The management of gravel extraction in alluvial rivers: A case study from the Avon River, southeastern Australia

A case study of the Avon River in Gippsland, southeastern Australia, demons trates the impacts of commercial sand and gravel extraction from alluvial r ivers. The Avon River has a long history of channel instability related in part to its recent change of course by avulsion and in part to destabilizat ion driven by human activities in the channel. Con tributing to this destab ilization has been the extraction of gravel, which occurred over most of th e past century and, in recent years, at a rate of at least 50,000 m(3)/yr. Analyses of the gravel and the material comprising the banks of the river i ndicate that the gravel is being replenished from bank erosion rather than from supply from the catchment. Catchment supply is estimated to be only 50 00 m(3)/yr. While this estimate of the annual bedload transport rate may be useful for indicating that gravel extraction rates are not sustainable, it cannot be assumed that extraction at the annual bedload transport rate wil l result in minimal impact on an alluvial river such as the Avon. Both past and present legislation has allowed management and monitoring of gravel ex traction. However, in practice, the ways in which government agencies have applied the legislation have led to largely uncontrolled gravel mining prim arily because of a lack of political determination to enforce the regulatio ns, It is concluded that responsibility for the management of gravel extrac tion should be in the hands of the agency with direct responsibility for ma nagement of the river, and that extraction should be allowed only where it is necessary to fulfil management objectives for the river and not for rout ine resource access.