Document Type : Research Paper

Authors

Department of Civil Engineering, Faculty of Engineering, University of Ayatollah Borujerdi, Borujerd, Iran

Abstract

Selection of low flow is necessary for water resource management, water supply planning, and watershed ecosystem restoration. In this study, FL approach was used, which is based on minimum flows and flow duration curve (Q80) categories. This approach was compared with the conventional 7Q10 approach used in low flow selection. For this purpose, the daily flow series from Gharesou catchment was applied. Low flow frequency analysis related to 7Q10 approach was done by fitting various distribution functions and using three frequency software, including HYFA, SMADA, and Easy fit. The results of both approaches show that low flows increased as time elapsed and the recurrence probability of low flow increased while the recurrence interval of low flow decreased as time elapsed. In addition, a low flow decline from 1971 to 2000 observed as 1.57 m3/s and 2.46 m3/s for 7Q10 and FL approaches respectively. The 7Q10 approach lead to selecting extremely low flows (approximately zero). The FL approach used in this study, could result in selecting low flows, considering role of the environment and minimum flow to protect the ecosystem of the catchment.

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Anonymous. (1974). WMO, World Meteorological Organization. International Glossary of Hydrology. WMO, Geneva. 
 
Eslamian S. S., Zarei A. and Abrishamchi A. (2004). Estimation of regional low flow in Mazandaran  rivers watershed. J. Sci. Technol. Agric. Natur. Resour., 8(1), 27-38 [In Persian].
 
Eslamian S. S., Ghasemi M. and Soltani Gerdefaramarzi S. (2012). Computation and regionalization of low flow indices and determination of hydrological drought durations in Karkhe watershed. J. Sci. Technol. Agric. Natur. Resour., Water Soil Sci., 16(59), 1-14 [In Persian].
 
Grandry M., Gailliez S., Sohier C., Verstraete A. and Degr´e A. (2013). A method for low-flow estimation at ungauged sites: a case study in Wallonia (Belgium). J. Hydrol. Earth Syst. Sci., 17, 1319–1330.
 
Hutson S. S. (1988). Instream flow analysis and monitoring procedure for little river in eastern Tennessee. Proc. 1988, the AWRA Symposium on Water-Use Data for Water Research Management, Bethesda; Maryland, USA.  
 
Keshtkar A. R. (2015). Low flow frequency analysis by L-moments method (Case study:  
Iranian Central Plateau River Basin). Desert, 20(2), 167-175.
 
Laaha G. and Bloschl G. (2007). A national low flow estimation procedure for Austria. Hydrol. Sci. J, 52, 625–644.
 
Mandal U. and Cunnane C. (2009). Low-flow prediction for ungaged river catchments in Ireland. 2009, Irish National Hydrology Seminar, Ireland.
 
McMahon T. A. and Mein R. G. (1986). River and reservoir yield. Water Resour Publication, CO., pp. 368.
 
Neubauer C. P., Hall G. B., Lowe E. F., Robison C. P., Hupalo B. R. and Keenan L. W. (2008). Minimum flows and levels method of the St. Johns River Water Management District, Florida, USA. Environ. Manage, 42, 1101– 1114.
 
Onoz B. and Bayazit M. (1999). GEV-PWM model of distribution of minimum flows. J. Hydraul. Eng., 4(3), 289 - 292.
 
Ouyang Y. (2012). A potential approach for low flow selection in water resource supply and management. J. Hydrol., 454-455, 56–63.
 
Reilly C. F. and Kroll C. N. (2003). Estimation of 7-day, 10-year low-stream flow statistics using baseflow correlation. Water Resour. Res, 39(9), 1236, doi:10.1029/2002WR001740
 
Samiee M. and Teluari A. (2008). Investigation of hydrologic drought severity and duration at Tehran Fars province watersheds. J. Pajouhesh Sazandegi, 79, 21-27 [In Persian].
 
SJRWMD, (2010) St. Johns River Water Management District, Chapter 40c–8, F.A.C. Minimum Flows and Levels. St. Johns River Water Management District, Palatka, Florida: 32178.
 
Smakhtin V.U. (2001). Low flow hydrology: a review. J. Hydrol, 240, 147–186.
 
Yue S. and Pilon P. (2005). Probability distribution type of Canadian annual minimum streamflow. Hydrolog. Sci. J, 50, 427–438.