Investigating the effects of best management practices on the reduction of point and non-point source pollution of water using SWAT model (Case Study: Seimareh River)

Document Type : Research Paper


1 University of Tehran

2 University of tehran


Surface water quality has a far-reaching impact on the human health and aquatic ecosystems. The sources of surface water pollutions include Point Source (PSP) and Non-Point Source Pollution (NPSP). The action of Identifying the point source and non-point source pollutions is critical to evaluate surface water quality and major pollutant sources in a watershed. In this study, Soil and Water Assessment Tool (SWAT) was used to investigate the influence of PS and NPS Pollution on the water quality. The model was calibrated for the period 2000-2009, and then it was validated for the period of 2010 to 2011. The values of Nash-Sutcliffe efficiency (ENS) and R2 for simulations of flow and nutrient loads range from 0.84 to 0.96 for calibration period, while they vary from 0.69 to 0.85 for the validation period used for flow simulation. The statistical results revealed that the SWAT model simulated the monthly flow and nutrient loads satisfactorily in Seimareh watershed. Also, SWAT model was used to identify the critical source areas (CSAs) of sediment, TN and TP at the watershed level. SWAT model identifiedof 9 sub-the watershed (33% of total watershed area) as CSAs for TN and TP.  The sub-watersheds 1, 6, 10, 17, 21,22, 25, 26 and 29 were identified as CSAs of TN and TP while most of these sub-watersheds were also identified as sediment CSAs. Then, the model was also used to simulate the impact of Best Management Practices (BMPs) at controlling nutrient losses. Major BMPs implemented were reducing chemical fertilizer application, and building a filter strip along the river bank. The result of WQI demonstrates that water quality at the upstream is generally better than the downstream with higher level of nutrient loads. Also, the seasonal variations  WQI clearly indicates the summer and autumn season as the critical time period for nutrient loads within the watershed. The result showed that the BMP scenario reduced the pollutant losses compared to the baseline condition, and the greatest reduction in the nutrient losses was observed in the filter strip located along the river with percentage reductions of 68%, 36% and 39% for sediment, TN and TP, respectively. Overall, this study helps our understanding of the status of water quality and the role of the best management practices (BMP) options to improve water quality.


Main Subjects

Abbaspour, K.C., Yang, J., Maximov, I., Siber, R., Bogner, K., Mieleitner, J., Zobrist, J. and Srinivasan.(2007). Modelling hydrology and water quality in the pre-alpine/alpine Thur watershed using SWAT. Journal of Hydrology, 333, 413– 430.
Abbaspour, K.C .(2015). SWAT‐CUP: SWAT calibration and uncertainty programs.1-100.
Arnold, J. G., Srinivasan, R., Muttiah, R. S. and Williams, J.R. (1998). Large area hydrologic modeling and assessment – part 1: model development. J. Am. Journal of Water Resource Associate, 34(2), 73–89.
Brown, L.C. Barnwell, J.T.O. (1987). The Enhancement Water Quality Models QUAL2E and QUAL2E –UNCAS Documentation and user Manual. USEPA, Athens, GA.
Behera, S. and Panda, RK: (2006). Evaluation of management alternatives for an agricultural watershed in a sub-humid subtropical region using a physical process based model. Agriculture, Ecosystems and Environment., 113, 62–72.
Carpenter, S.R., Caraco, N.F., Correll, D.L., Howarth, R.W., Sharpley, A.N. and Smith V.H. (1998). Nonpoint pollution of surface waters with phosphorus and nitrogen. Journal of Ecological Applications, 8 (3), 559–568.
Chen, Y., Shuai, J., Zhang, ZH., Shi, P. and Tao, F. (2014). Simulating the impact of watershed management for surface water quality protection: A case study on reducing inorganic nitrogen load at a watershed scale. Journal of Ecological Engineering, 62, 61– 70.
Douglas-Mankin, K R., Srinivasan, R. and Arnold, J. G. (.2010). Soil and Water Assessment Tool (SWAT) Model: Current Developments and Applications. Trans, 53, 1423–1431.
Gassman, P .W., Reyes, M. R., Green, C. H. and Arnold, J. G. (2007). The soil and water assessment tool historical development, applications, and future research directions. Trans. ASABE 50, 1211–1250.
Gholami, Sh. And Nasii, M. (2015). Simulation of Atrak River monthly discharge using SWAT model, Case study: Maraveh Tappeh watershed, Gholestan province. Journal of Watershed Engineering and Management, 7 (2), 126-135. (In Farsi)
Green, C. H. and Van Griensven, A: (2008). Autocalibration in hydrologic modeling: using SWAT2005 in small-scale watersheds. Journal of Environmental Model Software, 23: 422–434.
Lee, M.S., Park, G.A., Park, M.J., Park, J.Y., Lee, J.W. and Kim, S.J. (2010). Evaluation of non-point source pollution reduction by applying Best Management Practices Using a SWAT model and QuickBird high resolution satellite imagery. Journal of Environment Science, 22(6), 826-833.
Lam, Q D., Schmalz, B. and Fohrer, N. (2010). Modelling point and diffuse source pollution of nitrate in a rural lowland catchment using the SWAT model. Agricultural Water Management, 97, 317–325.
Niraula, R., Kalin, L., Srivastava, P. and Anderson Ch. (2013). Identifying critical source areas of nonpoint source pollution with SWAT and GWLF. Journal of Ecological Modelling, 268, 123– 133.
Neitsch, S. L., Arnold, J. G., Kiniry, J. R., Williams, J. R. and King, K. W. (2005). Soil and Water Assessment Tool Theoretical Documentation. Grassland, Soil and Research Service, Temple, TX.
Natural Resource Conservation Service NRCS. (2008). Natural Resource Conservation Practice standard: Filter strips.
Mwangi, JK., Shisanya, CA., Gathenya, JM., Namirembe, S. and Moriasi. (2015) A modeling approach to evaluate the impact of conservation practices on water and sediment yield in Sasumua Watershed, Kenya. Soil and Water Conservation, 70 (2),75-90.
Parajuli, P.B., Mankin, K.R. and Barenes, P.L. ( 2008). Applicability of targeting vegetative filter strips to abate fecal bacteria and sediment yield using SWAT. Journal of Agriculture and Water Management, 95 (10), 1189-1200.
Sahu, M. and Gu, R.R. (2009). Modeling the effect s of riparian buffer zone and contour strips on stream water quality. Journal of Ecological Engineering, 35(8), 1167-1177.
Strauss, P., Leone, A, Ripa, M.N., Turpin, N. and Lescot, R. (2007). Using Critical Source Areas for targeting cost –effective best management practices to mitigate phosphorus and sediment transfer at watershed scale. Journal of Soil use Management, 23,144-153.
Scavia, D., Allan, J. D., Arend, K.K., Bartell, S., Beletsky, D., Bosch, N., Brandt, S. B., Briland, R .D., Daloğlu, I., DePinto, J. V., Dolan, D. M., Anne Evans, M., Farmer, T.M., Goto, D., Han, H., Höök, T.O., Knight, R., Ludsin, S. A., Mason, D., Michalak, A. M., Richards, R. P., Roberts, J.J., Rucinski, D. K., Rutherford, E., Schwab, D. J., Sesterhenn, T. M., Zhang, H. and Zhou, Y. (2014). Assessing and addressing the re-eutrophication of Lake Erie: Central basin hypoxia. Journal of Great Lakes Research, 40, 226-246.
Shen, Z.Y., Liao, Q., Hong, Q. and Gong, Y.W. (2012). An overview of research on agriculture non-point source pollution modeling in china. Purif. Journal of Technology ,84, 104-111.
Shaikhzeinoddin, A., Esmaili, A.K. and Noshadi, M. (2016). The effect of irrigation management and fertilization strategies on nitrogen losses using SWAT model. Journal of Water and Soil Science, 19, 74, 141-153. (In Farsi)
Volk, M., Hirschfeld, J., Dehnhardt, A., Schmidt, G., Bohn, C., Liersch, S. and Gassman, P.W. (2008). Integrated ecological-economic modeling of water pollution abatement management options in the upper Ems River Basin. Journal of Ecological Economic, 66 (1), 66-76.
White, M.J., Storm, D.E., Busteed, P.R., Stoodley, S.H. and Philips, S.J. ( 2009). Evaluation non-point source critical source areas contribution at the watershed scale. Journal of Environment Quality, 38, 1654-1663.
Wu, Y. and Chen, J.( 2013). Investigating the effects of point source and nonpoint source pollution on the water quality of the East River (Dongjiang) in South China. Journal of Ecological Indicators, 32, 294– 304.
Zhang, X. and Zhang, M. (2011). Modeling effectiveness of agricultural BMPs to reduce sediment load and organophosphate pesticides in surface runoff. Journal of Science of the Total Environment, 409(10),1949-58.