The Gulf of Maine is an international watershed in the North Atlantic stretching north from Provincetown at the tip of Massachusetts Bay in the Commonwealth of Massachusetts to Cape Sable on the Bay of Fundy in the province of Nova Scotia in Canada. For over 13,000 years, the Gulf has been developed around access to the coast for fishing, trading, and recreation. Today, these coastal development patterns put the cultural landscapes, economies, communities, and aging infrastructure systems along the Gulf at risk.
Climate Futures on the Gulf of Maine uses place-based scenario planning to illustrate the risks, vulnerabilities, and plausible futures for ten infrastructure systems along the rim of the Gulf. Place-based scenario planning is a method of long-term strategic planning that creates representations of multiple, plausible futures that are used to inform decision-making in the present. While complementary to probabilistic models used to forecast future vulnerabilities, scenario-based planning shifts emphasis from statistical probability to ways of thinking about the future. The goal of place-based scenario planning is not to predict the most likely outcome, but to reveal biases and blind spots in complex and non-linear situations.
Climate Futures uses the medium of landscape representation to surface the cultural value systems embedded in existing infrastructural systems, and position landscape as a driver when evaluating design from individual infrastructures to the Gulf of Maine watershed.
Systems > Wastewater
WASTEWATER
Wastewater systems include wastewater treatment facilities, also known as sewage treatment plants, sewage disposal plants, wastewater disposal plants, sanity sewers, combined sewer overflows, sewer lines, septic systems, interceptors, sewer pump stations, and storm drains. 1 2
Wastewater treatment facilities are often located in low-lying areas to take advantage gravity-fed collection systems 3 that do not require expensive piping systems and are close to surface waters, like rivers, ponds, and the ocean, to discharge water. This makes these systems extremely susceptible to freshwater and coastal flooding, as well as climate impacts. 4
Sea level rise is causing high tide flooding to become deeper, more frequent, and severe, with impacts on wastewater systems that already see backflow from tidal waters through sewer and stormwater pipes that spill out of catch basins into streets. This presents a new issue, if combined sewer overflows (CSOs) 5 experience inflow from surfacing flooding on streets. While these CSOs have stops on outflow pipes to keep tide waters from entering the pipes, surface inflow can enter the sewer, sending tide waters to sewage treatment plants, and affecting wastewater infrastructure. 6
These newly arising issues exacerbate ongoing problems with wastewater discharge, which, before being treated, can contain untreated human and organic waste, nutrients, pathogens, microorganisms, suspended solids, and households and industrial chemicals. 7
Different municipalities and facilities treat their wastewater to varying degrees, ranging from primary to tertiary. 8 While the Gloucester Wastewater Treatment Plant is the only remaining primary treatment plant in New England, the provinces of Nova Scotia and New Brunswick still have significant populations (38.2% and 17.3%) that are only served by primary treatment. 9 In cities and towns where upgrading existing systems are not possible, and in rural areas, there are options to decentralize wastewater treatment systems and compliment them with nature-based solutions. These decentralized systems exist across scales, from individual residences to institutions using leaching chambers, community cluster systems, mechanized filter systems, aerobic and anaerobic bacteria. 10 Like all wastewater systems, they require consistent maintenance and monitoring to ensure that pollutants do not filter into the ocean.
1 “Wastewater,” American Society of Civil Engineers Infrastructure Report Card, accessed June 10, 2025, www.infrastructurereportcard.org/cat-item/wastewater-infrastructure.
2 In Massachusetts, the American Society of Civil Engineers (ACSE) estimates that there is $11.1 billion in wastewater needs. See “Massachusetts Infrastructure Report Card,” American Society of Civil Engineers, January 2025, infrastructurereportcard.org/Massachusetts.
3 Gravity-fed wastewater systems are conventional systems that transport sewage from homes through buried pipes to a central treatment facility. Pressure sewer systems are used in places where housing density is low, terrain is flat, and the water table is high. Pressure sewer mains are watertight, and therefore ensure minimal sewage leakage. United States Environmental Protection Agency, Wastewater Technology Fact Sheet (Washington, D.C.: Environmental Protection Agency, 2002).
4 Maine Infrastructure Rebuilding and Resilience Commission, “A Plan for Infrastructure Resilience” (Augusta, ME: State of Maine, May 7, 2025):28, www.maine.gov/future/sites/maine.gov.future/files/inline-files/Maine%20Infrastructure%20Resilience%20Plan_May2025.pdf.
5 The United States Environmental Protection Agency defines Combined Sewer Overflows (CSOs) as a “system that collects rainwater runoff, domestic sewage, and industrial wastewater into one pipe. Normally, it can transport all of the wastewater to a treatment plant. Sometimes the amount of runoff exceeds the capacity of the system. When that happens, untreated stormwater and wastewater flows into nearby waterbodies. [In the United States] these events, called combined sewer overflows, are subject to the National Pollutant Discharge Elimination System (NPDES) permitting program.” “Combined Sewer Overflows (CSOs), United States Environmental Protection Agency, May 28, 2025, www.epa.gov/npdes/combined-sewer-overflows-csos.
6 William V. Sweet, “Global and Regional Sea Level Rise Scenarios for the United States: Updated Mean Projections and Extreme Water Level Probabilities Along U.S. Coastlines” (Silver Spring, MD: National Oceanic and Atmospheric Administration, National Ocean Service, 2022): 53.
7 Identifying and monitoring these pollutants is challenging. On the Gulf of Maine, the Gulfwatch Contaminants Monitoring Program was administered between 1993 through 2012 to assess the types and concentration of contaminants in the tissue of blue mussels (Mytilus edulis) at sites ranging from the United States to Canada. The program has found that higher rates of contaminants are correlated to areas with large human population density and with proximity to large rivers which carry pollutants downstream. See M.E. Chase et al., “Gulfwatch: Monitoring Spatial and Temporal Patterns of Trace Metal and Organic Contaminants in the Gulf of Maine (1991-1997) with the Blue Mussel, Mytilus Edulis L,” Marine Pollution Bulletin 42, no. 6 (2001): 491–505.
8 Environment Canada summarizes the different levels of treatment as follows: “No treatment: no treatment process or only screening and/or grit removal; primary treatment: removing a portion of suspended solids and organic matter by physical and/or chemical processes; secondary treatment: removing organic matter and suspended solids using biological treatment processes and secondary settlement; tertiary treatment: removing specific substances of concern (solids, nutrients and/or contaminants) after secondary treatment using a number of physical, chemical, or biological processes.” See “Municipal Wastewater Treatment,” Government of Canada, August 31, 2023, www.canada.ca/en/environment-climate-change/services/environmental-indicators/municipal-wastewater-treatment.html.
9 “Municipal Wastewater Treatment,” Government of Canada, August 31, 2023, www.canada.ca/en/environment-climate-change/services/environmental-indicators/municipal-wastewater-treatment.html.
10 U.S. Environmental Protection Agency, “Decentralized Wastewater Treatment: A Sensible Solution” (Washington, D.C.: U.S. Environmental Protection Agency, 2015), www.epa.gov/sites/default/files/2015-06/documents/mou-intro-paper-081712-pdf-adobe-acrobat-pro.pdf.