Water is an essential resource that nourishes and supports all life on earth. Without it, our modern world simply could not exist. If we are to protect the very element that sustains us, we must adapt our built environment to accommodate and protect this vital resource, both from an environmental and human-made standpoint. To understand how changing water patterns effect the water cycle, we cab learn much from examining the history and evolution of water resources management as well as from exploring the future of predicting and protecting water resources and surrounding infrastructure.
Water is also a powerful natural element that can kill and destroy, if not intelligently managed with integrated environmental and built solutions. As water supports our changing world, continuous urbanization directly impacts the natural water cycle. These disruptions to natural hydrological cycles combined with climate change and resulting in increased rainfall are causing devastating global flooding that affects communities, the environment, and our access to quality water.
Global flooding is sounding an alarm!
Road Washout: Yellowstone National Park North Entrance | 2022
Flooding: Georges River at East Hills in Southwest Sydney Australia | 2022
Road Washout: Yellowstone National Park North Entrance | 2022
Flooding: Georges River at East Hills in Southwest Sydney Australia | 2022
In 2022, increased rainfall combined with a sudden warming and melting of spring snow caused catastrophic flooding in Yellowstone National Park – two park entrances were closed indefinitely, damage to roads and bridges isolated entire communities, and residents lost access to clean drinking water. Surrounding cities and towns throughout southern Montana face years of rebuilding crucial infrastructure. This was the worst flooding the Park has seen in its recorded history.1 After obtaining the rainfall data, the United States Geological Survey (USGS) categorized this as an unprecedented 500-year flooding event. *
Earlier in the year, eastern Australia endured similar record-breaking flooding – tens of thousands of residents in Sydney, Brisbane, and other cities along the sunshine coast evacuated homes, schools, and businesses to escape rising floodwaters, as rain in the greater Brisbane area eclipsed 26 inches in 3 days.2 The damage to Queensland’s infrastructure was significant; the prime minister declared, “these are floods that we have not seen in living memory in anyone's lifetime, and even before that.”3
These flood threats are not limited to rural or open areas. In the first week of 2023, parts of northern California experienced 100-year storms with record flooding in Sacramento, San Francisco and throughout the bay area, resulting in devasting losses of life and property.4
Indeed, a pattern of unprecedented flooding is taking place across the globe, with dense, urban areas suffering the most significantly. When modernized, populated regions lack adequate built and natural infrastructures to accommodate increased rainfall events and intensities, existing conveyance systems become overburdened, resulting in flooding.
Going with the Flow.
A basic understanding of the natural water (or hydrologic) cycle can help illustrate how urbanization affects the water cycle, and why flooding is a result.
In a natural, uninhibited hydrologic cycle, water, in its different states as a solid, liquid, and gas, moves through the atmosphere, down to the earth, and back up through the atmosphere to renew the cycle again (Figure 1). Rain, snow, or sleet (precipitation) falls to the ground, flows across the land (runoff), into the ground (infiltration), and through the ground (groundwater), naturally cleaning the water and nourishing plants (this groundwater is what constitutes 98% of available fresh water on earth5). Water evaporates from plants, surface water, snow, or ice back into the atmosphere as a gas, eventually condensing into clouds, which precipitate back to the ground, repeating the cycle.
Urban and suburban areas affect the water cycle by creating impervious surfaces (buildings, parking lots, pavement, etc.) that block proper water runoff and infiltration (Figure 2). Sewers, floodplains, and drainage ditches are meant to counterbalance this and collect runoff and channel infiltration, but, as we’ve seen with recent global flooding, this often isn’t enough. Current conveyance systems may not be built to accommodate the increased rainfall and intensities the earth is experiencing. This also affects the ability of groundwater to recharge, leading to secondary impacts on the environment.
When flooding occurs, it detrimentally affects the “Big Four” – Homes, Transportation, Infrastructure, and Water Quality. Buildings, roadways, and underground utility pipes and infrastructure are directly damaged by excess water, over capacity sewers and waterways result in flooding and erosion.
Urbanization affects the quality of our water in several ways. Runoff from urban environments contains more pollutants, and increased imperviousness limits water infiltration, thus depleting groundwater, our main source of freshwater.
It's hard to ignore catastrophic flooding – too many people are displaced, injured, and even killed. Too many buildings and crucial infrastructure – roadways, bridges, pipelines – are damaged, resulting in costly, lengthy repairs. Flooding highlights the impact of climate change/increased precipitation colliding with our built environment and detrimentally affecting our water resources. And water is too essential of a resource for us not to respond.
Learning from a History of Innovation in Water Resources Management.
When we think about how to tackle the evolving challenges of changing weather patterns and water flow, we also need to address the aging water management infrastructure and the disparities it is creating in our communities. Examining our history of problem solving and taking actionable steps in water management can help us find new solutions for our current challenges. Fortunately, humans have a history of being innovative, resourceful, and resilient, especially when motivated by pressure to adapt. Resilience is defined by the capacity of a system to retain essential functions before, during, and after a hazard strikes.
The legacy of innovation in flood control and water treatment are evidence of this, especially in the Chicagoland area. In the mid-1800’s, Chicago became one of the busiest ports in the world, leading to rapid urbanization, propelling Chicago to becoming the fastest growing city in the world. The rapid growth led to a polluted water supply, spurring the need for intervention. To protect the city’s water supply, Chicago accomplished what is considered one of the greatest engineering feats in US history by successfully reversing the flow of the Chicago River. Today, the Sanitary District is known as the Metropolitan Water Reclamation District, or MWRD, and serves more than five million people, processing approximately 1.3 billion gallons of sewage every day.6
When water challenges are caused by nature instead of humans, more far-reaching actions have been implemented through legislation.
- The National Flood Insurance Act of 1968 encouraged state and local governments to make appropriate land use adjustments and better manage the development of land at risk of flood damage and minimize damage caused by flood losses. The act also authorized continuing studies in flood hazards that still inform decision makers today.7
- Thanks to the Clean Water Act of 1972, billions of pounds of pollution have been kept out of our lakes, rivers, and streams, and the number of waterways that meet clean water goals nationwide has doubled since.8 The Act represented a huge step forward by requiring states to set clean water standards to protect uses such as swimming, fishing, and drinking, and for the regulation of pollution discharges. And yet – even at the 50th anniversary of this important law 2022, many of our rivers remain polluted by urban and agricultural runoff and sewer overflows, and almost half of our streams are in poor health.9
Efforts must continue to ensure the safety of our water supply everywhere, especially in disinvested communities. A 2018 study conducted by the Center for Neighborhood Technology (CNT) based on detailed analysis of flood claims date in the City of Chicago revealed that 87% of flood damage insurance claims were paid in communities of color.10 A variety of grants and community programs are in place to bring more equity to water resources management at the local level. Additionally, a Framework for Vulnerability Assessments guide is available to help lawmakers build flood management and water safety measures into their asset management plans and capital programs. Through the lens of history, we can look ahead to how communities, leaders, and lawmakers can work together to integrate equitable water management into daily lives.
Making Every Drop Count.
We know that flooding is not an equal opportunity villain. Too much water in some places, not enough in others, unsafe drinking water in the heart of some of our most vibrant cities – how can we make sense of it all?
Public agencies have started to adopt Green Infrastructure practices into their ordinances to ensure new developments include an integrated water system to ensure a reliable water supply and protect our communities from extreme events. This proactive approach has the added benefits of increasing vegetation and ecological balance and promoting aquatic life.
Coordinating these efforts is key to ensuring equity in implementation. Framework Analysis and Adaptability Assessment-FHWA has been developed to assist state and local agencies develop an asset management program to identify highest risk locations vulnerable to flooding, results then become part of the decision-making process. The goal? Provide actionable information to assist designers and agency leaders to consider and address how future climate change may impact their infrastructure.
These plans have allowed Metropolitan Planning agencies and state and local governments to conduct additional studies, such as mapping to assess flooding risk, identify critical facilities (Schools, Hospitals, Government Facilities).
What does this all mean for the future of water resiliency?
The evolution of water resources management tells us that addressing these issues takes foresight, innovation, and teamwork. From the Design and Engineering industries to city planners and municipal leaders, we must collaborate in search of solutions to proactively address seemingly insurmountable threats posed by water. By pushing the limits of our imagination, we can continue to innovate and create new ways to protect our built environment and our waterways for generations to come.
Footnotes and References:
*500-year flooding event: each year there is a 1 in 500 chance of a flood of this size occurring. Similarly, a 100-year flooding event indicates a 1 in 100 chance of a flood of a certain size occurring.
1 https://www.usgs.gov/observatories/yvo/news/how-might-devastating-june-2022-floods-and-around-yellowstone-national-park ; Yellowstone Picture https://www.flickr.com/photos/yellowstonenps/52156165036
2 https://www.weatherzone.com.au/news/677-mm-in-three-days-breaks-brisbane-rainfall-record/536318
7 https://www.fema.gov/flood-insurance/rules-legislation
8 https://www.epa.gov/laws-regulations/history-clean-water-act
