Dealing with Erosion: the Spectrum of Coastal Erosion Control Methods

2ND ANNUAL CAPE COASTAL CONFERENCE Linking Science with Local Solutions and Decision-Making

Dealing With Erosion: The Spectrum of Coastal Erosion Control Methods

Greg Berman (Woods Hole Sea Grant & Cape Cod Cooperative Extension)

Photo Credit: Ted Keon Climate Change Impacts In Coastal Environments

34 5 12 Coastal Adaptation

On Cape Cod we manage at parcel scale

http://www.ipcc.ch/ipccreports/sres/regional/index.php?idp=223 The Spectrum of Coastal Erosion Control Methods Why protect properties……..? Town of Brewster example

The Facts The Implications

Value = $333,000,000 (don’t want takings)

Only ~1% of properties To keep the same revenue, ~3% of town area the tax rate would go from 8.18 to 9.06 but they make ~10% of the real estate taxes or ~$300 per household The Spectrum of Coastal Erosion Control Methods • Do nothing

1. Will system recover by itself?

2. How far is the structure from the water?

3. Grandfathering protects structures (not lawn) before August 10, 1978

Photo Credit: Ann McNichol The Spectrum of Coastal Erosion Control Methods • Do nothing • Vegetation

Plant Natives: Root systems stabilize. Take up water. Break the impact of raindrops or wave-splash. Slow down runoff

Remove Invasive The Spectrum of Coastal Erosion Control Methods • Do nothing • Vegetation • Re-grade The Spectrum of Coastal Erosion Control Methods • Do nothing Horizontal • Vegetation • Re-grade • Managed retreat

V E R T I C A L The Spectrum of Coastal Erosion Control Methods • Do nothing Photo Credit: Ted Keon • Vegetation • Re-grade • Managed retreat • Beach nourishment = Fill of a CRA

Sacrificial Cobble (Mixed)

Photo Credit: CZM The Spectrum of Coastal Erosion Control Methods • Do nothing Popponesset Beach • Vegetation • Re-grade • Managed retreat • Beach nourishment

South Cape Beach Before

After

Repair Before Repair After The Spectrum of Coastal Erosion Control Methods • Do nothing • Vegetation • Re-grade • Managed retreat • Beach nourishment • Sand fencing The Spectrum of Coastal Erosion Control Methods • Do nothing • Vegetation • Re-grade • Managed retreat • Beach nourishment • Sand fencing The Spectrum of Coastal Erosion Control Methods • Do nothing • Vegetation • Re-grade • Managed retreat • Beach nourishment • Sand fencing The Spectrum of Coastal Erosion Control Methods • Do nothing • Vegetation • Re-grade • Managed retreat • Beach nourishment • Sand fencing The Spectrum of Coastal Erosion Control Methods • Do nothing • Vegetation • Re-grade • Managed retreat • Beach nourishment • Sand fencing • Fiber rolls Diameter 12”-20”

The Spectrum of Coastal Erosion Control Methods • Do nothing • Vegetation • Re-grade • Managed retreat • Beach nourishment • Sand fencing • Fiber rolls

The Spectrum of Coastal Erosion Control Methods • Do nothing • Vegetation • Re-grade • Managed retreat • Beach nourishment • Sand fencing • Fiber rolls • Coir Envelopes

Photo Credit: 2Fathom The Spectrum of Coastal Erosion Control Methods • Do nothing • Vegetation • Re-grade • Managed retreat • Beach nourishment • Sand fencing • Fiber rolls • Coir Envelopes

The Spectrum of Coastal Erosion Control Methods • Do nothing • Vegetation • Re-grade • Managed retreat • Beach nourishment • Sand fencing • Fiber rolls • Coir Envelopes C E S

WPA: Coastal engineering structure means, but is not limited to, any breakwater, bulkhead, groin, jetty, revetment, seawall, weir, riprap or any other structure that is designed to alter wave, tidal or sediment transport processes in order to protect inland or upland structures from the effects of such processes. The Spectrum of Coastal Erosion Control Methods • Do nothing notch • Vegetation • Re-grade • Managed retreat • Beach nourishment • Sand fencing • Fiber rolls • Coir Envelopes C E S • Groin

Direction of Direction of Longshore Current Longshore Current

Deposition Erosion Downdrift Coastal Structure The Spectrum of Coastal Erosion Control Methods

• Do nothing +3’/yr +4’/yr +5’/yr • Vegetation +8’/yr • Re-grade -2’/yr • Managed retreat -2’/yr -1’/yr • Beach nourishment 0’/yr • Sand fencing • Fiber rolls

• Coir Envelopes Source: MORIS: CZM’s Online Mapping Tool C E S • Groin

• Jetty

The Spectrum of Coastal Erosion Control Methods • Do nothing • Vegetation • Re-grade • Managed retreat • Beach nourishment • Sand fencing • Fiber rolls • Coir Envelopes C E S • Groin • Sand Bags

• Jetty

The Spectrum of Coastal Erosion Control Methods • Do nothing • Vegetation • Re-grade • Managed retreat • Beach nourishment • Sand fencing • Fiber rolls Gabion (10-20 yrs) • Coir Envelopes C E S • Groin • Sand Bags

• Gabion

• Jetty

• Gabion

• Breakwater / Sill

• Jetty

The Spectrum of Coastal Erosion Control Methods • Do nothing • Vegetation • Re-grade • Managed retreat • Beach nourishment • Sand fencing • Fiber rolls • Coir Envelopes 1.3mi C E S • Groin • Sand Bags

• Gabion

• Breakwater / Sill

• Revetment

• Jetty

• Gabion

• Breakwater / Sill

• Revetment

• Jetty

• Gabion

• Breakwater / Sill

• Revetment

• Jetty • Seawall

• Gabion

• Breakwater / Sill

• Revetment

• Jetty • Seawall

• Bulkhead The Spectrum of Coastal Erosion Control Methods • Do nothing How the “Spectrum” could be used: • Vegetation

• Re-grade Notice of Intent (NOI) →→→→ Alternative Analysis • Managed retreat …start at top and move down, • Beach nourishment explaining why each one isn’t suitable. • Sand fencing • Fiber rolls • Coir Envelopes C E S • Groin • Sand Bags

• Gabion

• Breakwater / Sill

• Revetment

• Jetty • Seawall

• Bulkhead The Spectrum of Coastal Erosion Control Methods • Do nothing • Not a complete list • Vegetation (and methods are being invented/modified) • Re-grade • Managed retreat • Beach nourishment • Sand fencing • Fiber rolls • Coir Envelopes C E S • Groin • Sand Bags

• Gabion

• Breakwater / Sill

• Revetment

• Jetty • Seawall

• Bulkhead The Spectrum of Coastal Erosion Control Methods • Do nothing • Not a complete list • Vegetation (and methods are being invented/modified)

• Re-grade • With revetments…if neighbors don’t do the same • Managed retreat then you’ll have to keep extending return. • Beach nourishment • Sand fencing • Fiber rolls • Coir Envelopes C E S • Groin • Sand Bags

• Gabion

• Breakwater / Sill

• Revetment

• Jetty • Seawall

• Bulkhead The Spectrum of Coastal Erosion Control Methods • Do nothing • Not a complete list • Vegetation (and methods are being invented/modified)

• Re-grade • With revetments…if neighbors don’t do the same • Managed retreat then you’ll have to keep extending return. • Beach nourishment • Very few projects only employ 1 method, and when • Sand fencing we are determining if it’s a CES we need to use the • Fiber rolls “hardest” aspect of the project. • Coir Envelopes C E S • Groin • Sand Bags

• Gabion

• Breakwater / Sill

• Revetment

• Jetty • Seawall

• Bulkhead The Spectrum of Coastal Erosion Control Methods • Do nothing Combination • Vegetation • Re-grade • Managed retreat • Beach nourishment • Sand fencing • Fiber rolls • Coir Envelopes C E S • Groin • Sand Bags

• Gabion

• Breakwater / Sill

• Revetment

• Jetty • Seawall

• Bulkhead The Spectrum of Coastal Erosion Control Methods • Do nothing • Vegetation • Re-grade • Managed retreat • Beach nourishment Combination • Sand fencing • Fiber rolls • Coir Envelopes C E S • Groin • Sand Bags

• Gabion

• Breakwater / Sill

• Revetment

• Jetty • Seawall

• Bulkhead The Spectrum of Coastal Erosion Control Methods • Do nothing • Vegetation • Re-grade • Managed retreat • Beach nourishment • Sand fencing • Fiber rolls • Coir Envelopes C E S • Groin • Sand Bags

• Gabion Combination

• Breakwater / Sill

• Revetment

• Jetty • Seawall

• Bulkhead The Spectrum of Coastal Erosion Control Methods • Do nothing • Vegetation • Re-grade • Managed retreat • Beach nourishment • Sand fencing • Fiber rolls Combination • Coir Envelopes C E S • Groin • Sand Bags

• Gabion

• Breakwater / Sill

• Revetment

• Jetty • Seawall

• Bulkhead The Spectrum of Coastal Erosion Control Methods ↑ Resilience ≠ ↓ Natural Systems Questions ?