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The worthiness of using information on land-use–land-cover in watershed models for Western Ghats: A case study

  • Mysuru R Yadupathi PuttyEmail author
  • B M Kavya
Article
  • 33 Downloads

Abstract

The variable source area (VSA) theory of runoff generation mechanisms has been proved to hold good in many wet mountainous areas, decades ago. According to this theory, infiltration-excess overland flow is limited to very small areas in mountainous and forested catchments. But, the perception that the land surface characteristics, including land-use–land-cover (LULC), form the major factors influencing the response of the catchment to rainfall has dominated the thought in hydrology to such an extent that models based on the overland flow theory continue to be used even in such areas. The present study was taken up in order to understand the worthiness of using parameters, including the curve number (CN), that are based on the physiographic characteristics of the catchment in a watershed model designed to estimate runoff in the wet mountainous areas of the Western Ghats in southern India, where the VSA theory has been proved to hold good. The study has been accomplished by applying the NITK model developed for estimating runoff using daily rainfall data. This model is believed to estimate reliably the streamflow in the region using parameter values that can be computed from catchment characteristics. In the present study, it is applied on three gauged streams in the region of Western Ghats in Karnataka. Initially, the performance of the model has been studied with the parameters fixed using the catchment characteristics. Later, the model has been used as a tool to test hypotheses concerning the catchment response, by varying the parameter values, adopting a trial and error procedure. Initial results showed that the model performance is poor as the coefficients of efficiency vary between –66.9 and 82%. The sensitivity analysis carried out subsequently showed that the model parameters are required to be altered greatly for good performance and that the model simulations are not sensitive to the parameter CN. Further, the performance of this model was compared with that of a VSA model, known to suit the region well. This showed that even after all the changes in the model parameters, the model results are not highly reliable. Hence, in order to understand the reasons for the poor performance of the model, a technique was developed to compute the CN values that would be actually necessary to simulate daily direct runoff (DRO) reliably in this method, the daily values of CN are computed by applying backwards the expression for runoff on the DRO estimated by the VSA model. The variations in the values of CN computed using this method are then studied. It is found that the variations in daily CN are high and highly random too, whereas the NITK model uses only three fixed values of CN. It is thus concluded that factors other than those on which the CN is popularly believed to depend control the runoff generation in the region and that influence of LULC on runoff is not discernible at all from the kind of data that is commonly available.

Keywords

Curve number method variable source area theory streamflow components influence of LULC curve number and contributing area 

Notes

Acknowledgements

This study is a part of the research project ‘Impact of LULC Changes on Streamflow Regime – A case study of Netravathi Catchment, Karnataka’, sponsored by ISRO, under its RESPOND Programme. The authors acknowledge the financial assistance provided for the project by ISRO. The authors also acknowledge the students of The National Institute of Engineering, Mysuru, who are involved in the studies concerning the project.

References

  1. Aitken A P 1973 Assessing systematic errors in rainfall-runoff models; J. Hydrol. 20 121–136.CrossRefGoogle Scholar
  2. Anderson M G and Burt T P 1985 Modelling strategies; In: Hydrological Forecasting (eds) Anderson M G and Burt T P, John Wiley & Sons Ltd.Google Scholar
  3. Borugeon G 1989 Explanatory booklet on the reconnaissance soil map of forest area: Western Karnataka and Goa; French Institute, Pondicherry, India, 95p.Google Scholar
  4. Chow V T, Maidment D R and Mays L W 1988 Applied Hydrology; McGraw Hill Book Co. Ltd.Google Scholar
  5. CUSU (Central unit for soil conservation), hydrology and sedimentation 1972 Handbook of Hydrology; Ministry of Agriculture, Government of India.Google Scholar
  6. CWC (Central Water Commission) 2010 Development of hydrological design aids (surface water) under HP-II, State of the Art Report Revision: R2vi Document: 2009097/WR/REP-02, October 2010.Google Scholar
  7. Darshan R 2016 Some studies on hydrological properties of soils in the upland areas of the Gundia Basin; Unpublished M.Tech dissertation, The National Institute of Engineering, Mysuru, India.Google Scholar
  8. Geetha K, Mishra S K, Eldho T I, Rastogi A K and Pandey R P 2008 SCS-CN-based continuous simulation model for hydrologic forecasting; Water Resour. Manag. 22 165–190,  https://doi.org/10.1007/s11269-006-9149-5.CrossRefGoogle Scholar
  9. Hawkins M 1978 Runoff curve numbers in varying site moisture; J. Irrig. Drain. 4 392–396.Google Scholar
  10. Hewlett J D and Hibbert R A 1967 Factors affecting the response of small watersheds to precipitation in humid areas; Proceedings of International Symposium on Forest Hydrology 1965, Pennsylvania State University, Pergamon Press, New York, pp. 275–289.Google Scholar
  11. Mishra S K 1998 Long-term hydrologic simulation using SCS-CN method; Technical Report, National Institute of Hydrology, Roorkee, India.Google Scholar
  12. Mishra S K 2000 SCS-CN based long term hydrologic simulation; Technical Reports, National Institute of Hydrology, Roorkee, India.Google Scholar
  13. Mishra S K and Singh V P 1999 Another look at the SCS-CN method; ASCE J. Hydrol. Eng. 4(3) 257–264.CrossRefGoogle Scholar
  14. Mishra S K, Geetha K, Rastogi A K and Pandey R P 2005 Long-term hydrologic simulation using storage and source area concepts; Hydrol. Process. 19 2845–2861.CrossRefGoogle Scholar
  15. Mishra S K, Goel N K, Seth S M and Srivastava D K 1998 An SCS-CN-based long-term daily flow simulation model in a hilly catchment; International Symposium on Hydrology of Ungauged Streams in Hilly Regions for small Hydropower Development, New Delhi, India.Google Scholar
  16. Mohan H S and Nair K S 1986 Hydro-climatic studies of the Western Ghats; Mausam 37(3) 329–331.Google Scholar
  17. Nandagiri L 2002 Calibrating hydrological models in ungauged basins: Possible use of areal evapotranspiration instead of streamflows; Proceedings of the PUB Kick-off meeting held in Brasilia, IAHS Publications, 309p.Google Scholar
  18. Nandagiri L and Shetty A 2009 Final report on the ISRO sponsored project – Integrating RS, GIS and hydrologic data for assessment of rural water sources (RESPOND Pr No 10/4/363).Google Scholar
  19. Nandagiri L, Shetty A and Rajesh M V S 2004 A hydrologic model with identifiable parameters for predictions in ungauged basins; Proceedings of Workshop on Predictions in ungauged basins for sustainable water resources planning and management, BITS, Pilani, pp. 43–48.Google Scholar
  20. Pascal J P 1984 Wet evergreen Forests of the Western Ghats; French Institute, Pondicherry, India.Google Scholar
  21. Prasad R and Malhotra K 1987 Some aspects of water resources in Karnataka; Department of Civil Engineering, Indian Institute of Science, Bengaluru, India.Google Scholar
  22. Putty M R Y 2006 Salient features of the hydrology of the Western Ghats in Karnataka; In: Hydrology and watershed services in the Western Ghats of India (eds) Krishnaswamy J, Lele S and Jayakumar R, Tata-McGraw Hill Publ. Co. Ltd., New Delhi, India.Google Scholar
  23. Putty M R Y 2009 A curve number based watershed model incorporating quick subsurface runoff, with applications in the Western Ghats, south India; ASCE J. Hydrol. Eng. 14(8) 876–881.CrossRefGoogle Scholar
  24. Putty M R Y 2010 Principles of Hydrology; IK Int. Publ. House Pvt. Ltd., New Delhi, India.Google Scholar
  25. Putty M R Y and Prasad R 2000a Understanding runoff processes using a watershed model – A case study in Western Ghats in south India; J. Hydrol. 228 215–227.CrossRefGoogle Scholar
  26. Putty M R Y and Prasad R 2000b Runoff processes in head water catchments – An experimental study in Western Ghats, south India; J. Hydrol. 235 63–71.CrossRefGoogle Scholar
  27. Putty M R Y, Pradeep M P and Nagaraj M K 2007 Catchment response simulated by two variable source area models in a Western Ghat catchment; Proceedings WNCE’07 (Watershed Management and impact of Environmental charges on Water Resources), JNTU, Hyderabad, India.Google Scholar
  28. Putty M R Y, Prasad V S R K and Ramaswamy R 2000 A study on the rainfall intensity pattern in Western Ghats, Karnataka; Proceedings of the Workshop on Watershed Development in Western Ghats, CWRDM, Kozikhode, Kerala, India, pp. 44–51.Google Scholar
  29. Putty R Y 1994 The mechanisms of streamflow generation in the Sahyadri ranges (Western Ghats) of south India; Unpublished Ph.D. thesis, Indian Institute of Science, Bangaluru, India.Google Scholar
  30. Putty R Y and Prasad R 1992 Application of a variable source area model for Western Ghats; Proceedings of International Symposium on Hydrology of Mountainous Areas, Shimla, India, pp. 439–450.Google Scholar
  31. Putty R Y, Reddy P M and Reddy J V S 1996 Developing the curve number method into a variable source area watershed model; Proceedings of National Seminar HYDRO-96, Kanpur, India, pp. 53–57.Google Scholar
  32. Subramanya K 2013 Engineering Hydrology; 4th edn, Tata McGraw Hill Publ. Co. Ltd., New Delhi, India.Google Scholar
  33. Ward R C 1983 Hypothesis testing by modelling catchment response; J. Hydrol. 67 281–305.CrossRefGoogle Scholar
  34. Ward R C 1984 On the response of head water streams in humid areas; J. Hydrol. 74 171–189.CrossRefGoogle Scholar

Copyright information

© Indian Academy of Sciences 2018

Authors and Affiliations

  1. 1.The National Institute of EngineeringMysuruIndia
  2. 2.BGSITBellur, Mandya DistrictIndia

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