Dorchester County, Maryland Climate risk & resilience profile

Dorchester is one of two Maryland counties where FEMA's model ranks coastal flooding as the costliest hazard, and the county's hazard plan explains why: about 56% of its land lies in the 100-year floodplain, most of it tidal. The mitigation money has followed one city. Two grants to Cambridge account for about 70% of the $2.9 million in federal share FEMA has committed in Dorchester since fiscal 2003.

What drives the risk

Coastal flooding accounts for 37% of expected losses, hurricanes for 22% and inland flooding for 15%. More than half of the county sits below 4.9 feet in elevation, and its plan says erosion and land subsidence are worst along the southern islands and that farmland in the south has turned to marsh. NOAA's tide gauge at Cambridge shows relative sea level rising about 1.6 inches a decade since 1943. Hurricane Isabel in 2003 drove a surge of more than eight feet into parts of the county, damaging the Hoopers Island bridge and 123 properties.

FEMA rates Dorchester's social vulnerability relatively high, at 60.6, putting it among four Maryland counties rated relatively high or very high. Its community resilience score of 97.5, second in the state only to Talbot County's, largely offsets that, and the overall risk rating is relatively low.

Where the mitigation money has gone

The Hazard Mitigation Grant Program supplied $2.4 million of the total, most of it under Maryland's COVID-19 declaration, whose mitigation money could address any hazard. The largest grant, $1.5 million, pays for design and permitting of the Make Cambridge Resilient flood project, a flood barrier and living shoreline along 1.6 miles of the Choptank River. FEMA has reserved $16 million for construction if it approves the final design, and a second Cambridge grant put $540 thousand into public education. Outside Cambridge, the record is mostly planning grants, a generator in Vienna and grants to elevate 11 flood-prone buildings, nine of them after Isabel.

The mitigation plan

The 2022 Dorchester County All-Hazard Mitigation Plan Update covers the county and its nine towns. FEMA approved it on January 17, 2023, and that approval runs through January 16, 2028. The update added a climate change chapter that uses Maryland's 2018 sea level projections, and its flood mitigation appendix doubles as the county's nuisance flood plan.

What we'd look at next

The Cambridge project is the county's largest mitigation effort, and it is not settled. In September the city extended the grant period through August 2028, but the design is still contested, and Delmarva Public Media reported in August that the estimated cost had risen from $16 million to $27 million. We'd use the plan update due before January 2028 to give the low-lying south county, which the plan describes as at or just above sea level, a project pipeline of its own.