Introduction

Chelsea, Massachusetts is located on Boston Harbor along the northern banks of the Mystic River. Mill Creek and the Chelsea River bound the city in the North and East, respectively. The city’s geography makes it particularly vulnerable to coastal storm surges and sea level rise as well as pluvial and riverine flooding. As a tidal river, the Mystic experiences coastal storm surges and sea level rise, putting approximately 36% of the city at risk of flooding today and nearly 50% at risk by 2070.[1] Pluvial and riverine flooding is becoming increasingly more threatening to Chelsea with elevated precipitation in the region due to climate change.[2] Warmer winter months cause increased precipitation to be especially problematic because the precipitation that once fell as snow is now more likely to fall as rain, overwhelming the current stormwater management system in Chelsea. The primary drainage system for stormwater is through Combined Sewer Overflows (CSOs), which result in wastewater overflowing into local waterbodies when there are strong storms.[3] Additionally, stormwater “represents the single largest source responsible for water quality impairments in the Commonwealth’s rivers, lakes, ponds, and marine waters,” proving the detrimental effects of pluvial and riverine flooding.[4]

Flood Pathways and Vulnerability Zones via Designing Coastal Community Infrastructure for Climate Change

Solution: Partial Consolidation

Partial consolidation should be used to create a regional stormwater management authority as a means of addressing flooding in Chelsea.

The US Water Alliance defines consolidation as the process, “when two or more legal entities become one operating under the same governance, management, and financial functions.”[5] Consolidating water infrastructure allows for systems to be managed as a decentralized, regional network.[6] For flood management, consolidation of stormwater authorities at a regional level allows the risk of flooding to be more evenly distributed across watershed communities and ensures neighboring municipalities are not negatively affecting one another with flood protection infrastructure.[7]

Two precedents for regionalization and consolidation of water infrastructure in Massachusetts are the Massachusetts Water Resources Authority (MWRA) and the Central Massachusetts Regional Stormwater Coalition (CMRSWC). “MWRA is a Massachusetts public authority established… to provide wholesale water and sewer services… in 61 metropolitan Boston communities,” including Chelsea, with operations funded by user fees and management governed by a Board of Directors appointed by the Governor and/or elected officials in MWRA customer communities.[8] CMRSWC is a group of 31 communities in central Massachusetts that manage their stormwater systems together with the primary goal of efficiently and cost-effectively meeting MS4 Permit requirements.[9] Originally financed by a state grant, CMRSWC has no dedicated funding, but receives dues from member communities.[10] The coalition provides member communities access to shared resources, documents efforts and submits reports, and educates the public about MS4 conversions, while also working to apply for grant funding, regionalize data management systems, standardize policies and procedures, and implement capital improvements.[11]

These precedents of regionalized water management suggest there is an opportunity to consolidate stormwater management for communities in the Mystic-Charles Watersheds, including Chelsea. This regional stormwater management authority would aid in addressing flooding in Chelsea and neighboring communities by creating a larger network of decentralized infrastructure allowing for a more even distribution of flood risks, more resiliency in the system, more efficient implementation and operations, and lower overall costs.

District 05: The Mystic-Charles Watersheds Region

Map of District 05 via ResilientCoasts

The 2025 ResilientCoasts Plan serves as a framework for organizing flood resiliency at a state and regional level. Part of Massachusetts’ ResilientMass initiative, the plan aims to achieve the state’s goals for climate adaptation and resiliency programs, policies, and initiatives.[12] The overall plan strives to coordinate proactive and comprehensive coastal hazard mitigation strategies among 98 communities.[13] These communities are grouped into 15 Coastal Resilience Districts (CRDs) which, “share common characteristics like geomorphology, natural environment, built infrastructure, population and development character, and coastal hazards.”[14] ResilientCoasts acknowledges that currently most resiliency and hazard planning happens at the local level, which is true of Chelsea, but recommends regional planning at the CRD level because, “flooding and erosion do not respect municipal boundaries,” and constraints on funding, staffing, and technical capacity mean wide-spread and high-cost resiliency measures can only be achieved through regional collaboration.[15] Consolidating to create a regional stormwater management authority for Chelsea and its surrounding communities should align with this ResilientCoasts recommendation to organize at the CRD level.

Chelsea is part of ResilientCoasts’ District 05, the Mystic-Charles Watersheds, along with the cities of Boston, Revere, Everett, Malden, Medford, Winchester, Arlington, Belmont, Cambridge, Somerville, Watertown, Newton, and Brookline. District 05’s geography was once characterized by tidal inlets and wetlands, but today much of this land has been filled in from urbanization leaving natural environments only in small areas of coastal beaches and salt marshes.[16] Built infrastructure on the Mystic and Charles Rivers include the Amelia Earhart and Charles River dams, respectively, as well as ports and wharves and bulkheads, revetments, and seawalls to armor the shorelines.[17] Encompassing some of the most urbanized areas in Massachusetts, District 05 is the most populated CRD in the ResilientCoasts plan with over 400,000 people and features many nearly completely built out communities with high density residential, commercial, and/or industrial areas placed along the rivers.[18] As such, 37,000 structures on 27 square miles of land lie within the 2070 0.1% annual excedence probability coastal floodplain.[19] Also, at risk in the Mystic-Charles Watersheds, are 4 Designated Port Areas which contribute to the 19% of industrial and commercial land that is exposed to flooding.[20] With shared natural resources, mutually beneficial port and harbor infrastructure, and similar development patterns, it makes sense for Chelsea to join forces with the other municipalities of the Mystic-Charles Watershed as a formal regional stormwater authority in order to address flood concerns across the district.

Timeline & Structure

The ResilientMass plan is slated to come out with an update in 2028, with the ResilientCoasts update to follow in 2030.[21] Ideally, implementation of the District 05 regional stormwater management authority would align with this timeline. The ReslientCoasts plan also proposes the state better support regionalization efforts in the next 5 years through better funding, technical assistance, and partnerships for regional planning.[22] Using these initiatives and recommendations as an incentive for beginning district-wide planning, Chelsea can build a coalition among Mystic-Charles Watershed communities with the goal of formalizing the regional stormwater management authority by the next plan update.

Timeline by Authors

Currently in Chelsea stormwater management is organized from the top-down with Federal Agencies as the overarching authority followed by the Massachusetts Governor, the Massachusetts Water Resources Commission (MA WRC) and the ResilientMass Action Team, ending with Chelsea and its Public Works Department (DPW). The Chelsea DPW does have a Stormwater Management Plan and a Hazard Mitigation Plan to address flooding, but the city’s capacity and funding are limited.[23]  Likewise, the Resilient Mystic Collaborative has released a plan called the Lower Mystic River Watershed Vision to align flood planning for communities along the Mystic, but the approach is hardly regional, with only lower Mystic municipalities included and a reliance on local implementation of strategies.[24]

Current Stormwater Management Structure by Authors

In contrast to this current structure, a regional stormwater management authority would be organized in a way that allows for a more bottom-up approach to governance. Rather than the City of Chelsea acting as the highest level over government before state authority, the District 05 stormwater authority would act on behalf of Chelsea and all other communities in the Mystic-Charles Watersheds. Assuming the adoption of District 05 as an official public authority established through state Legislature, the internal management structure could follow MWRA’s organization with an Advisory Board and a Board of Directors. Acting as advocates for the District 05 communities, the Advisory Board would be made up of Community Representatives, including a Chief Elected Official and a Designee from the each of the 14 Communities, as well as a member of the Metropolitan Area Planning Council (MAPC) and 3 Gubernatorial Appointees.[25] The 9 member Board of Directors would manage governance and operations of the stormwater authority and include the State Secretary of Environmental Affairs (Chair), a Representative of each watershed, and a Representative of each DPA appointed by the Governor as well as 3 representatives from the Advisory Board to be appointed by the Advisory Board.[26]

Regional Stormwater Management Authority Structure by Authors

Benefits of Regionalization

The importance of regionalizing stormwater management becomes clear when considering the case of Chelsea. The maritime industrial city has a relatively economically disadvantaged population base, meaning it carries an outsized critical industry burden for the region while having limited capacity to pay for climate resiliency improvements to protect said industry. In other words: all of New England has a vested interest in whether Chelsea floods, but the burden rests on Chelsea alone to plan and pay for flood protection. Notably, Chelsea is host to three-quarters of New England’s heating fuel, gasoline for thousands of gas stations on the East Coast, much of Greater Boston’s road salt, Boston Logan Airport’s jet fuel, and enough fresh produce to feed eight million people.[27] By partially consolidating its stormwater management and elevating it to a higher echelon of government, flood mitigation planning can be better integrated with regional infrastructure planning to make New England’s food, transportation, and heating systems more resilient and secure.

Chelsea Terminal for Biodiesel, Diesel, Heating Oil, Marine Fuels, and Residual Fuels via Global Partners LP

Another benefit of regionalizing stormwater management is that the financial capacity of Greater Boston can be leveraged to make targeted investments. Currently, only eight of 60 MWRA communities assess a stormwater fee, and five of those have been introduced since 2022.[28] Chelsea does not assess such a fee, instead relying on loans and bonds from MWRA that must be paid back from its Water and Sewer Enterprise Fund or, in other words, through “rate revenue.”[29] This funding mechanism for stormwater management is financially unsustainable. Chelsea is a low-income city, which motivates policymakers to keep water and sewer rates as low as possible. The city has kept combined water and sewer rates lower than the average community receiving services from MWRA. In 2025, the average household spending on water/sewer services was $1,976.40 compared to an MWRA average of $2,097.39. The average ratepayer has seen their bills increase 10.2% since 2019, well below the national 29.8% inflation during that time. The MWRA wrote in 2025 that Chelsea “limits water and sewer rate increases by adjusting other departmental spending.”[30] [31]

With local funding options for stormwater management being pushed to their limits, Chelsea has appealed to federal and state authorities to build flood infrastructure. But the downside to this approach was made clear last year when FEMA cancelled a $50 million grant to build out a floodwall between Everett and Chelsea.[32] If Chelsea’s – and all of Greater Boston’s – coastal economy is going to weather the challenge of Climate Change, it will need a sustainable funding mechanism for stormwater management that can be implemented on regional projects that can benefit multiple jurisdictions, especially those with fewer financial resources. A regional stormwater fee could be implemented based on impervious surface, capacity to pay, or a combination of both, which would create a fund that could finance projects on its own and serve as a local matching source for supplementary state and federal grants.   

One final, lower priority potential benefit of regionalization is the potential to diversify the region’s water portfolio by harvesting rainwater for non-potable usage. Currently, all the region’s stormwater is either discharged directly into local water bodies via runoff and CSO points or treated at the Deer Island Wastewater Treatment Plant, where effluent is released into Massachusetts Bay.[33] Pluvial flooding mitigation projects could capture precipitation for prolonged release into waterways or piped for industrial usage downriver in places like Chelsea, where the gravity-powered movement from high to low elevation could make moving captured rainwater more cost-effective than pumping recycled wastewater uphill from Deer Island. Rainwater Harvesting (RWH) projects can vary in economic efficiency, but some projects have been able to launch with reasonable payback timelines and could make sense for Massachusetts given the concentration of industry at low elevation along the waterfront.[34] Projects would need to be assessed on a case-by-case basis by the stormwater authority to ensure they meet economic efficiency standards and conserve enough water to be worthwhile, but there is potential for the proposed authority to also diversify the region’s water portfolio.

Projects for the Stormwater Authority in Chelsea

Chelsea’s Climate Change adaptation plan, Designing Coastal Community Infrastructure for Climate Change, outlines three types of programs that a stormwater authority could help facilitate: site-specific plans to protect critical infrastructure, shoreline measures to protect larger at-risk areas, and policies to improve resilience city-wide.

The site-specific measures are typically within Chelsea’s control and are smaller in scale, enabling near-term implementation. For example, the Carter St Pump Station redirects water during flooding but was at risk of water overtopping the brick façade and disabling the equipment during an extreme weather event. The rehabilitation of the station is estimated to cost $3-$5 million.[35]

Carter St Pump Station via Stantec and City of Chelsea

Policy measures for stormwater management are “free” to implement but take longer to take effect. A stormwater management authority could incentivize or even mandate regional land use policies to reduce the impact of flooding, such as reducing impervious coverage, retreating from waterways where possible, and structural resilience. Chelsea’s own plan focuses on policies around structural resilience using a resiliency review checklist and existing municipal code, which makes sense for the most downriver city in the watershed.[36] However, a more regional approach to flood management could enable policy to have a greater effect by adjusting land-use in communities upriver to more effectively reduce precipitation from overwhelming downriver communities like Chelsea. Notably, policy aimed at elevating structures or strategically retreating from vulnerable areas could be the most effective tool at combating sea level rise, since building a flood wall cannot effectively stop rising water from coming from below.  

The shoreline infrastructure measures have the greatest potential to adapt Chelsea to increased coastal flooding due to climate change in the coming decades. Chelsea’s plan recommends five adaptation measures (a mix of green and grey infrastructure) to protect each flooding vulnerability zone, all costing in the millions of dollars.[37] A regional stormwater management authority would have two major benefits here. First, it would be able to better connect Chelsea with financing resources to get these proposed projects underway. Second, it would ensure Chelsea’s infrastructure projects do not merely “push” water onto nearby communities. Flood walls can be highly effective at guarding against storm surges but can make flooding worse on either side of the flood wall, making regional planning a significant part of grey infrastructure planning.

Birds Eye View of Lower Chelsea Creek Adaptation Map via City of Chelsea

Conclusion

ResilientCoasts was an excellent first step in addressing the enormous challenge of adapting coastal Massachusetts to climate change. We recommend that the commonwealth build on the district-based framework and regionalize stormwater management in the Mystic-Charles watershed, which is currently applied in a patchwork manner that leaves under-resourced communities scrambling to respond individually. The urgency and scale of the crisis have inspired communities to engage in some impressive ground-up collaborative planning via the Lower Resilient Mystic Collaborative, but this model can be strengthened by formalizing this approach into a higher echelon of government and adding missing stakeholders to the table via a regional stormwater authority. Chelsea, as a particularly under-resourced community, stands to benefit from a partial consolidation of stormwater management into a regional authority. But other communities stand to benefit as well from sharing resources and planning, especially due to amount of critical infrastructure Chelsea hosts. Massachusetts should act early in the planning process of the next ResilientCoasts to ensure the cities of Greater Boston can partially consolidate their stormwater planning and ameliorate the worst effects of climate change together.

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[1] City of Chelsea, Massachusetts, “Designing Coastal Community Infrastructure for Climate Change” (2017), 2.

[2] Metropolitan Area Planning Council, “Hazard Mitigation Plan 2022 Update” (Final Plan, Chelsea, MA, 2022),

20-23.

[3] “Combined Sewer Overflows,” City of Chelsea, Massachusetts, accessed March 23, 2026, https://www.chelseama.gov/departments/water___sewer/wsd_programs___systems/combined_sewer_overflows/index.php.

[4] Massachusetts Department of Environmental Protection, “Changes to the Massachusetts Stormwater Management Standards,” AMWS Newsletter, 1.

[5] US Water Alliance and UNC Environmental Finance Center, “Strengthening Utilities Through Consolidation: The Financial Impact” (2019), 5.

[6] Allison Lassiter, “Decentralization and digitalization” (Week 13 presentation, University of Pennsylvania, 2026).

[7] Lassiter, “Decentralization and digitalization,” (2026).

[8] “About MWRA,” & “Governance & Management,” Massachusetts Water Resources Authority, accessed May 2, 2026, https://www.mwra.com/about-mwra & https://www.mwra.com/about-mwra/governance-management.

[9] Central Massachusetts Regional Stormwater Coalition, “What is CMRSWC?”(Presentation, 2019).

[10] CMRSWC, “What is CMRSWC?”(Presentation, 2019).

[11] Robin Craver and Michael Knox, “Central Massachusetts Regional Stormwater Coalition, Case Studies of Stormwater Management Approaches Used In Massachusetts & Wrap-Up” (Presentation, 2013).

[12] ResilientMass. “ResilientCoasts Final Plan,” (2025), 5.

[13] ResilientMass. “ResilientCoasts Final Plan,” (2025), 10.

[14] ResilientMass. “ResilientCoasts Final Plan,” (2025), 10.

[15] ResilientMass. “ResilientCoasts Final Plan,” (2025), 78.

[16] ResilientMass. “ResilientCoasts Final Plan,” (2025), 90-1.

[17] ResilientMass. “ResilientCoasts Final Plan,” (2025), 90-1.

[18] ResilientMass. “ResilientCoasts Final Plan,” (2025), 90-1.

[19] ResilientMass. “ResilientCoasts Final Plan,” (2025), 90-1.

[20] ResilientMass. “ResilientCoasts Final Plan,” (2025), 90-1.

[21] ResilientMass. “ResilientCoasts Final Plan,” (2025), 264-5.

[22] ResilientMass. “ResilientCoasts Final Plan,” (2025), 256-7.

[23] Weston & Sampson, “Stormwater Management Plan,” (MS4 General Permit Compliance, City of Chelsea, Massachusetts, 2021 Update).

MAPC, “Hazard Mitigation Plan 2022 Update” (Final Plan, Chelsea, MA, 2022).  

[24] Resilient Mystic Collaborative. “Lower Mystic Waterfront Vision. Final Report. June 2025.” 2025.

[25] “Who We Are & What We Do, The Advisory Board,” MWRA Advisory Board, accessed May 2, 2026, https://www.mwraadvisoryboard.com/advisory-board/.

[26] “Governance & Management,” Massachusetts Water Resources Authority, accessed May 2, 2026, https://www.mwra.com/about-mwra/governance-management.

[27] Connecticut Public. “How One Massachusetts City Came to Bear Environmental Burdens for the Region,” August 10, 2021. https://www.ctpublic.org/environment/2017-08-16/how-one-massachusetts-city-came-to-bear-environmental-burdens-for-the-region.

[28] Romero, “Annual Water and Sewer Retail Rate Survey,” 190-191.  

[29] ⁸ “Capital Improvement Plan” (City of Chelsea, Massachusetts, FY2027– 2031), 18-30. 

[30] Matthew A. Romero, Exec. Dir., “Annual Water and Sewer Retail Rate Survey” (Survey Results, The Community Advisory Board to the Massachusetts Water Resources Authority, 2025), 33-34.

[31] “CPI Inflation Calculator,” U.S. Bureau of Labor Statistics, accessed April 6, 2026, https://www.bls.gov/data/inflation_calculator.htm. 

[32] Commonwealth of Massachusetts. “Trump Administration Cancels $90 Million in Disaster Prevention Aid.” 2025.

[33] MWRA. “Your Sewer System,” n.d. https://www.mwra.com/your-sewer-system.

[34] Dallman, Suzanne, Anita M. Chaudhry, Misgana K. Muleta, and Juneseok Lee. “Is rainwater harvesting worthwhile? A benefit–cost analysis.” Journal of Water Resources Planning and Management 147, no. 4 (2021): 04021011.

[35] MAPC, “Hazard Mitigation,” 122.  

[36] City of Chelsea, “Designing Coastal Community,” 7-34. 

[37] City of Chelsea, “Designing Coastal Community,” 7-11.