<p>The aging water infrastructure
system in the United States has posed considerable hindrance to policy-makers
as they seek to provide safe, reliable, and clean drinking water for
communities. The deterioration of the physical water infrastructure negatively
affects the economics of water utilities and can lead to increases in water
rates for consumers, so that utilities can recover the financial losses.
However, the dynamics emerging from the interactions among changes in water
service reliability, water-rates, consumer behavior (with respect to water
consumption and willingness to support water-rate changes in response to
changes in water rates, and water utility economics, are still unknown factors
in the management of water infrastructure systems. </p>
<p>The overarching objective of
this dissertation is the creation and demonstration of the dynamics of coupled
human and water infrastructure systems under conditions of water main breaks
and water-rate increases. First, using
water-main break data for a 21-year period from two U.S. cities in the Great
Lakes region, the dissertation demonstrates a methodology to estimate the
system-wide monthly frequency of water main breaks as a function of a number of
explanatory variables. Using a random-parameters negative-binomial approach,
the statistical estimations show that pipe diameters, average pipe age,
distribution of pipe age, pipe material, time of year, and mean monthly
temperature all have a significant impact on monthly water main break
frequencies. The results can assist asset managers in quantifying the effect of
factors may have on the likelihood of water main breaks, as well as in making
cost-effective decisions regarding pipe renewal.</p>
<p>Next, by incorporating
qualitative survey data and using quantitative econometric methods, consumer
behaviors in responses to the water-rate increases, and based on perceptions of
water service reliability and quality in a Midwestern U.S. city was evaluated.
Using a multivariate binary probit approach, the results provide insights as to
how individuals are likely to respond to water-rate increases based on the
reliability of current water services and the quality of the supplied water.
The outputs of the econometric enable utility managers to better understand the
behavior of consumers under different rate conditions and help water utilities
in their long-term and short-term financial analyses.</p>
<p>Finally, the aforementioned two
components are integrated into the interdependency analysis to evaluate the
interactive effects of features of the physical water infrastructure (pipeline
characteristics, water and associated energy losses, and the revenue loss for
water utilities) and the behavior of stakeholders (water utilities and
consumers). The developed hybrid system dynamics and agent-based model examines
interdependencies between the physical water infrastructure, the water utility,
and the water consumers to explore possible emergent behavior patterns of water
users during water rate increases over time. The model is demonstrated over the
2001–2010 period on a case study city with a large water distribution system
that includes 4,000 miles of pipeline and nine water treatment plants serving a
population of 863,000. This model was then verified and validated throughout
the development of simulation models and included the following steps: 1) data
validity, 2) conceptual model validity, 3) computerized model validity, and 4)
operational validity. The results suggest the simulated behavior of the model
was reasonable and the output of the simulation model regrading water main
break frequency, amount of water and associated energy losses, generated
revenue, and payoff periods for implementing proactive maintenance strategies
had the accuracy required for the model’s intended purpose. </p>
<p>The framework developed in this doctoral study can be
applied to different size classifications of cities, as well as different
classifications of utility companies (such as electricity and gas) by updating
the parameters in the model to reflect the characteristics of the
infrastructure system components. The distinctive methodological approach in
this doctoral work could capture the emergent behaviors of human-water
infrastructure interactions such as the impact of increasing water-rates on
residential consumers, the impact of water price elasticity cascading into the
water utility revenue, and the impact of residential consumers’ water
consumption on water utility revenues. In conclusion, the results of this
doctoral research can assist asset managers in understanding their systems,
identify pathways for growing revenue through reducing non-revenue water and
increasing water-rates, and implementing a proactive pipeline asset management
program towards the provision for safe, reliable, and clean drinking water.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/12217670 |
| Date | 30 April 2020 |
| Creators | Hamed Zamenian (8781884) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/Dynamics_of_Coupled_Human-Water_Infrastructure_Systems_Under_Water_Main_Breaks_and_Water-Rates_Increase_Events/12217670 |
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