An optimization model of sand and gravel mining quantity considering healthy ecosystem in Yangtze River, China

River sand and gravel are industrial construction materials that are an essential part of rivers. Therefore, an important issue is to determine how to produce the maximum economic benefit of river sand and gravel resources under the premise of ensuring river stability and health, as well as flood control security. This study analyzed the limited quantities of sand and gravel mining during the mining planning period, including the total quantity of sand and gravel mining, the minimum annual quantity of sand and gravel mining, the maximum annual quantity of sand and gravel mining, as well as the maximum quantity of sand and gravel mining quantity in two consecutive years. Taking the above restrictions as constraints, this paper constructed optimization models of annual and multi-year exploitation of river sand and gravel resources with economic benefit as the objective function. Through exploring the regulating capability of sand market, we put forward that the sand and gravel supply price should be regulated by controlling sand and gravel supply quantity appropriately under sand and gravel mining permission system, and discussed the characteristics of different quantity-price relationships of river sand and gravel. On the basis of discussing the relationship between quantity and price, cost and price, we analyzed the optimization models for annual and multi-year exploitation of river sand and gravel resources. Lastly, we take the sand and gravel mining in a section of the Yangtze River as a calculation example to validate the optimization models' rationality and feasibility. This study can serve as a reference for sand and gravel mining planners, and provide support for the optimal utilization of river sand and gravel resources in the future. (c) 2019 Elsevier Ltd. All rights reserved.