Indicators of Catchment Condition in the Intensive Land Use Zone of Australia – Suspended sediment load ratio

\n\nA\n\nIt should be noted that this data is now somwhat dated!\n\nSuspended sediment in waterways influences catchment condition by causing\nturbidity, usually with higher levels of salts, phosphorus and nitrogen, and\nmore sluggish water movement. Elevated levels of salt, nitrogen and phosphorus\ncan make streams uninhabitable for many aquatic species and reduce its quality\nfor human uses. Turbidity restricts light transmission and can restrict\nphotosynthesis and oxygen uptake by aquatic species. Phosphorus bound with\nclay particles may be released in water and with nitrogen, can lead to toxic\nalgal blooms.\n\nMany waterways are ephemeral but the amount of suspended sediment can have a\nmajor effect on biota that need to use this water resource opportunistically.\nLarge waterways such as the Darling and Murray Rivers have high suspended\nsediment ratios but, as a proportion of the total catchment, are restricted in\ntheir overall impact on catchment condition. Increases in the suspended load\nof Australian streams reflect increases in rates of erosion in the wider\ncatchment (both hillslope and channel), typically an outcome of human-induced\nland degradation. Turbid water adversely affects stream water quality and\naquatic habitat.\n\nThe eroding areas require some level of management intervention to retard\nprocess and/or repair surface condition. The data set will be of use to\nresearchers and policy makers in need of national or regional scale land-use\ndata. Erosion is sensitive to land-use practice.\n\nThe data sets used to estimate stream sediment loads are the vector streams\ncoverage generated from the AUSLIG 9eDEM data set and the 1:1 M scale National\nLand-Use Mapping data set (NLWRA). Data has been mapped at 1:250K. The ratio\nof current suspended sediment load to natural suspended sediment load is used\nto indicate turbidity changes in Australian rivers since European settlement.\n\nData are available as:\n\n * continental maps at 5km (0.05 deg) cell resolution for the ILZ;\n * spatial averages over CRES defined catchments (CRES, 2000) in the ILZ;\n * spatial averages over the AWRC river basins in the ILZ.\n\nSee [further metadata](http://data.daff.gov.au/anrdl/metadata_files/pa_iccilr9ab\n__05721axx.xml) for more detail.\n\n