Introduction
Water, wastewater and stormwater utilities, collectively referred to as water systems throughout this blog, are vital to public health, functioning economies, and clean environments. When disaster strikes, whether natural or human-made, disruptions in drinking water and wastewater systems can have immediate rippling effects that can prevent or slow recovery efforts and put people at additional risk. In this blog, we review the types of disruptions that impact water systems and present some proven planning tools to enhance resilience against these challenges. (see the EPA’s water resilience website for a host of resilience planning tools across a variety of hazards).
Risks to public infrastructure can be categorized as related to longer-term stressors (chronic) and event-driven disruptions (acute). Acute disruptions like flooding typically amplify chronic stressors. For example, acute flooding could destroy aging assets that would otherwise withstand the event if it were in good repair.
Chronic stressors can go unnoticed and unaddressed, yet they have material effects on operations. Some chronic stressors include:
- Aging infrastructure: deteriorating pipes, pumps and other critical components that can lead to frequent breakdowns and inefficiencies.
- Financial constraints: limited budgets can restrict the ability to maintain and upgrade infrastructure, leading to deferred maintenance.
- Population pressures: Increasing demand for water resources can strain existing systems that require adaptation and expansion.
- Climate change: Long-term changes in temperatures, precipitation, wildfire risk and other known climate-driven impacts can lead to changes in water supply availability, and stress aging infrastructure through long-term temperature and precipitation patterns.
- Workforce challenges: An aging workforce and difficulties in attracting new skilled workers can impact the operational capacity and institutional knowledge of water systems.
Acute events span a range of risks with varying levels of pre-warning. Examples include:
- Natural disasters and extreme weather events such as floods, earthquakes, extreme precipitation, and wildfires
- Contamination events such as chemical spills, waterborne pathogens outbreaks, or algal blooms
- Sudden infrastructure failures such as pipe breaks or leaks, power outages, or pump station failures
- Cybersecurity breaches that compromise control systems or data integrity
- Terrorism or vandalism that cause operational disruption and damage
- Supply chain interruptions that cause delays in receiving necessary materials or chemicals needed for treatment processes.
Examples of the relationship between chronic stressors and acute events are outlined in Table 1 below.
| Table 1: Examples of the Relationship Between Chronic Stress and Acute Events | |||
| Chronic Stressor | Acute Event | Impacts on Water Utilities | Impacts on Water Resources |
| Aging Infrastructure | Floods | Increased likelihood of pipe failures and system breakdowns | Wastewater contamination of local waterways or contamination of drinking water supplies |
| Financial Constraints | Supply chain interruptions | Limited funds to purchase materials at inflated prices | Reduced capacity to maintain water infrastructure, leading to increased risk of operational failures |
| Population pressures | Droughts | Inadequate capacity to meet demand | Over-extraction of water sources, leading to depletion of groundwater and surface waters |
| Climate change | Increased frequency and intensity of heatwaves | Increased demand for water resources and challenges in supply management | Decreased water availability due to increased evaporation and reduced precipitation |
| Workforce | Cybersecurity breaches | Decreased capacity to plan for and respond to security events | Increased potential for data leaks and critical failures |
Water utilities throughout the United States face large chronic stressors, even without taking climate change into account. For example, the Pew Trusts found that state and local governments will need to spend about $625 billion over the next 20 years to maintain and improve drinking water systems. In addition, water systems in the US will require another $448 billion to $944 billion through 2050 to adapt both drinking water and wastewater systems to the consequences of climate change. Chronic under-investment has already increased the vulnerability of water infrastructure to operational failure. Growing climate-driven stressors multiply these vulnerabilities.
In addition, disaster-driven interruptions in water systems disproportionately impact vulnerable populations. The US Water Alliance points out that declining federal funding for water infrastructure has put more strain on local ratepayers. An average of 20 percent of households in the United States are in arrears to their water utility. Households at 75 percent of poverty level can spend up to 40 percent of their income on water and sewer bills.
Fortunately, investments in resilience measures in water systems yield large savings for rate payers while significantly reducing chronic and acute risks. A report from the National Institute of Building Sciences in 2019 found that adopting enhanced life safety building measures could save systems $4 for every $1 of cost.
Resilience Planning Frameworks
There are a myriad ways to plan for and mitigate chronic and acute stressors to water systems, including traditional emergency management practices, water resource management planning, and community engagement practices. Climate resilience guides incorporate these best practices and integrate climate vulnerability assessments.
Two leading resilience guides available to water system operators include:
- The Environmental Protection Agency’s (EPA) Climate Resilience Evaluation and Awareness Tool (CREAT). CREAT is an online planning tool designed to assist drinking water, wastewater, and stormwater utility operators evaluate, then mitigate chronic and acute risks to water systems. CREAT has five modules: 1) Climate Awareness; 2) Scenario Development; 3) Consequences & Assets; 4) Adaptation Planning; and 5) Risk Assessment.
- The Water Resilience Assessment Framework: Guidance for Water Utilities by the Pacific Institute, CEO Water Mandate, and AGWA.
The above tools are organized around identifying vulnerabilities, and cost-effective mitigation strategies to reduce or eliminate vulnerabilities.
Step 1: Understand risks by completing a vulnerability assessment
Risks to water systems are unique to the local environment, the type and age of the water system, the needs of the population, and other relevant conditions. To understand these risks, water system managers should conduct a vulnerability assessment with a systematic inventory of chronic and acute liabilities.
The CREAT tool assesses risks to the following areas:
- Water supply management, vulnerabilities to drought, seasonal demand, snowpack, reservoir storage, and low streamflow conditions;
- Peak service challenges from stormwater runoff, seasonal demand, and discharge;
- Water quality management related to runoff, treatment, violations, saltwater intrusion, source water turbidity, and algal blooms;
- Natural disasters such as fires, floods, and wind, ice, and snow storms;
- Ecosystem and landscape management, including coastal erosion, wetland loss, and endangered species protection;
- Population and demographic changes, including customer base, median household income and utility burden, and land use and workforce availability;
- Business sector water service needs, including an inventory of industries and water needs to support economic development;
- Interdependent sector / supply chain reliability for power, transportation, chemical supplies, etc.;
- Sea level rise projections, including saltwater intrusion and coastal storm surge.
Most communities have already documented many of the above vulnerabilities. Consider partnering with entities like municipal planning offices, which may have a local Hazard Mitigation Plan or Climate Action Plans.
The Water Resilience Assessment Framework recommends developing a “water status” assessment of existing attributes, including “water quantity and quality, storage, uses, connectivity, legal and institutional elements, and eco-hydrological characteristics.” They also recommend an assessment of water trends, including the “historical, current or predicted future water status of a system, based on historical data.” Together, water status and trends assessments create a baseline from which to measure the resilience of the water system to future changes. If water trends indicate a decline in source water, for example, that information could be used to model future states and changes in infrastructure requirements.
Water status and trends can also be used to develop future scenarios based on Global Climate Models, which are used to support the International Panel on Climate Change (IPCC) assessment reports. The CREAT tool uses these models to provide projections for a range of potential future climate conditions. Projected changes in temperature, precipitation, extreme weather events, stream flows, and sea level rise are provided.
Step 2: Identify cost-effective resilience measures
A vulnerability assessment will reveal risks and potential operational losses, which can be mitigated based on potential economic losses and operational failures. The CREAT tool provides detailed methods to calculate the economic consequences from identified vulnerabilities. It offers tools to set appropriate debt coverage and operating ratios to help mitigate economic losses. A resilience strategy can then be designed to minimize or eliminate risks.
The Water Resilience Assessment Framework recommends identifying indicators that can measure progress toward resilience outcomes. A benchmark resilience score can determine the system’s status against those indicators in a simple rubric of “poor, medium, good, and high.” Resilience actions can then be targeted to increase indicator status. See Figure 1 below.
Infrastructure-based resilience measures can look like traditional built, “grey” infrastructure, such as elevating mechanical or electrical systems to higher elevation to withstand flooding, or “green” infrastructure: nature-based solutions like planting rain gardens and bioswales to hold and/or filter floodwater onsite. Nature-based solutions may also offer co-benefits such as providing habitat for pollinators, enhancing shade and offsetting urban heat island effects, and sequestering carbon and providing climate change mitigation benefits. In general, nature-based solutions are less capital-intensive than grey infrastructure, however, their performance can be more complex to measure. Environmental Impact Bonds (EIBs) are designed to mitigate the risk to systems if nature-based solutions under-perform by shifting some of that risk to impact investors.
EIBs are part of a larger suite of outcomes-based financing tools that calculate a return on investment based on co-benefits and avoided losses that are not typically considered in traditional financing. A detailed vulnerability assessment can help to calculate the economic value of resilience measures that benefit whole communities, and justify investments based on their economy-wide benefits.
State Revolving Funds (SRFs) for drinking water, wastewater and stormwater can be used for resilience-focused infrastructure upgrades, including green infrastructure. Each state has an Intended Use Plan (IUP) that defines what projects the SRF can finance. For assistance navigating the SRF in your state, contact your Environmental Finance Center, which provides free technical assistance.
Closing Thoughts
Water systems provide the most essential services to communities, yet they are often the most expensive to operate and the most vulnerable to disruption, especially from climate impacts.
Resilience planning tools, like those provided by the EPA and the Pacific Institute, offer a structured path to identify vulnerabilities and assess the risks associated with both chronic stressors and acute events. By understanding these risks, utilities can prioritize and implement targeted, cost-effective measures that are not only beneficial for infrastructure stability but also economically viable for communities.
Climate change presents complex challenges that are not confined to a single sector, and water is often at the center of these challenges. As the effects of climate change intensify, issues like droughts, floods, and water quality degradation can affect multiple areas including agriculture, energy production, and public health. Water systems thus become a crucial connecting thread, underscoring the need for integrated planning that encompasses these diverse impacts.
Thinking holistically about water resilience is essential because vulnerabilities in one area can magnify challenges in others. For instance, a disruption in water supply can lead to agricultural stress, energy shortages, and health crises. This interconnectedness means any resilience strategy must consider the broader ecosystem of interdependencies.
By adopting a holistic approach, stakeholders can collaborate across sectors to develop solutions that address multiple needs simultaneously. Implementing targeted measures such as upgrading infrastructure and adopting nature-based solutions can help manage risks while offering additional benefits such as enhancing local ecosystems and supporting climate mitigation efforts. Ultimately, strengthening water systems through comprehensive, cross-sectoral strategies not only ensures their continued functionality but also contributes to the overall resilience of communities, making them better equipped to handle the multifaceted challenges posed by climate change.