremely difficult, perhaps even futile, to assess the overall condition of land: good condition for one purpose might be poor condition for another purpose.
It is known that human activity has caused soil-loss rates to increase by a factor of several hundred times since European settlement, however there is no benchmark against which to assess the risk of continued degradation (Feehan 2012).
The capability of land and soils to sustainably support different uses depends on the type of use, the soil (depth, texture, acidity, stoniness, etc.) and the land (slope, aspect and geology) (Feehan 2012).
Some key components of land condition that relate to existing defined uses and values and which are amenable to management have been rated in Table 1.
The threat from high watertables, with associated salinity and waterlogging, is one land condition that applies to most uses and values, including agriculture, roads, housing, biodiversity and wetland health.
The condition of land related to irrigation salinity in the Shepparton Irrigation Region (SIR) improved from poor in 1990 to good in 2012, although the return of high rainfalls in 2010-2012 has recharged the soil profile. Improvements in salinity management since 1990, including infrastructure, will be severely tested if rainfall continues.
The story of land health, including dryland salinity condition, is similar, although the condition is expected to be more rainfall dependent because there has not been an equivalent installation of infrastructure to manage salinity.
The condition of land related to invasive plants and animals is considered to remain poor, with terrestrial and aquatic environments continuing to be vulnerable to new and emerging weeds and animal species, as well as long-established species, such as Paterson’s Curse and foxes.
The condition of water has been rated by separating its components according to how it is managed. For the purposes of this RCS, assessment of water condition includes environmental flows, water quality, riparian and instream habitat and channel form, and floodplain management, which includes protection of infrastructure (Table 1). In addition, stream salinity is assessed with irrigation and dryland salinity because its causes and management have to be considered simultaneously. Land-use change has resulted in flooding and high and saline watertables, threatening livelihoods and property.
Condition assessments considers both the benefits from water resources and the risks they present.
The condition of riparian and instream habitat and channel form and water quality are satisfactory (Table 1).
Stream regulation and degraded soils from changed land uses and natural events such as fire have caused the health of river reaches (related to instream and channel condition and water quality and supply) to decline.
The 2004 assessment of selected river reaches in the Goulburn and Broken basins indicated the following conditions: 5 per cent of reaches were excellent, 11 per cent were good, 55 per cent were moderate, 23 per cent were poor, and 6 per cent were very poor (DSE 2005).
Since European settlement the extent of some wetland types has declined by 20 to 60 per cent. These have predominantly been smaller and less permanent wetlands as they are more susceptible to threats, such as drainage and water regulation. Conversely, the construction of artificial impoundments has increased the total extent of wetlands. Assessment of 116 wetlands since 2009 indicated the following conditions: 6 per cent were in excellent condition, 38 per cent were good, 39 per cent were moderate, 15 per cent were poor, and less than 2 per cent were very poor.
Many wetlands are still under threat and public land wetlands are generally in better condition than private land wetlands, although there are still examples of wetlands in good condition on private land.
Floodplain flood management involves balancing provision of flood patterns for natural assets with reduced flooding impacts on built environments. Pre-development planning and flood response systems have improved significantly since 1990, although large opportunities for aligning floodplain flood management with the Environmental Water Reserve program, such as the lower Goulburn River floodplain, remain uncaptured. Flood protection is rated poor, although condition states for both measures have improved over time (Table 1). The condition of the Catchment related to environmental flows has improved significantly, consistent with greater government emphasis since 1990 on providing water for natural assets (Table 1).
For every dollar invested by government, regional communities, including landholders, contribute more than one dollar, despite continuing challenges (GB CMA 2012b). This commitment, coupled with local leadership, has led to significant investment by Victorian and Australian Governments in major initiatives such as the Farm Water Program.
Because successful catchment management depends on individual land managers and groups to implement most of the changes, understanding their capabilities and motivations helps when developing support tools. It is difficult to assess ongoing involvement of individuals in catchment management, although some indicators are available for groups. For example the Goulburn Broken CMA collects information about community-based groups via an annual report card process. These reports indicate how Landcare groups see themselves. In 2010-2011, the average network health self-rating was 4.5 out of 6, while the average group health self-rating was 3.5 (GB CMA 2012c). Overall, Landcare group health is variable, depending on such factors as viable projects, funding and group and member activity.
Collaborations between organisations, including community groups and other agencies, have been critical to successful catchment management in the Catchment for more than two decades. The overall condition of people involvement, as indicated by the "collaborations and communities" rating is satisfactory (Table 1).
Table 1. Long-term strategy implementation progress and Catchment condition