The number of impoundments in a 100 km2 area in Australia's Intensive Landuse Zone was a surrogate indicator for hydrological changes occurring in catchments during National Land and Water Resources Audit . The impoundments included dams, locks, weirs, reservoirs and farm dams extracted from the Australian Rivers and Catchment Condition Database (formerly Wild Rivers [2,3]).
The regulation of rivers through the construction of dams, locks and weirs has changed natural flow regimes, and altered the amount (and timing) of freshwater flow entering some coastal waterways.
More information and maps showing 'impoundment density' can be found at the Catchment Condition Online Maps website at Agriculture, Fisheries & Forestry Australia . Appendix I (pp. 311-312) in Volume 2 of the Australian Catchment, River and Estuary Assessment, 2002 contains a map of Australia's River Basins and Drainage Divisions in which each river basin has been assigned a number. These catchment numbers can be matched to a large number of coastal waterways in pages 316-363 of the same document. The impoundment density scores for a large number of river basins are available in Appendix B (pg 65-76) of the Assessment of Catchment Condition in Australia's Intensive Land Use Zone: A Biophysical Assessment at the National Scale .