Application of Integrated Watershed Management Measures to Minimize the Land Use Change Impacts

Abstract

Non-point source pollution is a major factor in excessive nutrient pollution that can result in the eutrophication. Land use/land cover (LULC) change, as a result of urbanization and agricultural intensification (e.g., increase in the consumption of fertilizers), can intensify this pollution. An informed LULC planning needs to consider the negative impacts of such anthropogenic activities to minimize the impact on water resources. The objective of this study was to inform future land use planning by considering nutrient reduction goals. We modeled the LULC dynamics and determined the capacity for future agricultural development by considering its impacts on nitrate runoff at a watershed scale in the Tajan River Watershed in northeastern Iran. We used the Soil and Water Assessment Tool (SWAT) to simulate the in-stream nitrate concentration on a monthly timescale in this watershed. Historical LULCs (years 1984, 2001 and 2010) were derived via remote sensing and were applied within the Land Change Modeler to project future LULC in 2040 under a business-as-usual scenario. To reduce nitrate pollution in the watershed and ecological protection, a conservation scenario was developed using a multi-criteria evaluation method. The results indicated that the implementation of the conservation scenario can substantially reduce the nitrate runoff (up to 72%) compared to the business-as-usual scenario. These results can potentially inform regional policy makers in strategic LULC planning and minimizing the impact of nitrate pollution on watersheds. The proposed approach can be used in other watersheds for informed land use planning by considering nutrient reduction goals.