These U.S. States Are Planning for Salinization

Climate change is adding new stresses to many drinking water systems. Coastal water systems are facing changes in inland precipitation, sea level rise, and storm surges. These factors bring ocean tides further inland, contaminating some source waters with salt. How are municipalities, regions, and states preparing for salinization?

In "Planning for Drinking Water Salinization in the U.S. Atlantic and Gulf Coast Regions" (Journal of the American Planning Association, Vol. 90, No. 4) Allison Lassiter evaluates to what extent states are experiencing and preparing for salinization.

Lassiter argues that, without state or federal leadership, there's a potential for exacerbating existing inequities among drinking water suppliers and well owners.

Whose water?

The author estimated the number of water systems potentially threatened by salinization by intersecting intake locations with a three-foot sea level rise scenario, the projected high scenario for most of the study area by 2060 or 2070. This method identified 346 water systems along the Atlantic Coast with at least one threatened intake. Together, these systems serve 17 million people.

This estimation is coarse — projected inundation from sea level rise is not equivalent to salinization. However, the threat of salinization is likely both pervasive and substantial.

Beyond water systems, private well owners are also likely at risk from salinization, though it was not possible to calculate their total number with the available data.

Missing Plans

The author examined 13 coastal states in the mid-Atlantic, South Atlantic, and Gulf Coast regions, focusing on where governments address drinking water salinization in planning documents and evidence of monitoring or adaptation efforts.

Out of 13 states:

• Twelve explicitly discussed the challenge of drinking water salinization
• Eight provided recommendations for adapting to salinity
• Seven showed evidence of implemented monitoring or adaptation actions
• Seven state water plans demonstrated evidence of managing salinity, though this was not always explicitly about climate change.

Seawater intrusion and salinization are widely recognized issues; however, actions were concentrated in only a few states. Maryland, Delaware, Virginia, Florida, and Texas demonstrated high levels of engagement. In contrast, Louisiana, Mississippi, Alabama, and Georgia showed little evidence of planning for salinization in climate or state water plans.

Overall, the author found that state-level salinization planning did not match the threat levels.

The author acknowledges that evaluating climate adaptation plans likely underestimates the total number of implemented actions. However, there is a simple barrier to finding evidence of salinization and adaptation actions directly from water systems — very few water systems have plans.

There are approximately 50,000 community water supply systems in the U.S. About 80 percent serve fewer than 3,300 people, with a median annual revenue of $130,000 or less. Approximately 10 percent serve 3,301 to 10,000 people, with a median annual revenue of $390,000.

At these water systems, available revenue tends to be directed toward daily operations, with little allocated for long-term planning. The EPA encourages planning in small systems through capacity development programs, though this approach is not widely implemented.

Figure 1. CWS systems with at least one intake are projected to be inundated based on a spatial overlay with NOAA's 3-ft sea level rise scenario. This overlay conveys the possibility of salinization threat but not certainty. Models including local hydrologic and geologic conditions, combined with other natural and anthropogenic factors, are necessary to evaluate the precise nature of salinization at each water system. Source: Water system population data are from the Safe Drinking Water Information System (EPA, 2023b). Planning for Drinking Water Salinization703

Strategies Mentioned

Among state water plans, the most commonly discussed salinity adaptation strategy was desalination. Attitudes toward desalination varied widely.

Texas's state water plan embraced the strategy without directly naming climate change or sea level rise, while states such as Virginia, Florida, New Jersey, and Georgia mentioned it but de-emphasized the strategy, citing its cost or lesser appeal.

There are no established best practices for salinization adaptation. Desalination is difficult to fund and finance and does not produce the volumes most U.S. water users are accustomed to consuming.

The range of alternative approaches remains up for debate. Potential strategies include blending higher-salinity water with a lower-salinity source, relocating intakes, building salinity barriers, repelling seawater encroachment with managed freshwater flows, and purchasing water from neighboring suppliers. The efficacy and timeline of these strategies are highly localized.

Why Plan

Many smaller and under-resourced systems already struggle to provide clean and reliable freshwater. Without leadership from federal or state governments, planning for salinization will likely fall to coastal water suppliers and well owners. These providers may lack the capacity, budget, or jurisdiction to adequately monitor and protect supplies.

Planners can help bridge gaps in water governance and contribute to adapting drinking water systems to seawater intrusion and salinization. However, in most of the plans reviewed in this study, explicit efforts to address administrative, policy, capacity, and funding gaps were rare.

Longstanding questions remain about the governance structures needed to support equitable drinking water provision. Arguments for scaling up water governance in the U.S. highlight the large number of very small, vulnerable drinking water systems facing complex planning challenges, including salinization of source water.

Matching the scales of biophysical and socioeconomic systems continues to be an ongoing issue for planners working in areas affected by climate change. For all of us, the question persists: As the environment changes, how can water governance adapt?

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