The holistic prioritisation of proactive sewer maintenance

Abstract

In sewerage asset management, there has been a concerted move away from primarily assessing system capacity or physical performance, to focus on "serviceability" as a key performance indicator. After identifying flooding due to blockages as a key failure mode, this paper documents the development of a tool which can contribute towards efficient sewerage asset management within the context of maintaining "serviceability" to customers, the public and the environment. Against the background of poor availability of reliable data, the reported project provides a process based on FMECA which can be implemented with limited information and without the need for additional data gathering. Land use and network characteristics data have been used alongside a hydrodynamic model to determine critical points in a network. Based on this, a methodology for identifying where blockage likelihood lies is outlined alongside an approach which allows failure consequence to be quantified. The text then outlines a framework which allows failure likelihood and consequence to be combined to prioritise sewerage asset maintenance.

Analysing spatial patterns in lateral house connection blockages to support management strategies

“…In Germany, the DIN 1986DIN -30 (2012 requires evidence of the water tightness of existing lateral house connections. Arthur, Crow, Pedezert, and Karikas (2009) analysed a complaint database and reported an increased blockage likelihood for pipe diameters smaller than 0.225 m. These findings are in line with Post, Pothof, Ten Veldhuis, Langeveld, and Clemens (2015), who found blockage rates of lateral house connections to be two orders of magnitude greater than rates for main sewers. The authors suggested these results reflect differences in physical properties and governing flow regimes.…”

“…The negative weights β associated with separate sewer systems demonstrate that combined lateral connections are more prone to blockages. Arthur et al (2009) arrived at similar findings for a sewer system in the UK. Ground settlement was found to be the dominant continuous factor for Rotterdam (β ground settlement = 0.337 according to Table 4).…”

Spatial Distribution of Flood Incidents Along Urban Overland Flow-Paths

“…Reports can be used to analyze the impacts related to the typically subtle water-depths of pluvial floods and even account for the intangible caused damage (Arthur et al 2009;Caradot et al 2010;Veldhuis and Clemens 2010;Veldhuis 2011;Veldhuis et al 2011).…”

Automatic classification of municipal call data to support quantitative risk analysis of urban drainage systems

“…Yet call data have proven to provide valuable information for the quantification of risks that cannot be provided by other types of monitoring data. Arthur et al (2009) and ten used call data to detect failure mechanisms of urban flooding and to quantify their probabilities of occurrence. In addition, ten Veldhuis (2010) demonstrated how consequences of urban flooding can be analysed and quantified based on call data and how the results can be used to establish risk curves that depict cumulative probability of damage as a function of the damage amount.…”