Study of Scour Characteristics Downstream of Partially-Blocked Circular Culverts

Abstract

Debris accumulations upstream and through crossing hydraulic structures such as culverts cause the upstream water level and the downstream scour depth to increase, which can lead to structure failure. This experimental study aimed to investigate the effects of various inlet blockage ratios on culvert efficiency and scour hole depth. In a non-blocked case, various submergence ratios (S = 1.06, 1.33, 1.60, and 1.90) were tested with different discharge rates. In a blocked case, the effects of inlet blockage with various blockage ratios (Ar = 10%, 20%, and 30%) were seen as sediment blockage on the pipe bed or floating debris upstream of the culvert. The results show that as the submergence ratio increases, the maximum scour depth decreases at the same discharge rate, and the relative energy loss also decreases in the non-blocked case. In the sediment blockage (Ar d) case, the relative maximum depth increases with increasing densimetric Froude number and with an increasing blockage ratio. An empirical equation was developed to predict the relative scour depth under the present study conditions.

Effects of Bottom-Up Blockage on Entrance Loss Coefficients and Head-Discharge Relationships for Pipe Culvert Inlets: Comparisons of Theoretical Methods and Experimental Results

“…Culverts constrict flow and are therefore prone to blockage by debris, increasing the risk of cross-drainage failure (Rigby et al 2002;Cafferata et al 2004;Bradley et al 2005;Ho 2010;Schall et al 2012;Weeks and Rigby 2016). The causes and effects of culvert blockage have been studied in the field (Rigby et al 2002;Cafferata et al 2004;Ho 2010;Weeks and Rigby 2016) using physical scale models (Goodridge 2009;Ho 2010;Sorourian et al 2015;Kramer et al 2016;Taha et al 2020) and numerical simulations (Ho 2010;Rowley 2014;Günal et al 2019). In situ blockage conditions have been found to depend on many factors, such as the amount and type of available material, flood magnitude, and interactions between the stream, catchment, mobilized materials, and the drainage structure (Bradley et al 2005;Ho 2010;Kramer et al 2016;Jaeger and Lucke 2016;Iqbal et al 2021;Miranzadeh et al 2022).…”

Urban Rainwater and Flood Management

“…Taha et al [5] published "Study of Scour Characteristics Downstream of Partially Blocked Circular Culverts". The aim of this study was to investigate the effects of different inlet blockage ratios on clear-water scour depth and culvert transport efficiency.…”