<meta http-equiv="refresh" content="0; url=https://r.sealevelrise.org/https://sealevelrise.org/states/maryland/"/> Maryland's Sea Level Rise - Sea Level Rise

Overview

Maryland's Sea Level Has Risen 10” Since 1950

And Initial Solutions Will Cost Over $3 Billion

The sea level off Maryland’s coast is 10 inches higher than it was in 1950.1 This increase is mostly due to land sinkage.2 Solutions in Maryland can be complicated because the state has a vast amount of assets to protect from sea level rise; not only cities and towns, but the Chesapeake Bay, other coastal wetland areas, historic districts, and a naval academy.3 The state is planning over $3 billion in sea level rise solutions, which include beach renourishment projects, flood prevention, and raising homes.

Sea level rise is speeding up

Although the sea has only risen by 10 inches since 1950, its speed of rise has accelerated over the last ten years and it’s now rising by about 1 inch every 5 years.1 We know this because the sea level is measured every 6 minutes.5 Scientists use different equipment like satellites, floating buoys off the coast, and tidal gauges to accurately measure the local sea level as it accelerates and changes.

Created with Highcharts 6.2.0

Sea level measurement from Annapolis area tide gauge since 1950

Causes & Complications

Why Are Sea Levels Rising?

While there are four main causes of sea level rise in Maryland, land sinkage is the largest contributor.2 Because the land is getting lower each year, due to a process called subsidence, Maryland is particularly vulnerable to an increased rate of sea level rise in the future. Click here to learn more about sea level rise causes.

How Land Sinkage Increases Sea Level Rise

Most flooding happens during the fall

King tides are unusually high tides that generally occur during a new for full moon, or when the sun, moon, and earth align. In some places, king tides are brought on by changes in the weather and ocean patterns. In places like Maryland, king tides are typically over a foot higher than normal.1 Add that to the 10 inches of sea level rise since 1950, and you end up with flooding even on sunny days.

Solutions aren’t simple

In Maryland the sea level is rising more rapidly than some coastal areas because as the ocean water is rising, the land is sinking. Solutions can be complicated because the state must find solutions that not only work for cities and towns, but also natural areas like barrier islands and coastal wetlands. Maryland will need to take an integrated approach to adaptation that incorporates transportation planning, shoreline buffer management, land use planning, building codes and infrastructure design planning, and natural resource management.3

Forecast

What's the Future of Sea Level Rise?

In the last decade, the speed at which Maryland’s sea level is rising has increased, and is now rising by about 1 inch every 5 years. Around Annapolis, it took 26 years for the sea level to rise around 6 inches.1 Scientists now forecast that in the next 13 years, the speed will double, causing the sea to rise by another 6 inches.6

Scientists are not certain how fast the ocean will warm and ice will melt. They expect water levels to continue to rise faster, but are not sure just how fast. Therefore scientists from the National Oceanic and Atmospheric Administration (NOAA) and the US Army Corps of Engineers (USACE) have made predictions based on ranges from low to high.

Below you can see the range of the NOAA and USACE high and intermediate forecasts for various locations around Maryland.7 We are currently closest to the USACE high forecast, which is the darkest red line.

SLR speeding up - Maryland English
SLR speeding up - Maryland English
Annapolis
Created with Highcharts 6.2.0Annapolis Sea Level Rise Forecasts

Flooding

Why Are Floods More Frequent?

When the ocean rises high enough, high tides cause flooding even on sunny days. Even though the sea level has only risen by around 5 and a half inches, tidal flooding has increased by 250% in Maryland since 2000.8

Flooding
How sea level rise affects Maryland

Flooding even when there’s no rain

Drainage systems are designed to channel excess rainwater from the streets and drain it into the sea. But with the pressure from rising sea levels and higher tides, seawater can get pushed into these pipes and spill out into the streets. This causes flooding even on days without rain.

Drain A
Drainage Under Normal Tidal Conditions
Drainage With King Tide / Sea Level Rise

Increased storm surge flooding

Unfortunately, slightly higher sea levels make hurricanes even more damaging. Just a few more inches of sea level rise allow a hurricane to push more water onto the land, even if the hurricane itself doesn’t make landfall.

Maryland-sandy

Hurricane Sandy, 2011

Higher sea levels create a higher launching point for storm surge. These small changes in sea level rise are enough to turn what were 100-year storm surges into much more frequent events. In fact, in a third of 55 coastal sites studied throughout the US, 100-year storm surges will be 10-year or more frequent events by 2050.9

This means that in many coastal cities, if you bought a house with a 30-year mortgage today, by the time you paid off your mortgage you could be experiencing extreme 100-year storm surges ten times more frequently due to sea level rise alone. This does not include the added risk of more intense storms resulting from warmer water and a warmer atmosphere, which could further increase storm surge damage.

In 2012, Hurricane Sandy hit Maryland, bringing powerful storm surge that cost over $35 million in damage and devastated Somerset County.10 Without sea level rise, Sandy’s storm surge would have been lower.

Maryland-sandy

Hurricane Sandy, 2011

Costs

What's at Risk in Maryland?

There’s a lot at risk from sea level rise and flooding in Maryland. Sea level rise is already causing coastal flooding and beach erosion, but also has the potential to carry saltwater inland to bays, rivers, and wetlands and cause saltwater intrusion into freshwater aquifers. This can pollute drinking water and cause soil to become too salty for the trees, vegetation, and crops that grow in low-lying areas.11 Future sea level rise could submerge thousands of acres of tidal wetlands and low-lying lands including Smith Island, which is Maryland’s last Chesapeake Bay island community.3 Sea level rise is also causing major flood issues in Ocean City, which threatens $3 billion of the state’s economy.12

Business & Economy
Business & Economy

Flooding can damage sales, shop interiors, and merchandise, and force businesses to close. Tourism and port industries can be impacted or shut down by sea level rise.

Military Infrastructure
Military Infrastructure

Rising seas erode the beaches of important military infrastructure and damage ports. Flooding can make it impossible for service-people to reach or leave bases.

Coastal Wetlands
Coastal Wetlands

Sea level rise can disrupt coastal wetlands, which puts important ecosystems in danger, threatens habitats, and leaves communities exposed to dangerous storm surge.

Maryland is spending over $3 billion on solutions

Some cities have sufficient resources to deal with this problem while others do not. Maryland will need solutions at the individual, local, state, and federal levels to protect its coastal communities.

Ocean City
 Ocean City

Ocean City has a beach renourishment plan that extends through 2044 and will cost nearly $300 million.12

Annapolis
Annapolis

Annapolis has a $10 million flood mitigation engineering plan to address tidal flooding in City Dock, a downtown historic district of the city.13

James Island
James Island

The Army Corps of Engineers has proposed a dredging project that will replenish Barren Island and James Island, with a cost estimated of $2.8 billion.16

What can you do?

Individuals, mayors, legislators, governors, and Congress can work together to build protections before flooding, to build back stronger after flooding, and to create plans that future-proof our communities. Click here to see what solutions can help protect your home or what your community can do.