An Export Coefficient Based Linear Programming Model for Regional Land-Use Optimization Considering Control of Non-Point Source Pollution

Abstract

Non-point source (NPS) pollution is increasingly regarded as the main contributor to water quality degradation. Land-use structure can influence surface runoff and soil erosion, which can further affect the export of NPS pollution. Thus, optimization of land-use structure is critical for water environmental protection. Taking the Xinfeng County in China as the study area, total nitrogen and phosphorus loads from different land-use types were first simulated in this research, based on the export coefficient model. Then, regional land-use structure was optimized through a linear programming model. Simultaneously, the characteristics of pollution output and the economic benefits of land-use after optimization were also analyzed. Results showed that the optimal areas of construction land and water would increase, while those of grassland and agricultural land would decrease. The optimal area of forestland would increase under the pollution reduction scenarios 1 and 2 (i.e., reducing the NPS pollution loads by 5% and 10%) and decrease under scenarios 3 and 4 (i.e., reducing the NPS pollution loads by 15% and 20%). In terms of the economic benefits of the land-use system, with the increase of NPS pollution reduction requirements, they would present a downward trend. These results can provide decision-makers with optimal land-use structures under multiple pollution reduction scenarios considering control of NPS pollution.