Factors affecting river health and its assessment over broad geographic ranges: The Western Australian experience

Abstract

AusRivAS is an Australia-wide program that measures river condition using predictive models to compare the macroinvertebrate families occurring at a river site with those expected if the site were in natural condition. Results of assessment of 685 sites across all major rivers in Western Australia are presented. Most rivers were in relatively natural condition in the northern half of the state where the human population is low and pastoralism is the major land use. In the south, where the human population is higher and agriculture is more intensive, rivers were mostly more disturbed. AusRivAS assessment produced some erroneous results in rivers of the south-west cropping zone because of the lack of appropriate reference site groups and biased distribution of sampling sites. Collecting low numbers of animals from many forested streams, because of low stream productivity and samples that were difficult to sort, also affected assessments. Overall, however, AusRivAs assessment identified catchment processes that were inimical to river health. These processes included salinisation, high nutrient and organic loads, erosion and loss of riparian vegetation. River regulation, channel modification and fire were also associated with river degradation. As is the case with other assessment methods, one-off sampling at individual sites using AusRivAS may be misleading. Seasonal drought, in particular, may make it difficult to relate conditions at the time of sampling to longer-term river health. AusRivAS has shown river condition in Western Australia is not markedly different from other parts of Australia which, as a whole, lacks the substantial segments of severely degraded river systems reported in England.

Riparian vegetation research in Mediterranean-climate regions: common patterns, ecological processes, and considerations for management

“…In Australia, the AUSRIVAS system is in common use (Halse et al, 2007), and in Europe, assessment systems include the Mean Trophic Rank system (MTR; Holmes et al, 1999) and the Macrophyte Biological Index for Rivers (IBMR; Haury et al, 2006). Some water-quality assessment approaches use riparian trees as bioindicators of trace metals (Madejón et al, 2004) or extremely acidic conditions (Rufo et al, 2011).…”

The challenge of monitoring impacts of water abstraction on macroinvertebrate assemblages in unregulated streams

“…The more affordable alternative is to apply rapid biological assessment (RBA) methods, which are widely used for the biological monitoring of Australian rivers, particularly with macroinvertebrates (e.g. Metzeling et al, 2003;Halse et al, 2007). These methods are cheaper because they use only semiquantitative sampling gear, subsample a small proportion of the organisms collected, and seldom identify macroinvertebrates below family level.…”

Development of a GIS-Based Decision Support System for Diagnosis of River System Health and Restoration

“…In December 2008, the Ministry of Water Resources of China ratified a statement of planning tasks in the Act of Aquatic Ecosystem Conservation and Restoration of Main Rivers and Lakes in China, in which the restoration and maintenance of "healthy" river ecosystems was designated as an important objective of river management [1]. The concept of river health originated in Europe, America, and Australia [4], and some river health assessment systems, such as ASSEES-HKH (Assessment System to Evaluate the Ecological Status of Rivers in the Hindu Kush-Himalayan Region) [4] and AusRivAS (Australian River Assessment System) [5][6][7] have been developed. These systems feature complexly linked multi-scale data and assessment models, and they aim to evaluate the ecological status of rivers to provide a scientific basis for applied decision making.…”