Scour estimation for hydraulic structures in rivers/streams with coarser bed materials with special reference to Erin stream Bandipora, J&K, India

Abstract

ABSTRACT This study investigates the scour depth of coarser beds constituting boulders up to 100 mm in size. The independent parameters viz. particle size (dm), bed slope (S), and unit discharge (q) were determined experimentally at five bridge sites of Erin Nallah, J&K over a 7 Km stretch, along with a dependent parameter scour depth (D). The relationship between the dependent parameter, scour depth, and independent parameters, namely, particle size, bed slope, and unit discharge were established in the form of an exponential equation through logarithm and matrix method. The established equation was validated using an experimental data set of another site, along with the different models available in the literature. The insignificant variance was observed in reference to available models of estimation of scour depth. A sensitivity analysis is done. Lastly, multiple non-linear regression was also done. The relationship obtained was in corroboration with the relationship derived using the logarithm and matrix method. The coefficient of determination, R2, was found to be 0.99, which signifies relationship is strong. The established empirical equation may be used to estimate scour depth of coarser beds, however further study is needed to make it a common practice.