Planning staff present 2025 high-tide flood mitigation update; modeling and community-level planning cited as next steps

Calvert County planning and emergency management staff presented the county's 2025 high tide flood mitigation plan update on July 30, describing rising incidences of high-tide flooding, local relative sea-level rise trends and a menu of mitigation measures to improve resiliency in waterfront and low-lying communities.

Molly Fleetham, environmental planner with Planning and Zoning, with Dr. Kara Buckmaster from Public Safety Emergency Management, said the update evaluates risks and vulnerabilities from high-tide flooding (the county is using the term "high tide flooding" in place of "nuisance flooding") and is required under state law. Staff noted they secured a state grant to help fund the update.

Staff described how local measurements show the rate of sea-level rise in the Solomons area increased from about 3.88 millimeters per year (reported in 2019) to 4.11 millimeters per year in recent tracking, and that 2024 saw more than double the frequency of high-tide flooding events compared with earlier years going back to 1980. The presentation noted that, regionally, the Chesapeake Bay area is seeing faster sea-level rise than the global average and that Southern Maryland is experiencing relatively faster land subsidence.

The plan identifies geographic and topical vulnerabilities, listing waterfront communities, critical infrastructure (transportation, wastewater treatment, electricity and communications), historic and cultural sites (for example Lower Oyster House and Cove Point Lighthouse), recreational resources, aquaculture and agriculture subject to saltwater intrusion, and natural features such as marshes that help absorb floodwaters. Staff said some infrastructure, for example the enhanced nutrient removal wastewater treatment plant in Chesapeake Beach, was compromised in the past during a tropical storm but that high-tide flooding alone was unlikely to have caused that event.

Chapter 6 of the draft summarizes mitigation actions and progress since 2020: the county developed a flooded-roadway tracking tool with Public Works and Technology Services; communications staff produced public-facing videos explaining floodplain regulations; staff encouraged community reporting via the state DNR MyCoast app; parks and recreation and DNR are pursuing site-specific shoreline restoration projects (for example at Breezy Point and Halloween Point); and improved floodplain regulations adopted earlier in 2025 helped the county improve its community rating score for insurance purposes.

Mitigation recommendations in the draft include expanding modeling to better identify parcel- and building-level impacts under sea-level rise scenarios; deploying sensors to track water levels; encouraging reporting of blocked shoreline stormwater infrastructure; studying frequently flooded roadways; tracking saltwater intrusion impacts to agriculture; seeking funding and partnerships for nature-based solutions; strengthening public education and preparedness; and developing methods to protect heritage sites.

Commissioners asked whether the county intends to develop community-level, property-specific flood mitigation plans similar to prior private-sector studies for some communities. Staff said the county plans to improve modeling and data layers to better reflect on-the-ground conditions but that community-specific planning resources would require additional funding and staff capacity and are not guaranteed at this time. Emergency management staff noted they can provide community outreach and preparedness support in the interim.

Staff closed the presentation with practical guidance for residents: report flooded roadways to highway maintenance, document flood incidences via MyCoast, and follow safety guidance such as "turn around, don't drown." No formal board action was taken on the plan update at the meeting; the presentation was informational.