Controlled, Realistic-scale, Experimental Study of How the Quantity and Erodibility of Discolouration Material Varies with Shear Strength

Cohesive discolouration material accumulates on the walls of distribution mains and is eroded by increases in boundary shear stress. Understanding how these accumulation and erosion processes vary with material shear strength is important for estimating discolouration risk. To study these relationships, material that had accumulated in two similar pipe systems over three months was eroded by increasing the shear stress in equal increments. By processing the turbidity responses, accumulation and erosion rates were found to be invariant with shear strength at all but the weakest strengths, for which more accumulation was detected.