We are Water | Green and gray: Is Evanston rain-ready?

This is part four of a seven article series from We are Water Evanston, a community-based participatory research project that examines our relationship with water and its water concerns. More information about this series can be found here.

Over the past year, floods have wreaked havoc around the world, from Bangladesh to Germany, from New York City to Louisiana. Evanston himself experienced multiple flash flood warnings due to severe storms that summer. As climate change brings heavier rainfall to the region, the city’s drainage system will be put to the test.

We Are Water Evanston, a community-based participatory research project, found that 60% of respondents expressed concern about road flooding. Given the effects of climate change, the question arises: what can we do about it? But to know what can be done, we must first know what is happening.

What do we do with our wastewater?

Evanston has a mixed channel system, which means that the water that goes down the toilet on a rainy day and the water that goes into a rain drain on a rainy day end up in the same place. This mixture of sewage and rainwater mostly reaches a sewage treatment plant, where it is cleaned and discharged into the Chicago River.

In large storms, however, the system can be overwhelmed if large amounts of water enter within a short period of time. Uncleaned wastewater is fed directly into the river, a so-called mixed water overflow (CSO). Heavier rainfall could cause the combined system to become overloaded more often, leading to more flooding, more CSOs and, as a result, more beach closings. All of this can affect the quality of life of residents at the local level. However, there are many solutions that can help reduce this impact.

Combined sewer and overflow schemes. (Drawings by Friends of the Chicago River)

Local flooding solutions

Most flood solutions fall into two categories: gray infrastructure or green infrastructure.

The gray infrastructure includes what we often refer to as typical engineering projects, dike walls and tunnels – for example the Deep Tunnel project, which offers additional water storage during heavy rain events to prevent overloading of the drainage system.

A look into the deep tunnel system. (Photo of the Metropolitan Water Reclamation District)

In recent years there has been a shift towards more natural solutions, such as green infrastructure, which “let nature do the work,” as Julia Bunn, local landscape architect and owner of The Spirited Gardener, puts it.

Green infrastructure, which includes natural green spaces such as forests and swamps, and man-made green spaces such as residential rain gardens, takes in and absorbs water before it enters the drainage system, thereby reducing the stress on the city’s infrastructure during heavy rainfall events.

A rain garden at Evanston’s Morton Civic Center is designed to absorb water into the ground. (Photo by Wendy Pollock)

Green infrastructure can also provide benefits beyond reducing flooding. It can provide habitat for endangered species like the rusty rag bumblebee and, in some cases, help reduce exposure to harmful air pollutants that exacerbate COVID-19, which disproportionately affects people of color in Evanston.

In interviews for the We Are Water Evanston project, local residents expressed their support for both gray and green solutions to flooding. Some residents mentioned in-house flood solutions, such as sump pumps. However, these preventive strategies can come with a bill in excess of $ 1,000, making them too expensive for many households. Respondents also suggested improving the maintenance of rain drains and sewers and installing more rain drains, especially in areas where excess water accumulates on roads.

Due to the design, rainwater can often be temporarily stored on roads in order to prevent the sewer system from being overloaded in the event of heavy rain and to keep the water out of the cellars of the residents. However, some local residents we spoke to, especially those with mobility issues, told us that this made navigating these streets quite a challenge.

Green infrastructure generally received positive responses from respondents, with one ombudsman saying, “I think the more green infrastructure we can have, the better.” Many local residents were also unfamiliar with the role of green infrastructure and natural systems in flood control and others voiced concerns ranging from cost to appearance.

“I mean, a lot of my neighbors can spend $ 3,000 to $ 4,000 on landscaping, but we can’t. You know, we look at native plants and think about the amount of plants we need to use for grasses. And it adds up. So, you know, these changes come at a cost, ”said a Sixth Ward resident.

While some types of green infrastructure can be expensive, there are also low-budget options like DIY rain gardens in the backyard.

Volunteers work on a rain garden at Oakton Elementary School. (Photo by Clare Tallon Ruen)

Respondents also expressed concern about the cost of maintaining green infrastructure and who would be responsible for it, especially on public land. “When you start a project, you have to make sure it’s being looked after or it’s just useless,” remarked a First Ward resident. However, urban forest expert Cherie LeBlanc Fisher told us, “Maintenance costs are sometimes cited as a reason not to use green infrastructure, but all infrastructure needs maintenance, including gray infrastructure like rain gutters.”

Many residents also recognized tensions between land use for housing and green infrastructure. However, some argue that while green infrastructure is not a panacea for all flood problems, it does not mean that it is not worth it. “It won’t solve problems on a global level, but we can do it on a neighborhood level,” said Wendy Pollock, co-chair of Evanston’s environmental committee.

Policy measures for flood resilience

Both green and gray infrastructure will be vital to managing the flooding in Evanston. However, we also need to address the root cause of these increasingly common floods: climate change.

Many local residents expressed concern about the effects of climate change, ranging from heat waves to poor air quality. Some worried about how climate change would affect future flood events. As communities of color tend to be hardest hit by the effects of climate change, reducing the risk for those on the front lines of flooding is an important equity issue.

Evanston has taken several steps to plan and prepare for the effects of climate change. In 2018, the city approved the Climate Action and Resilience Plan (CARP), which sets goals for climate action and resilience, including steps to build a more flood-resistant Evanston, such as promoting green infrastructure and improving existing rainwater systems.

As mentioned in our previous article, the city is also in the process of completing a hydraulic and hydrological study with the help of Hey & Associates, a local engineering consultancy. The study, which should help identify risks of future storms, is expected to be completed in the spring of this year.

Upon completion, the city plans to develop a capital improvement plan that includes projects to address the current and future flood risks identified in the study. Other cities with mixed sewer systems, such as Philadelphia and Bloomington, Illinois, have levied stormwater supply fees to fund stormwater projects. These fees are based on the amount of impervious surface such as sidewalk, asphalt, and roofs on the property. The cost of a residential property in cities like Philadelphia and Bloomington ranges from $ 6 to $ 16 a month.

What can residents do?

A concrete way of counteracting local flooding is to reduce personal water consumption on rainy days. By postponing non-critical, water-intensive activities such as washing clothes or washing the dishwasher until after the rain, the residents can reduce the amount of water that flows into the mixed water system so that the sewer system can better cope with the flow of water.

Evanston residents can even sign up for a rain alert to remind them to postpone these tasks until later by visiting https://www.cityofevanston.org/rain or sending COE RAIN to 468311.

Local residents interested in installing green infrastructure on their own property can also visit the city’s website or contact [email protected] for more information on building a residential rain garden.

Flooding can have long-term effects on our health and wellbeing, from mold and mosquitoes to the loss of priceless mementos. With the effects of climate change becoming more pressing by the day, it has never been more urgent to take action to combat its causes and adjust to the new normal.

Residents who want to become more involved in local climate change action can turn to organizations like Citizens’ Greener Evanston, Environmental Justice Evanston, the Evanston Environmental Association, and E-town Sunrise.

We are Water Evanston is a collaboration between researchers from the Northwestern Center for Water Research and community water activists at the Watershed Collective, a subcommittee of Citizens’ Greener Evanston. This article is the fourth in a seven-part series sharing key insights and actions related to water in Evanston. Follow We are Water Evanston on Instagram (@wearewaterevanston) and Twitter (@waterevanston).

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