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Sediment Management in the
Coastal Bays
• Introduction – Need for ecosystem view of sediment management in Coastal
Bays • Island loss and restoration
• Navigation needs
• Habitat Trade offs
• Living Shoreline Requirements
• Background – Barrier Island dynamics
• Goals – Discussion
• Sediment Management Plan
• Navigation Committee Resurrection?
• Permit Streamlining?
Completed
1. Restoration of northern end of Assateague Island
2. Restore a total of 5 ha (12 ac) of salt marsh at the
Isle of Wight Wildlife Management Area and
3. Restore a total of 3.4 ha (8.5 ac) of salt marsh at
Ocean Pines,
Ocean City Feasibility Study 1998
Sand management plan to implement navigation
improvements and restore fish and wildlife
habitat
Ocean City Feasibility Study 1998
• To Be Done
• 4. Stabilize the eroding South Point Island to its 1997 size of approximately 0.93 ha (2.3 ac),
• 5. Construct a new 1.2 ha (3 ac) island in proximity to South Point to create vegetated habitat for colonial waterbirds, and
• 6. Create a 1.2 ha (3 ac) island near Dog Island that will be bare substrate with a shell surface for colonial waterbird nesting. The island created near Dog Island will also include three additional cells that will be available to local citizens, businesses, and government for the placement of material dredged locally. Thus, an additional 1.2 ha (3 ac) area of salt marsh will be added in the near future, and up to 8 ha (19 ac) area could eventually be created, increasing the size of this island to as much as 10 ha (25 ac).
Navigation and Dredging Advisory Group (NADAG) for
Maryland’s Coastal Bays (met initially Dec 1999, stopped meeting ~ 2003)
Navigation and Dredging
Planning Guide
for Maryland’s Coastal
Bays
edited by Cornelia Pasche
Wikar
Chair, Navigation and
Dredging Advisory Group
August, 2005
Recommendation:
A.i.i. Support for and promotion of the beneficial
use of dredged materials, including
- habitat restoration and creation.
- restoration of underwater grasses;
- restoration of islands;
- stabilization of eroding shorelines;
- creation or restoration of wetlands; and
- creation, restoration, or enhancement of
fish or shellfish habitats
• Beneficial Uses Introduction Decision Process Sediment Types Glossary Links References K-12 Lessons Lead Organizations Authorities Calendars
• Agricultural/Product Uses Aquaculture Construction Materials Decorative Landscaping Products Topsoil
• Engineered Uses Beach Nourishment Berm Creation Capping Land Creation Land Improvement Replacement Fill Shore Protection
• Environmental Enhancement Fish & Wildlife Habitats Fisheries Improvement Wetland Restoration
Beneficial Use of Dredge Material
http://el.erdc.usace.army.mil/dots/budm/budm.cfm
Maryland Case Studies
Barren Island, MD
Bodkin Island, MD
Eastern Neck National Wildlife
Refuge, MD
Hart-Miller Island CDF, MD
Kenilworth, MD
Slaughter Creek, MD
Twitch Cover Seagrass Plantings
Dead end canals
North end of Assateague
Inlet, commercial harbor,
Assawoman channel
Sediment Sources
Source: COE 1998
Uses for sediments
Isle of Wight marsh restoration using
dredge material from the Assawoman
channel
View from pier looking south
Stone sill
Uses for sediments
Marsh protection and enhancement
behind low profile stone sills
along high energy shorelines
Assawoman Bay
Sunset Island
Carlson (Thoroughfare)
Marsh creation in low energy shorelines
Herring Crk
Source: Shifting Sands 2009 Chap 12
Barrier Island Formation
Barrier Island Dynamics
Source: Shifting Sands 2009 Chap 12
Source: Shifting Sands, 2009 Chap 12
Islands: Overlooked
Coastal Landforms
Island Formation:
Mainland: high topographies
and the degree to which
sedimentation is able
to offset submergence
Back barrier islands
washover fans, storm-surge
platforms, old beach ridges,
portions of flood deltas
.
Source: Shifting Sands, 2009 Chap 12
Source: Shifting Sands, 2009 Chap 12
Former flood
tidal delta
Source: Shifting Sands, 2009 Chap 12
Source: Shifting Sands, 2009 Chap 12
Sediment Distribution Based on Island Dynamics
Source: Shifting Sands, 2009 Chap 12
Sea Level Rise
Potential mid-Atlantic coastal
landform responses to three sea-
level rise scenarios. Most
coastal areas are currently
experiencing erosion, which is
expected to increase with future
sea-level rise.
In addition to undergoing erosion,
coastal segments denoted with a
“T” may also cross a threshold
where rapid barrier island
migration or segmentation will
occur.
U.S. Climate Change Science Prog Synthesis and Assessment
Product 4.1, Coastal Sensitivity to Sea Level Rise:
A Focus on the Mid-Atlantic Region, 2009
Source: Sea Level Rise Response Strategy
Worcester County, Maryland
September 2008
Source: Sea Level
Rise Response
Strategy,
Wor Co, MD 2008
Goals
1. Review and update extent of dredging needs
2. Identify/and Explore capabilities and
opportunities for dredged material
management
3. Engage user-groups and community in
developing the Sediment Management Plan
4. Develop a Sediment Management Plan for the
Coastal Bays
5. Establish a Committee to oversee, match and
traffic sediments
Goals Con’t
• The commission would navigate between 1) projects that generate sediments, such as navigation dredging projects; and 2) projects that require sediments such as various restoration projects (e.g. Skimmer Island other wetland restorations).
• Permitting should be streamlined. Specific projects such as the Skimmer Island restoration or Dog Island site would be set up, ready to accept sediments; with permitting requirements in place. That way, when a dredging job, either private or public, comes along, everything would be ready to go. The only thing needed is an assessment of the type of sediment being dredged, analyses including textural and chemistry.
• If the sediment is sand, then it’s good for island restoration or beach replenishment; if it’s fine-grained, then it’s good for wetland creation or maybe island restoration.
Sediment Management Plans
• San Francisco Bay area
• Columbia River, Oregon
• Great Lakes,
• Jamaica Bay , Long Island, NY