Research into the US sand and gravel resource management system and relevant policies under the background of urbanization

The supply of sand and gravel resources is restricted not only by the natural endowment but also economic and social factors.To provide improvement policies,this article researches on the US sand and gravel resource management system and relevant policies with the background of urbanization.The analysis indicates that there are three characteristics of the US sand and gravel resource management system:pyramid type,diversity management and the philosophy of ecological and environmental protection first.Furthermore,this article proposed five suggestions like comprehensive mapping survey,integrated zoning and SD planning on the basis of exemplary station cases.Besides,the pyramid type,diversity and delicacy management are effective management methods,which deserve to be adopted in order to promote the reformation of China’s aggregate resources management system.