Society and sediment in the Mining Rivers of California and Australia

People and water intersect in the movement of sediment downstream in rivers. Social processes and geomorphological processes become entangled as each system moves in ways that trigger corresponding responses from the other. Long-term dialectical relationships emerge that span multiple human generations. The power of sediment and water to change physical environments is in constant tension with the power of human actions informed by social, cultural, legal, economic and engineering imperatives. The Pacific Rim gold rushes that began in the mid-nineteenth century provide an opportunity to examine how the interplay of people, water and sediment unfolds over historic time. The mass discharge of mining sediment in California and Victoria that began over 150 years ago was a catastrophic human alteration of river systems. Subsequently, mining sediment has had a long and complex entanglement with society and rivers in both regions and continues to be an active agent in reshaping riparian environments. Mining sediments also have a toxic legacy as associated contaminants, including mercury and arsenic, that are discharged into waterways and dispersed in windblown dust. The changes to river systems caused by gold mining committed societies and rivers to new trajectories of mutual engagement. Anthropogenically induced sedimentation that resulted from mining is an issue that will continue to impact watersheds for generations to come.