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Management Goal: Maintain Shorelines Using "Soft" Measures
CREATING MARSHES IN THE CHESAPEAKE BAY, MARYLAND SHORE EROSION CONTROL PROGRAM
Management Goal: Maintain Shorelines Using "Soft" Measures
Climate Stressor Addressed: Sea level rise
Through the Maryland Department of Natural Resources, the Shore Erosion Control program has created over 300 marsh fringe sites along the Chesapeake Bay. The marshes have been created as "living shoreline" in order to control erosion and reduce land lost to sea level rise. These non-structural shoreline stabilization methods create a vegetative buffer for the land, improve water quality, and provide habitat to many species. The marshes were created with sand fill and stabilized through the planting of marsh grasses and the use of soils, stones, gravels, and biodegradable protective materials. Individual property owners who wish to construct these types of erosion control measures can also receive financial assistance to do so through the Shore Erosion Control program.
Source: IPCC AR4 WGII, Chapter 3
; Maryland Department of Natural Resources Shore Erosion Control
Approaches for maintaining shorelines in the face of sea level rise include both "soft" measures and "hard" measures. Each of these approaches or some combination of them may be appropriate depending on the characteristics of a particular location (e.g., shore protection costs, property values, the environmental importance of habitat, the feasibility of protecting shores without harming the habitat). "Soft" measures aim to develop living shorelines through beach nourishment, planting dune grasses, marsh creation, and planting submerged aquatic vegetation (SAV).
| Adaptation Option | Climate Stressor Addressed | Additional Management Goals Addressed | Benefits | Constraints | Examples |
|---|---|---|---|---|---|
| Replace shoreline armoring with living shorelines - through beach nourishment, planting vegetation, etc. | Sea level rise; changes in storm climatology | Maintain/ restore wetlands; Preserve habitat extent; Preserve coastal land/ development |
Reduces negative effects of armoring (downdrift erosion); maintains beach habitat | Can be costly, requires more planning and materials than armoring | Peconic Bay (NY)1; Living Shorelines Stewardship Initiative (Chesapeake Bay)2 |
| Remove shoreline hardening structures such as bulkheads, dikes, and other engineered structures to allow for shoreline migration | Sea level rise | Maintain sediment transport | Allows for shoreline migration | Costly for and destructive to shoreline property | King County, Washington3; Puget Sound Action Team4 |
| Plant SAV (such as sea grasses) to stabilize sediment and reduce erosion | Changes in precipitation; Sea level rise | Maintain/restore wetlands; Preserve habitat extent; Preserve coastal land/ development | Stabilizes sediment; does not require costly construction procedures | Seasonality - grasses diminish in winter months, when wave activity is often more severe because of storms; Light availability is essential | Chesapeake Bay (Living Shoreline Stewardship Initiative)5; Tampa Bay NEP6 |
| Create marsh by planting the appropriate species - typically grasses, sedges, or rushes - in the existing substrate | Sea level rise | Maintain water quality of wetlands; Maintain/restore wetlands; Preserve habitat extent; Invasive species management | Provides protective barrier; maintains and often increases habitat | Conditions must be right for marsh to survive (e.g., sunlight for grasses, calm water); can be affected by seasonal changes | MD Shore Erosion Control Program7; Chesapeake Bay (Living Shoreline Stewardship Initiative)8 |
| Create dunes along backshore of beach; includes planting dune grasses and sand fencing to induce settling of wind-blown sands | Sea level rise | Preserve coastal land/ development | Protects both the beach and inland areas from sea level rise | Costs of importing sand; takes land away from public use | Chesapeake Bay (VA, in particular)9 |
| Use natural breakwaters of oysters (or install other natural breakwaters) to dissipate wave action and protect shorelines | Increases in water temperatures; Sea level rise; Changes in precipitation; Changes in storm climatology | Preserve coastal land/ development; Maintain water quality of wetlands; Invasive species management | Naturally protect shorelines and marshes and inhibit erosion inshore of the reef; will induce sediment deposition | May not be sustainable in the long-term, because breakwaters are not likely to provide reliable protection against erosion in major storms | SC Oyster Restoration and Enhancement (SCORE)10; NY/NJ Baykeeper Oyster Restoration Program11; VIMS Oyster Restoration Programs (VA)12; Oyster Reef Restoration in the Mid-Atlantic13 |
| Install rock sills and other artificial breakwaters in front of tidal marshes along energetic estuarine shores | Sea level rise; Changes in storm climatology | Preserve coastal land/ development; Maintain water quality of marshes and wetlands | Naturally protect shorelines and marshes and inhibit erosion inshore of the reef; will induce sediment deposition | May not be sustainable in the long-term, because breakwaters are not likely to provide reliable protection against erosion in major storms; Requires encroachment bayward or riverward, usually beyond the property limit, complicating the process for obtaining permits for construction | St. Mary's County, MD14; Mississippi-Alabama Sea Grant Consortium (MASGC)15 |
| Restrict or prohibit development in erosion zones | Sea level rise; Changes in precipitation | Preserve coastal land/ development; Maintain/restore wetlands | Allows for more land available to protect estuaries | Will not help areas already developed; difficult to get all parties to agree | MD16; NJ (limits development)17; San Mateo, CA18 |
| Redefine riverine flood hazard zones to match projected expansion of flooding frequency and extent | Sea level rise; Changes in precipitation; Changes in storm climatology | Preserve coastal land/ development; Maintain wetlands | Protects riverine systems and zones accordingly | Impacts on flood insurance; may require changing zoning ordinances, which can be difficult | King County, WA19 |
| Increase shoreline setbacks | Sea level rise; Changes in storm climatology | Preserve coastal land/ development | Protects coastal property in the long term and prevents development directly on the shoreline | Will not help areas already developed | Buzzards Bay20; NC Coastal Resources Commission (CRC) is developing new setback rules21; South Carolina22 |
| Composite systems - incorporate elements of two or more methods (e.g., breakwater, sand fill, and planting vegetation) | Sea level rise; Changes in storm climatology | Preserve coastal land/ development | Incorporates benefits of multiple systems, can address longer stretches of coastline | "Softer approaches" (e.g., vegetation, beach nourishment) require more maintenance over time; can become costly | Chesapeake Bay; James City County, VA23; Mississippi-Alabama Sea Grant Consortium (MASGC)24 |
1 SAP 4.1, Coastal Sensitivity to Sea Level Rise; A Focus on the Mid-Atlantic, Appendix A
2 Maryland Department of Natural Resources Living Shorelines; Chesapeake Bay Trust Living Shorelines Grant Program; Campbell Foundation Living Shorelines Stewardship Initiative (PDF) (7 pp, 1.4MB)
3 Seahurst Bulkhead Removal and Beach Restoration Assessment
4 Puget Sound Alternative Shoreline Stabilization Evaluation Project (PDF) (43 pp, 849K)
5 Maryland Department of Natural Resources Living Shorelines; Chesapeake Bay Trust Living Shorelines Grant Program; Campbell Foundation Living Shorelines Stewardship Initiative (PDF) (7 pp, 1.4MB)
6 Tampa Bay Sea Grass Planting Initiative
7 Maryland Dept. of Natural Resources Shore Erosion Control
8 Maryland Department of Natural Resources Living Shorelines; Chesapeake Bay Trust Living Shorelines Grant Program; Campbell Foundation Living Shorelines Stewardship Initiative (PDF) (7 pp, 1.4MB)
9 NRC, Mitigating Shore Erosion Along Sheltered Coasts, Chapter 3; Maryland Department of Natural Resources Living Shorelines; Chesapeake Bay Trust Living Shorelines Grant Program; Campbell Foundation Living Shorelines Stewardship Initiative (PDF) (7 pp, 1.4MB)
10 South Carolina Oyster Restoration and Enhancement
11 NY/NJ Baykeeper
12 Virginia Institute of Marine Science, Molluscan Ecology Program
13 University of New Hampshire - Oyster Restoration Program
14 NRC, Mitigating Shore Erosion Along Sheltered Coasts, Chapter 3
15 Shoreline Protection Alternatives (PDF) (4 pp, 426K)
16 SAP 4.1: Coastal Sensitivity to Sea Level Rise: A Focus on the Mid-Atlantic, Chapter 10
17 New Jersey Department of Environmental Protection – Coastal Zone Management Rules (PDF) (203 pp, 898K)
18 California Environmental Resources Evaluation System – County of San Mateo Local Coastal Program Policies
19 King County, WA 2007 Climate Action Plan (PDF) (178 pp, 1.1MB)
20 Buzzards Bay Action Plan: Planning for a Shifting Shoreline (1991 CCMP) (PDF) (5 pp, 176K)
21 North Carolina Coastal Resources Commission
22 South Carolina Code of Regulations
23 NRC, Mitigating Shore Erosion Along Sheltered Coasts, Chapter 3
24 Shoreline Protection Alternatives (PDF) (4 pp, 426K)