the activity. This would explain the relatively small volume of the dams on Hodgsons Creek compared the volume of sediment produced. Inference Increased regulation led to much greater storage of sediment proximal to mine sites. Sludge yields would have decreased, although there would still have been sediment accidentally or deliberately discharged during flood events. The result is that there are pockets of fine sediment stored in stream headwaters, and these sediments may include contaminants. As environmental regulation of sludge was being enforced there was also a decline in gold yields. Fixed gold prices and the First World War meant the end for large scale alluvial and quartz reef mining. Stage 6: Dredging (1899–1950) Evidence “Since dredging started the sludge had alarmingly increased in volume, and now possessed chemical properties which threatened to gradually convert the flats into waste land. Farmers stated that there was no place within six miles south of Eddington where stock could obtain water at the river, and serious losses must occur during the summer. The capacity of the Laanecoorie Weir had been reduced by fully one half, and the water trusts should know that the weir would be practically useless in a few years. It was estimated that at high’ water mark there was an average depth of only four feet”(The Age 1905, 6) Dredging commenced at around 1899 and was the last major technological change in gold mining in Victoria (Davies et al. 2018b). Initially steam driven, and later electric powered, dredges minimised the use of manpower and maximised the volumes of sediment that could be excavated (Figure 14). There are various types of dredging. Within the VicProd, VicMine and Mineral tenements“Minten”(DEDJTR 2013) databases dredging data can be extracted, however these data include sluicing as well as dredging. We have extracted bucket dredging from the data as this was extensive across Victoria and had reasonable records. From these data we estimate over 100 000 000 m3 of sediment was excavated by more than 115 bucket dredgers, mostly in the Ovens and Loddon catchments in northern Victoria. LiDAR and aerial data from 2009–2010 were used to examine the sites identified using the spatial data. These data were used to look for any evidence of dredging. Features included Figure 13.  Sludge dams on Hodgsons Creek imaged using aerial photography and a LiDAR DTM. (source: Department of Environment, Land, Water and Planning). Figure 14.  A photo of the Newstead Dredge on the Avoca River floodplain showing the buckets at the front of the machine. (source: Avoca Historical Society). Feature Mining to mud 52 PREVIEW JUNE 2019