What's in this Toolkit
I. Why Green Infrastructure Matters
II. Global Trends
III. Scales of Green Infrastructure
IV. 25 Actions to Get Spongy
Why green infrastructure matters
Stormwater runoff is a major cause of water pollution in urban areas. It carries harmful pollutants into our waterways. Violent rainstorms produce destructive flooding that threatens lives and property. Gray infrastructure, like pipes and gutters, is getting old and can't keep up with the amount of rainwater we're getting now. The specter of climate change demands a high-functioning built environment that can handle increasingly extreme weather.
One of the most effective ways to tackle these challenges is through green infrastructure. Green infrastructure helps reduce stormwater runoff and keeps pollutants from getting into our waterways by imitating natural processes. It filters and soaks up stormwater where it falls, reducing the urban heat island effect and bringing more nature into our cities.
It even serves to reduce greenhouse gas emissions and increase carbon sequestration to mitigate flooding and heat waves, common by-products of global warming.
The interventions in this toolkit are especially crucial for the 700+ U.S. cities with combined sewer and stormwater systems that pump over 850 billion gallons (3.2 trillion liters) of raw sewage into rivers, streams, and lakes each year during significant rain events (US EPA, 2004). These actions are also essential for many Canadian cities that collectively dump 237 billion gallons (900 billion liters) of raw sewage into waterways every five years, equivalent to approximately 355,000 Olympic-sized swimming pools (Environment Canada, 2020).
Global trends
The idea of "green infrastructure" or "natural infrastructure" has been around for a long time, but formal definitions and policies have only come about in the last several years. National governments around the world are now prioritizing the development of green infrastructure, learning from Indigenous knowledge keepers who have been applying many of these ideas for generations. The definitions of "green infrastructure" vary among the nations that are most committed to using it. Some of the highlights include:
- 1959: Colombia's "National System of Protected Areas" includes conservation, restoration, and sustainable land management practices.
- 1965: Brazil's Forest Code requires landowners to preserve natural vegetation.
- 1995: India's National River Conservation Plan includes promoting green infrastructure such as afforestation, wetland restoration, and riverfront development. The "Green India Mission" aims to increase forest cover and improve ecosystem services.
- 1998: The Japanese government's policy on green infrastructure focuses on parks, gardens, green roofs, and walls to reduce climate change effects, improve air and water quality, and enhance cities' environment.
- 2007: The African Union Commission's "Great Green Wall for the Sahara and Sahel Initiative" promotes sustainable land management and restores degraded land in the region.
- 2010: The Netherlands refer to green infrastructure as "nature-based solutions," including green roofs, walls, rain gardens, and urban forests that improve air and water quality and provide flood protection and climate adaptation.
- Mid-2000s: Australian policy uses green infrastructure such as parks, gardens, green roofs, and bioswales to enhance cities' resistance to climate change, biodiversity, and social and economic benefits.
- 2011: China's Five-Year Plan focuses on green spaces such as parks, gardens, green roofs, and wetlands to increase green space in urban areas, promote biodiversity, and improve urban environments.
- 2012: The United Arab Emirates' National Strategy for Green Growth aims to reduce carbon footprint by promoting sustainable development and green infrastructure.
- 2013: The European Union's Green Infrastructure Strategy includes natural and semi-natural areas like parks, gardens, green roofs, walls, and forests to improve health and well-being, biodiversity, and climate change mitigation.
- 2017: Canada's Investing in Canada Plan defines "green infrastructure" as natural or engineered systems that provide ecosystem services and benefits to communities.
- 2019: The US Water Infrastructure Improvement Act defines "green infrastructure" as measures that reduce stormwater flow using plants, soil systems, permeable pavement, stormwater harvesting, and landscaping.
While there are differences in the specific features and goals included in each country's green infrastructure policies, they all share a common focus on using natural or engineered systems to provide benefits to communities, the environment, and the economy. Definitions and policies are constantly evolving as the understanding of green infrastructure benefits grows, which drives the global trend toward incorporating natural and engineered systems to provide a wide range of benefits to communities and the environment.
Scales of green infrastructure
Green infrastructure can be implemented on scales of the block, neighborhood, and watershed. Block-scale green infrastructure includes rain gardens, bioswales, rain barrels, tree-lined city streets, and greening alleyways. Neighborhood-scale initiatives include green streets, open park space, rain gardens, and wetlands. Larger initiatives at the watershed level involve preserving or restoring open natural spaces, riparian areas, wetlands, and forests, and greening steep hillsides.
When these green infrastructure systems are integrated throughout a community or regional watershed, they provide cleaner air and water, flood protection, diverse habitats, and beautiful green spaces, adding significant value to the community. The 25 actions in this toolkit are basic principles that require adaptation to local and regional conditions, such as the degree to which the local climate is naturally wetter or more arid.
25 actions to get spongy
1. Raise awareness for water conservation and stewardship.
To promote good stewardship and conservation measures, it's essential to create and implement public education practices on all scales, from the neighborhood to the region. This includes protecting existing green spaces and promoting "soft engineering" measures such as rain barrels, rain gardens, green roofs, permeable pavement, gardens over lawns, and edible landscapes to encourage volunteer green infrastructure. It's also important to raise awareness of individual actions that can make a difference, such as picking up animal waste to reduce pathogens like E. coli, planting bare soil to reduce sediments, and conserving water.
Indigenous collaboration
Collaborating with Indigenous environmental leaders is vital for effective green infrastructure strategies, as their communities have been sustainably using and preserving natural resources for centuries. Indigenous lands comprise around 22% of Earth's land area and contain 80% of its biodiversity. (International Union for Conservation of Nature, 2022) By partnering with Indigenous leaders, we can learn from their sustainable practices and empower them to protect their lands. This cooperation fosters innovative, culturally-sensitive projects, promoting both social and environmental justice.
2. Adopt the NACTO Urban Street Stormwater Guide.
Context-sensitive green streets use a range of green infrastructure techniques to manage runoff and enhance the street experience for pedestrians, cyclists, and transit users. They prioritize infiltration and natural processes to manage stormwater and enhance neighborhood livability.
Interventions
To incorporate these and related measures into practice, many local governments are adopting the NACTO (National Association of City Transportation Officials) Urban Street Stormwater Guide, which is an excellent, comprehensive resource that provides guidance for designing streets that manage stormwater, reduce flooding, and enhance the urban environment.
3. Legalize compact development to reduce impervious surfaces.
The use of impervious surfaces like traditional pavement and rooftops worsens polluted runoff, but compact development can help limit their spread in watersheds. Incentivize de-paving and passive cooling by allowing smaller setbacks, skinny streets, reduced surface parking, green spaces, smaller lots, and street trees. With careful building orientation, this approach can reduce water and energy use and provide shade in summer and microclimates in winter.
Interventions
Compact development patterns help tackle the challenge of rising water and sewer costs, which have doubled in cities like Cleveland and Chicago over the last decade due to aging infrastructure, fewer resources, extreme weather, and suburban development. As a result, ratepayers, particularly those in low-income, Black, and Latino neighborhoods, are unable to cope. To put this in perspective, water and sewer costs are rising faster than anything else, partly due to outdated pipes and a dispersed development pattern that is more expensive to service. (A Water Crisis Is Growing In A Place You'd Least Expect It 2019, APM Reports) The solution to this problem is complex and requires a mix of gray and green infrastructure, transportation and urban design, and land use policies. Compact development patterns can help limit the need for costly infrastructure and ensure that we use resources more efficiently. We need to prioritize more sustainable and efficient land use patterns to ensure that our cities are livable, affordable, and resilient for everyone.
4. Build green infrastructure every time public works mobilizes.
Every time public works initiates a project for routine repairs to streets and parks, upgrade public infrastructure to incorporate green infrastructure components, such as permeable slotted curbs, rain gardens, bioswales, reduced street widths, and street trees.
Reminder
Prioritize the reduction or elimination of plastic in the upgrade process to reduce the prevalence of microplastics in ecosystems and human bodies.
5. Legalize community gardening.
Guerrilla gardening refers to the act of gardening on land that is not owned by the gardener, often in abandoned or neglected spaces, or in the tree lawn between the curb and the sidewalk. Despite its many benefits, including improving the aesthetics of a neighborhood and promoting community engagement, it is often considered illegal. As such, there is a need to legalize gardening in the public realm by creating regulations or guidelines that would permit it. This would require local governments to develop policies that would protect gardeners from being penalized and would allow for the creation of more community gardens and green spaces. By encouraging community gardening, communities can benefit from the increased beauty, cleaner air, and improved quality of life that come with more green space.
Interventions
Numerous inspiring examples show how gardening transforms communities. In Los Angeles, the efforts of Ron Finley, known as the "Gangsta Gardener," have revitalized neglected spaces by turning them into thriving community gardens. His work has brought fresh produce to food deserts and inspired others to follow his lead in improving their neighborhoods. Richard Reynolds creates pop-up gardens on the Lower East Side in New York City, which beautify the area and provide educational opportunities for local residents. The Guerrilla Gardeners of Parkdale in Toronto turn vacant lots into flourishing green spaces and vegetable gardens, providing fresh food for the community and fostering a sense of pride. This transformative power highlights the need to provide legal support and protection for such community-driven initiatives.
6. Organize tree stewards.
To promote the planting and maintenance of trees in both public and private spaces, local governments should organize and deputize tree stewards. This involves recruiting and training volunteers who are passionate about trees and providing them with the necessary knowledge and skills to plant and care for trees in their communities.
Interventions
The Virginia Tree Stewards program is an example of how this can be done effectively. By deputizing tree stewards, local governments can ensure that their community is well-versed in tree maintenance practices and has the resources to make their community greener and more sustainable.
7. Develop grants.
To promote the implementation of green infrastructure projects, local governments can develop green infrastructure grant programs that offer funding opportunities to neighborhood associations and non-profit organizations. These grants can be awarded annually to support the construction of projects such as rain gardens, bioswales, green roofs, permeable pavements, and other types of green infrastructure.
Interventions
By making these grants available, communities can increase their capacity to create sustainable stormwater management solutions and enhance the overall quality of life in the area. This approach can encourage community involvement and collaboration, leading to a more engaged and invested population in green infrastructure development.
8. Create a wetlands preservation program.
To preserve wetlands and prevent future flooding in areas that are projected to undergo significant development, a wetlands preservation program should be established.
Interventions
The program can follow the example of Milwaukee Metropolitan Sewerage District Greenseams, which currently covers 3,700 acres and is estimated to hold 2 billion gallons of floodwater. The program should include the purchase and protection of undeveloped land that can be used for recreational activities while also enhancing the land's ability to store water and support biodiversity. The preservation of these wetlands can help mitigate the impact of future storms and support the local ecosystem.
9. Construct wetlands.
Construct reed beds and floating wetlands along every waterway that abuts combined sewer and stormwater pipes then measure the outcomes of downstream rivers, streams and lakes.
Interventions
Reed beds are natural or constructed wetland systems dominated by reeds (Phragmites spp.) and other emergent aquatic plants. They play a crucial role in water purification and pollution control, particularly in the treatment of wastewater and stormwater runoff. The dense root systems of the reeds and associated microorganisms break down contaminants, remove excess nutrients, and filter out sediments and pollutants from the water. Reed beds are also valuable habitats for a wide range of wildlife, including birds, amphibians, and insects, supporting local biodiversity.
Floating wetlands are engineered ecosystems that mimic the functions of natural wetlands while floating on the surface of a water body. They consist of buoyant structures that support the growth of wetland plants, such as sedges, rushes, and other aquatic vegetation. The roots of these plants extend into the water, absorbing nutrients and providing a surface for beneficial microorganisms to colonize.
Floating wetlands contribute to water quality improvement by filtering out pollutants, reducing excess nutrients, and breaking down organic matter in the water column. They also provide important habitats for aquatic organisms, promote biodiversity, and offer aesthetic and recreational benefits. Floating wetlands can be implemented in various water bodies, including ponds, lakes, stormwater retention basins, and wastewater treatment facilities.
It is crucial for floating wetlands to be constructed from environmentally friendly materials rather than plastics, as plastic materials can contribute to pollution and harm aquatic ecosystems. Over time, plastics can break down into microplastics, which pose a significant threat to aquatic life and water quality. Instead, floating wetlands should be made from alternative materials such as natural fibers, coir, or wood, which are biodegradable and have a lower environmental impact. By using sustainable materials, floating wetlands not only improve water quality and promote biodiversity, but also minimize the potential harm to ecosystems.
Floating wetlands can remove up to 90% of total phosphorus and up to 80% of total nitrogen. They can improve water clarity by reducing suspended solids and turbidity, improve oxygen levels by increasing photosynthesis, reduce algal blooms, and support biodiversity. (Singh, et al., 2020, 110898)
Reed beds demonstrate remarkable performance in removing contaminants, such as organic matter, nutrients, and heavy metals from wastewater and stormwater runoff. They can reduce biochemical oxygen demand (BOD) by up to 90%, total suspended solids (TSS) by up to 80%, and total nitrogen and phosphorus by more than 50% (Kadlec & Wallace, 2009). Reed beds promote cleaner water and healthier ecosystems, while supporting local biodiversity.
10. Network parks and streams.
By connecting parks and streams through non-compacted soils and indigenous plant species, it is possible to create green and blue corridors that provide numerous ecological benefits. These corridors provide habitat and travel routes for wildlife, help filter pollutants from runoff, and can also serve as recreational areas for people.
Note
The use of non-compacted soils in the creation of greenways and blueways is essential, as compacted soil can lead to stormwater runoff and erosion.
11. Upgrade parks to double duty for water cherishing.
Replace traditional asphalt squares and playgrounds with more absorbent surfaces to help reduce flooding and control runoff. Consider reducing the elevation of parks and sports facilities to maximize their ability to hold water during rain events, and emulate Dutch "water cherishing" techniques like water squares, sponge gardens, and tidal parks. These green infrastructure solutions can help manage stormwater and reintroduce biodiversity.
Sponge gardens, made up of materials like clay, rubble, and peat, can quickly absorb and hold rainwater before slowly releasing it back into the ground. Tidal parks, which feature terraced, vegetated slopes along river banks, can also help manage stormwater while providing soft ecological spaces for community members.
Interventions
Seaside, Florida's town square, pictured here, does double duty as a stormwater pond during storms. Milwaukee plans to replace asphalt with permeable surfaces over the next 15 years to hold 740 million gallon rain events.
Rotterdam's Watersquare can hold up to 450,000 gallons of water during rainfall events and can also be used as a multi-purpose space for community activities. The Hofbogenpark in Rotterdam is an example of a circular water management system that purifies rainwater naturally through soil on the roof, stores it in an aquifer, and reuses it to irrigate the park's landscape.
12. Reinforce coastal nature.
In addition to creating oyster reefs, which are artificially constructed habitats that mimic natural oyster reefs and promote oyster growth, or planting mangroves, which are salt-tolerant trees and shrubs that grow in coastal areas and provide a unique ecosystem and natural barrier against erosion, reinforcing river banks with Indigenous methods can also be a sustainable way to protect against flooding and erosion. Indigenous communities in Canada and Australia have long used techniques such as planting vegetation, constructing rock walls, and creating fish traps to manage river flow and protect against erosion. These methods not only provide effective flood control and erosion protection but also contribute to the preservation of local ecosystems and cultural heritage.
Reinforcing coastal nature has many benefits beyond flood protection and ecosystem health. It can also boost tourism, create jobs, and enhance community resilience. Coastal communities that prioritize green infrastructure over seawalls may experience lower maintenance costs over time and be better equipped to adapt to changing climate conditions. Reinforcing coastal nature in a way that is respectful of Indigenous knowledge and traditions can also promote cultural preservation and reconciliation efforts. Collaborating with Indigenous communities and incorporating their knowledge and practices can lead to more effective and culturally sensitive approaches to coastal management.
Interventions
The Billion Oyster Project in New York City is a prime example of oyster reef restoration, where volunteers work to repopulate the New York Harbor with oysters to filter water and create habitat for marine life. In Vietnam, Mangroves and Markets has successfully planted mangroves along the coast, providing vital storm protection and nurturing local fisheries. The Australian Aboriginal community of Ngarrindjeri has implemented Indigenous techniques to protect the Coorong coastline. By building fish traps and weaving plants into the riverbank, they have effectively managed water flow, reduced erosion, and preserved both the environment and cultural heritage. In Canada, the Squamish River Watershed Society has applied traditional Indigenous methods to stabilize riverbanks and enhance fish habitats, benefiting both ecological preservation and community well-being. These projects demonstrate the value of combining traditional knowledge with modern approaches to address environmental challenges.
13. Plant microforests.
Selectively planting microforests is a method of restoring natural habitat in small areas within an urban or suburban landscape. These microforests, also known as pocket forests, can range in size from a few square feet to several acres and can be created in parks, public spaces, and private properties. The purpose of microforests is to provide habitat for wildlife, absorb carbon dioxide, mitigate the urban heat island effect, and reduce stormwater runoff. When selectively planting microforests, it is important to consider the needs of the local environment and the species that are native to the area. By selecting the right mix of trees and plants, microforests can provide valuable ecological services while also enhancing the beauty of the surrounding landscape.
Interventions
The L.A. Park Forest Initiative by the Los Angeles Parks Foundation is an excellent example of how microforests can be used to enhance urban environments. The initiative involves the planting of over 10,000 trees in Los Angeles parks, with a focus on underserved communities. The trees will help improve air quality, provide shade, and enhance the beauty of the parks. The Nelson Whakatu Microforest Initiative in New Zealand is another successful example of selectively planting microforests. The initiative involved planting a mix of native trees and shrubs on a steep hillside in the Enner Glynn suburb. The microforest provides habitat for native birds and insects, helps stabilize the soil, and enhances the aesthetic value of the area.
14. Daylight waterways.
To reduce the intensity of flash floods and to provide more green space for people and plants, an approach called "daylighting" can be used. This involves selectively excavating old waterways by uncovering underground streams and rivers and bringing them back to the surface. By reclaiming these spaces, they can be used for public enjoyment and recreation, and the increased vegetation can help mitigate flooding.
Selectively daylighting streams offers a powerful green infrastructure solution for stormwater management as well as passive cooling. Just as trees and plants contribute to cooling their surroundings, water bodies have a similar effect by absorbing heat from the air. When water evaporates, it carries away heat, lowering the ground-level temperature.
Interventions
To combat flood risks and urban heat islands, cities worldwide are uncovering buried rivers. Paris is daylighting Bièvre River, Auckland removed clay and pipes to reveal city center streams, Manchester uncovered a section of the River Medlock, and Seattle restored Thornton Creek. Other cities that have similar initiatives in the works include New York, Boston, Providence, Napa, Berkeley, Kalamazoo, Dubuque, Norfolk, Detroit, St. Louis and Charlotte.
15. Map watershed slopes and soils.
Develop a comprehensive map of watershed slopes and soils to identify the most suitable locations for green infrastructure practices, such as wetlands, forests, regional parks/ponds, rain gardens, and bioswales. Utilize this information to target areas that would benefit the most from these nature-based solutions.
Interventions
Resources like the links below provide valuable guidance to support and streamline this process, promoting more sustainable and resilient communities. Encourage private investment in green infrastructure most appropriate for various parts of the watershed by offering incentives for implementing well-matched practices on private properties.
16. Crowdsource flood data to map urban flood zones.
Current flood-zone mapping is outdated because many regions are experiencing more precipitation than in the past. As a result, we need to update the maps and, to do that, we need updated data. Atlas 14 is a multi-volume publication by the National Oceanic and Atmospheric Administration (NOAA) that presents precipitation frequency estimates for various locations across the United States. The publication is a result of the Precipitation-Frequency Atlas of the United States project, which aims to provide a set of precipitation frequency data for use in hydrologic design, risk assessments, and other water resource management activities. The precipitation frequency estimates are for various durations (from 5 minutes to 60 days) and return periods (from 1 year to 1,000 years). These estimates are derived from analysis of historical precipitation data and are critical for designing infrastructure like stormwater systems, flood control structures, and bridges that can withstand extreme precipitation events.
Interventions
NOAA must update Atlas 14 with local rainfall records. Until then, cities need to collaborate with universities to fill this data gap, such as the effort underway in New York University's FloodNet. Existing gray stormwater infrastructure is often sized to decades past, as shown by the increasing precipitation in the contiguous 48 states. Even cities with giant underground tunnels and above-ground reservoirs are finding them undersized because the stormwater inlets are too small. This is the result of building big stormwater solutions without knowing the scale of the problem:
- Chicago: $4 billion tunnels and reservoirs; 17.5 billion gallons; <350’ underground; green infrastructure: 69 projects; 12 million gallons
- Cleveland; $3 billion tunnels; green infrastructure: $42 million
- Milwaukee; $4 billion tunnels; 520 Million gallons; <340’ underground; green infrastructure: 3,700 acres; 2 billion gallons; Milorganite fertilizer: $5 million
- Indianapolis; $2 billion tunnels and reservoirs; 5 billion gallons; <200’ underground
According to ASCE's 2021 Infrastructure Report Card, in the U.S. our 2.2 million miles of water pipe get a Grade C- because we use 82 gallons of water per person per day with a water main break every 2 minutes that costs us $7.6 billion / year. Maintenance costs: $50.2 billion above capital in 2017, in part due to deferred capital projects — an all-time high.
17. Analyze cost and benefits of green and gray infrastructure.
Conduct a thorough cost-benefit analysis to compare the effectiveness of implementing green and gray infrastructure measures in stormwater management and flood prevention. This analysis should take into account the cost of implementing both types of infrastructure as well as the benefits they provide. It should also include an evaluation of the environmental impact of gray infrastructure (dams, levees, reservoirs and tunnels), such as the emission of greenhouse gasses, and the carbon sequestration potential of green infrastructure.
Interventions
By transforming Houston's existing non-absorbent infrastructure into green infrastructure, the city could potentially prevent approximately 199,000 metric tons of carbon emissions by 2050. This carbon reduction is equivalent to planting 3.3 million tree seedlings and nurturing them for a decade. These eco-friendly measures could yield significant cost savings, estimated at $12 billion over three decades, compared to traditional infrastructure investments. (Rocky Mountain Institute, 2023)
18. Write a stormwater master plan.
Developing a stormwater master plan that integrates green infrastructure can be an important asset to any jurisdiction seeking to reduce the impact of runoff on the environment. A key component of this plan should be the creation of a capital improvement plan for the natural green infrastructure portion of the stormwater system, which is often overlooked in capital plans in favor of traditional gray infrastructure. This capital improvement plan should prioritize the implementation of green infrastructure projects, such as bioswales, green roofs, rain gardens, and permeable pavements.
Interventions
A stormwater master plan should consider the unique characteristics and needs of the community, such as topography, land use patterns, and existing infrastructure, like the Town of Whitehall, Delaware, context pictured here. Community input and engagement should be integral to the planning process to ensure that the plan meets the needs and desires of all stakeholders. The key performance indicators (KPIs) of a stormwater management plan can vary depending on the goals and objectives of the plan.
Common KPIs for a stormwater management plan may include:
Water quality: measuring the amount of pollutants in stormwater runoff, the effectiveness of green infrastructure in reducing pollutants, and the overall impact of the stormwater management plan on water quality in nearby water bodies.
Flood reduction: measuring the amount of stormwater runoff that is captured and stored by green infrastructure, the frequency and severity of flooding events before and after implementation of the plan, and the number of properties and residents protected from flood damage.
Biodiversity: measuring the number and diversity of plant and animal species supported by green infrastructure, the success of efforts to reintroduce native species to the area, and the overall health of the ecosystem.
Aesthetic value: measuring the public perception of green infrastructure projects, the amount of green space created or restored, and the overall improvement in the visual quality of the area.
Cost-effectiveness: measuring the overall cost of implementing the stormwater management plan, the cost savings resulting from reduced flooding and other benefits, and the return on investment for green infrastructure projects compared to traditional gray infrastructure solutions.
19. Update stormwater policy and regulations.
Stormwater regulations are rules and guidelines set by local, state, or federal governments to manage stormwater runoff from developed areas. These regulations typically outline requirements for stormwater management plans, construction site erosion and sediment control, stormwater treatment practices, and post-construction stormwater management.
Update stormwater regulations to incentivize green infrastructure and implement the Stormwater Master Plan. Municipalities can offer financial incentives such as grants, tax credits or rebates to property owners who install green infrastructure on their properties, for retrofits, redevelopment and new development. This can help to offset the cost of installation, making it more attractive to property owners. Regulatory incentives for green infrastructure include lower stormwater fees for properties that implement green infrastructure. Municipalities can also consider using stormwater fees to fund green infrastructure projects.
Interventions
In addition to financial incentives, municipalities can also implement regulations that require developers to implement green infrastructure as a condition of their permits, or require that certain types of properties implement green infrastructure as part of their stormwater management plans. Updating stormwater regulations to incentivize green infrastructure and implement the Stormwater Master Plan can help municipalities to achieve their stormwater management goals in a cost-effective and sustainable manner while also improving water quality, enhancing biodiversity, improving air quality, and increasing aesthetic value.
20. Update the stormwater ordinance/bylaw.
A stormwater ordinance or bylaw is a local law or regulation that sets forth specific requirements for stormwater management within a particular jurisdiction. These ordinances typically address issues such as the design and construction of stormwater facilities, stormwater fees, and penalties for noncompliance.
While stormwater regulations (action 19) and stormwater ordinances or bylaws (action 20) share a common goal of managing stormwater runoff, they differ in their scope and authority. Stormwater regulations are typically broader in scope, applying to a wider geographic area and covering a range of stormwater management issues. In contrast, stormwater ordinances or bylaws are typically more localized and specific to a particular jurisdiction, such as a city or county, and may have more detailed requirements, like the City of Ranson, West Virginia, Light Imprint Stormwater Management by Transect Zone example pictured here.
The stormwater ordinance is a part of the unified development code in some localities, and it can aid in reducing flooding and managing the flow of pollutants into waterways. This can be done by mandating or encouraging the use of green and gray infrastructure. For municipalities that do not currently require a Stormwater Pollution Prevention Plan (SWPPP) for individual sites, the Stormwater Ordinance can be particularly beneficial in reducing flooding and controlling the runoff of pollutants into waterways.
SWPPPs are required by the U.S. Clean Water Act and by state and local stormwater regulations. SWPPPs are required in Ontario, Quebec, and B.C., for large developments and industrial uses. A SWPPP is a site-specific document that outlines a plan for controlling stormwater pollution at a particular construction site or industrial facility. The SWPPP typically includes measures to prevent or minimize the discharge of pollutants, such as sediment, debris, chemicals, and oils, into nearby waterways.
Interventions
Paris: 44 storm drains discharge 2 million cubic meters of combined sewer & stormwater into the Seine River every year. A new 46,000 cubic meter (per event) holding tank + reed beds are intended to make the Seine safe for swimming for the first time in 101 years, in time for the 2024 Summer Olympics to host the triathlon wild swimming in the Seine. Paris is also daylighting other rivers to help meet climate action goals, like the Bièvre River.
New York: 60% of the system is combined stormwater and sewage. Now can handle 1.75” of rain per hour, but needs to handle 3.5” rain per hour to avoid overflows into the river. To separate the stormwater and sewer pipes would take 10+ years and cost over $100 billion. The city can’t afford that, so it's becoming a spongy city with nature-based green infrastructure. Over 9,000 street-side rain gardens and bioswales are planned or in progress. The Highline plus Hurricane Sandy sparked a paradigm shift for the city that really was a watershed moment. NYC is storing water in recreational areas like playgrounds, lowering basketball courts below surface level to create a storage space that can hold 300,000 gallons of stormwater. +POOL New York City is planned in the Hudson River, to raise awareness for water stewardship.
Ranson, West Virginia’s Light Imprint Stormwater Management by Transect Zone, pictured here, is a modification of the Light Imprint Handbook.
21. Assess a stormwater fee to reduce future flooding.
To reduce the risk of future flooding, municipalities can establish a public utility district utilizing their city and/or county stormwater systems and assess a stormwater fee on ratepayers. This fee can be utilized to finance stormwater management programs aimed at flood prevention.
Interventions
A recent example is the Louisiana law authorizing municipalities to charge utility fees to fund their stormwater management programs. Another example is in Edmonton, Alberta, where the utility EPCOR provides a significant amount of green infrastructure services funded by rate payers.
22. Sell waste into a circular economy.
Selling waste into a circular economy supports green infrastructure by promoting sustainable practices and resource conservation. Repurposing waste materials reduces the demand for new resources, helping to conserve natural ecosystems vital to green infrastructure. The revenue generated can be allocated to fund green projects, contributing to improved stormwater management, urban resilience, and a healthier water cycle.
This approach minimizes waste accumulation, reduces the strain on waste management systems, and allows more resources to be directed towards green infrastructure initiatives. The circular economy model encourages innovation, fostering the development of novel green technologies or materials and promoting sustainable behavior, ultimately supporting a healthier planet and more resilient urban environments.
Interventions
One example of selling waste is making fertilizer pellets from sewage sludge, as seen with the Milorganite product in Milwaukee. This process involves treating and processing sewage sludge to create a nutrient-rich fertilizer used in agriculture and landscaping. The sewerage district generated $10 million in sales in 2020-2021, funding ongoing operations and maintenance, including green infrastructure programs. Another example is composting, where organic waste decomposes into nutrient-rich soil amendments used in gardening and landscaping. The Ojai Sanitation District in California accepts organic waste from residents and businesses, turning it into high-quality compost sold to local farmers and landscapers, providing a valuable resource while reducing waste.
23. Update financing strategies.
To effectively fund green infrastructure projects, it is important to aggregate funding from a variety of public and private sources. This can involve working with government agencies at the local, state, and federal levels to secure grants and other funding opportunities. It can also involve partnering with private investors, foundations, and other organizations that are interested in supporting sustainable infrastructure projects.
Interventions
One example of this type of funding aggregation is the Green Infrastructure Fund in Philadelphia. This fund was established by the city to provide financing for green infrastructure projects, including stormwater management systems and green roofs. The fund aggregates funding from a variety of sources, including the Philadelphia Water Department, the federal Environmental Protection Agency, and private investors.
Update and expand stormwater management financing strategies (ie. interest earning escrow accounts) that could support new or retrofitted green infrastructure programs and opportunities and aiding Homeowner Associations in fiscal responsibilities for privately owned stormwater infrastructure.
While stormwater management escrow accounts are already required by some local governments, they are often viewed solely as emergency funds. By updating and expanding these accounts to support green infrastructure programs and opportunities, local governments can provide developers and homeowners with incentives to implement sustainable stormwater management practices. This not only benefits the environment but also can save money over time by reducing the need for expensive stormwater infrastructure maintenance and repairs. Steps to take:
- Develop a plan for updating and expanding stormwater management financial programs such as escrow accounts to support green infrastructure programs and opportunities.
- Work with local stakeholders, such as developers, homeowners' associations, and environmental organizations, to identify specific programs and opportunities that could be supported by revenue earned on the escrowed funds.
- Encourage the use of green infrastructure practices, such as rain gardens, bioswales, and permeable pavements, that can help to reduce stormwater runoff and improve water quality.
- Provide education and outreach to developers and homeowners about the benefits of green infrastructure practices and the availability of funding through the innovative accounts.
- Monitor and evaluate the effectiveness of the updated escrow account in promoting sustainable stormwater management practices and adjust the program as needed.
By aggregating funding as well as updating and expanding stormwater management escrow accounts to support green infrastructure programs and retrofit opportunities, local governments can help to promote sustainable stormwater management practices and improve the health of local waterways.
24. Partner with neighbors.
Partnering with governments upstream and downstream within a watershed can provide significant benefits for stormwater management. These partnerships can allow for the sharing of best practices, engineering standards, and RFP templates that reflect new processes and do not require extensive experience, making it easier for smaller municipalities to participate. Additionally, skills training can be provided to local workers to aid in natural infrastructure preservation, repair, and construction. By working together, these partnerships can provide a more comprehensive approach to stormwater management. They can share information on the design, construction, and maintenance of natural infrastructure like wetlands, rain gardens, and green roofs. They can also collaborate on developing and implementing policies and regulations that support natural infrastructure, like the Tuskegee, Alabama team pictured here.
These partnerships can be especially effective when they span the entire watershed, as they can help to identify and address stormwater issues at their source, reducing the overall impact on downstream communities. For example, a partnership between communities in the upper watershed can work to reduce runoff and erosion by implementing practices like conservation tillage, while downstream communities can work to manage and treat stormwater as it enters their area. Partnerships between governments within a watershed can provide a more coordinated and effective approach to stormwater management, benefiting both the environment and the communities that depend on it.
25. Encourage safe relocations.
To ensure the safety of communities, it is important to develop a relocation strategy that enables individuals to find secure and affordable housing away from flood-prone areas. This can be achieved by encouraging safe relocations to higher ground within the region, as well as to climate receiver cities.
Climate receiver cities are urban areas that are expected to experience an influx of people migrating from other regions due to climate change-related factors. These factors could include rising sea levels, increasing temperatures, prolonged droughts, or other extreme weather events that make certain areas less habitable. Climate receiver cities often have more stable and accommodating environmental conditions, making them more attractive destinations for people seeking refuge from the impacts of climate change.
These cities need to prepare for the growing populations by developing infrastructure, housing, and essential services that can accommodate the needs of incoming residents. Planning for climate receiver cities involves considering the social, economic, and environmental aspects of integrating new populations while ensuring long-term sustainability and resilience to future climate challenges.
Organizations such as Place Initiative have already begun to implement such strategies. By relocating to safer areas, individuals can protect themselves from the dangers of flooding while maintaining access to the resources and amenities they need to thrive.
Where to from here?
Need insights on how all this is going to help? Want to know how spongy communities and urban form pays back to health, safety, welfare, the environment, as well as the economy? Code Score does just that, as it consolidates 135 peer reviewed studies that make the link.
Want to discuss these ideas on your local media outlets or talk about how to implement them locally? For English, get in touch with: Hazel Borys, President, PlaceMakers, LLC, USA; CEO, PlaceMakers, Inc., Canada +1-204-960-0100 direct, hazel@placemakers.com. For other languages, click on the authors below for contact information.
