Shoreline Protection Methods used in the Chesapeake Bay
People that live and recreate on beaches and the organisms that need beaches to survive all want the same thing – wide, sandy, natural beaches. But the beaches are rapidly disappearing and may not be around much longer. The constant shifting, moving, and erosion of sand that make up the beaches places homes and property at risk of damage or loss and the species that live on the beaches at risk of extinction from loss of habitat.
Protecting Land,
Reshaping Beaches
Shoreline structures have become a common way to manage erosion of beaches and protect coastal land and properties, but not all solutions are created equal. From “hard” structures built of rigid and solid materials like wood, boulders (rip rap), and metal to less intrusive, more natural “soft” solutions made of sand, these approaches play a major role in shaping the Chesapeake Bay’s beaches.
Hard engineering solutions
These solutions come in two broad categories—those that armor the coast and protect the land behind them from waves and flooding, like revetments and bulkheads, and those that alter natural processes to encourage sand deposition and widen the beach, like groins and breakwaters. The use of both types has increased dramatically in the Bay over the past several decades. While effective in the short term, they can disrupt natural processes, leading to unintended consequences like increased erosion at the structure site and/or locations some distance away from the structure or they can have limited usefulness.
Soft Solutions
In contrast, soft engineering solutions—like beach nourishment, dune restoration and living shorelines—work with nature to provide coastline resilience. These methods create and preserve natural habitats and recreational beaches, support ecosystems, and adapt to changing conditions.Understanding the differences among the different types and designs of hard and soft solutions is critical for making informed decisions that balance coastal protection and resilience with the health of the Chesapeake Bay’s coastline.
Comparing Protection Methods
Comparison summary of shoreline defenses (shoreline protection methods) used in the Chesapeake Bay
- Bulkheads
- Revetments (rip rap)
- Groins
- Breakwaters
- Reduce or eliminate mainland erosion
- Protect against storms and flooding
- Lock the shoreline into a fixed location
- Reduce beach and mainland erosion
- Enable sand deposition (build beaches)
- Variable depending on materials, design, location, and environmental factors
- Generally higher per linear foot than groins
- Breakwaters are generally more expensive than groins but vary by number and design
- Reduce or eliminate mainland erosion
- Protect against storms and flooding
- Lock the shoreline into a fixed location
- Reduce beach and mainland erosion
- Enable sand deposition (build beaches)
- Prevents inland migration of wetlands, marshes, and beaches
- Beaches will ultimately and sometimes immediately disappear
- Wave reflection erodes bay bottom preventing submerged aquatic vegetation
- Prevents submerged aquatic vegetation from growing
- Can accumulate and/or stabilize beach and habitat quality sand over the short-term, can cause downdrift erosion to beaches or land.
- Breakwaters accumulate sand best, but sandy habitat can be lost to vegetation encroachment.
- Can be immediate and strong in achieving design purpose but research has shown that beaches will be lost and not return in front of these structure types
- Can have a long lifespan when properly maintained and are effective at reducing erosion and flooding in high-energy environments
- Can take 2-3 years to achieve design purpose of sand deposition
- Breakwaters can provide immediate wave protection
- Beach longevity depends on various factors like sand supply and engineering design
- Research has shown that beaches return to their pre-structure width after about 15 years on average
Hard vs. Soft Shore Protection
Comparison of hard and soft shore protection solutions in the Chesapeake Bay
- Groins
- Breakwaters
- Revetements
- Bulkheads
- Beach nourishment
- Dune restoration
- Living shorelines
- Managed retreat
- Rarely adaptive
- Shoreline armoring (defensive barriers that dissipate wave energy or retain land elevation behind structure)
- Process altering structures
- Adaptive
- Can require a source of sediment
- Works with natural processes
- High initial cost
- Maintenance required (can be expensive)
- Lower initial cost
- Ongoing maintenance
- Can be either disruptive or helpful to ecosystems over the short-term depending on type
- May cause increased erosion in adjacent areas (e.g., downdrift erosion)
- Generally more environmentally friendly
- Supports natural habitats and biodiversity
- Can be immediate or take 2-3 years depending on structure type, design, coastal processes, sand supply
- Can fail and not achieve desired results
- Limited lifespan, up to 15 years on average
- Slower but potentially sustainable over time
- Limited lifespan, up to 15 years on average depending on wave and storm climate
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