PAUL HARTFIELD, U.S. Fish and Wildlife Service, 6578 Dogwood View Parkway, Jackson, Mississippi 39213, USA

Sand and gravel mining within or adjacent to river and stream channels can initiate channel degradation and erosion. Instream mining (dredging) changes channel geometry and creates local inflection in stream gradient. Point bar mining (removal) increases gradient by effectively straightening the stream. Inappropriately sited flood plain mines may capture the river during flood events, causing a relocation and inflection of the thalweg. Such changes are accompanied by increased water velocity above the mined areas precipitating local channel scouring and erosion. Where mining activities are numerous and concentrated, an upstream progression of channel degradation and erosion occurs that is consistent with the process of headcutting. Mining has been identified as a causative factor in active headcuts on the Amite, Bogue Chitto, and Tangipahoa Rivers in Mississippi and Louisiana, and on the Buttahatchee and East Fork Tombigbee Rivers in Mississippi. Mining induced channel erosion destroys upstream private and public property, reduces recreational and fish and wildlife values, and has contributed to the extirpation and extinction of stream fauna. Geomorphic theory, as well as published field observations and evidence of the damaging effects of channel and riparian mining in alluvial systems is currently more than adequate to prohibit or severely regulate such practices.