Restoring coastal wetlands for climate resilience
A case study at Naval Base Ventura County Point Mugu
Rising sea levels threaten communities around the world.
Globally, about 40% of the world’s population lives within 60 miles of the coast.
Coastal regions are hubs for economic activity, global trade, and job centers, all of which is threatened by sea level rise.[1] It is estimated that without action, sea level rise “could cost the world more than 4% of the global economy each year by 2100.”[2]
California is at risk now from impacts brought on by a changing climate. Rising sea levels have already begun to creep up California’s shores, bringing with them a host of problems for local communities. In California, sea levels are projected to rise 2 feet by 2050 and around 5 feet by the end of the century.[3]
Climate change is also increasing the frequency and intensity of coastal storms. As sea levels continue to rise, floodwaters will reach farther inland, and the frequency and extent of coastal flooding and erosion will be much more than it is today.
It is estimated that by 2100, sea level rise and associated flooding will threaten over 600,000 people and nearly $150 billion worth of property along the California coast.[4]
Sea level rise will also have profound effects on our coastline and its natural resources.
Coastal habitats are at risk of being submerged along with their associated plants and wildlife.
With 5 feet of sea level rise, 59% of California’s coastal habitat area is estimated to be highly vulnerable to loss.[5]
These losses will not only affect the many unique, rare, endemic, and migratory species that rely on these habitats, but also cascade to impact the critical natural functions that coastal habitats provide to humans.
Wetlands, dunes, and beaches act as natural buffers from coastal storms by absorbing floodwaters and dissipating wave action, protecting coastal communities from flooding.
Healthy coastal habitats also provide other beneficial ecosystem services, including water purification, nurseries for fish, habitat for threatened and imperiled plants and animals, and carbon sinks.
The global extent of wetlands is estimated to have already declined between 64-71% in the 20th century, and California has lost more than 90% of its coastal wetlands.[6,7]
The further loss of coastal habitats due to sea level rise will greatly exacerbate the loss of their many ecosystem benefits.
Threat to Military Bases
The effects of a changing climate are a national security issue with potential impacts to Department of Defense missions, operational plans, and installations. – U.S. Department of Defense, 2019
The United States operates thousands of military installations in the U.S. and worldwide, worth about $1.2 trillion.[8] These facilities are where personnel train and test weaponry, with the specific aim of ensuring the nation’s security.
With climate change, coastal installations are now being impacted by rising sea levels, erosion and increasingly powerful storms.
For example, in 2018, Hurricane Michael damaged 95% of the infrastructure at Tyndall Air Force Base in Florida, with experts projecting a cost of over $3 billion for repairs.[9]
With 53 coastal installations in the U.S. and over 1,700 worldwide, climate change poses a major threat to Department of Defense infrastructure.[8,10]
Sea level rise, extreme weather, drought, floods, you name it—there is a growing recognition that those are real impacts on national security and the ability of the DoD to operate. – Bob Barnes, Retired Brigadier General, U.S. Army
DoD Resilience Efforts
The seriousness of these disruptions prompted the U.S. Congress and the Department of Defense (DoD) to declare climate change a major threat to America’s national security.[11]
To tackle this threat, Congress and DoD leadership mandated that military services incorporate climate considerations into infrastructure and operations planning, and recently began pursuing climate-adaptive actions that increase base resilience.[8]
In 2020, an amendment to U.S. law now requires major bases to, over three years, develop military resilience components to installation master plans to deal with climate impacts.[12] Congress has also expanded funding to DoD’s Readiness and Environmental Protection Integration (REPI) statute, which encourages climate resilience through land conservation, preventing encroachment on military installations.[13]
Several military installations throughout the U.S. are already using coastal restoration projects to combat erosion. For example, the Earle Naval Weapons Station in New Jersey has installed a living shoreline of restored oyster reefs .[14] The US Army Corps of Engineers recently launched an Engineering With Nature initiative, a collection of case studies on nature-based resilience solutions at military installations and bases around the country.
Case Study: Point Mugu
In California, where DoD controls over 200,000 acres of coastal land, rising sea levels are projected to contribute to more severe flooding from El Niño events, higher storm surges, and wave-driven erosion.
Among DoD’s California installations is Naval Base Ventura County (NBVC) Point Mugu, a premier testing and training facility for the DoD.
Point Mugu occupies over six miles of coastline about an hour’s drive northwest from Los Angeles.
NBVC—which also includes Port Hueneme and San Nicolas Island—supports a population of 19,000 personnel, over 80 tenant commands, three warfare centers and two airfields.
It’s a major employer in the region, annually contributing about $2 billion to the regional economy.
Ormond Beach, a two-mile strip of sandy beach, dunes and wetland, lies directly north of Point Mugu and connects it to Port Hueneme.
In addition to its strategic military significance, NBVC Point Mugu contains 6.5 miles of dune backed beach and one of the largest remaining salt marsh habitats in coastal southern California.
The base is home to Mugu Lagoon, a several mile long pool of brackish water surrounded by fringing salt marsh, fed by fresh water from Calleguas Creek.
Together, Ormond Beach and Mugu Lagoon comprise the largest coastal wetland in southern California. This complex of beach, dune, estuary, marsh, and uplands supports a diversity of plants and animals including rare and imperiled species.
Salt marsh bird’s beak (Chloropyron maritimum ssp. Maritimum), endangered species found in Point Mugu
Sea Level Rise and Flooding
Because NBVC Point Mugu is currently set within low-lying coastal wetlands, the base experiences flooding, erosion, and storm damage to its facilities. These hazards are increasing in intensity, frequency, and duration and will increase further as sea levels rise, damaging built infrastructure and natural habitats of the base.
The Navy has deemed ensuring base resilience mission-critical.
If no action is taken, a large portion of NBVC Point Mugu, including roads, buildings, beaches and wetlands, would convert to open water by 2060 due to sea level rise and associated erosion and flooding.
Losing the mosaic of intertidal habitats will result in the loss of ecosystem services, including protection from hazards and critical habitat for species.
We knew it was important to start looking at the impacts of climate change on the naval base more closely. What should we expect the impacts to be in the future? How will it affect our mission? We knew we needed to start planning for it.– Kimberly Jacobsen, Deputy Director of Public Works at NBVC
Partnership
In 2016, the Navy entered into a partnership with The Nature Conservancy to assess the base’s current and future climate change vulnerability.
The project team, made up of Navy personnel, Nature Conservancy scientists, and Environmental Science Associates, was tasked with assessing vulnerabilities and developing specific recommended actions that would both improve base resilience and enhance natural resources.
Groundwork for the Navy’s partnership with The Nature Conservancy was laid years before when the two partnered (along with other stakeholders), to protect and restore Ormond Beach, which is considered by many experts to be one of the most important coastal wetlands in southern California.
Nature-Based Adaptation
Traditionally, when faced with flooding or erosion, one of the most common responses is to build a sea wall or other form of coastal hardening. While hardening is sometimes still necessary, robust evidence now indicates that natural systems including salt marshes, beaches, dunes, oyster and coral reefs are often more effective and more resilient against storms and flooding than seawalls.
This natural infrastructure offers long-term protection to built assets and provides habitats for a variety of species, while providing ecosystem services, including clean waters, recreation, and carbon sequestration.[15,16]
Traditional coastal armoring (left) compared to natural infrastructure (right)
NBVC Adaptation Vision
With expertise from across NBVC, The Nature Conservancy developed the Coastal Adaptation Vision for Naval Base Ventura County Point Mugu —a holistic vision to adapt to sea level rise and increase resilience at NBVC.
The team mapped five hazards—tidal inundation, storm flooding, wave run-up, erosion, and fluvial flooding (from Calleguas Creek)—for the entire base, for the years 2010, 2030, 2060 and 2100.
The team measured how exposure to these hazards will impact both built assets and natural habitats over time, quantifying the hazard risk for each individual asset on the base (including buildings, roads, and utilities).
The analysis shows that if the base stays in its current configuration—with infrastructure crisscrossing through low-lying wetlands—the installation’s frontline of beaches, dunes, marsh, and mudflats, along with many built assets, would continue to erode or will be submerged by open water.
This map compares how current infrastructure, salt marsh, and beaches (left) will be threatened by open water and tidal inundation in 2100 (right) without adaptation action. Swipe to see the change.
The NBVC Point Mugu Adaptation Vision recommends a suite of actions to improve the resilience of built assets and restore natural habitats to preserve base functionality.
This includes moving hard infrastructure out of hazard zones into safer grounds where possible, and restoring natural habitats and ecological processes in their place.
The team evaluated whether the function of each asset was specific to that location or could if it could be removed or relocated landward.
Defend
Certain base assets, such as the airfield, were deemed critical to defend in place. By enhancing the protective services of surrounding restored coastal habitats, less armoring will be needed to defend what assets need to remain in place.
Relocate
Assets whose specific location is not critical to their function were identified to be relocated to a more resilient upland area. Pre-emptively moving military assets further from the many hazards along the shoreline is a strategic, forward-thinking military readiness tactic. Relocating assets away from the shifting coastline also creates a pathway for beaches and wetlands to adjust and migrate with sea level rise.
Remove
Built areas and assets that are no longer needed (redundant, derelict, or obsolete) will be removed.
Restore
Locations where infrastructure is removed will be restored to coastal habitat. Restored expanses of connected, healthy coastal ecosystems further enhance the resilience of base assets, bolstering nature’s capacity to absorb the impact of storm surges and flooding.
Implementing these measures would reduce the overall footprint of built assets by approximately 30%, consolidating assets within the most resilient area of the base.
This Vision has the potential to protect billions of dollars of assets from storm and flood damage, helping the military in its objectives to ensure military readiness, and increase long-term resilience of coastal beaches and vital wetland habitat, maintaining the benefits these habitats provide to nature and people alike.
Increased resilience in one coastal area also increases resilience in nearby areas, so actions taken here enhance coastal resilience regionally.
Next Steps
The project team identified several recommendations that will further lay the groundwork to achieve the Adaptation Vision for NBVC Point Mugu. These include:
- Integration into existing plans
- Refined vulnerability assessment
- Development of a full Adaptation Plan
Scaling Up
These efforts can serve as an example to other installations facing coastal hazards.
DoD controls enough total land that its influence is comparable to that of a nation, and has a long history of performing environmental conservation on the more than 30 million acres under its control.
Adopting a natural infrastructure buffering strategy could lead to the restoration of a significant portion of coastal lands, bolstering long-term protection for billions of dollars of military assets and reducing the need for costly repairs.
Coasts are connected, and what the DoD does impacts the function and resilience of adjacent and down coast areas.
Additionally, through legislation such as the REPI Program, communities near military lands can partner with the military to fund and implement nature-based resilience programs.
As Congress continues to expand the REPI budget, there will be more opportunities for projects and partnerships that will enhance coastal resilience.
Department of Defense installations are, of course, far from being the only stakeholders impacted by sea level rise – many coastal landowners in the world are facing similar challenges.
Loss of coastal habitats would be devastating to shorebirds and many other endangered species that depend on these environments.
The loss of coastal habitat would reduce protection from coastal flooding and impact communities whose economies are coastal dependent.
Many of these extreme loss scenarios could be avoided if relocation and restoration approaches become more widespread.
Making room for natural infrastructure ensures habitats can migrate with sea level rise and continue to act as buffers, providing protection to coastal communities, infrastructure, and ecosystems.
The collaborative, science-based plan demonstrated by the NBVC Adaptation Vision can be replicated locally, regionally and globally, to ensure beaches and wetlands continue to thrive and can provide protection to coastal communities and critical infrastructure.
If natural infrastructure and coastal restoration strategies are adopted more broadly and supported through substantial DoD investment, it could significantly increase the buffering capacity of a portion of the world’s coastal lands, provide long-term protection for billions of dollars of military assets, reduce the need for extremely costly repairs, and set an example for the world.
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