River floor instability analysis using critical shear stress and discharge critical unit (Galali river case study, Qorve, Kurdistan)

Subject Areas : rosub

Mohammad Mehdi Hoseinzadeh ¹ , Milad Rostami ²

1 - Associate professor, Department of Natural Geography, Faculty of Earth Science, Shahid Beheshti University
2 - Ph.D student of Geomorphology, Department of Natural Geography, Faculty of Earth Science, Shahid Beheshti University

Received: 2017-03-15 Accepted : 2017-08-05 Published : 2017-08-23

Keywords: Move threshold sediment particles, Critical shear stress, critical unit discharge, Galali river,

Abstract :

One of the key issues of erosion and stability of the river is the beginning the movement of sediment particles. River sediment yield caused water turbidity, nutrients and pollution problems of water, buried in the water diversion facilities as well as filling the water storage lakes. Flow that will start moving particle, called the critical flow. The initial move threshold sediment particles has been investigated in several different methods, most important of which are the average critical velocity, critical shear stress and critical unit discharge. To investigate the stability of the Galali river bed sediments in the city of Qorveh, according to river conditions used the critical shear stress and critical unit discharge methods. To determine initial move threshold sediment particles in the bed of the river were two cross-section of the river, two cross-section conditions were assessed. After that, the critical shear stress and critical unit discharge for four particle size D16, D50, D84 and D95 in each cross-section was calculated, and showed that in cross-section (1,2) in the bankfull discharge conditions all particles with sizes D16, D50, D84 and D95 begin to moving, and so in the bankfull discharge, sediment conditions will generally change. In cross-section (3) particles with a diameter D95 and the more it will be remain stable in the river bed, and other smaller particles of this size are starting to move. Due to further slope of the bed and width less active channel in the cross-section (1,2) has caused that all particles are unstable. Finally, the results from both methods were highly concordant, and this confirms that the use of these methods for stabilizes studies and sediment yield of river are appropriate. 

References:

 

 

References:

1. Haddadchi, A., M. H. Omid, & A.A, Dehghani, 2011. Evaluation of Bed Load Discharge Formulas in Alpine Gravel Bed Rivers (Case study: Chehel Chai river in Golestan province). Journal of Water and Soil Conservation, 18(3): 149-167 (In Persian).


2. Khastar Broojeni, M., H. Samadi Broojeni, & K. Esmaeli, 2013. Experimental study of shear stress threshold of sediments deposited clay - silt at different concentrations. Iranian Water Research Journal, 13: 131-138 (In Persian).


3. Hosseinzadeh, M.M., R. Esmaeali, 2013. Fluvial Geomorphology: concepts, forms and processes, Shahid Beheshti University Press, Tehran (In Persian).


4. Rezayi Moghaddam, M.H., M.R. Servati, & S. Asghari, 2012. Analysis of the Stability of River Channels Using Methods of Bed Shear Stress and the Relative Strength Index (Ranging Between 30 km Miyaneh City to the Zanjan Political Boundaries). Journal of Quantitative Geomorphological Research, 1: 33-46 (In Persian).


5. Asghari Saraskanroud. S., & B. Zeinali, 2014. Investigation Resistance of Sediment Particle to Erosion in Saraskanchai River by Use of Mathematical Methods. Environmental Erosion Research Journal, 12: 30-42 (In Persian).


6. Fooladfar .H, Shafai Bajestan .M ,& Fathi Moghaddam. M,( 2012). Experimental study and modeling of critical shear stress for cohesive sediment erosion, Irrigation and water engineering journal. 8 (3): 78-94 (In Persian).


7. Ghamshi, M., & N. Vejdani, 2005. Erosional critical shear stress of sticky sediments and their impact on modelling of outdoor channels, International Journal of Engineering. 18 (3): 83-93 (In Persian).


8. Madadi, A., E. Beheshti Javid, & M.H. Fathi, 2012.  Detection of river bed changes and river morphology survey on the effects of geological structures (case study: Zarinehroud), Journal of Hydrogeomorphology. 1 (2): 25-40 (In Persian).


9. Niri, H., 2010. Dynamic analysis and duct shape in the catchment area of ​​the Mahabad River, Natural Geography Ph.D thesis, Geomorphology Orientation, Faculty of Geography, Tabriz University (In Persian).


10. Bizzi.,s and Lerner.,D.N. 2015, The use of stream power as an indicator of channel sensitivity to erosion and deposition processes, River research and application River Res.applic.31: 16-27


11. Coryat., M, 2014, Analysis of the Bank Assessment for Non-point Source consequences of Sediment (BANCS) Approach for the Prediction of Streambank Stability and Erosion along stony Clove Creek in the Catskills, Master Theses, Syracuse University.


12. Mighui, Y., Hongyan, W.,Yanjie, L., and Chunyan, H., 2010, Study on Stability of Noncohesive River Bank, International Journal of Sediment Research, Vol. 25, No. 4,pp.391-398


13. Rinaldi M; Simoncini C; Piegay H. (2009). Scientific design strategy for promoting sustainable sediment management: the case of the magra river (central northern Italy) river research and application 25. pp. 607-625.


14. Tokaldany E.A., Darby S. E., and P. Tosswell.,2007. Coupling bank stability and deformation models to predict equilibrium bad topography in river bends. Journal of Hydraulic Engineering, Vol. 133, No10, pp 1167-1170.


15. Wallerstein N.P; Soar P.J; Thorne C.R. (2006). River energy auditing scheme(REAS) for catchment flood management planning, International conference on fluvial hydraulics. Pp. 1923-1932. Lisbon Portugal.


16. Wohl, E. (2000). Mountain Rivers. American Geophysical Union. Washington, D.C