Evaluation of Non-Point Source N and P Loads in a Small Mixed Land Use Land Cover Watershed

Ashok Mishra, Rajendra Singh, Vijay P. Singh

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DOI: 10.4236/jwarp.2010.24042                

Abstract

Non-point source pollution (NPS) of water resources has become a major problem in recent years due to more human interactions and disturbances to natural landscapes. The problem can have more impacts in sub-humid subtropical regions where high intensity monsoon rains have greater effects on hydrologic proc-esses and thus the assessment of those effects is necessitated for strategic water resources and environmental management. Since spatial and temporal changes of NPS pollutants are difficult to assess on a watershed scale, the assessment can be done effectively using a suitable water quantity-quality model coupled with GIS and remote sensing that incorporates spatial variations. The objective of this study was to assess the N and P loads from a small mixed type watershed comprising different land use land covers with the aid of Soil and Water Assessment Tool (SWAT)-a hydrologic-water quality model. The model was calibrated for runoff and sediment transport and then simulation of associated N and P loads as NPS pollution was done and compared with measured values at the outlet of the watershed which is part of the DVC Command, Hazaribagh, India. The calibrated SWAT model was used to estimate the water soluble NO3-N, NH4-N, P, organic N and or-ganic P loads being transported as pollutants by runoff and percolated water. The estimates of these pollut-ants provided information on the extent of NPS pollution of water downstream. The results of the study re-veal that the NPS pollutant load in runoff varies with seasonal rainfall patterns and ranges from 2.57 to 4.52 kg/ha in case of NO3-N which accounts for a maximum load of 7661.40 kg of NO3-N in surface runoff from the watershed under study. The total loss of N from the watershed accounts for as high as 8.84 kg/ha, whereas the P load is 0.02 kg/ha. These losses can be as high as 14984.14 kg of total N and 50.85 kg of total P when estimated as NPS pollutants from the watershed. The study is therefore important to get an estimate of the extent of these pollutants and develop measures for mitigating the losses as nutrient as well as pollu-tion of water resources.

Keywords

Modeling, Watershed, Swat, N&P Nutrient Load, NPS Pollution

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	M. Neill, “Nitrate Concentrations in River Water in the South-east of Ireland and their Relationship with Agri-cultural Practices,” Water Science Research, Vol. 23, 1989, pp. 1339-1355.
[2]	G. G. Wright, A. C. Edwards, J. G. Morrice and K. Pugh, “North East Scotland River Catchment Nitrate Loading in Relation to Agricultural Intensity,” Chemistry and Ecol-ogy, Vol. 5, 1991, pp. 263-281.
[3]	B. Kronvang, R. Grant, S. E. Larsen, L. M. Svendsen and P. Kristensen, “Non-point-source Nutrient Losses to the Aquatic Environment in Denmark: Impact of Agricul-ture,” Marine Freshwater Research, Vol. 46, 1995, pp. 146-177.
[4]	Z. Liu, D. E. Weller, D. L. Correll and T. E. Jordan, “Effects of Land Cover and Geology on Stream Chemistry in Watersheds of Chesapeake Bay,” Journal of the American Water Resources Association, Vol. 36, No. 6, 2000, pp. 1349-1365.
[5]	I. Y. Yeo, S. I. Gordon and J. M. Guldmann, “Optimizing Patterns of Land Use to Reduce Peak Runoff Flow and Nonpoint Source Pollution with an Integrated Hydro-logical and Land-use Model,” Journal of Earth Interac-tions, Vol. 8, No. 6, 2004, pp. 1-20.
[6]	O. Nagafuchi, T. Inoue and S. Ebise, “Runoff Pattern of Pesticides from Paddy Fields in the Catchment Area of Rikimaru Reservoirs, Japan,” Water Science and Technology, Vol. 30, No. 7, 1994, pp. 137-144.
[7]	O. Kawara, K. Hirayma and T. Kunimatsu, “A Study on Pollutant Loads from the Forest and Rice Paddy Fields,” Water Science and Technology, Vol. 33, No. 4-5, 1996, pp. 159-165.
[8]	J. Kammerbauer and J. Moncada, “Pesticide Residue Assessment in Three Selected Agricultural Production Systems in the Choluteca River Basin of Honduras,” En-vironmental Pollution, Vol. 103, No. 2-3, November 1998, pp. 171-181.
[9]	H. E. Andersen, B. Kronvang and S. E. Larsen, “Agricultural Practices and Diffuse Nitrogen Pollution in Denmark: Empirical Leaching and Catchment Models,” Water Science and Technology, Vol. 39, No. 12, 1999, pp. 257-264.
[10]	USEPA, “Guidance Specifying Management Measures for Sources of Non-point Pollution in Coastal Waters,” United States Environmental Protection Agency, Office of Water, Washington, D.C., EPA/840-B-92-002, 1993.
[11]	USEPA, “Chesapeake Bay: A Framework for Action,” United States Environmental Protection Agency, Phila-delphia, Pennsylvania, 1983.
[12]	M. Borin and E. Bigon, “Abatement of NO3-N Concen-tration in Agricultural Waters by Narrow Buffer Strips,” Environmental Pollution, Vol. 117, 2002, pp. 165-168.
[13]	G. D. Liu, W. L. Wu and J. Zhang, “Regional Differen-tiation of Non-point Source Pollution of Agriculture-derived Nitrate Nitrogen in Groundwater in Northern China,” Agriculture, Ecosystems and Environment, Vol. 107, 2005, pp. 211-220.
[14]	J. R. Scudlark, J. A. Jennings, M. J. Roadman, K. B. Savidge and W. J. Ullman, “Atmospheric Nitrogen Inputs to the Delaware Inland Bays: The Role of Ammonia,” Environmental Pollution, Vol. 135, 2005, pp. 433-443.
[15]	D. K. Mondal and S. Kar, “Soil Loss of Nitrogen under Rice,” Journal of Indian Society of Soil Science, Vol. 39, 1991, pp. 764-766.
[16]	G. D. Agrawal, “Diffuse Agricultural Water Pollution in India,” Water Science and Technology, Vol. 39, No. 3, 1999, pp. 33-47.
[17]	G. D. Agrawal, S. K. Lunkad and T. Malkhed, “Diffuse Agricultural Nitrate Pollution of Groundwaters in India,” Water Science and Technology, Vol. 39, No. 3, 1999, pp. 67-75.
[18]	S. Kar, R. K. Malla, N. Mogilaiah and K. J. Parashram, “Modelling Fertilizer Nitrogen Transport in Rice Ecosys-tems,” In: B. B. Jana, R.D. Banergee, B.Guterstam and J. Heeb Ed., Waste Recycling and Resource Management in the Developing World: Ecological Engineering Approach, University of Kalyani and University of Switzerland, 2000, pp. 647-656.
[19]	K. A. Poiani and B. L. Bedford, “GIS-based non-point Source Pollution Modelling: Considerations for Wetlands,” Journal of Soil and Water Conservation, Vol. 49, No. 6, 1995, pp. 613-619.
[20]	M. D. Yang, C. J. Merry and R. M. Sykes, “Integration of Water Quality Modelling, Remote Sensing, and GIS,” Journal of American Water Resources Association, Vol. 35, No. 2, 1999, pp. 253-263.
[21]	M. Noguchi, T. Hiwatashi, Y. Mizuno and M. Minematsu, “Pollutant Runoff from Non-point Sources and its Esti-mation by Runoff Models,” Water Science and Technol-ogy, Vol. 46, No. 11-12, 2002, pp. 407-412.
[22]	F. Morari, E. Lugato and M. Borin, “An Integrated Non- point Source Model-GIS System for Selecting Criteria of Best Management Practices in the Po Valley, North It-aly,” Agriculture, Ecosystems and Environment, Vol. 102, No. 3, 2004, pp. 247-262.
[23]	R. Nielsen, T. Sobecki, R. Bigler and D. Lytle, “Applica-tion of Soil Survey Attribute Data to GIS Pollution As-sessment Models,” In: D. L. Corwin and K. Loague Ed., Applications of GIS to the Modeling of Non-point Source Pollutants in the Vadose Zone, Soil Science Society of America Special Publication, Madison, No. 48, 1996, pp. 175-183.
[24]	Yong Li and J. Zhang, “Agricultural Diffuse Pollution from Fertilizers and Pesticides in China,” Water Science and Technology, Vol. 39, No. 3, 1999, pp. 25-32.
[25]	V. de Vlaming, C. DiGiorgi, S. Fong, L. A. Deanovic, M. D. Carpio-Obeso, J. L. Miller, M. J. Miller and N. J. Richard, “Irrigation Runoff Insecticide Pollution of Riv-ers in the Imperial Valley, California (USA),” Environ-mental Pollution, Vol. 132, No. 2, 2004, pp. 213-229.
[26]	A. Kull, E. Uuemaa, V. Kuusemets and Ü. Mander, “Modelling of Excess Nitrogen in Small Rural Catch-ments,” Agriculture, Ecosystems and Environment, Vol. 108, 2005, pp. 45-56.
[27]	J. G. Arnold and P. M. Allen, “Estimating Hydrologic Budgets for Three Illinois Watersheds,” Journal of Hy-drology, Vol. 176, 1996, pp. 57-77.
[28]	A. D. McElroy, S. Y. Chiu, J. W. Nebgen, A. Aleti and F. W. Bennett, “Loading Functions for Assessment of Water Pollution from Non-point Sources,” Environmental Pro-tection Technology and Service, EPA 600/2-76-151, 1976.
[29]	J. R. Williams and R. W. Hann, “Optimal Operation of Large Agricultural Watersheds with Water Quality Con-straints,” Texas Water Resources Institute, Texas A&M University Technical Report, No. 96, 1978.
[30]	R. G. Menzel, “Enrichment Ratios for Water Quality Modeling,” In: W.G. Knisel, Ed., CREAMS: A Field Scale Model for Chemicals, Runoff, and Erosion from Agricultural Management Systems Conservation Re-search Report, No. 26, 1980, pp. 486-492.
[31]	“USDA Soil Conservation Service,” Section 4: Hydrol-ogy, National Engineering Handbook, Washington, D.C., 1972
[32]	J. E. Nash and J. V. Sutcliffe, “River Flow Forecasting Through Conceptual Models, Part 1: A Discussion of Principles,” Journal of Hydrology, Vol. 10, No. 3, 1970, pp. 282-290.
[33]	R. L. Bingner, C. E. Murphee and C. K. Mutchler, “Comparison of Sediment Yield Models on Watershed in Mississippi,” Transactions of the ASAE, Vol. 32, No. 2, 1989, pp. 529-534.
[34]	M. W. Liew and J. Garbrecht, “Hydrologic Simulation of the Little Washita River Experimental Watershed Using SWAT,” Journal of American Water Resources Associa-tion, Vol. 39, No. 2, June 2007, pp.413-426.
[35]	M. Rahman and I. Salbe, “Modelling Impacts of Diffuse and Point Source Nutrients on the Water Quality of South Creek Catchment,” Environment International, Vol. 21, No. 5, 1995, pp. 597-603.
[36]	A. Saleh, J. G. Arnold, P. W. Gassman, L. M. Hauck, W. D. Rosenthal, J. R. Williams and A. M. S. McFarland, “Application of SWAT for the Upper North Bosque River Watershed,” Transactions of ASAE, Vol. 43, No. 5, 2001, pp. 1077-1087.
[37]	B. Grizzetti, F. Bouraoui, K. Granlund, S. Rekolainen and G. Bidoglio, “Modelling Diffuse Emission and Retention of Nutrients in the Vantaanjoki Watershed (Finland) Us-ing the SWAT Model,” Ecological Modelling, Vol. 169, No. 1, 2003, pp. 25-38.