In 2022, the Exchange plans to work with partners to develop an inaugural ‘National State of Green Stormwater Infrastructure Report’. This report will aim to create a shared vision for future investments needed to accelerate equitable implementation of GSI. The report will tell a data-informed story about the national state of GSI including the pace and direction of implementation progress. It will identify current barriers and information gaps to further scaling, and will recommend where to focus future efforts to accelerate progress. It will offer a set of high-level metrics to better measure such progress.

This ‘State of Equity Practice in Public Sector GSI Report’ will be incorporated within the full report. It also stands on its own, telling the equity part of the story from the perspective of those public sector entities primarily responsible for managing stormwater. Drawing mainly from a comprehensive survey issued to capture equity-focused experiences, it is an attempt to develop a national baseline understanding of the extent to which equity considerations are being centered within GSI planning, implementation and monitoring and are contributing towards achieving the equity objectives of communities. Future editions of this report will include additional data that informs a collective understanding of the extent to which this is playing out in different parts of the country.

The voices of communities are absent in this baseline report. The degree to which communities would agree with how public entities have self-evaluated on different GSI equity elements would enrich this report significantly, and is a critical element that will be built into the full ‘State of GSI Report’ 2022 report. In the meantime, this report aims to serve as a solid foundation from which to start or continue those critical conversations between communities and the public sector needed to ensure that GSI efforts realize their full potential to deliver water quality and quantity outcomes, but also the promise of other critical co-benefits.

Read the report

While many municipalities are implementing and advancing components of asset management for green stormwater infrastructure (GSI) assets, for example, developing asset inventories and maintenance protocols, few have made the leap from managing assets to asset management, in other words, creating and implementing an asset management plan. The Green Stormwater Infrastructure Asset Management Resources Toolkit (the Toolkit) was born out of the need to provide more specific guidance and case studies on how to incorporate GSI into asset management.

The development of Toolkit was funded by Green Infrastructure Leadership Exchange (“Exchange”) and involved a collaborative effort among six Exchange members: the City of Toronto, Ontario; City of Vancouver, British Columbia; City of Atlanta, Georgia; City of Portland, Oregon; Metropolitan Sewer District of Greater Cincinnati, Ohio; and City of Palo Alto, California, as well as two subject matter experts: the Southwest Environmental Finance Center (SWEFC) and the Green Infrastructure Ontario Coalition (GIO).

SWEFC developed a free, online Integrated Asset Management Framework for combining green and gray assets into asset management which was released in 2021. The GSI Asset Management Resources Toolkit project aimed to build upon this work by beta testing SWEFC’s Framework and applying it to GSI assets that are commonly used within the right-of-way: pervious pavement, bioretention planters, and stormwater trenches, as well as streams, which provide essential stormwater services. These asset types represent a cross section of assets ranging from entirely engineered/built (permeable pavement) to natural (streams), with bioretention planters in the middle.

The major goal of this project was to develop a toolkit that includes guidance on establishing a GSI asset management program and case studies sharing outcomes, tools, progress, challenges, and lessons learned from participating agencies developing their asset management plans for GSI.

Review the GSI Asset Management Resources Toolkit

The Exchange held its second annual Midyear Convening on Nov 30th-Dec 2nd. This Convening provides our network with an opportunity to touch base on what’s going on across the network, share resources, explore opportunities to learn and collaborate, and get input from our members on priority topics.

Below are recaps of our three main sessions. Exchange members can email Kasey ( for session recordings and/or presentations.

Session 1: Midyear Updates: Peer Learning & Collaboration Across the Network (and How to Get Involved!)

Peer Learning Descriptions

In this session, we provided an overview of the current focus areas and “juicy questions” being explored in our Learning Circles. We also spent time in breakout rooms with a “meet your peers” activity, and heard from our Learning Circle co-chairs on why new members would benefit from participating in specific groups. Staff provided an overview of the current and recent project work being conducted by members as well as by staff and partners.

Session 2: Learn About the GSI FAQ

GSI FAQ Purpose Statement

The newly released GSI FAQ includes talking points, data, and case studies to support proactive and productive conversations with leadership and colleagues related to the adoption of GSI. In this session, we walked through this resource and explored how members can make the most use of it. Additionally, we heard from members both what their biggest needs and challenges are in communicating about GSI. Members also generated ideas for ways in which they can utilize this new tool including pulling data that informs “sticky” issues, using this to explain the different benefits of various GI systems, and using it as a reference for various communication needs across departments.

Session 3: Brainstorming Leadership Development in the Exchange

Personal reflection questions

This session continued an ongoing discussion about how the Exchange can support members in developing their leadership skills to address obstacles being faced across the field. In this session, we engaged in reflection and broke out into small group discussions to further explore members’ needs and interests related to leadership development and ideas for how to best utilize newly acquired funding to develop leadership programming in the Exchange. Members spoke to common themes around the need to be able to provide clear messaging and to “make the case” for GSI, as well as the need to effectively build trust and collaborate within their teams, among other things. Exchange members can email Alison ( if you are interested in staying involved in this discussion moving forward.

The City of Vancouver’s award-winning Rain City Strategy reimagines how rainwater is managed – a significant step toward becoming a water-sensitive city. It is a cross-departmental initiative that ushers in a paradigm shift in water management, building upon past actions and leadership around green rainwater infrastructure (GRI) both in Vancouver and beyond. The Strategy provides a long-term, pragmatic roadmap for evolving rainwater practices around nine transformative directions, alongside three action plans that outline the immediate steps required. Approved in 2019, the strategy is now in its 3rd year and has been repeatedly recognized for its trailblazing approach, winning 8 regional, national, and international awards.


There has historically been a strong identification with water in the City of Vancouver, where it rains approximately 169 days per year – precipitation that exceeds that of Seattle and Portland. The Rain City Strategy started with an impetus around water quality, but the City of Vancouver quickly realized that it was a unique opportunity to think strategically about current and future challenges in a different way, as climate change had not been a significant part of thinking about rainwater management prior and the conventional thinking had been under-evaluating the risks plus the potential for green rainwater infrastructure to be a significant part of the solutions. Public health concerns also didn’t fully figure into the dialogue, including those related to urban heat islands and sewage pollution from Combined Sewer Overflows (CSO).

Inspired by the work being done at Washington Stormwater Center, multiple Vancouver departments, including Engineering Services; Planning, Urban Design and Sustainability; Development, Buildings and Licensing; Real Estate Facilities Management Finance, Risk and Supply Chain Management; and the Vancouver Board of Parks and Recreation  came together around a new water management approach centered on new goals that emphasized multiple objectives and benefits beyond just water quality. The new core goals became to:

  1. Improve and protect Vancouver’s water quality;
  2. Increase Vancouver’s resilience through sustainable water management; and
  3. Enhance Vancouver’s livability by improving natural and urban ecosystems.


This collaborative effort was a shift from the past, around an idea that water management was the responsibility of many departments and different people, which created shared accountability and impetus among the different departments. An expert panel was recruited and engaged throughout the development process, consisting of 23 very diverse advisors – from landscape architects, to hydrology engineers, to environmental groups, to attorneys. The panel held 5 sessions and contributed substantial thought leadership towards the creation of a rainwater management process city-wide. Vancouver also hosted 94 external events to properly acclimate and engage the public throughout the planning and decision-making process, connecting with over 14,000 professionals.


This collective initiative was named the Rain City Strategy and laid out 9 TRANSFORMATIVE DIRECTIONS that were a paradigm shift in how the City thinks about rainwater. They are as follows:

  1. Strive to become a water sensitive city;
  2. Respond with urgency to climate change;
  3. Accelerate action to protect the health and vitality of surrounding waterbodies;
  4. Revitalize watersheds and waterfronts to enable communities and natural systems to thrive;
  5. Shape systems to integrate and value all forms of water;
  6. Explore intersectionality, equity and reconciliation with Indigenous Peoples through urban water management;
  7. Drive innovation and system effectiveness through data and analytics;
  8. Enable a culture of collaboration; and
  9. Invest in education, capacity-building and partnerships to mobilize action.


A cross-departmental initiative, the Rain City Strategy, alongside three action plans (Streets and Public Spaces, Buildings and Sites, and Parks and Beaches), outlines the immediate steps required to reimagine rainwater in the City of Vancouver and beyond. In the first two years of this strategic effort, close to $8 million in GI projects were implemented, including the 63rd and Yukon St. project, which received 3rd place in the Exchange’s GSI Trailblazers campaign earlier this year for the pioneering work in GRI as well as the 2020 Engineer and Geoscientists of BC Award for Sustainability. In the years since, many other projects have followed suit, with nearly 59 GI projects completed and 48 million liters of rainwater captured and cleaned to date.


With its innovative approach to rainwater management and inter-agency collaboration, the Rain City Strategy has received extensive recognition to date across multiple sectors, which includes the following major awards:

  • Canadian Society of Landscape Architects National Award of Excellence for Planning and Analysis
  • Water Next Award for Stormwater Projects & Technology
  • Water Next Award for 2020 Project of the Year
  • Canadian Institute of Planners National Award of Excellence for Climate Change Planning
  • Planning Institute of BC Gold Award for Excellence for Policy Planning in City and Urban Areas
  • BC Water and Wastewater Association for Excellence and Innovation in the Water and Waste Industry
  • Union of BC Municipalities Community Excellence Award for Sustainability
  • International Erosion Control Association Environmental Excellence Award


  1. Articulate the vision – that’s key before you begin – it starts with demands & expectations and how these can best be met
  2. Embrace a top-down, bottom-up process – engage contribution from diverse constituents internally
  3. Connect through multiple perspectives & entry points to optimize a “Transformative” Change Process
  4. Foster possibility thinking (adopting the US Water Alliance leadership terms) & harness the power of imagery to inspire & validate
  5. Harness values & culture to drive transformation – ask what is important to people and also what are the team & organizational values (what drives & motivates people)
  6. Recognize transformation as a process – create new narratives and work to achieve buy-in, as they can really make a difference, as does contesting ingrained narratives that are flawed, including dispelling myths & misinformation
  7. Invest in education, community building, and partnerships
  8. Mobilize – empower internal & external supporters
  9. Enable collaborative approaches to planning & implementation – pay attention to power related to decision-making & spheres of influence
  10. Enable learning, celebrate progress and inspire others to join the transformation journey
  11. REMEMBER that change management is a journey that evolves but never ends.

With questions about the Rain City Strategy or GRI projects currently underway, please contact Julie McManus with the City of Vancouver at

The Green Infrastructure Leadership Exchange, in partnership with Earth Economics, recently completed a Green Stormwater Infrastructure (GSI) FAQs to help Exchange members have effective conversations with agency leadership and colleagues about the adoption of GSI, with intent to preventing GSI budget cuts in the short term and expand funding in the long term. This is the second of several deep dives that aims to help members better navigate and internalize this comprehensive document. 

The first two sections of the document describe its purpose and the key terms used. The third and fourth sections – “Performance Considerations” and “Cost Considerations” – were already summarized here.

The fifth section of the document – summarized below – includes 5 case studies that demonstrate examples of utilities that have opted to implement some type of green stormwater infrastructure (GSI), typically as part of a hybrid approach, to achieving water quality and volume reduction goals.

Camden County, NJ: Camden County Municipal Utilities Authority (CCMUA) and the two city permittees (City of Camden and Gloucester City) face combined sewer overflow (CSO) problems and need to meet updated National Pollutant Discharge Elimination System (NPDES) permit regulatory requirements from the State of New Jersey, while also addressing street flooding and water quality optimization. The goal is to capture 85% of the annual combined sewage generated during precipitation events for treatment by optimizing current grey infrastructure systems with expanded treatment capacity at a water pollution control facility (WPCF). In addition, they are committed to mitigating 10% of all system-wide directly connected impervious areas (DCIA) from contributing runoff to the combined sewer system by using GSI. While they know they’ll be unable to meet all concerns with GSI, results thus far indicate that hybrid annual and life cycle operations and maintenance (O&M) costs will be lower than a solely grey approach.

Metropolitan Milwaukee, WI: Milwaukee’s urban core consists of combined sewer systems (CSS) that experience approximately two CSO events each year, but many residents continue to experience basement backups. In addition to these concerns, updated discharge permit conditions required MMSD to annually install one million gallons of green infrastructure (GI) capacity to the region. To meet these goals, a Green Infrastructure Plan was established with the goal of capturing the first half inch of rainfall on impervious surfaces by 2035 – an equivalent of 740 million gallons of stormwater storage. To address stormwater concerns and meet permit requirements, MMSD analyzed 10 GI alternatives, from greenways to green parking lots, for performance and costs, and also, a system-wide triple-bottom line analysis was conducted on the economic, social, and environmental benefits of the GI strategy. Most GI options were estimated to be more cost-effective than the deep tunnel alternative per gallon of storage, and the benefits included $44 million in cost savings by avoiding the need for deep tunnel storage; creating over 500 maintenance jobs at full implementation; $1.4 million in public health benefits, and $1.5 to $2.1 million in energy savings.

City of Lancaster, PA: Historically, about 1 billion gallons of polluted stormwater flowed into the Conestoga River from Lancaster’s CSS annually. The city was placed under a US Environmental Protection Agency (EPA) consent decree for CSO)and total maximum daily load (TMDL) violations within the Chesapeake Bay watershed. Despite repeated efforts and substantial investments to mitigate the concerns, the city still struggles. Numerous green infrastructure (GI) investments have sought to address this long-standing concern. A 2011 plan considered additional GI options, comparing various GI types with overflow storage tanks and the city implemented multiple GI pilot projects to monitor the effectiveness. The city are finding the best approach is to make GI a core part of its Public Works activities as roads, alleys, parks, and other public infrastructure are improved, relying on opportunities for available funding and integrating with other infrastructure and planning efforts.

City of Vancouver, BC: The City of Vancouver has a rapidly growing population and with urbanization, the natural infiltration ability of the land decreases, leading to greater runoff. In areas with CSS, this can lead to more frequent and intense overflow events. At the same time, the increasing development to meet growing population needs creates competition for land that often impedes GI implementation. Vancouver discovered that Stormwater Tree Trenches (STT) fit well into many developments and transportation projects being implemented through the citywide Integrated Rainwater Management Plan (IRMP). A literature review was conducted for four STT designs in conjunction with bioswales and grey infrastructure approaches, in addition to a life cycle cost analysis of these various scenarios within a boulevard reconstruction project. STT were found to be 20% – 30% cheaper than bioswales and conventional grey infrastructure. And although GI options were 28% – 59% more expensive over the project life cycle than a pave only approach, that approach alone will not meet the City’s sustainability goals. Furthermore, the capital expenditures were the costliest for conventional approaches with water quality treatment devices.

City of Gresham, OR: The City of Gresham requires new and redevelopment projects that add or replace at least 1,000 square feet of impervious surface to manage stormwater quality and quantity, in accordance with requirements in the City’s Stormwater Management Manual. To identify the most cost-effective approaches, the City conducted a lifecycle cost analysis of commonly used green and gray infrastructure alternatives. Streetside planters were found to be the most expensive option due to their relatively high maintenance costs, followed by the Contech filters. Pervious asphalt, despite its initial high cost, was found to be comparable on an annual basis to Stormwater Tree Wells, because it doesn’t require additional maintenance beyond what is already conducted on other conventional streets. Ponds/swales were the most cost-effective, with low capital and maintenance costs. Finally, a “hybrid” option that blends street-side stormwater planters with large downstream centralized vegetated facilities is almost half the cost of street-side planters alone.

City of Harrisburg, PA: The City of Harrisburg, PA has a combination of CSS and MS4 . Capital investments are needed to meet National Pollution Discharge Elimination System (NPDES) permit baseline levels of control, capturing 85% of CSS volume in a typical year. Capital Region Water conducted an analysis to determine the most cost-effective approach to meet regulatory requirements while avoiding unreasonable ratepayer burdens over the next 20-years. They assessed alternatives at both the systemwide scale and locally in 10 catchment planning areas. At the systemwide level, rehabilitation and replacement of treatment and conveyance components were more feasible than the deep storage tunnel option. Among the localized alternatives, the decentralized green/grey hybrid approach was predominantly the most cost-effective option. In the few areas where it did not meet the baseline levels of control, it was found that adding targeted localized sewer separation alongside it was most effective. In addition, a Triple Bottom Line evaluation found the hybrid approach provides the most benefits.

To review all of the details of each case study, along with related data tables, check out the full GSI FAQ document.

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