Living Shoreline Concept Designs

98 Pages·2016·3.21 MB·English

by  Karen Duhring

Living Shoreline Concept Designs:

What needs to be considered?

Karen Duhring
Virginia Institute of Marine Science
College of William & Mary

March 17, 2016
Delaware Living Shoreline Training Workshop
Lewes, Delaware
Acknowledgments
Thank You for contributions to this presentation
DNREC & CIB Staff
Jon Miller et al., Stevens Institute
Partnership for the Delaware Estuary
Joe Reiger, Elizabeth River Project, Virginia
Jim Cahoon, Bay Environmental, Virginia
Molly Mitchell, VIMS
Scott Hardaway, VIMS
Walter Priest, III VIMS-NOAA-Wetland Design
Bobbie Burton, Longwood University
Pat Menichino, James City County Virginia
Bhaskar Subramanian, Maryland DNR
David Burke, Burke Environmental Associates
Rob Schnabel, Chesapeake Bay Foundation
Living Shoreline Concept Designs
• Review of basic considerations
• Explore design parameters
– Why they are important
– How to get site-specific information
• Project types & lessons learned
• Putting the pieces together for concept designs
Shoreline Management Decision Process
Review
1. Risk assessment & decision to act
Erosion history & forecast not tolerable?
Can upland land use adjustments solve problem?
If not, TAKE SHORELINE ACTION

2. Basic location & land use suitability considerations

3. Can adverse environmental harm be avoided?
Stabilization Alternatives
Simplistic Order of Preference
from least to most environmental impact
 Minor erosion with low risk  Maintain / enhance vegetation

 Minor erosion with some risk  Non-Structural Living Shoreline

 Major erosion with some risk,
 Hybrid Living Shoreline
natural buffers present or

feasible to create

 Traditional Structures
 Major erosion with high risk,
natural buffers absent or not e.g. revetment, offshore breakwaters
feasible
Living Shoreline Project Categories
Non-Structural Hybrid
Planted Marshes Rock Sills
Fiber Logs & Mats Pre-Fabricated Concrete
Sand Fill Biogenic Reefs
Slope Changes
Beach Nourishment

Is there a simple formula to know which approach to use?
Parameters Typically Used in the Design of Living Shorelines
Source: Living Shorelines Engineering Guidelines 2015
System Parameters Ecological Parameters
Erosion History Water Quality
Tidal Range Soil Type
Sea Level Rise Sunlight Exposure
Large scale - long term Local scale for natural elements
Hydrodynamic Parameters Terrestrial Parameters
Wind Waves Upland Slope
Boat Wakes Shoreline Slope
Currents Width
Ice Nearshore Slope
Storm Surge Offshore Depth
Soil Bearing Capacity
Forces acting on the shoreline
Affect how shoreline
short term
responds to forces
Parameters Typically Used in the Design of Living Shorelines
Source: Living Shorelines Engineering Guidelines 2015
Additional Parameters
Permits/Regulatory
End Effects
Constructability
Native/Invasive Species
Debris Impact
Project Monitoring

Property Owner Interest
Multiple parameters are not equally weighted
Just one alone might make a difference
Some may be more critical than others
Site Evaluation Parameters

Desktop - Map Parameters Site Visit Parameters
• Existing information available • Not easily captured by
from maps or Internet remote sensing
resources

• Site-specific characteristics
• Not readily visible or

measurable at ground level
• Local setting

• Data availability may be
• Local knowledge
limited for some parameters
SYSTEM & HYDRODYNAMIC
PARAMETERS