Impact Assessment of Best Management Practices (BMPs) on the Water Footprint of Agricultural Productions

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RESEARCH PAPER

Impact Assessment of Best Management Practices (BMPs) on the Water Footprint of Agricultural Productions Shervin Jamshidi1   · Somaye Imani2 · Majid Delavar3 Received: 20 June 2020 / Revised: 24 September 2020 / Accepted: 1 October 2020 © University of Tehran 2020

Abstract Agriculture is the main source of diffuse nutrient pollution in surface waters. It requires best management practices (BMPs) for controlling the discharges of pollutants like total nitrogen (TN) and total phosphorous (TP). In addition, these pollutants are accounted in the grey water footprint (GWF) of agricultural productions. This study proposes an integrated methodology with two steps for assessing the impacts of BMPs on the water footprints (WF) of agricultural productions. First, this approach uses the soil and water assessment tool (SWAT) for basin modeling and calculating the required data for WF assessment. In the second step, the WFs of agricultural productions are quantified and compared in different BMP scenarios, including fertilizer and irrigation reduction (FIR) and the application of vegetated filter strips (VFS). The SWAT modeling shows that FIR and VFS are more effective on TN and TP reduction, respectively. It can estimate that the combination of BMPs has the potential of abating 60% of the TN and TP concentrations of lake in 8 years. However, the WFs of agricultural productions may not be significantly reduced by BMPs as the average GWF only constitutes 4.2% of WF in this basin. For instance, the combination of FIR and VFS can reduce the average WF of cereals from 44 to 41 m3/km2. Nevertheless, this practice is relatively more effective for irrigated crops. The WF of rain-fed crops remains constant on 37 m3/km2, while it is reduced 24% (from 91 to 69 m3/km2) for irrigated crops by BMPs. In addition, it is realized that FIR can adversely reduce the production yields up to 32%. All these findings verify that the proposed methodology can integrate BMP and WF assessments by SWAT modeling and is recommended for basins, where farmlands are the dominated land-use. Article Highlights • The soil and water assessment tool (SWAT) is used for water quality assessment • Best Management Practices (BMPs) are evaluated by the SWAT model • Water footprint of agricultural productions are quantified in different BMPs

Keywords  Agriculture · Best management practices (BMP) · Eutrophication · Grey water footprint (GWF) · Pollution · SWAT​ * Shervin Jamshidi [email protected] Somaye Imani [email protected] Majid Delavar [email protected] 1



Department of Civil Engineering Faculty of Civil Engineering and Transportation, University of Isfahan, Hezar Jerib Ave., Azadi Sq., 81746‑73441 Isfahan, Iran

2



Water Research Institute (WRI), Ministry of Energy, Tehran, Iran

3

Department of Water Resources Engineering, Tarbiat Modarres University, Tehran, Iran



Introduction Eutrophication is a common water quality and environmental problem in basins. Provided that rivers and lakes are enriched with the nutrient polluti