Very-broad-scale assessment of human impacts on river condition

摘要: 1. Management of whole rivers and river catchments requires a comprehensive set information about condition use, both existing historical, the links between them at regional, state or national scales. This paper outlines new approach to assessment condition, using small team was able assess 210 000 km across more than 3 million km(2) Australia in little year. 2. The driven by hierarchical model function, which assumed that broad-scale catchment characteristics affect local hydrology, habitat features, water quality and, ultimately, aquatic biota. provided basis for selecting important ecologically relevant features indices should represent. For each reach we derived biological index an environmental based on measures quantifying hydrological condition. Data came from databases, satellite images, site measurements process models. 3. All were calculated as deviation reference range-standardised divided into equivalent bands Amalgamation components sub-indices determined consideration their ecological effects; example, general degradation might be additive, but toxic effects one component would override all others. 4. Several internal external validation methods employed, with all-important final assessments undertaken comparison similar locally measured data. 5. classified 14% reaches largely unmodified, 67% moderately modified 19% substantially human impacts. modelled data invertebrates indicated 70% 30% significantly impaired. Catchment disturbance, elevated sediment nutrient loads, contributed these results. These impacts have occurred during last 200 years (post-European settlement). 6. Partly result this study Australian Government has begun adopt environmentally sustainable management.