in a feedback effect, increasing the extent that water, and its associated sediment, could flow over the floodplain. In some systems the mining of tributaries and the main channel led to aggradation to such an extent that tributaries were blocked and the streams back filled. This was the case in Tullaroop Creek and the Loddon River, where the confinement of the valley sides near the confluence resulting in the river channel being completely choked. Whilst the fine and dissolved sediment fractions would have been transported all the way down river system, such as into the River Murray, the rest of the sediment appears to have deposited proximal to the mine sites, and was only transported 10’s of km. Fans of sediment built up on floodplains downstream of the mines. The stream type and network configuration clearly played a part in determining how far sediment travelled. By 1886 stream avulsions were reported in 11 streams, forming new channels on the floodplain. Stage 4: High volume mining (1880–1905) Evidence In the 1880s there was a gradual transition from a high number of dispersed mining leases with relatively low output operations, to a lower number mining leases in higher production centres. This transition was partly a result of technological advances, and partly a consequence of the reduction in the grade of available ore. Hydraulic sluicing was a progression from ground sluicing, and was introduced into Victoria in 1860. Water was pumped under pressure through a monitor (nozzle) at the base of mining claims (Figure 9). Undercutting the sediment led to collapses from which the large clasts were extracted and stacked locally. The rest of the sediment was directed into sluice boxes, eventually ending up in the river system. Giant monitors were introduced in the 1880s and needed large volumes of water. This equipment was mainly used in northeast Victoria particularly around Beechworth, Yackandandah and Mitta Mitta. Mineral Statistics of Victoria reveals that that up to 1.5 million m3 of washdirt was produced per year (MSV, 1888). This resulted in around 13% of the state-wide sediment yield being produced by hydraulic mining between 1859 and 1891 (Davies et al. 2018a). The scars left on the landscape from sluicing can be detected using LiDAR imagery. One distinctive method of sluicing, also found in New Zealand, was herringbone sluicing (Figure 10). This concentrated sluicing approach results in a feather type pattern on the LiDAR. Subsequent revegetation makes this impact harder to distinguish in photographic imagery. The upper part of one of our study catchments, 3 Mile Creek, a tributary of Hodgsons Creek (Figure 3) had been hydraulically sluiced. Using the LiDAR available from DEWLP we mapped the area of the hole left behind by the sluicing (Figure 11). A 35° slope was used as a mask to help delineate the top of the scarp faces. This produced an area of 1 185 740 m2. Mining had not Figure 8.  Depths of overbank and in-channel deposition reported in the 1887 sludge inquiry. Feature Mining to mud 49 PREVIEW JUNE 2019