Curve Number: Empirical Evaluation and Comparison with Curve Number Handbook Tables in Sicily
Publication: Journal of Hydrologic Engineering
Volume 19, Issue 12
Abstract
The curve number (CN) method is widely used for estimating direct runoff depth from rainstorms. The procedure is on the basis of the parameter CN, a lumped expression of basin absorption and runoff potential, and a second parameter, initial abstraction (IA), which represents the interception, infiltration, and surface depression during the early part of a storm. The evaluation of CN in Sicily at a basin scale from rainfall-runoff multiday events is done using rainfall-runoff observations during the period 1940–1997 (mean record length of 20 years) in 61 Sicilian watersheds using three different methods: (1) the national engineering handbook, section 4 hydrology (NEH4) method (NEH4M) (the median CN for the annual flood events); (2) asymptotic fitting of ordered and natural data; and (3) least-squares method using rainfall-runoff using both ordered and natural data. Asymptotic fitting showed a major occurrence of the standard CN response (43 basins), with a lesser complacent response (10 basins), and a few cases of violent behavior (three basins). For five basins, the data quality and/or small sample size did not allow the identification of a CN. The least-squares and asymptotic fittings furnished similar results but showed that the original assumption of the initial abstraction ratio ( or ) of 0.20 in watersheds with a standard and violent CN response is unusually high. Using both natural and ordered rainfall-runoff data, a median value of 0 and 0.05 was found for natural data and ordered data, respectively. The CNs found by the recommended handbook method (NEH4 method) were higher than those found from the handbook tables. The asymptotic fitting and least-squares fitting methods were all lower than the table values. Comparisons were made between the CNs estimated using hydrologic soil-cover complexes on the basis of Soil Conservation Service (SCS)–National Resources Conservation Service (NRCS) handbook tables and the CN evaluated from rainfall-runoff multiday events in 36 of the basins. Overall, although comparisons were poor, the NEH4 method and asymptotic fitting method that used all of the ordered data were closest to the CNs from the handbook tables. The link between the CN estimated with the asymptotic fitting method (AFM) (T-series, ordered data) and the watersheds’ morphoclimatic and hydrologic characteristics was also investigated, and a useful relationship for basins with a larger drainage area () was found.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The writers thank the Agenzia Regionale per i Rifiuti e le Acque—Settore Osservatorio delle Acque for providing the data necessary for this work.
References
Agnese, C., D’Asaro, F., Grillone, G., and Drago, A. (2008). “Comparison of temperature data collected in urban and agricultural areas surrounding.” Ital. J. Agrometeorol., 13(1), 48–49.
Annali Idrologici. (1997). “Rainfall-runoff data.” Osservatorio delle Acque, 〈http://www.osservatorioacque.it〉 (Feb. 2, 2009).
Baltas, E. A., Dervos, N. A., and Mimikou, M. A. (2007). “Technical note: Determination of SCS initial abstraction ratio in an experimental watershed in Greece.” Hydrol. Earth Syst. Sci., 11(6), 1825–1829.
Chapman, T. G., and Maxwell, A. I. (1996). “Baseflow separation-comparison of numerical methods with tracer experiments.” Proc., Hydrological and Water Resources Symp., Institution of Engineers Australia, Hobart, Australia, 539–545.
D’Asaro, F., and Grillone, G. (2010). “Runoff curve number method in Sicily: CN determination and analysis of the initial abstraction ratio.” Proc., 4th Federal Interagency Hydrologic Modeling Conf., Advisory Committee on Water Information (ACWI), Washington, DC.
D’Asaro, F., and Grillone, G. (2012). “Empirical investigation of curve number method parameters in the Mediterranean area.” J. Hydrol. Eng., 1141–1152.
D’Asaro, F., Grillone, G., and Hawkins, R. H. (2014). “Curve numbers seasonal variation in Sicily.” J. Hydrol. Eng., in press.
Fennessey, L. A. (2000). “The effect of inflection angle, soil proximity and location on runoff.” Ph.D. dissertation, Pennsylvania State Univ., State College, PA.
Grillone, G., Agnese, C., and D’Asaro, F. (2009). “Estimation of solar radiation in Sicily by daily data maximum and minimum temperature.” Ital. J. Agrometeorol., 14(2), 84–85.
Grillone, G., Agnese, C., and D’Asaro, F. (2012). “Estimation of daily solar radiation from measured air temperature extremes in the mid-Mediterranean area.” J. Irrig. Drain. Eng., 939–947.
Grillone, G., Baiamonte, G., and D’Asaro, F. (2014). “Empirical determination of the average annual runoff coefficient in the Mediterranean area.” Am. J. Appl. Sci., 11(1), 89–95.
Hawkins, R. H. (1984). “A comparison of predicted and observed runoff curve numbers.” Symp., Proc., Water Today and Tomorrow, ASCE, Reston, VA, 702–709.
Hawkins, R. H. (1990). “Asymptotic determination of curve numbers from rainfall-runoff data.” Symp. Proc., Watershed Planning and Analysis in Action, ASCE, Reston, VA, 67–76.
Hawkins, R. H. (1993). “Asymptotic determination of runoff curve numbers from data.” J. Irrig. Drain. Eng., 334–345.
Hawkins, R. H., and Ward, T. J. (1998). “Site and cover effects on event runoff, Jornada experimental range, New Mexico.” Symp. Proc., Conf. on Rangeland Management and Water Resources, American Water Resources Associations, Middleburg, VA, 361–370.
Hawkins, R. H., Ward, T. J., Woodward, D. E., and Van Mullem, J. A. (2009). Curve number hydrology: State of practice, ASCE, Reston, VA, 106.
Hawkins, R. H., Ward, T. J., Woodward, D. E., and Van Mullem, J. A. (2010). “Continuing evolution of rainfall-runoff and the curve number precedent.” Proc., 4th Federal Interagency Hydrologic Modeling Conf., Advisory Committee on Water Information (ACWI), Washington, DC.
Hjelmfelt, A. T. (1980). “Empirical investigation of curve-number technique.” J. Hydraul. Div., 1471–1476.
Manfreda, S., Giordano, C., and Iacobellis, V. (2003). “Stima dei deflussi di base mediante un filtro fisicamente basato.” Proc., Giornata di Studio: Metodi Statistici e Matematici per l’Analisi delle Serie Idrologiche, CNR-GNDCI, Rome, 247–258 (in Italian).
McKnight, T. L., and Hess, D. (2000). Physical geography: A landscape appreciation, Prentice Hall, Upper Saddle River, NJ, 624.
National Resources Conservation Service (NRCS). (2004). National engineering handbook, Part 630 hydrology, USDA, Washington, DC.
National Resources Conservation Service (NRCS). (2009). National engineering handbook, Part 630 hydrology, USDA, Washington, DC.
Noto, L., La Loggia, G., and Pirrello, M. (2001). “Un sistema informativo territoriale per l’analisi del rischio idraulico delle infrastrutture viarie.” Atti della 5a Conferenza Nazionale ASITA, Artestampa s.a.s., Daverio, Italy (in Italian).
Peel, M. C., Finlayson, B. L., and McMahon, T. A. (2007). “Updated world map of the Koppen-Geiger climate classification.” Hydrol. Earth Syst. Sci., 11(5), 1633–1644.
Ponce, V. M., and Hawkins, R. H. (1996). “Runoff curve number: Has it reached maturity?” J. Hydrol. Eng., 11–19.
Sicilian Informative Agrometeorological Service (SIAS). (2002). “Sicilian climatologic atlas.” Dept. of Agriculture of Sicilian Autonomous Region, Sicily, Italy.
Simanton, J. R., Hawkins, R. H., Mohseni-Saravi, M., and Renard, K. G. (1996). “Runoff curve number variation with drainage area, Walnut Gulch, Arizona.” Trans. ASAE, 39(4), 1391–1394.
Soil Conservation Service. (1964). National engineering handbook, section 4 hydrology, USDA, Washington, DC.
Soil Conservation Service. (1972). National engineering handbook, section 4 hydrology, USDA, Washington, DC.
Soil Conservation Service. (1985). National engineering handbook, section 4 hydrology, USDA, Washington, DC.
Stewart, D., Canfield, E., and Hawkins, R. H. (2012). “Curve number determination methods and uncertainty in hydrologic soil groups from semiarid watershed data.” J. Hydrol. Eng., 1180–1187.
Tan, S. B. K., Lo, E. Y., Shuy, E. B., Chua, L. H. C., and Lim, W. H. (2009). “Hydrograph separation and development of empirical relationships using single parameter digital filters.” J. Hydrol. Eng., 271–279.
Titmarsh, G. W., Cordery, I., and Pilgrim, D. H. (1995). “Calibration procedures for rational and USSCS design hydrographs.” J. Hydraul. Eng., 61–70.
Titmarsh, G. W., Cordery, I., and Pilgrim, D. H. (1996). “Closure of calibration procedures for rational and USSCS design flood methods.” J. Hydraul. Eng., 177.
Titmarsh, G. W., Pilgrim, D. H., Cordery, I., and Hossein, A. A. (1989). “An examination of design flood estimations using the U.S. soil conservation services method.” Proc., Hydrology and Water Resources Symp., Institution of Engineers, Barton, ACT, Australia.
Tudisca, S., Di Trapani, A. M., Sgroi, F., and Testa, R. (2013a). “The cost advantage of Sicilian wine farms.” Am. J. Appl. Sci., 10(12), 1529–1536.
Tudisca, S., Di Trapani, A. M., Sgroi, F., and Testa, R. (2014). “Organic farming and economic sustainability. The case of Sicilian durum wheat.” Quality Access Success, 15(138), 93–96.
Tudisca, S., Di Trapani, A. M., Sgroi, F., Testa, R., and Squatrito, R. (2013b). “Economic analysis of PV systems on buildings in Sicilian farms.” Renew. Sustain. Energy Rev., 28, 691–701.
Van Mullem, J. A., Woodward, D. E., Hawkins, R. H., Hjelmfelt, A. T., and Quan, Q. D. (2002). “Runoff curve number method: Beyond the handbook.” Proc., 2nd Federal Interagency Hydrologic Modeling Conf., Advisory Committee on Water Information (ACWI), Washington, DC.
Viola, F., Noto, L. V., Cannarozzo, M., and La Loggia, G. (2011). “Regional flow duration curves for ungauged sites in Sicily.” Hydrol. Earth Syst. Sci., 15(1), 323–331.
Woodward, D. E., Hawkins, R. H., Hjelmfelt, A. T., Van Mullem, J. A., and Quan, Q. D. (2002). “Curve number method: Origins, applications and limitations.” Proc., 2nd Federal Interagency Hydrologic Modeling Conf., Advisory Committee on Water Information (ACWI), Washington, DC.
Woodward, D. E., Van Mullem, J. A., Hawkins, R. H., and Plummer, A. (2010). “Curve number completion study.” Consultant’s Rep. to USDA, National Resources Conservation Service, Beltsville, MD.
Information & Authors
Information
Published In
Journal of Hydrologic Engineering
Volume 19 • Issue 12 • December 2014
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Nov 8, 2013
Accepted: Mar 6, 2014
Published online: Mar 15, 2014
Published in print: Dec 1, 2014
Discussion open until: Dec 21, 2014
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.