%0 Journal Article
%T Assessment of bank-river stability versus erosion and factors for its management strategy in the Vaz river, Mazandaran province
%J Researches in Earth Sciences
%I Shahid Beheshti University
%Z 2008-8299
%A rostami, milad
%A Hosseinzadeh, Mohammad mehdi
%A Esmaili, Reza
%D 2021
%\ 01/20/2021
%V 11
%N 4
%P 1-14
%! Assessment of bank-river stability versus erosion and factors for its management strategy in the Vaz river, Mazandaran province
%K Vaz river
%K Bank riprap
%K Stability coefficient
%K Bank erosion
%K Lin model
%R 10.52547/esrj.11.4.1
%X IntroductionChanges in river channel, bank erosion and sedimentation are the natural processes in alluvial rivers which might destruct and damage surrounding human facilities and farms. Regarding this, the study of bank-river instability is done for engineering activities in order to form the necessary proceedings to stabilize the banks against erosion.Material and methodsIn this study using the Lin shear stress, the rate of instability coefficient has been investigated in the Vaz River in Mazandaran province. All the required parameters are assessed in geomorphology library using field surveys, google earth images and granometry. At first, a two-kilometer reach is determined and eight cross sections were chosen in this reach. After that, to riprap the instable bank bed slope, shear stress, bank angle, stability coefficient and effective rock size of the Vaz River is defined as the management strategy. Discussion and resultsAfter measuring the parameters affecting the shear stress index of river-banks in the Vaz River, the rate of bank stability, the rock size in the incipient motion and the effective rock size to riprap the river is estimated in two scenarios including 20° and 30° angles of slope. To determine the effective rock size the highest angle of repose and shields parameters are considered as 42 and 0.054, respectively. In phase two with hypothetical bank slope of 20° and 30°, the rock size in the sixth to ninth steps for different rock sizes are repeated constantly, since SF=1 was obtained. In this situation, the effective riprap rock size and the rock size in the incipient motion is estimated for the two suggested scenarios. Conclusions The results reveal that the sections 6, 2, 8, 3, 5, 7, 1, 4 have the most and least stability coefficients, respectively. Therefore, the suitable rock size to riprap the bank and protect the bank-river would be different from the size of rock in the incipient motion. Furthermore, considering the situation of each section, the suitable angle or the bank slope are different to riprap the bank. In the reach of the Vaz River in section 1 the coarsest required rock sizes are 1.21 m in 20° angle of slope and 0.69 m in a slope with 30° angle. In the section 6 the smallest required rock size is 0.248 m in 20° of slope and 0.115 m in 30 degree of slope.
%U https://esrj.sbu.ac.ir/article_97423_a23704cf2eb5ae4bc475ecc149d2ba30.pdf