• Mark Reiner, PhD, PE

The Life Cycle Cost and other KPIs of Urban Decaying Infrastructure

Updated: Jul 29

Unquantified costs, i.e. ‘indirect costs’, are borne by residents in a city to pay for failed infrastructure. Yet, these costs are not included in how a utility manages their system. And, what are the real costs, economic and societal, for the omnipresent road construction in the urban environment. City leadership needs to be empowered with information to be a stakeholder in urban infrastructure.


Part 3 presented utility tunnels as a possible environment that would reduce collocation and deferred maintenance hazards while increasing adaptability to changing conditions. However, in order to convert a utility tunnel from an ‘environment’ to a new paradigm, a key stakeholder is required that views urban infrastructure as a ‘series of systems’ [1], and understands that any infrastructure failure could negatively disrupt urban life. This is where city leadership (e.g. city manager, mayor, and senior staff) must play a key role. However, for city leadership to adopt utility tunnels as part of a new urban infrastructure paradigm, long-term economic and social impacts must be quantified and expressed as a vision for the foundation of a resilient city.


In many mental images of a smart and resilient city, the roads are never closed and autonomous vehicles (AVs) are omnipresent. But the current reality and trend includes daily closures of roads/lanes for the maintenance/repair/replacement of decaying infrastructure. And, despite the efforts of smart and resilient city initiatives, there is no evidence that this trend will reverse. A new urban infrastructure paradigm requires a framework that makes economic and social sense that city leadership can support as a quantifiable vision. This begins by examining existing city data with existing city personnel to develop a knowledge level [2] of key performance indicators (KPIs) that quantify the everyday costs of the RABID paradigm. And, with these calculated costs, an alternative paradigm must be provided that utilizes an accepted approach for engineers and planners, and that politicians can easily articulate as a vision for the future.


Life-Cycle Cost Categories for the RABID Paradigm

The need to account for the much broader spectrum of life-cycle costs (LCCs) of infrastructure is not a new concept to a utility; but including those costs that are borne by the city for failed infrastructure is a concept that is not currently practiced. The trend in urban infrastructure costing includes “…a strengthening argument against open-cut being the predominant form of pipe installation and renewal.” [3]. As summarized by Hunt, et al, there is a growing body of research that suggests the total costs borne by the city for open-cut utility placement goes well beyond the premature failures of infrastructure assets and direct economic costs borne by the utility [3].


When a utility conducts an LCC, and considers the impacts of asset failure (aka, ‘unintended end of service life’), the costs are limited to the materials and staffing required to restore services. These are referred to as direct costs. However, when an asset fails in a city, there are potentially significant costs that are borne by city taxpayers and those residents and businesses that suffer property damage as a result of the failure. These costs are considered as indirect and are not included in the utility LCC calculus. However, these indirect costs are very real and suffered disproportionally near the site of asset failure. While all tax payers in the city will have to compensate for repurposing city staff (e.g. fire and police personnel) to respond to the site of an asset failure; individual residents and business owners may suffer losses not covered by the utility or their insurance [4]. For example, flooding of a house or business by a failed water main is not covered by regular flood insurance, and utility indemnification limits compensation.


From an academic perspective, the sum of Direct and Indirect costs has been called the Total Cost of infrastructure failure [3, 5, 6, 7]. To determine the proportions of indirect and direct costs, Piratla, et al, conducted an analysis of 11 case studies of large diameter (24” or greater) water main breaks in the United States and found that indirect costs (also referred to as ‘Societal’ costs [6]) averaged two-thirds of the Total Costs [7]. In other words, the city and the individual residential and business owners that were directly impacted by infrastructure failure, are paying the lion’s share of the Total Costs for large diameter water main breaks. When these indirect costs of failure are not directly borne by a utility, the utility’s risk calculus changes to favor extracting as much economic life from an asset as possible, i.e. often pushing assets well-beyond service life [8]. In other words, not including indirect costs promotes the aging (decaying) of our urban infrastructure.


Of note, the concept of referring to costs as either direct or indirect is founded on a single perspective, i.e. typically the utility’s perspective. However, when infrastructure fails, the costs of failed infrastructure borne by the city are not ‘indirect’, but rather very direct to city taxpayers, and the individual residents and businesses that suffer property damage. Therefore, the term ‘indirect costs’ that a city must pay when infrastructure fails is a misnomer. The following subsections represent multiple perspectives that should be considered for the costs of urban infrastructure.


RABID Costs: Premature Asset Failure, Accident Costs, and Non Revenue Water

As previously mentioned in Parts 1 and 2, the RABID paradigm contributes to the reduced life-span for all infrastructure systems, e.g. the average age of water main at failure is only 47 years [9]. This is only slightly more than one-half of expected service life of the asset [10]. That is, because of the characteristics of the RABID paradigm: corrosive soil, differential settlement due to quick patches, heavily trafficked roads, and inaccessibility, we are only getting approximately 50 percent of the intended service life of our assets. Yet, we are paying full-price. Associated with the inaccessibility to infrastructure due to RABID is the 2 trillion gallons (ASCE Report Card) of lost treated water from pipe leaks (aka, non revenue water). Utility customers already pay for this loss, but should not accept this as the status quo as water mains will continue to decay. These leaks are shown in Figure 1 (the figure links to an interactive map hosted by the Los Angeles Times).


In addition, even though the locations of buried infrastructure are marked (spray painted, aka urban hieroglyphics) by each utility prior to repair and maintenance, mistakes are common and damage to buried infrastructure is common. Costs in New York City, as one example, are an estimated $300 million every year – which will be paid by the utility customers one way or another. And, while these two examples are part of a utility’s direct cost, they are a result from the current RABID paradigm – inaccessible buried infrastructure. A new paradigm could eliminate these costs.


City KPIs of the Operations and Maintenance Phase

As mentioned in Part 2, the streets in New York City are sliced open 200,000 times per year, an average of almost 550 cuts per day [11], to facilitate buried infrastructure repairs, replacements, and new construction. KPIs in this phase should establish: accidental asset damage; the number of daily/annual road cuts for maintenance; and, the number of full-time employees (FTEs) that a city must hire to manage the permitting and oversight of road cuts.


City KPIs Post-Failure Phase

In the area disrupted by failed infrastructure, the KPIs include: costs of repair materials, labor, and construction debris (this may, or may not be paid by the utility depending on frequency); disruption to businesses by loss of sales or employer tax [8]; loss of wages [8] disruption to individual residents that suffer property damage without insurance [8]; and, the number of traffic vehicle/ped/bike accidents caused by road closures. These latter KPIs are presented in more detail and are the subject of a pending paper (or blog) that provides an alternative term to ‘indirect’ costs – Total Economic Disruption (TED) [8].


Significant Pre-Failure Phase KPI – the Weak-link Impact

Consider that when infrastructure fails in the RABID paradigm, the primary driver for the utility is to restore services as soon as possible – especially in busy and highly trafficked areas. For example, a failed water main can be restored to service much quicker by cutting a smaller hole in the road and applying a patch, rather than removing and replacing a full 30ft pipe segment (‘bell-to-bell’). However, patching leaves the majority of the decaying water main buried below the road, creating a network of ‘weak-links’ (the decaying water main between the patches, however the material used for patches can themselves also be a weak-link) that are prone to further failures [8, 12]. Although this phase may be difficult to quantifiably add to the LCC, it is worthwhile to provide a pre-failure KPI to better prepare for future city disruptions. Consider the scale of potential disruption in Los Angeles, CA. The Los Angeles Department of Water and Power already experiences 3 water main breaks per day and by 2030, will have 90 percent of its water mains (6,800 miles of 7,600 miles) exceeding 90 years old [13], i.e. beyond the intended service life [10]. An interactive map provided by the Los Angeles Times shows real-time water leaks across the city, as shown on Figure 1 [10].

By simply identifying where these patches are located using the city’s geographic information system (GIS), the weak-links (remaining older main) can generate a heat map for comparison with areas of the city that should remain disruption-free (see below, and Part 5). Every city that restores service by patching failed mains will experience these weak-link failures, including Denver, Colorado [12].


Establishing a New Environment and Paradigm

Other research has estimated that the improved inspection and condition assessment that occurs with the increased accessibility to infrastructure that a utility tunnel would reduce asset failures by approximately 80 – 95% and extend asset life by approximately 15–30% [14]. The utility tunnel also removes the need for repeated excavation and repaving procedures over its lifetime (60–100 years) and therefore eliminates many of the longer-term costs [3]. This creates an urban road environment where it is possible to design roads for longevity, be pothole free, and as stated in Part 1, the goals of new urban smart roads (e.g. improved data collection, traffic efficiency, and safety) would not be limited by the RABID paradigm.


However, what makes a new paradigm is based more than just lower costs. It must translate to reducing/eliminating the ‘lock-in’ for all infrastructure sectors to achieve required adaptability, and, more importantly, translate to how it impacts urban society. What areas of a city should be disruption-free? The first step is to recognize that not all failed infrastructure causes a disruption. For example, a 2” diameter water main in a quiet residential neighborhood is not nearly as disruptive as a 20” diameter water main below a critical commuting corridor on a Monday morning. Therefore, only a few areas in a city need to be designed to protect against disruptions. Characteristics for these areas may include significant commuter corridors, high residential and commercial densities, and even areas of special events, e.g. a failed water main on Federal Blvd. just before a Denver Broncos play-off game. But this exercise should be a customized approach developed by urban planners, not a one-size-fits-all approach, as politics and demographics may add significant weighting. The process of selecting ‘disruption-free’ areas are the subject of a pending paper (and/or blog) [8] and discussed in Part 5.


And, while a utility tunnel adds upfront capital costs; from an LCC timeframe, e.g. +50 years, the total cost difference is almost equal to traditional open-cutting the road [3]. Therefore, any additional value a city may place in having critical corridors as being disruption free, or leading the discussion in smart and resilient cities, would push the needle forward towards a new paradigm – given the right KPIs that would support such a decision.


The parts to this blog include:

Part 1 – From Appian Way to Modern Decaying Infrastructure in the RABID Paradigm

Part 2 – Defining Decaying Infrastructure as a Hazard as part of City Resilience Planning

Part 3 – Encouraging Trends and Old Technology for Reversing Urban Decaying Infrastructure

Part 5 – The Smart Appian Way and the Smart/Resilient City


Footnotes

[1] Pollalis, Spiro N. Planning Sustainable Cities: An infrastructure-based approach, 1st Edition

2018 Routledge, 20160520. VitalBook file.

[2] Refers to the DIKW pyramid https://en.wikipedia.org/wiki/DIKW_pyramid where ‘big data’ is nothing unless it is meaningful to the stakeholder

[3] Hunt, D., Nash, D., & Rogers, C. (2014). Sustainable utility placement via Multi-Utility Tunnels. Tunneling And Underground Space Technology, 39, 15-26. doi: 10.1016/j.tust.2012.02.001

[4] “indirect costs” are also by the NIST Community Resilience Guide used when the infrastructure failure is caused by natural hazards, i.e. no utility to blame (Gilbert, Butrey, Helgeson & Chapman, 2015). And, there are differences between ‘societal costs’ and indirect costs. This will be covered in the pending paper [8], but not in this blog.

[5] Cromwell, J. (2002). Costs of infrastructure failure. Denver, CO: AWWA Research Foundation and American Water Works Association.

[6] Gaewski, P., & Blaha, F. (2007). Analysis of Total Cost of Large Diameter Pipe Failures. In AWWA Distribution System Research Symposium. Denver: AWWA. Retrieved from http://infra-tect.com/wp-content/uploads/2014/11/Analysis-of-Total-Cost-of-Large-Diameter-Pipe-Failures.pdf

[7] Piratla, K., Yerri, S., Yazdekhasti, S., Cho, J., Koo, D., & Matthews, J. (2015). Empirical Analysis of Water-Main Failure Consequences. Procedia Engineering, 118, 727-734. doi: 10.1016/j.proeng.2015.08.507

[8] Reiner, M., Fisher, S., Fang, A. Total Economic Disruption of Failed Infrastructure as an Urban Key Performance Indicator. Sustain. Resilient Infrastruct. 2019 Pending.

[9] Folkman, S. (2018). Water Main Break Rates in the USA and Canada: A Comprehensive Study. Mechanical and Aerospace Engineering Faculty Publications, Paper 174. Retrieved from https://digitalcommons.usu.edu/mae_facpub/174

[10] AWWA. (2010). Buried No Longer: Confronting America’s Water Infrastructure Challenge. Denver, Colorado: AWWA.

[11] Bloomberg News, retrieved from: https://www.bloomberg.com/news/features/2017-08-10/nobody-knows-what-lies-beneath-new-york-city?src=longreads

[12] For those that actually read footnotes, a treat. A water main break occurred today (August 29th, 2019) near the massively busy intersection of Colorado Blvd and Mississippi shut down the road for several hours.https://www.denverpost.com/2019/08/28/denver-colorado-blvd-water-line-break-traffic/ Interestingly, this happened at the same location just a few weeks ago (August 8, 2019) https://www.denverpost.com/2019/08/08/colorado-boulevard-closed-at-mississippi-avenue/ This ‘weak-link’ also shut down Colorado Blvd just months ago a couple blocks north that shut down the road for 24 hours: https://www.9news.com/article/traffic/water-main-break-forces-overnight-closure-of-stretch-of-colorado-boulevard/73-72af41bb-242d-4654-a851-ed13d0e275d5 And, in

Water Main Break Closes Colorado Blvd. At Evans May 17, 2018

https://www.youtube.com/watch?v=9a0svU0n0C8

January 2016 a water main broke at same location as today. https://www.youtube.com/watch?v=qe6LYVlFSxA

Another water main break occurred on May 8, 2020 that closed down the southbound lanes of Colorado Boulevard at Yale Avenue Thursday. Jose Salas with Denver Water said an eight-inch line broke at the intersection. Denver Water said Friday morning that crews worked through the night to repair the broken water pipe and water was restored at 5:30 a.m. Denver Water's paving contractor will work throughout the day Friday to repair the road. About five customers are without water -- most of them businesses, according to Salas. https://www.9news.com/amp/article/traffic/water-main-break-at-colorado-and-yale/73-a95b61dd-b066-4b9b-9f2a-2c30f4a44d98

[13] Poston, B.; Stevens, M. L.A.’s Aging Water Pipes: A $1-Billion Dilemma. 16 February 2015. Available online: http://graphics.latimes.com/la-aging-water-infrastructure/ (accessed on 25 June2018).

[14] Laistner, A., 1997. In: Utility Tunnels – Long Term Investment or Short Term Expenses? 1997 International No-Dig Conference, Taipei.

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